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Objectives Tumor-associated antigens (TAAs) are frequently overexpressed in several cancer types. The aim of this study was to investigate the expression of TAAs in breast cancer. Material and methods A total of 250 selected invasive breast cancers including 50 estrogen receptor (ER)-positive (Luminal B like), 50 triple-negative (TN), 50 ER-positive lobular type, 50 ER- and progesterone receptor (PgR)-positive (Luminal A like) and 50 cerbB2-positive breast cancers, were assessed for New York esophageal squamous cell carcinoma-1 (NY-ESO-1), Wilms tumor antigen (WT-1) and PReferentially expressed Antigen of MElanoma (PRAME) antigen expression by immunohistochemistry (IHC). Results A significantly higher expression of cancer testis (CT)-antigens NY-ESO-1 and WT-1 antigen was detected in TN breast cancers compared with ER-positive tumors. NY-ESO-1 overexpression (score 2 + and 3+) assessed by monoclonal and polyclonal antibodies was detected in 9 (18%) TN cancers as compared to 2 (4%) ER-positive tumors (p = 0.002). WT1 over-expression (score 2 + and 3+) was confirmed in 27 (54%) TN tumor samples as compared to 6 (12%) ER-positive (p, Highlights • Tumor-associated antigens are frequently overexpressed in several cancer types, being also associated with poorer patients’ survival outcomes. • Our study confirmed that NY-ESO-1 and WT1 antigens are higher expressed in triple-negative than in other breast cancer subtypes. • Given the limited therapeutic options for triple-negative breast cancer patients, the assessment of WT1 and NY-ESO-1 antigens expression in breast cancer tissue at surgery may allow to identify patients potentially candidate to adjuvant peptide vaccines, alone or in combination with other systemic therapies.

Off-the-shelf allogeneic CAR T cells derived from healthy donor cells have the potential to overcome many of the issues associated with the time-consuming manufacturing of autologous CAR T cells. However, adoptive transfer of allogeneic T cells carries the risk of graft-versus-host disease (GvHD). Most of the clinical experience with allogeneic CAR T cells is based on gene editing to eliminate T cell receptor (TCR) to mitigate the risk of GvHD. While clearly effective, the downsides of gene editing include multiple manufacturing steps requiring multiple clinical grade reagents, thus extending culture times, which can be associated with T cell exhaustion. As an alternative, we have explored short hairpin RNA (shRNA) as a means to knockdown TCR expression at the mRNA level. This shRNA is co-expressed along with the CAR in a single clinical grade vector, therefore requiring just one step of genetic modification. CYAD-211 is an allogeneic anti-BCMA CAR T that co-expresses a shRNA targeting CD3z which results in reduction of cell surface TCR expression. IMMUNICY-1 is an ongoing open-label Phase 1 trial (NCT04613557) designed to evaluate CYAD-211 in adult patients with refractory or relapsed multiple myeloma (MM) following at least two prior MM regimens. Patients receive non-myeloablative preconditioning (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, for 3 days) followed by a single CYAD-211 infusion in a 3+3 dose escalation design evaluating three dose-levels (DL): 30x10 6, 100x10 6 and 300x10 6 cells/infusion. As of July 29, 2021, nine patients were enrolled across the 3 DLs. Patients had received a median of four prior lines of treatment. Seventy-eight percent of patients were previously exposed to all three major MM drug classes (proteasome inhibitors, immunomodulatory drugs, and anti-CD38 antibody therapy). Eight patients had prior autologous stem cell transplantation. CYAD-211 was well tolerated. One patient developed grade 1 cytokine release syndrome. Two patients had Grade ≥ 3 hematologic toxicities possibly related to the experimental treatment. Two patients experienced infectious adverse events (1 grade 1 rhinitis and 1 grade 2 upper respiratory infection). There was no neurologic toxicity and no GvHD. There was no dose-limiting toxicity. Eight patients were evaluated for activity per IMWG criteria. Two patients achieved partial response at dose-levels 1 and 2 while 5 patients had stable disease (SD). One patient with an ongoing SD (3 months +) showed evidence of reduction in size of plasmacytomas. Analysis of peripheral blood samples by molecular methods confirmed the engraftment of CYAD-211. All patients had detectable CAR T cells. However, the engraftment was short lasting (3-4 weeks). There was a correlation between the depth of lymphodepletion and engraftment. There was also a dose-response in terms of CYAD-211 kinetics with a level neighboring 8,000 copies of CAR T per microgram of input DNA in patients at DL3. These early data indicate that CYAD-211 is well tolerated with a good safety profile. While further study is required to fully understand the anti-BCMA potency of the CAR used in this trial, the lack of observed GvHD despite engraftment of CYAD-211 provides proof of concept of the safe administration of CAR T using a shRNA-allogeneic platform. The lack of sustained engraftment of CYAD-211 can be explained by rejection of the allogeneic cells by the recovering immune system of the recipient and calls for exploring the role of augmented lymphodepletion. Furthermore, given the ability to include multiple shRNA within the single CAR vector, future strategies will also examine knocking down other molecules that are important in driving immune rejection. Disclosures Al-Homsi: BMS: Other: Independent Medical Education Grant; Daichii Sankyo: Consultancy; Celyad Oncology: Other: Advisory Board. Deeren: Alexion: Consultancy; BMS: Consultancy; Incyte: Consultancy; Novartis: Consultancy; Sanofi: Consultancy, Research Funding; Sobi: Consultancy; Takeda: Consultancy. Nishihori: Karyopharm: Research Funding; Novartis: Research Funding. Meuleman: iTeos Therapeutics: Consultancy. Abdul-Hay: Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Speakers Bureau; Abbvie: Consultancy; Jazz: Other: Advisory Board, Speakers Bureau; Servier: Other: Advisory Board, Speakers Bureau. Braun: Celyad Oncology: Current Employment. Lonez: Celyad Oncology: Current Employment. Dheur: Celyad Oncology: Current Employment. Alcantar-Orozco: Celyad Oncology: Current Employment. Gilham: Celyad Oncology: Current Employment. Flament: Celyad Oncology: Current Employment. Lehmann: Celyad Oncology: Current Employment.

