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Supplementary Figure 3. CONSORT diagram with patient disposition.

Supplementary Figure 2. Schematic showing how sipuleucel-T is designed to activate a patient's immune system by ex vivo cellular activation during manufacture and subsequent in vivo immune response.

Supplementary Figure 1. Schematic of the STAMP trial design.

Purpose: This phase II open-label study evaluated the effect of concurrent or sequential administration of abiraterone acetate plus prednisone (AA + P) on sipuleucel-T manufacture and immune responses in metastatic castration-resistant prostate cancer (mCRPC) patients.Experimental Design: mCRPC patients received sipuleucel-T followed by AA + P 1 day (concurrent) or 10 weeks (sequential) after the first sipuleucel-T infusion. AA + P treatment continued for 26 weeks. The primary endpoint was cumulative antigen presenting cell (APC) activation, and secondary endpoints included cumulative APC number and total nucleated cell counts. Additional endpoints included in vivo peripheral immune responses to sipuleucel-T (T-cell responses, T-cell proliferation, humoral responses, and antigen spread) as well as safety.Results: Sixty-nine mCRPC patients were enrolled, with 35 and 34 patients randomized to the concurrent and sequential arms, respectively. Ex vivo APC activation was significantly greater at the second and third infusions compared with baseline in both arms (P < 0.05), indicative of an immunologic prime-boost effect. In both arms, sipuleucel-T product parameter profiles and peripheral immune responses were consistent with previously conducted sipuleucel-T phase III trials. Antigen spread was similarly observed in both arms and consistent with the other immunologic endpoints.Conclusions: These data suggest that sipuleucel-T can be successfully manufactured during concurrent administration of AA + P without blunting immunologic effects or altering immune parameters that correlate with sipuleucel-T's clinical benefit. Combination of these agents was well tolerated, with no new safety signals emerging. Clin Cancer Res; 21(17); 3862–9. ©2015 AACR.

Supplementary Tables 1-3, Figure Legends. ST1. Median cumulative product parameters, all randomized patients; ST2. Summary of maximal percent decrease from baseline in serum PSA; ST3: Most common AEs occurring within 1 day of infusion in >5% of patients.

Objectives Berzosertib (formerly M6620, VX-970) is an intravenous, highly potent and selective, first-in-class ataxia telangiectasia and Rad3-related (ATR) protein kinase inhibitor. We assessed the safety, tolerability, preliminary efficacy, and pharmacokinetics (PK) of berzosertib plus gemcitabine in an expansion cohort of patients with advanced non–small cell lung cancer (NSCLC). The association of efficacy with TP53 status and other tumor markers was also explored. Materials and Methods Adult patients with advanced histologically confirmed NSCLC received berzosertib 210 mg/m2 (days 2 and 9) and gemcitabine 1000 mg/m2 (days 1 and 8) at the recommended phase 2 dose established in the dose escalation part of the study. Results Thirty-eight patients received at least one dose of study treatment. The most common treatment–emergent adverse events were fatigue (55.3%), anemia (52.6%), and nausea (39.5%). Gemcitabine had no apparent effect on the PK of berzosertib. The objective response rate (ORR) was 10.5% (4/38, 90% confidence interval [CI] 3.7–22.5). In the exploratory analysis, the ORR was 30.0% (3/10, CI: 9.0–61.0%) in patients with high loss of heterozygosity (LOH) and 11.0% (1/9, 90% CI: 1.0–43.0%) in patients with low LOH. The ORR was 33.0% (2/6, CI: 6.0–73.0%) in patients with high tumor mutational burden (TMB), 12.5% (2/16, 90% CI: 2.0–34.0%) in patients with intermediate TMB, and 0% (0/3, 90% CI: 0.0–53.6%) in patients with low TMB. Conclusions Berzosertib plus gemcitabine was well tolerated in patients with advanced, pre-treated NSCLC. Based on the observed clinical efficacy, future clinical trials should involve genomically selected patients.