While CAR T cell therapy has delivered impressive clinical efficacy in B cell malignancies, similar levels of clinical activity have not been demonstrated in acute myeloid leukemia (AML). One underlying reason for this lack of translation is the relative paucity of validated CAR T targets. Major Histocompatibility Complex Class 1 related proteins MICA and MICB along with the UL16 binding proteins 1-6 (ULBP1-6) are frequently over-expressed on AML and myelodysplastic syndrome (MDS) blasts. The Natural Killer Group 2D (NKG2D) is a single receptor able to bind MICA, MICB and ULBP1-6, thus providing a potentially powerful approach that could be exploited to target this family of targets thereby providing a novel CAR T approach for AML/MDS. Expressing the NKG2D receptor fused to the human CD3z cytoplasmic domain generates a CAR that, when expressed in primary T cells, generates a CAR T product (termed CYAD-01) that showed good anti-tumor activity in preclinical models. In clinical trials, CYAD-01 showed a good tolerability profile but with a disappointing level of clinical activity when combined with cyclophosphamide / fludarabine preconditioning (DEPLETHINK trial, NCT03466320). We hypothesised that the transient expression of MICA/MICB on the CAR T itself may inhibit the activity of the NKG2D CAR through self-targeting and consequent fratricide. We developed a single shRNA able to knockdown both MICA and MICB. Co-expression of this shRNA with the NKG2D CAR generated a second generation CAR T product termed CYAD-02 which was examined in a highly similar AML/MDS patient population and preconditioning regimen as employed in the DEPLETHINK trial. CYAD-02 was evaluated in the the first-in-human CYCLE-1 trial (NCT04167696) in patients with r/r AML/MDS. The dose-escalation phase evaluated three dose-levels (DL) (1x10 8, 3x10 8 and 1x10 9 total cells per infusion), administered as a single infusion after standard preconditioning chemotherapy (cyclophosphamide 300 mg/m²/day and fludarabine 30 mg/m²/day, daily for 3 days) according to a classic 3+3 design. As of July 2021, 11 patients have been treated with CYAD-02 at the different dose-levels (3 at each DL1 and 2 and 5 at DL3). In terms of safety and tolerability, there was no evidence of a differential safety profile of CYAD-02 within the CYCLE-1 trial as compared to that observed in the CYAD-01 clinical trial. Of note, five patients enrolled in all 3 DLs experienced Grade ≥ 3 adverse events (AE) at least possibly related to CYAD-02 (cytokine release syndrome, febrile neutropenia, white blood cell count decreased, infusion related reaction). With respect to clinical activity, seven patients in total achieved stable disease (2 at DL1, 3 at DL2 and 2 at DL3) with 4 demonstrating evidence of transient blast reduction or anti-leukemic activity (decrease of at least 50% of the bone marrow blasts). In addition, two MDS patients at DL3 achieved a marrow complete response. Overall, this suggests dose dependent response to CYAD-02. Furthermore, patients receiving CYAD-02 cells seem to display a greater duration of response and stronger blast reduction as compared to patients who received CYAD-01 in DEPLETHINK. Interestingly, peak engraftment levels were higher for CYAD-02 compared to CYAD-01 at the same dose (DEPLETHINK trial). At DL3, CYAD-02 cells could be readily detected in peripheral blood of 4/5 patients through month 2. In addition, and unlike what is reported in B cell CAR T-cells trials, there was very limited evidence of elevated homeostatic cytokines (IL-7/IL-15) following CyFlu administration with IL-15 not detected in any of the patients and IL-7 showing only a minor increase in 2 patients. The knockdown of MICA/MICB appears to have a positive contribution to the initial clinical activity of CYAD-02 as compared to that achieved with the first generation CYAD-01 CAR T, together with good safety and tolerability. The lack of homeostatic cytokines after preconditioning, likely limiting the engraftment and activity of CAR T cells, may be related to the biology of myeloid malignancies. One approach to further drive the potency of NKG2D-based CAR T cells would likely be armoring the CAR T through using the T cell as a vehicle to secrete cytokines alongside the CAR. Overall, shRNA knockdown technology provides a means to modify CAR T function and here shows that single shRNA can target two independent genes to enhance the phenotype of the CAR Ts. Disclosures Deeren: Alexion: Consultancy; BMS: Consultancy; Incyte: Consultancy; Novartis: Consultancy; Sanofi: Consultancy, Research Funding; Sobi: Consultancy; Takeda: Consultancy. Lin: AbbVie, Aptevo Therapeutics, Astellas Pharma, Bio-Path Holdings, Celgene, Celyad, Genentech-Roche, Gilead Sciences, Incyte, Jazz Pharmaceuticals, Novartis, Ono Pharmaceutical, Pfizer, Prescient Therapeutics, Seattle Genetics, Tolero, Trovagene: Research Funding. Alcantar-Orozco: Celyad Oncology: Current Employment. Dheur: Celyad Oncology: Current Employment. Breman: Celyad Oncology: Current Employment. Braun: Celyad Oncology: Current Employment. Lonez: Celyad Oncology: Current Employment. Gilham: Celyad Oncology: Current Employment. Flament: Celyad Oncology: Current Employment. Lehmann: Celyad Oncology: Current Employment.

BackgroundThe peptide-based allogeneic chimeric antigen receptor (CAR) T-cell treatment CYAD-101 utilizes an NKG2D receptor that targets eight ligands expressed on tumor cells and non-malignant stromal cells of many cancer types. CYAD-101 also co-expresses a peptide intended to eliminates the potential of graft versus host disease (GvHD). In the phase 1 alloSHRINK study (NCT03692429), CYAD-101 was administered with FOLFOX preconditioning chemotherapy to 15 patients with metastatic colorectal cancer (mCRC). The treatment was well tolerated with no evidence of GvHD, no treatment-related adverse events ≥ Grade 3 and only two patients who presented a cytokine release syndrome grade 1. By contrast, encouraging clinical activity was observed including two partial responses. Evidence of changes in the TCR repertoire and modulation of the cytokine profile four months post-treatment with CYAD-101 were also observed implying that the NKG2D CAR T may also be modulating the immune suppressive environment in patients reflecting that seen in pre-clinical models (ASCO GI 2021 abstract #74).Given the expansion of the T cell repertoire after CYAD-101 therapy, we considered that employing a checkpoint inhibitor to release this expanded T cell population may drive more durable clinical responses beyond that currently seen with the CAR T alone.MethodsThe KEYNOTE-B79 trial evaluates the safety and clinical activity of multiple infusions of CYAD-101, administered post FOLFOX preconditioning chemotherapy, then followed three weeks after CYAD-101 by a pembrolizumab consolidation treatment (200 mg every three weeks for a maximum two years total treatment duration) in microsatellite stable/mismatch-repair proficient mCRC patients with recurrent/progressing disease after at least one metastatic line of therapy which must include FOLFOX chemotherapy.The schedule of administration of three CYAD-101 infusions at the dose 1x109 cells/infusion Q2W post-FOLFOX preconditioning chemotherapy are based on the alloSHRINK study.This sequencing of checkpoint inhibitor at a timepoint after CYAD-101 therapy ensures that the modulated endogenous immune response is enabled by pembrolizumab. This study is not focused on impacting the CAR T cell itself largely since CYAD-101 cells at the time of manufacture show negligible expression of PD-1 and that this sequencing ensures no overlap of potential toxicities that could arise from the CAR T or checkpoint inhibitor therapies.The KEYNOTE-B79 study is planned to be initiated in Q4-2021.Ethics ApprovalThe study was approved by all relevant authorities and submitted to Institution’s Ethics Boards for their approval before study initiation.

Chimeric antigen receptor-T cells (CAR-Ts) are an exciting new cancer treatment modality exemplified by the recent regulatory approval of two CD19-targeted CAR-T therapies for certain B cell malignancies. However, this success in the hematological setting has yet to translate to a significant level of objective clinical responses in the solid tumor setting. The reason for this lack of translation undoubtedly lies in the substantial challenges raised by solid tumors to all therapies, including CAR-T, that differ from B cell malignancies. For instance, intravenously infused CAR-Ts are likely to make rapid contact with cancerous B cells since both tend to reside in the same vascular compartments within the body. By contrast, solid cancers tend to form discrete tumor masses with an immune-suppressive tumor microenvironment composed of tumor cells and non-tumor stromal cells served by abnormal vasculature that restricts lymphocyte infiltration and suppresses immune function, expansion, and persistence. Moreover, the paucity of uniquely and homogeneously expressed tumor antigens and inherent plasticity of cancer cells provide major challenges to the specificity, potency, and overall effectiveness of CAR-T therapies. This review focuses on the major preclinical and clinical strategies currently being pursued to tackle these challenges in order to drive the success of CAR-T therapy against solid tumors., SCOPUS: re.j, info:eu-repo/semantics/published

Introduction Treatment of non-small cell lung cancer (NSCLC) is an important and often unmet medical need regardless of the disease stage at the time of first diagnosis. Antigen-specific immunotherapy may be a feasible therapeutic option if tumor associated antigens (TAAs) that can be targeted by the patient's immune system are identified. The study objective (NCT01837511) was to investigate the expression rates of MAGE-A3 and PRAME in tumors from East Asian NSCLC patients, and the associations between TAA expression and clinico-pathologic patient characteristics. Methods Archived formalin-fixed paraffin-embedded tumor tissue specimens were tested for MAGE-A3 and PRAME expression by quantitative reverse transcription polymerase chain reaction. Exploratory analyses of the impact of patient and tumor characteristics on antigen expression were performed by multivariate logistic regression analyses. Results A total of 377 specimens were tested and a valid expression result was obtained for 86.5% and 92.6% for MAGE-A3 and PRAME , respectively. Of the specimens with valid test results, 26.4% expressed MAGE-A3 , 49.9% PRAME , 20.0% both and 57.5% expressed at least one TAA. The same pattern of associations between antigen expression and patient and tumor characteristics was found for both TAAs: higher rates of antigen-positive tumors were found in squamous cell carcinomas compared to adenocarcinomas, and for smokers compared to non-smokers. Conclusions Expression of MAGE-A3 and PRAME suggests an association with tumor histology and the patient's smoking status. The rates of TAA-positive tumors found in these East and South East Asian NSCLC patients indicate that both antigens may serve as targets for antigen-specific immunotherapies.

74 Background: CYAD-101 is a first-in-class, non-gene edited allogeneic CAR T-cell product that combines the broad breadth of tumor targeting of the NKG2D-based chimeric antigen receptor (CAR) with a peptide-based approach that controls graft versus host disease (GvHD). NKG2D binds eight ligands commonly over-expressed across many tumors while the co-expressed T-cell receptor (TCR) inhibitory (TIM) peptide interferes with signaling by the endogenous TCR. A bank of CYAD-101 cells was produced from a single donor and evaluated in the AlloSHRINK phase 1 study (NCT03692429) in patients with unresectable metastatic colorectal cancer (mCRC). Methods: Three CYAD-101 infusions, each administered following a FOLFOX standard cycle as preconditioning chemotherapy, were tested in a 3+3 dose-escalation study (dose-levels (DL): 108, 3x108 and 109 T-cells per infusion) in patients with relapsed/refractory mCRC who progressed after previous treatment with oxaliplatin-based chemotherapy, with or without irinotecan-based chemotherapy. Results: Fifteen patients (pts) were enrolled (3 pts at DL-1, 3 pts at DL-2, 9 pts at DL-3). No dose-limiting toxicity (DLT), Grade ≥ 3 related adverse events or GvHD were reported after any of the CYAD-101 infusions, thus confirming the overall good safety profile of CYAD-101 post FOLFOX. Encouraging anti-tumor activity was observed with 2 confirmed partial responses (PR), including one response in a KRAS mutated patient. In addition, 9 pts achieved stable disease (SD), with 7 SD lasting at least 3 months. The median progression-free survival in this heavily pre-treated population was 3.9 months (95% CI). Whilst engraftment of the CYAD-101 cells was observed after each infusion, the relative level of systemic cytokines appeared to be primarily modulated by cell dose with some suggestion that the magnitude of modulation might be associated with clinical response. Interestingly, preliminary analysis of the T-cell repertoire identified some evidence of TCR diversity after therapy in the patient showing the most durable partial response. Conclusions: These clinical results demonstrate the safety and tolerability of a fist-in-human non-gene edited allogeneic CAR T-cell treatment with early promising anti-tumor activity in advanced mCRC pts. Preliminary translational analysis present intriguing observations that the modulation of systemic cytokine levels may be associated with dose which is uncommon in CAR T-cell therapies reported to date while limited T-cell clonal diversification in the best responding patient underscores the likely central role of the adoptively transferred T-cell in driving therapeutic response in this particular patient. Extension cohort evaluating CYAD-101 following other preconditioning chemotherapy is expected to be initiated end 2020. Clinical trial information: NCT03692429.

3032 Background: In contrast to autologous CAR-T cell therapies, allogeneic donor-derived CAR-T cells can be banked and used in a timely fashion overcoming the critical time delay of just in time autologous cell manufacture. CYAD-101 is an allogeneic CAR-T that uses a non-gene edited peptide-based technology (TIM) to control graft versus host disease (GvHD) combined with a NKG2D-based CAR. Pre-clinical studies confirmed that CYAD-101 maintained CAR-directed anti-tumor activity in the absence of the induction of GvHD. Clinical grade CYAD-101 cells were produced for the phase 1 alloSHRINK trial (NCT03692429). Methods: A bank of clinical grade CYAD-101 cells was generated through two production runs using a single donor apheresis. Together, the bank generated > 53 billion CYAD-101 cells suitable for the entire dose escalation segment and short expansion phase of the trial (15 patients in total). Both runs showed high consistency with the CYAD-101 product generated composed mainly of CD4+ T cells (>85%) with a transduction level of > 92%, low relative expression of CD69/CD25 and largely absent expression levels of PD-1/LAG-3. The CYAD-101 cells were predominantly (>80%) CD45RA−/ CD62L−/ CD27− suggestive of an effector memory T cell population. Results: Upon co-culture with target K562 cells, CYAD-101 readily produced IFN-γ that was blocked by a NKG2D blocking antibody confirming specificity of the CAR. CYAD-101 cells showed in vitro cytotoxicity against tumor cells and produced an array of Th1 (IFN-γ, IL-2 and TGF-β) and Th2 (IL-4, IL-5) cytokines. Importantly, minimal IFN-γ was produced upon TCR stimulation while stimulation with a non-TCR mitogen (PMA + ionomycin) lead to high levels of IFN-γ. Together, these data show that clinical grade CYAD-101 cells were able to functionally respond through the CAR but showed minimal TCR-driven activation. Fifteen refractory metastatic CRC patients who had previously failed at least one line of oxaliplatin—containing therapy were treated with three doses of CYAD-101 cells given on Day 3 of three successive FOLFOX chemotherapy cycles. Updated clinical results continue to demonstrate an encouraging clinical activity (2 patients with partial response and 9 with stable disease) and the absence of GvHD in the context of CYAD-101 cell engraftment. Conclusions: These early clinical results demonstrate the safety and tolerability of a non-gene edited predominantly CD4+ CAR-T therapeutic approach. The initial observations of clinical activity in metastatic CRC patients warrants the continued development of this therapy. Clinical trial information: NCT03692429 .

Purpose This study assessed clinical activity, safety and immunogenicity of MAGE-A3 immunotherapeutic in patients with MAGE-A3-positive metastatic melanoma. Patients and methods In this open-label, multicentre, uncontrolled, Phase II study (ClinicalTrials.gov NCT00896480),patients received ≤24 doses of MAGE-A3 immunotherapeutic (4-cycle schedule). At screening, two skin lesions were biopsied for MAGE-A3 expression analysis and presence/absence of a previously identified gene signature (GS) associated with favourable clinical outcome. Clinical activity was assessed in terms of clinical response, time-to-treatment failure (TTF) and progression-free survival (PFS). Adverse events (AEs) and serious AEs (SAEs) were recorded. MAGE-A3-specific immune responses were assessed. Clinical activity and immunogenicity were analysed overall and separately in patients with 2/2 (GS+/+), 1/2 (GS+/-) or 0/2 (GS-/-) biopsies presenting GS. Results Of 49 screened patients, 32 had MAGE-A3-positive tumours; 24 (8 GS+/+, 8 GS+/-, 8 GS-/-) were treated. Two complete (GS+/+ patients) and two partial responses (one GS+/+, one GS+/-) were reported; of note, one of the two complete responses was unlikely to be related to the study treatment. Median TTF and PFS were 14.8 and 7.2 months for GS+/+, 2.3 and 2.8 months for GS+/- and 2.4 and 2.9 months for GS-/- patients. Three grade 3 AEs and two SAEs unrelated to treatment were reported. All patients were seropositive for MAGE-A3 antibodies on vaccination with no differences between the different GS profiles. MAGE-A3-specific CD4+ and CD8+ T cell immunogenicity was detected; 12/16 (75.0%) of patients presented CD4+ T cell responses. Conclusion Treatment with MAGE-A3 immunotherapeutic showed signs of clinical activity in GS+/+ patients. Treatment was well tolerated and immunogenic. No differences in immune responses according to GS status were observed. Trial registration number NCT00896480 (Results).