PURPOSE Trastuzumab deruxtecan (T-DXd, formerly DS-8201a) is a novel human epidermal growth factor receptor 2 (HER2)-targeted antibody drug conjugate (ADC) with a topoisomerase I inhibitor payload. A dose escalation and expansion phase I study evaluated the safety and activity of T-DXd in patients with advanced HER2-expressing/mutated solid tumors. Here, results for T-DXd at the recommended doses for expansion (RDE) in patients with HER2-low (immunohistochemistry [IHC] 1+ or IHC 2+/in situ hybridization−) breast cancer (ClinicalTrials.gov identifier: NCT02564900 ) are reported. PATIENTS AND METHODS Eligible patients had advanced/metastatic HER2-low–expressing breast cancer refractory to standard therapies. The RDE of 5.4 or 6.4 mg/kg T-DXd were administered intravenously once every 3 weeks until withdrawal of consent, unacceptable toxicity, or progressive disease. Antitumor activity and safety were assessed. RESULTS Between August 2016 and August 2018, 54 patients were enrolled and received ≥ 1 dose of T-DXd at the RDE. Patients were extensively pretreated (median, 7.5 prior therapies). The confirmed objective response rate by independent central review was 20/54 (37.0%; 95% CI, 24.3% to 51.3%) with median duration of response of 10.4 months (95% CI, 8.8 month to not evaluable). Most patients (53/54; 98.1%) experienced ≥ 1 treatment-emergent adverse event (TEAE; grade ≥ 3; 34/54; 63.0%). Common (≥ 5%) grade ≥ 3 TEAEs included decreases in neutrophil, platelet, and WBC counts; anemia; hypokalemia; AST increase; decreased appetite; and diarrhea. Three patients treated at 6.4 mg/kg suffered fatal events associated with T-DXd–induced interstitial lung disease (ILD)/pneumonitis as determined by an independent adjudication committee. CONCLUSION The novel HER2-targeted ADC, T-DXd, demonstrated promising preliminary antitumor activity in patients with HER2-low breast cancer. Most toxicities were GI or hematologic in nature. ILD is an important identified risk and should be monitored closely and proactively managed.

Background: HER2-targeted therapies have improved survival for advanced HER2-positive breast cancers (BC), but none have been approved for tumors with low levels of HER2 expression (ie, HER2 IHC 1+ or 2+/ISH-negative). Trastuzumab deruxtecan (DS-8201a) is a novel HER2-targeted antibody-drug conjugate with a humanized HER2 antibody attached to a potent topoisomerase I inhibitor payload by a cleavable peptide-based linker, which is designed to have broad antitumor activity in HER2-expressing tumors. It has a drug-to-antibody ratio of 7 to 8, a novel linker that is stable in plasma and that is selectively cleaved by lysosomal cathepsins which are upregulated in cancer cells, and its payload has a short systemic half-life. In 2015, a phase 1 study (NCT02564900) was initiated to evaluate the safety and efficacy of DS-8201a in subjects with advanced HER2-expressing or HER2-mutated solid tumors, including HER2-low expressing BC. In this study, the overall confirmed response rate (ORR) in the evaluable subjects was 49.3% (103/209) (April 2018 data cutoff; Iwata H, et al. ASCO 2018). Expanded results from the HER2-low expressing BC subjects are presented here. Methods: This ongoing phase 1 trial included 2 parts. The dose escalation part served to determine the dose-limiting toxicities, the maximum tolerated dose, and to select the recommended dose for expansion (RDE). The dose expansion part further evaluated the safety, tolerability, and efficacy of the DS-8201a at the RDE (5.4 and 6.4 mg/kg; q3wks) in various advanced HER2-expressing or HER2-mutated solid tumors, including heavily pretreated HER2-low BC (IHC 1+ or 2+, ISH-negative). Enrollment of HER2-low subjects is ongoing. Results: At the cutoff date of 18 April 2018, data from 34 HER2-low BC subjects were collected. The median age was 55.8 (range; 33, 75) years, the median number of prior endocrine therapies was 2, and the median number of prior chemotherapies was 3. In this HER2-low BC population, most patients had hormone receptor (HR)-positive disease (85.3%; 29/34); of which 17.2% (5/29) received prior treatment with a CDK4/6 inhibitor. The confirmed ORR was 50.0% (17/34), the disease control rate was 85.3% (29/34), the median time to response was 2.8 (range; 1.2, 13.8) months, the median duration of response (DOR) was 11.0 months, and the median progression-free survival (PFS) was 12.9 months. In the subgroup with HR-positive disease, the ORR was 55.2% (16/29), the median DOR was 11.0 months, and the median PFS was 13.6 months. After exclusion of 8 HER2-low subjects who received prior HER2-targeted therapy, the ORR was 46.2% (12/26). In the overall study, among the 145 BC subjects who received ≥1 dose of DS-8201a (5.4 or 6.4 mg/kg), the most frequent grade ≥3 adverse events included anemia (14.5%), and decreased counts of neutrophils (13.8%) and white blood cells (10.3%). There were 4 fatal cases of interstitial lung disease/pneumonitis in BC subjects, including 2 fatal cases in HER2-low BC subjects. Conclusions: In this study, DS-8201a showed substantial antitumor activity and acceptable safety in heavily pretreated HER2-low BC. Citation Format: Modi S, Tsurutani J, Tamura K, Park H, Sagara Y, Murthy R, Iwata H, Krop IE, Doi T, Redfern C, Moreno-Aspitia A, Redman R, Lee C, Sugihara M, Fujisaki Y, Takahashi S. Trastuzumab deruxtecan (DS-8201a) in subjects with HER2-low expressing breast cancer: Updated results of a large phase 1 study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-02.