Background aims Adoptive cell therapy employing natural killer group 2D (NKG2D) chimeric antigen receptor (CAR)-modified T cells has demonstrated preclinical efficacy in several model systems, including hematological and solid tumors. We present comprehensive data on manufacturing development and clinical production of autologous NKG2D CAR T cells for treatment of acute myeloid leukemia and multiple myeloma ( ClinicalTrials.gov Identifier: NCT02203825). An NKG2D CAR was generated by fusing native full-length human NKG2D to the human CD3ζ cytoplasmic signaling domain. NKG2D naturally associates with native costimulatory molecule DAP10, effectively generating a second-generation CAR against multiple ligands upregulated during malignant transformation including MIC-A, MIC-B and the UL-16 binding proteins. Methods CAR T cells were infused fresh after a 9-day process wherein OKT3-activated T cells were genetically modified with replication-defective gamma-retroviral vector and expanded ex vivo for 5 days with recombinant human interleukin-2. Results Despite sizable interpatient variation in originally collected cells, release criteria, including T-cell expansion and purity (median 98%), T-cell transduction (median 66% CD8+ T cells), and functional activity against NKG2D ligand-positive cells, were met for 100% of healthy donors and patients enrolled and collected. There was minimal carryover of non–T cells, particularly malignant cells; both effector memory and central memory cells were generated, and inflammatory cytokines such as granulocyte colony-stimulating factor, RANTES, interferon-γ and tumor necrosis factor-α were selectively up-regulated. Conclusions The process resulted in production of required cell doses for the first-in-human phase I NKG2D CAR T clinical trial and provides a robust, flexible base for further optimization of NKG2D CAR T-cell manufacturing.

NKG2D ligands are widely expressed in solid and hematologic malignancies but absent or poorly expressed on healthy tissues. We conducted a phase I dose-escalation study to evaluate the safety and feasibility of a single infusion of NKG2D-chimeric antigen receptor (CAR) T cells, without lymphodepleting conditioning in subjects with acute myeloid leukemia/myelodysplastic syndrome or relapsed/refractory multiple myeloma. Autologous T cells were transfected with a γ-retroviral vector encoding a CAR fusing human NKG2D with the CD3ζ signaling domain. Four dose levels (1 × 106–3 × 107 total viable T cells) were evaluated. Twelve subjects were infused [7 acute myeloid leukemia (AML) and 5 multiple myeloma]. NKG2D-CAR products demonstrated a median 75% vector-driven NKG2D expression on CD3+ T cells. No dose-limiting toxicities, cytokine release syndrome, or CAR T cell–related neurotoxicity was observed. No significant autoimmune reactions were noted, and none of the ≥ grade 3 adverse events were attributable to NKG2D-CAR T cells. At the single injection of low cell doses used in this trial, no objective tumor responses were observed. However, hematologic parameters transiently improved in one subject with AML at the highest dose, and cases of disease stability without further therapy or on subsequent treatments were noted. At 24 hours, the cytokine RANTES increased a median of 1.9-fold among all subjects and 5.8-fold among six AML patients. Consistent with preclinical studies, NKG2D-CAR T cell–expansion and persistence were limited. Manufactured NKG2D-CAR T cells exhibited functional activity against autologous tumor cells in vitro, but modifications to enhance CAR T-cell expansion and target density may be needed to boost clinical activity.

Celyad recently initiated several clinical trials with the CYAD-01 product, a natural killer group 2D (NKG2D)-based chimeric antigen receptor (CAR), in both solid and hematologic tumor types. This review discusses the unique properties of CYAD-01, expecting to provide a new paradigm to fight against solid tumors.

Background We assessed safety, immunogenicity and clinical activity of recombinant MAGE-A3 antigen combined with AS15 immunostimulant (MAGE-A3 immunotherapeutic) in association with dacarbazine in patients with metastatic melanoma. Methods In this open-label, phase I/II, uncontrolled multicentre trial conducted in Belgium and France, patients with MAGE-A3-positive melanoma received up to 24 doses of MAGE-A3 immunotherapeutic (four cycles) coadministered with eight doses of dacarbazine. Adverse events (AE) were recorded until 31 days postvaccination, and serious AEs (SAE), until 30 days following the last dose. MAGE-A3-specific antibodies were measured by ELISA. Clinical activity of MAGE-A3 immunotherapeutic was assessed in patients positive/negative for previously identified gene signature (GS) associated with clinical outcome. Results Forty-eight patients were enrolled and treated (32 GS+, 15 GS−, 1 unknown GS status); two patients completed the study. All patients reported AEs, the most common were ‘general disorders and administration site conditions’ (94%). Treatment-related AEs were reported by 85% of patients; the most common was pain at injection site (38%). Sixteen SAEs were reported by 21% of patients; two were considered as treatment related (neutropenia and thrombocytopenia; grade 4). Postdose 4, all patients were seropositive for MAGE-A3-specific antibodies, with a geometric mean titre of 2778.7 ELISA units (EU)/mL (95% CI 1638.3 to 4712.8). One complete and three partial responses were reported (only in GS+ patients). Median overall survival was 11.4 months for GS+ and 5.3 months for GS− patients. Conclusion Although this trial shows poor results compared with the new results with checkpoint inhibitors, it gives an interesting insight in rapidly developing fields like combinations of immunotherapy and chemotherapy, new generation vaccines and the use of gene profile as a predictive marker. Trial registration number NCT00849875.

Purpose Active immunization against the tumor-specific MAGE-A3 antigen is followed by a few but impressive and durable clinical responses. This randomized phase II trial evaluated two different immunostimulants combined with the MAGE-A3 protein to investigate whether a more robust and persistent immune response could be associated with increased clinical benefit. Patients and Methods Patients with MAGE-A3–positive stage III or IV M1a melanoma were randomly assigned to receive the MAGE-A3 protein combined either with AS02B or with AS15 immunostimulant. Clinical end points were toxicity and rates of objective clinical responses, progression-free survival (PFS), and overall survival (OS). Results Seventy-five patients were treated, with 36 eligible patients per arm. Both treatments were well tolerated. In the AS15 arm, four objective responses were observed (three complete responses and one partial response) versus one partial response in the AS02B arm. In the AS15 and AS02B arms, the PFS rates after 6 months were 25% and 14%, respectively; and the median OS times were 33 months and 19.9 months, respectively, with a median observation period of 48 months. Antibodies against MAGE-A3, found in all patients, showed three-fold higher titers in the AS15 arm. The anti–MAGE-A3 cellular response was also more pronounced in the AS15 arm. Conclusion In the MAGE-A3+AS15 arm, clinical activity was higher and the immune response more robust. Therefore, the AS15 immunostimulant was selected for combination with the MAGE-A3 protein in phase III trials.

Purpose The MAGE-A3 protein is expressed in approximately 35% of patients with resectable non–small-cell lung cancer (NSCLC). Several immunization approaches against the MAGE-A3 antigen have shown few, but often long-lasting, clinical responses in patients with metastatic melanoma. Patients and Methods A double-blind, randomized, placebo-controlled phase II study was performed assessing clinical activity, immunologic response, and safety following immunization with recombinant MAGE-A3 protein combined with an immunostimulant (13 doses over 27 months) in completely resected MAGE-A3–positive stage IB to II NSCLC. The primary end point was disease-free interval (DFI). Results Patients were randomly assigned to either MAGE-A3 immunotherapeutic (n = 122) or placebo (n = 60). After a median postresection period of 44 months, recurrence was observed in 35% of patients in the MAGE-A3 arm and 43% in the placebo arm. No statistically significant improvement in DFI (hazard ratio [HR], 0.75, 95% CI, 0.46 to 1.23; two-sided P = .254), disease-free survival (DFS; HR, 0.76; 95% CI, 0.48 to 1.21; P = .248), or overall survival (HR, 0.81; 95% CI, 0.47 to 1.40; P = .454) was observed. Corresponding analysis after a median of 70 months of follow-up revealed a similar trend for DFI and DFS. All patients receiving the active treatment showed a humoral immune response to the MAGE-A3 antigen, although no correlation was observed with outcome. No significant toxicity was observed. Conclusion In this early development study with a limited number of patients, postoperative MAGE-A3 immunization proved to be feasible with minimal toxicity. These results are being investigated further in a large phase III study.

This Phase I dose-escalation study (NCT00058526) assessed the safety and immunogenicity of an anti-cancer immunotherapeutic (recombinant HER2 protein (dHER2) combined with the immunostimulant AS15) in patients with early-stage HER2-overexpressing breast cancer (BC). Sixty-one trastuzumab-naive patients with stage II-III HER2-positive BC received the dHER2 immunotherapeutic after surgical resection and adjuvant therapy. They were allocated into four cohorts receiving different doses of dHER2 (20, 100, 500 A mu g) combined with a fixed AS15 dose. Safety and immunogenicity (dHER2-specific antibody responses) were assessed. After completing the immunization schedule (three or six doses over 14 weeks) and a six-month follow-up, the patients were followed for 5 years for late toxicity, long-term immunogenicity, and clinical status. The immunizations were well tolerated, and increasing doses of dHER2 had no impact on the frequency or severity of adverse events. Few late toxicities were reported, and after 5 years 45/54 patients (83.3 %) were still alive, while 28/45 (62 %) with known disease status were disease free. Regarding the immunogenicity of the compound, a positive association was found between the dHER2 dose, the immunization schedule, and the prevalence of dHER2-specific humoral responses. Among the patients receiving the most intense immunization schedule with the highest dHER2 dose, 6/8 maintained their dHER2-specific antibody response 5 years after immunization. The dHER2 immunotherapeutic had an acceptable safety profile in early HER2-positive BC patients. dHER2-specific antibody responses were induced, with the rate of responders increasing with the dHER2 dose and the number and frequency of immunizations

NKG2D is a receptor with specificity for a broad range of stress ligands expressed on the majority of tumors (MICA, MICB and ULBP1-6). In vivo preclinical studies in acute myeloid leukemia (AML), ovarian, multiple myeloma (MM) and pancreatic cancer models all showed potent efficacy of T cells engrafted with a NKG2D Chimeric Antigen Receptor (CAR) indicating the possible effectiveness of CYAD-01 (a.k.a NKR-2) in the clinic. To evaluate the susceptibility of several malignancies to NKG2D ligand targeting in a clinical setting, and the safety of CYAD-01, an open-label phase I THINK (THerapeutic Immunotherapy with NKR-2, NCT03018405) trial was initiated. CYAD-01 was administered three successive times with 2-week intervals, and without prior lymphodepletive conditioning, in refractory or relapsed patients with different metastatic solid tumors and hematological malignancies (AML/MDS and MM), which failed from standard treatments. The study was designed to have two segments. The first dose escalation segment (3+3 design) includes three dose levels: 3x108, 1x109 and 3x109 CYAD-01 per injection, in both solid and hematological arms. The second, open-label phase I expansion segment of the study will evaluate the recommended dose in each tumor type. By December 2017, within the solid tumor arm, 4 patients had received three CYAD-01 administrations at dose-level 1 and three patients had received three CYAD-01 administrations at dose-level 2 and completed the safety period with no DLT occurrence. Within the hematologic arm, two AML patients and 1 MM patient have received the three CYAD-01 administrations at dose-level 1 and completed the safety period with no dose-limiting toxicity (DLT) occurrence. One relapsed AML patient to salvage CLAG-M chemotherapy reached a morphologic leukemia-free state (MLFS) after the CYAD-01 treatment, and resolution of symptoms with improved hematopoiesis at 3 months follow up at which time he started conditioning therapy for allo-HSCT. At 3 months post allo-HSCT, the patient is in complete remission with 100% donor chimerism. Interestingly, even at this early stage of the evaluation, there is variation in the phenotype of the CYAD-01 cells (e.g. CD4/CD8 ratio) and an early observation of a relative increase in the systemic levels of SDF-1 and RANTES in the patient who achieved MLFS. In summary, we report the first objective response to CAR-T in r/r AML using CYAD-01 without preconditioning chemotherapy and with no significant toxicities, highlighting the potential of targeting NKG2D ligands in AML. Citation Format: David A. Sallman, Jason B. Brayer, Xavier Poire, Tessa Kerre, Philippe Lewalle, Eunice S. Wang, Bikash Verma, Eytan Breman, Marco Davila, Nathalie Braun, Caroline Lonez, David E. Gilham, Frédéric F. Lehmann. The THINK clinical trial: Preliminary evidence of clinical activity of NKG2D chimeric antigen receptor T cell therapy (CYAD-01) in acute myeloid leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT129.

We recently developed a novel chimeric antigen receptor (CAR) T-cell therapy, called CYAD-01 (a.k.a. NKR-2), incorporating the full-length human natural killer receptor NKG2D fused with the human CD3 zeta signaling domain, which associates with the adaptor molecule DAP10 to provide co-stimulatory signal upon ligand binding. CYAD-01 is currently evaluated in multiple intravenous administrations in the ongoing THINK study (NCT03018405) in both hematological and solid indications. Classical CAR-Ts has yet to demonstrate positive results in the context of solid tumors. Underlying reasons for this reduced clinical activity include the need to extravasate from the peripheral circulation, infiltrate into the tumor and overcome the hostile immune suppressive tumor microenvironment (TME) to deliver anti-tumor effector responses. To address the challenge related to the difficulty of CAR-T cells to access the site of metastasis, the LINK trial (Locoregional Immunotherapy with NKR-2) has been developed to assess the safety and clinical activity of multiple hepatic transarterial administrations of CYAD-01 treatment (every 2 weeks x 3 infusions) in colorectal cancer patients with unresectable liver metastases (NCT03370198). The hepatic transarterial administration (HTAA) cell therapy may offer the advantage of lower systemic toxicity and higher and more persistent concentration of the infused cells on the TME compared with systemic administration. The difference in blood supply between uninvolved liver parenchyma and metastases may favor CYAD-01 tumor homing. Moreover, based on the potential impact of the CYAD-01 treatment on the host immune system, combined with the tumor antigens spreading induced by its direct anti-cancer cells activity, the CYAD-01 HTAA may boost the adaptive immune response and therefore may control any distant lesion (aboscopal effect). This dose escalation study will use a 3+3 design including 3 dose levels of CYAD-01 (3x108, 1x109 and 3x109 cells per injection) to evaluate the maximum tolerated dose of the CYAD-01 hepatic transarterial administration. Peripheral blood samples, as well as tumor biopsies will be collected to determine systemic CYAD-01 kinetics and within the liver tumor tissues, NKG2D ligand expression and systemic cytokine levels in peripheral blood post-infusion. This study will enroll 12 patients in case of no DLT and is open for recruitment. Citation Format: Nathalie Braun, Alain Hendlisz, Leila Shaza, Michaël Vouche, Vincent Donckier, Philippe Aftimos, Ahmad Awada, Caroline Lonez, Bikash Verma, David E. Gilham, Frédéric F. Lehmann. A phase I study assessing the safety and clinical activity of multiple hepatic transarterial administrations of a NKG2D-based CAR-T therapy CYAD-01, in patients with unresectable liver metastases from colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT134.

Purpose The PRAME tumour antigen is expressed in several tumour types but in few normal adult tissues. A dose-escalation phase I/II study (NCT01149343) assessed the safety, immunogenicity and clinical activity of the PRAME immunotherapeutic (recombinant PRAME protein (recPRAME) with the AS15 immunostimulant) in patients with advanced melanoma. Here, we report the phase I dose-escalation study segment. Patients and methods Patients with stage IV PRAME-positive melanoma were enrolled to 3 consecutive cohorts to receive up to 24 intramuscular injections of the PRAME immunotherapeutic. The RecPRAME dose was 20, 100 or 500 µg in cohorts 1, 2 and 3, respectively, with a fixed dose of AS15. Adverse events (AEs), including predefined dose-limiting toxicity (DLT) and the anti-PRAME humoral response (ELISA), were coprimary end points. Cellular immune responses were evaluated using in vitro assays. Results 66 patients were treated (20, 24 and 22 in the respective cohorts). AEs considered by the investigator to be causally related were mostly grade 1 or 2 injection site symptoms, fatigue, chills, fever and headache. Two DLTs (grade 3 brain oedema and proteinuria) were recorded in two patients in two cohorts (cohorts 2 and 3). All patients had detectable anti-PRAME antibodies after four immunisations. Percentages of patients with predefined PRAME-specific-CD4+T-cell responses after four immunisations were similar in each cohort. No CD8+ T-cell responses were detected. Conclusions The PRAME immunotherapeutic had an acceptable safety profile and induced similar anti-PRAME-specific humoral and cellular immune responses in all cohorts. As per protocol, the phase II study segment was initiated to further evaluate the 500 µg PRAME immunotherapeutic dose. Trial registration number NCT01149343, Results.