Background DS-8201a is a HER2 targeting antibody-drug conjugate (ADC) with high drug to antibody ratio (8:1), a novel linker and topoisomerase I inhibitor as the payload. In preclinical studies, DS-8201a showed efficacy against both trastuzumab emtansine (T-DM1) resistant HER2 positive breast cancer (BC) and against BC with low HER2 expression. The current phase 1 trial is comprised of dose escalation (Part 1) and dose expansion (Part 2) cohorts including patients (pts) with BC, gastric cancer and other HER2 expressing tumors. Only the results from BC cohorts are presented here. Methods Part 1 used a modified continual reassessment model to identify the recommended phase 2 dose (RP2D) of DS8201a in pts with BC or gastric cancer of any HER2 status. Two out of planned 4 expansion cohorts included BC: T-DM1-treated HER2 positive BC (Cohort 2a; IHC 3+ or IHC 2+/ISH +) and HER2 low BC (Cohort 2c, IHC 2+/ISH- or IHC 1+). Efficacy endpoints of objective response rate (ORR), disease control rate (DCR: CR + PR + SD), durability of response, progression free survival (PFS) and adverse events (AEs) were assessed. Results Overall, 146 subjects were included (24 Part 1; 122 Part 2). DS-8201a was administered up to 8.0 mg/kg in Part 1 without any DLTs, maximum tolerated dose was not reached. Based on available results, the dose levels of 5.4 and 6.4 mg/kg IV every 3 weeks were chosen for Part 2. In Part 2, a total of 56 BC pts were enrolled; 46 pts in Cohort 2a and 10 pts in Cohort 2c. The median age was 56 and number of prior regimens in the metastatic setting was 5 (range: 1-16). 37 BC pts had follow-up imaging scans and were evaluable for response at the time of data cutoff. Confirmed ORR was 41% (15/37) including 1 CR; DCR was 97% (36/37). The median duration of treatment was not reached. For Cohort 2a, where all pts had received prior T-DM1, treatment with DS-8201a achieved a higher ORR of 41% (11/27) and DCR of 100% (27/27) compared to the reported response these patients had to their prior T-DM1 treatment with ORR of 23% (5/22) and DCR of 73% (16/22). In the subset of 24 pts from cohort 2a who had received prior treatment with pertuzumab and T-DM1, the confirmed ORR was 44% (11/25). In Cohort 2c, confirmed ORR was 40% (4/10), DCR was 90% (9/10). Of the 46 BC pts in Part 2 who received at least one dose of DS-8201a, 4 pts discontinued treatment due to disease progression and 3 pts discontinued due to AE. The most common AEs of any grades were nausea, decreased appetite, vomiting, alopecia, and diarrhea. Only 2 pts experienced grade 4 AEs (thrombocytopenia and neutropenia) and 46 % (21/46) experienced grade 3 AEs (most commonly anemia, neutropenia, thrombocytopenia, leukopenia, lymphocytepenia, and vomiting). Conclusions DS-8201a was well tolerated and has significant activity in pts with T-DM1 and T-DM1/ pertuzumab pretreated HER2 positive BC and in pts with HER2 low BC, with durable disease control. Promising efficacy of this ADC in BC warrants further investigation. Citation Format: Modi S, Tsurutani J, Takahashi S, Iwata H, Park H, Redfern CH, Doi T, Li B, Iwasa T, Taira S, Hattori M, Ma CX, Fisher JM, Naito Y, Yonemori K, Kawasaki Y, Saito K, Jikoh T, Shahidi J, Lee CC, Yver A, Tamura K. Safety and efficacy results from a phase 1 study of DS-8201a in patients with HER2 expressing breast cancers [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD3-07.