We assessed the tolerability, safety, pharmacokinetics and dose-limiting toxicity (DLT) of the recombinant humanized IgG4 anti-vascular endothelial growth factor (VEGF) monoclonal antibody, HuMV833, in patients with advanced cancer. Cohorts of patients with progressive solid tumours received escalating doses of HuMV833 as a 1-h intravenous (I.V.) infusion on days 1, 15, 22, and 29. Twenty patients (median Eastern Cooperative Oncology Group (ECOG) score 1) were accrued. HuMV833 infusions were well tolerated and there were no grade III or IV toxicities definitely related to the antibody. Grade I or II toxicities probably related to the antibody included fatigue, dyspnoea and rash. There were two episodes of asymptomatic hypocalcaemia, one at grade III and one grade IV, which were recorded in early follow-up. There were eight grade I episodes of asymptomatic elevation of activated partial thromboplastin time (APTT) and two grade III events; one in a patient receiving 1 mg/kg and the other receiving extended doses of 10 mg/kg. Pharmacokinetic analysis revealed a non-linear kinetic and an elimination half-life of between 8.2 (0.3 mg/kg) and 18.7 (10 mg/kg) days. One patient with ovarian cancer experienced a partial response (PR) of 9 months duration and eight had disease stabilisation (SD) including one patient with colorectal carcinoma whose disease was stable for 14 months. In 13 of the 14 samples taken from 12 patients, the plasma concentration of hepatocyte growth factor (HGF) was reduced 24 h after drug administration. HuMV833 is safe and lacked DLT at doses up to 10 mg/kg on this schedule. Multiple doses were well tolerated, despite occasional asymptomatic elevations in APTT. By combining pharmacokinetic, pharmacodynamic and toxicity data, we can identify doses of 1 and 3mg/kg for further investigation. HuMV833 appears to possess some clinical activity.

The EORTC Melanoma Group (MG) was founded in 1969 by both clinicians and scientists from various disciplines and fields of research with a common interest in malignant melanoma. This collaborative approach has always been the foundation of the groups strength. With an interest in tumour biology and especially the immunological aspects of the disease, the group has always pursued a scientific approach to treatment development in malignant melanoma. Over the years, the group has performed many clinical trials, epidemiological studies, histopathological studies defining standards and guidelines, translational research regarding prognostic factors and various metastatic and immunological aspects of melanoma, and developed quality assurance programmes for immunological and molecular biological assays in laboratory networks. At present, the EORTC MG runs the worldwide largest clinical trial programme in stages II, III and IV melanoma involving some 140 cancer centres in and outside Europe. Each trial is associated with the appropriate translational research programmes.

Early drug development at EORTC has always been subject to structural changes to adapt to the rapid changes that occur in oncological drug development. The expertise of early drug developers has always been cross-fertilised with disease-/tumour-oriented groups and also backwards to the laboratory research groups. This results in the establishment of a solid and dedicated network of medical oncologists with focused expertise in cancer drug development. The EORTC Data Center is fully equipped with all expertise to support clinical research activities and includes regulatory, safety, and quality assurance desks. The EORTC New Drug development Programme (NDDP) provides methodological expertise to early clinical trials and coordinates phase I and phase II studies addressing various approaches. Through NDDP, the early clinical groups and the disease-/tumour-oriented groups have created specific networks to address early drug development in specific tumour types. This results in very efficient networks which have the resources and the patients to address and conduct challenging clinical trials in a standardised fashion ensuring the highest standards in cancer treatment.

TPS3093 Background: Chimeric Antigen Receptor (CAR)-T therapy has potentially serious limitations related to target antigen loss, toxicity due to pre-conditioning regimen, and lack of activity in many tumor types. To overcome these limitations, we have developed a novel CAR-T, called NKR-2, incorporating the full-length human natural killer receptor NKG2D fused with the human CD3 zeta signaling domain. When expressed in T-cells, the naturally-expressed DAP10 provides co-stimulatory signals to NKR-2 to produce cytokines and selectively target tumor cells upon recognition of up to 8 different stress-induced NKG2D ligands expressed in many solid and hematologic malignancies. In preclinical studies, NKR-2 demonstrated long-term anti-tumor activity towards a breadth of tumor indications, in the absence of pre-conditioning, whilst simultaneously targeting tumor cells and cells from the local tumor neo-vasculature and suppressive immune environment. In our recently completed First-in-Human Phase 1 study (NCT02203825) in hematologic cancers, a single administration of autologous NKR-2 was safe with initial signs of clinical benefit. Methods: Exploiting the multiple ligand targeting capability and unique mode of action of NKR-2, the THINK trial (THerapeutic Immunotherapy with NKR-2) is an open-label Phase I study that will assess the safety and clinical activity of multiple infusion NKR-2 treatment (every 2 weeks x 3 infusions) in relapse/refractory patients with metastatic or locally advanced CRC, urothelial carcinoma, TNBC, pancreatic cancer, recurrent epithelial ovarian and fallopian tube carcinoma, AML/MDS and MM, post standard treatment. The study contains two consecutive segments. The dose escalation segment will enroll 18 patients in two separate hematologic and solid malignancy arms, and will evaluate 3 dose levels of NKR-2 (3x108, 1x109 and 3x109 per injection) following a 3+3 design. The expansion segment will then enroll 96 additional patients in 7 separate cohorts for each indication with 3 steps of statistical analysis (overall futility, cohort futility and final evaluation). The study is open for recruitment in both EU and US. Clinical trial information: NCT03018405.

Purpose To detect a pretreatment gene expression signature (GS) predictive of response to MAGE-A3 immunotherapeutic in patients with metastatic melanoma and to investigate its applicability in a different cancer setting (adjuvant therapy of resected early-stage non–small-cell lung cancer [NSCLC]). Patients and Methods Patients were participants in two phase II studies of the recombinant MAGE-A3 antigen combined with an immunostimulant (AS15 or AS02B). mRNA from melanoma biopsies was analyzed by microarray analysis and quantitative polymerase chain reaction. These results were used to identify and cross-validate the GS, which was then applied to the NSCLC data. Results In the patients with melanoma, 84 genes were identified whose expression was potentially associated with clinical benefit. This effect was strongest when the immunostimulant AS15 was included in the immunotherapy (hazard ratio [HR] for overall survival, 0.37; 95% CI, 0.13 to 1.05; P = .06) and was less strong with the other immunostimulant AS02B (HR, 0.84; 95% CI, 0.36 to 1.97; P = .70). The same GS was then used to predict the outcome for patients with resected NSCLC treated with MAGE-A3 plus AS02B; actively treated GS-positive patients showed a favorable disease-free interval compared with placebo-treated GS-positive patients (HR, 0.42; 95% CI, 0.17 to 1.03; P = .06), whereas among GS-negative patients, no such difference was found (HR, 1.17; 95% CI, 0.59 to 2.31; P = .65). The genes identified were mainly immune related, involving interferon gamma pathways and specific chemokines, suggesting that their pretreatment expression influences the tumor's immune microenvironment and the patient's clinical response. Conclusion An 84-gene GS associated with clinical response for MAGE-A3 immunotherapeutic was identified in metastatic melanoma and confirmed in resected NSCLC.

TPS3102Background: Canonical CAR-T cell constructs encode a single chain antibody variable fragment, costimulatory domain, and signaling domain of CD3 zeta. This restricts recognition to 1 tumor an...

Background Patients with HER2-overexpressing metastatic breast cancer, despite initially benefiting from the monoclonal antibody trastuzumab and the EGFR/HER2 tyrosine kinase inhibitor lapatinib, will eventually have progressive disease. HER2-based vaccines induce polyclonal antibody responses against HER2 that demonstrate enhanced anti-tumor activity when combined with lapatinib in murine models. We wished to test the clinical safety, immunogenicity, and activity of a HER2-based cancer vaccine, when combined with lapatinib. Methods We immunized women (n = 12) with metastatic, trastuzumab-refractory, HER2-overexpressing breast cancer with dHER2, a recombinant protein consisting of extracellular domain (ECD) and a portion of the intracellular domain (ICD) of HER2 combined with the adjuvant AS15, containing MPL, QS21, CpG and liposome. Lapatinib (1250 mg/day) was administered concurrently. Peripheral blood antibody and T cell responses were measured. Results This regimen was well tolerated, with no cardiotoxicity. Anti-HER2-specific antibody was induced in all patients whereas HER2-specific T cells were detected in one patient. Preliminary analyses of patient serum demonstrated downstream signaling inhibition in HER2 expressing tumor cells. The median time to progression was 55 days, with the majority of patients progressing prior to induction of peak anti-HER2 immune responses; however, 300-day overall survival was 92% (95% CI: 77-100%). Conclusions dHER2 combined with lapatinib was safe and immunogenic with promising long term survival in those with HER2-overexpressing breast cancers refractory to trastuzumab. Further studies to define the anticancer activity of the antibodies induced by HER2 vaccines along with lapatinib are underway. Trial registry ClinicalTrials.gov NCT00952692

In order to define the antigens recognized by cytolytic T lymphocytes (CTLs) on autologous tumors, we derived tumor-specific CTL clones from autologous mixed lymphocyte tumor cell cultures. The gene coding for a tumor rejection antigen expressed on a melanoma was isolated by transfecting genomic DNA of the tumor into an antigen-loss variant of the melanoma. Transfectants were identified on the basis of their ability to stimulate tumor necrosis factor release by the CTL clone. The gene that transferred the expression of the antigen was named MAGE-1. It is a new gene, silent in normal tissues with the exception of testis, but expressed in several types of tumors. The antigen recognized by the CTL clone is a nonapeptide derived from the protein encoded by gene MAGE-1, and presented by the HLA class I molecule HLA-A1. Using two other antimelanoma CTL clones, we identified the tyrosinase gene as coding for an antigen presented by HLA-A2 on this type of tumors. The identification of these tumor rejection antigens open new possibilities for the specific immunotherapy of cancer.

Limiting numbers of peripheral-blood mononuclear cells (PBMC) from melanoma patients were stimulated with irradiated autologous tumor cells in the presence of interleukins-2 and -4 and in the absence of feeder cells. The responder cells were restimulated every week. After 2 to 4 weeks, the microcultures were tested for their lytic activity against the autologous tumor cells. Significant lysis of the tumor cells was observed with a fraction of these microcultures, whereas no lysis was observed with control microcultures seeded without stimulator melanoma cells. Because our aim was to measure the precursor frequency of CTL showing specificity for the tumor, and not that of NK-like effectors that were also capable of lysing the melanoma cells, we used cold-target inhibition with an excess of NK target K562 to inhibit the NK-like activity. Microcultures whose lysis on the tumor cells was not abolished by K562 competition were observed. The specificity of these CTL clones was confirmed by the absence of lytic activity on autologous T-cell blasts. The numbers of microcultures with anti-tumor CTL activity fitted the zero-order of the Poisson distribution equation, indicating that they resulted from the activity of single T-cell clones. The frequency of anti-tumor CTL precursor cells (CTL-P) of 7 melanoma patients ranged from 1/900 to 1/33,000. Frequencies of anti-tumoral CTL-P were higher and NK-like effectors were less frequent when sorted CD8+ T lymphocytes were used as responder cells.

Melanoma lines MEL.A and MEL.B were derived from metastases removed from patient LB33 in 1988 and 1993, respectively. The MEL.A cells express several antigens recognized by autologous cytolytic T lymphocytes (CTL) on HLA class I molecules. The MEL.B cells have lost expression of all class I molecules except for HLA-A24. By stimulating autologous lymphocytes with MEL.B, we obtained an HLA-A24-restricted CTL clone that lysed these cells. A novel gene, PRAME, encodes the antigen. It is expressed in a large proportion of tumors and also in some normal tissues, albeit at a lower level. Surprisingly, the CTL failed to lyse MEL.A, even though these cells expressed the gene PRAME. The CTL expresses an NK inhibitory receptor that inhibits its lytic activity upon interaction with HLA-Cw7 molecules, which are present on MEL.A cells and not on MEL.B. Such CTL, active against tumor cells showing partial HLA loss, may constitute an intermediate line of anti-tumor defense between the CTL, which recognize highly specific tumor antigens, and the NK cells, which recognize HLA loss variants.

7013 Background: Previous trials with the MAGE-A3 recombinant (rec) protein formulated with an immunostimulant have shown induction of specific immune responses and signals of clinical activity in different cancer diseases. In this phase I/II study (NCT 00455572), we evaluated the safety profile of the MAGE-A3 cancer immunotherapeutic (CI), formulated with the rec MAGE-A3 protein and the AS15 immunostimulant, and the induction of specific immune response with or without adjuvant chemotherapy (CT). Methods: MAGE-A3 CI was administered i.m. 8q3w in resected MAGE-A3+ stage IB-III NSCLC patients (pts). Three cohorts (C) were evaluated: Immunization with concurrent cisplatin plus vinorelbine (C1), sequentially after the same CT (C2) or with no CT (C3). The anti-MAGE-A3 humoral and cellular immune responses were evaluated by ELISA and intracellular cytokine staining (T cells producing both IFNg and TNF) respectively. Adverse Events (AEs) were graded according to CTCAE v. 3.0. Results: A total of 38/55 treated pts received the 8 doses schedule (15/19 in C1, 14/18 in C2, 9/18 in C3). Almost all pts reported at least one AE, mostly general constitutional disorders and administration site reactions. Six patients reported related grade 3 AEs. No related grade 4-5 AE or related SAE were reported. Immunogenicity results in the total treated population are reported in the table below. Conclusions: In this trial, patients in cohorts 2 and 3 correspond to the two populations enrolled in the Phase III MAGRIT trial evaluating the same MAGE-A3 CI. The phase I/II results suggest that this CI is well tolerated and induces in all treated pts specific antibodies against MAGE-A3 after 4 doses in presence or not of concurrent or sequential adjuvant CT. About 25% of the treated pts are considered as CD4 responders in presence or not of concurrent or sequential adjuvant CT. [Table: see text]

8535 Background: Active immunization towards MAGE-A3 tumor antigen is a potential new approach to treat cancer. Current data from pilot studies have shown that a strong and persistent immune respon...

Clinical data today highlight the encouraging potential of the MAGE-A3 Antigen-Specific Cancer Immunotherapeutic (ASCI) for cancer treatment. The MAGE-A3 gene encodes a tumor-specific antigen expressed on tumor cells only. When used as a recombinant protein and combined with an immunological Adjuvant System designed to enhance the immune response to the MAGE-A3 antigen, it was shown to induce specific T-cell responses and long-lasting clinical objective responses in metastatic melanoma (Phase II NCT00086866 trial) (Kruit et al. JCO 2008 26:9065), and demonstrated proof-of-concept in Non-Small Cell Lung Cancer (NSCLC; Phase II NCT00290355 trial) (Vansteenkiste et al. JCO 2007 25:7554). In these 2 trials, gene expression profiling by microarrays was used to identify biomarkers predictive of the clinical activity of the MAGE-A3 ASCI. A first analysis carried out on samples from melanoma patients using supervised hierarchical clustering of 2 objective responders and 2 non-responders identified 2 gene clusters based on differential gene expression. This immune gene expression signature was then confirmed in an analysis of 22-patient samples, and independently validated on an additional 30-patient testing set; furthermore these analyses confirmed the association of clinical benefit and the molecular signature. Most of the identified genes are immune-related, defining a particular biological context present in the tumor environment before immunization. This was confirmed by selecting genes using all patients eligible for gene expression profiling. Upon crossvalidation, median overall survival was improved significantly in the population of patients whose tumor presented the gene signature (GS): 28 months in the GS+ population, 16.2 months in the GS−. The predictive value of the melanoma signature was tested in NSCLC. A subset of 49 genes discovered in the melanoma Phase II trial was assayed by qPCR on biopsies taken prior to any ASCI treatment from 137 patients of the lung Phase II trial. Applied to NSCLC patients, this biomarker showed that the relative reduction in the risk of recurrence upon MAGE-A3 ASCI treatment is increased by about 2 fold in the patients with the predictive gene signature as compared to the overall population: from 25% relative improvement in the overall population to 53% in patients whose tumor presents the predictive gene signature. In conclusion, two clinical proof-of-concepts have been obtained with the MAGE-A3 ASCI in 2 different types of tumors, NSCLC and melanoma. More importantly, we have identified a gene expression signature predictive of clinical activity of the MAGE-A3 ASCI treatment. The initiation of Phase III studies in NSCLC (MAGRIT) and melanoma (DERMA) is a unique opportunity to validate prospectively these biomarkers with the ultimate goal to select patients that are the most likely to benefit from the MAGE-A3 ASCI therapy. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A37.

7501 Background: A phase II randomized trial in 182 patients (pts) with completely resected stage IB or II MAGE-A3 (+) NSCLC comparing postoperative MAGE-A3 recombinant protein combined with an Adjuvant System to placebo (q3w x 5, followed by q3m x 8) showed a strong positive signal for activity (J Clin Oncol 25 Suppl 18:398S, 2007). We report here the analysis of gene expression profiling of tumors prior to treatment to identify a predictive signature that correlates with clinical activity of MAGE-A3 ASCI treatment. Methods: Microarray analysis (Affymetrix) was performed on 159 fresh-frozen tumor biopsies (MAGE-A3: 108; placebo: 51; stage IB: 109; stage II: 50). Clinical data on relapse are based on a median follow-up of 44 months. Results: Study of tumor samples from pts in the placebo arm led to identification of a gene signature associated with a high risk of postoperative relapse. The absence of this signature correlated with a very low relapse rate in stage IB pts: placebo 0%; MAGE-A3: 4%. In the MA...

9065 Background: The MAGE-A3 antigen, expressed in ±60% of metastatic melanomas, is a target of anti-tumor CD4+ and CD8+ T-cells. Previous data showed a few clinical responses of MAGE-A3 Antigen-Sp...

9045 Background: Gene expression profiling by microarrays was used to identify markers predictive of the clinical activity of the MAGE-A3 Antigen-Specific Cancer Immunotherapeutic (ASCI) recorded in a phase II study in metastatic melanoma. Methods: 75 patients with progressive, unresectable stage III or stage IV M1a MAGE-A3 (+) melanomas, were randomized as 1st-line therapy between immunization with MAGE-A3 protein combined with GSK proprietary Adjuvant Systems AS15 or AS02B. Gene expression profiling was performed on tumor biopsies taken prior to any immunization. Results: Initial analysis using supervised hierarchical clustering of 2 objective responders (OR) with 7 non-responders identified 2 gene clusters based on differential expression. The correlation of this gene expression signature (GS) and objective response was further confirmed on 22 patients. Interestingly, mixed response (MR) and stable disease > 6 months (SD) clustered with OR, suggesting a strong association between the identified signatu...

7554 Background: After complete resection, about 50% of patients with stages IB-II NSCLC disease die within 5 years. Adjuvant chemotherapy improves overall survival at the expense of substantial toxicity. Activity of MAGE-A3 immunotherapeutic (i.e. recombinant MAGE-A3 protein and a potent GlaxoSmithKline adjuvant) was previously demonstrated in metastatic melanoma. As about 35% of NSCLCs express MAGE-A3 antigen, post-operative MAGE-treatment may be a tumor-specific, well tolerated, and effective adjuvant therapy. Methods: Patients with completely resected, MAGE-A3 (+), stage pIB or pII were randomly assigned to postoperative MAGE-A3 or placebo (2:1), with 5 administration at 3-week intervals, followed by 8 administrations every 3 months. Randomization was stratified for stage (IB vs. II), histology (squamous vs. other), and lymph-node (LN) procedure (sampling vs. dissection). Primary endpoint was disease-free interval (DFI); other endpoints were safety, disease-free survival (DFS), and overall survival (OS). This exploratory Phase II study was designed to detect a clinically relevant HR with a 10% one-sided a. Results: 182 patients (122 stage IB, 60 stage II) from 59 centers in 14 countries were randomized over 2 years: Median age 63 (45–81); 87% male; 65% squamous cell carcinoma; 65% lymph-node dissection. After a median follow-up of 28 months, 67 recurrences and 45 deaths were recorded. Group comparisons of DFI, DFS and OS gave respectively a hazard ratio (HR) of 0.74 (95% CI 0.44–1.20, p=0.107), 0.73 (95% CI 0.45–1.16) and 0.66 (95% CI 0.36–1.20) in favor of the MAGE-A3 group. Overall, treatment was well tolerated, with excellent protocol compliance. Subset analysis also suggests that LN dissection may have an effect on survival. Conclusions: The final analysis of this randomized phase II study shows a positive trend for activity of MAGE-A3 treatement in NSCLC with a relative improvement of DFI and DFS of 27%. Further phase III evaluation is planned. This study also suggests that complete lymph-node dissection may have an effect on survival and should be confirmed prospectively. [Table: see text]

7019 Background: About half of the patients with completely resected early-stage NSCLC will relapse. Adjuvant chemotherapy reduces the number of relapses at the expense of substantial toxicity. Activity of MAGE-A3 vaccination (i.e. recombinant MAGE-A3 protein and a potent GSK immunological adjuvant) has been proven in advanced melanoma. As about 35% of NSCLCs express the MAGE-A3 antigen, post-operative MAGE-A3 vaccination may be a targeted, well tolerated, and effective adjuvant therapy. Methods: Patients with completely resected, MAGE-A3 positive (assessed by quantitative RT-PCR), stage pIB or pII were 2:1, double-blind, randomly assigned to postoperative MAGE-A3 vaccination or placebo. Vaccination was started ≥6 weeks after surgery, with 5 vaccinations at 3-week intervals, followed by 8 vaccinations every 3 months. Randomization was stratified for stage (IB vs. II), histology (squamous vs. other), and lymph node procedure (sampling vs. dissection). Other anti-cancer adjuvant therapy was not allowed. Primary endpoint was time-to-recurrence, other endpoints were recurrence rates at different times, and survival. A sample size of 180 patients (120 active, 60 placebo) was chosen, to achieve 48% power (α=10%) to detect a 10% difference, assuming a 40% recurrence rate at month 30 in the placebo group (log rank test). A thorough interim efficacy analysis by an independent statistician (blinded to investigators and sponsor) is planned for 18 months after completion of recruitment. Results: 35% of 1,089 biopsies from 59 sites were MAGE-A3 positive. In two years, 182 patients were randomized (121 stage IB, 61 stage II). Overall, treatment was well tolerated, with high protocol compliance. Data collection for the interim efficacy analysis was initiated on December 19th, 2005. Median follow-up was 21 months, with 62 recurrences recorded. Conclusions: This study confirms expression of MAGE-A3 antigen in 35% of early NSCLC cases, and demonstrates good tolerability of postoperative MAGE-A3 vaccination. Efficacy results of the interim analysis will be available in February 2006. [Table: see text]

The landscape for cancer research is profoundly different today from that only one decade ago. Basic science is moving rapidly and biotechnological revolutions in molecular targeting and immunology have completely modified the opportunities and concepts for cancer treatment. In contrast to the recent past where cytotoxic molecules were screened in the laboratory and then tested in early clinical studies with toxicity as endpoint instead of the often poorly defined mechanism for its potential anti-tumor effect, we now have entered the age of molecular therapeutics, rationally designed to target "strategic" checkpoints that underlie the malignant phenotype. Translational research in early clinical trials (Phase I and II) is an integral aspect of the development of the new generation of cancer drugs as it is necessary to implement radically different early phase clinical trial design and to validate new biological end-points if the full potential of these new agents is to be realized. The "proof of principle with mechanistic analysis" strategy will allow optimisation of therapy from the beginning, and provide important feedback to pre-clinical drug developers. Translational research is also essential in late (phase III) clinical trials in defining different patient populations that may benefit to differing degrees from new treatments, and thus provide further insight and refine clinical practice in a more and more patient-tailored approach. In this editorial we will discuss the integration of Translational Research in the Organization for Research and Treatment of Cancer (EORTC).