234 Background: A Phase II trial showed that addition of olaparib (O) to abiraterone (A) led to significant radiographic progression-free survival benefit for patients (pts) with mCRPC vs placebo (P) + A (hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.44–0.97). We report predefined exploratory HRQoL analyses. Methods: This randomized, double-blind trial enrolled pts with mCRPC, post-docetaxel. Pts were randomized (71 per arm) to receive either O (300 mg bd, tablets) + A (1000 mg od) or P + A; all received prednisone (5 mg bd). Pts completed Functional Assessment of Cancer Therapy-Prostate (FACT-P total score [TS]; range 0–156, higher score = better HRQoL), Brief Pain Inventory–Short Form (BPI-SF) and worst bone pain (wbp) questionnaires (both range 0–10, higher score = more severe pain). Adjusted mean change from baseline was analysed using a mixed model for repeated measures, improvement by logistic regression and deterioration by log-rank test. Results: Overall compliance rates (O + A vs P + A) were 97% vs 96%, 92% vs 85%, and 96% vs 92% for FACT-P, BPI-SF and wbp, respectively. Best FACT-P TS response of ‘improved’ (increase ≥6 points from baseline at two consecutive visits) was reported by 22/67 (33%) evaluable pts in the O + A vs 18/64 (28%) pts in the P + A arm; the odds ratio (1.32; 95% CI 0.64–2.78) favored the O + A arm. Best FACT-P TS response of ‘worsened’ (decrease ≥6 points from baseline) was reported by 15 (22%) vs 22 (34%) pts. Adjusted mean change from baseline in FACT-P TS across all visits was -0.60 vs -2.09 in the O + A and P + A arms, respectively (difference 1.48; 95% CI -3.96–6.92). Time to deterioration (TTD) results are shown in the table. Clinical trial information: NCT01972217. Conclusions: Whilst not statistically significant, in this study a higher percentage of pts treated with O + A vs P + A had improved HRQoL, with fewer pts negatively affected. Ongoing phase III studies will help elucidate the impact of O on HRQoL in pts with mCRPC. (NCT01972217)[Table: see text]

Background Sipuleucel-T, an autologous active cellular immunotherapy, has shown evidence of efficacy in reducing the risk of death among men with metastatic castration-resistant prostate cancer. Methods In this double-blind, placebo-controlled, multicenter phase 3 trial, we randomly assigned 512 patients in a 2:1 ratio to receive either sipuleucel-T (341 patients) or placebo (171 patients) administered intravenously every 2 weeks, for a total of three infusions. The primary end point was overall survival, analyzed by means of a stratified Cox regression model adjusted for baseline levels of serum prostate-specific antigen (PSA) and lactate dehydrogenase. Results In the sipuleucel-T group, there was a relative reduction of 22% in the risk of death as compared with the placebo group (hazard ratio, 0.78; 95% confidence interval [CI], 0.61 to 0.98; P = 0.03). This reduction represented a 4.1-month improvement in median survival (25.8 months in the sipuleucel-T group vs. 21.7 months in the placebo group). The 36-month survival probability was 31.7% in the sipuleucel-T group versus 23.0% in the placebo group. The treatment effect was also observed with the use of an unadjusted Cox model and a log-rank test (hazard ratio, 0.77; 95% CI, 0.61 to 0.97; P = 0.02) and after adjustment for use of docetaxel after the study therapy (hazard ratio, 0.78; 95% CI, 0.62 to 0.98; P = 0.03). The time to objective disease progression was similar in the two study groups. Immune responses to the immunizing antigen were observed in patients who received sipuleucel-T. Adverse events that were more frequently reported in the sipuleucel-T group than in the placebo group included chills, fever, and headache. Conclusions The use of sipuleucel-T prolonged overall survival among men with metastatic castration-resistant prostate cancer. No effect on the time to disease progression was observed. (Funded by Dendreon; ClinicalTrials.gov number, NCT00065442.)

5003Background: mCRPC pts with a homologous recombination repair mutation (HRRm) previously showed improved response to the PARP inhibitor olaparib (Lynparza) as monotherapy vs pts without a HRRm (...

e21048Background: Ataxia telangiectasia and Rad3-related protein (ATR) is an essential regulator of the DNA damage response and is required for the survival of proliferating cells. DNA-damaging age...

2501Background: DS-8201a is a HER2-targeted antibody drug conjugate with novel topoisomerase I inhibitor payload and linker technology. Methods: This ongoing phase 1 study (NCT02564900) enrolls subjects (sbj) with HER2+ breast cancer (BC) post T-DM1, HER2+ gastric cancer (GC) post trastuzumab, HER2 low BC (IHC 1+ or 2+, ISH-), and other HER2-expressing solid tumors (IHC ≥1+). Results: [Results will be updated for presentation at meeting] From Sep 2015–Dec 2017, 212 sbj received ≥1 dose of DS-8201a; 200 at 5.4 or 6.4 mg/kg. Median (mdn) age was 59 y with mdn of 4 prior regimens. At data cutoff, 121/200 (60.5%) sbj remain on treatment (tx). Mdn duration of tx was 10.3 mo (range 0.7+, 21.2+ mo). Overall, RECIST-confirmed overall response rate (ORR) in the evaluable sbj was 81/160 (50.6%) with the highest ORR in HER2+ BC (64.2%). Mdn duration of response was not reached (NR, range 0.03+, 15.2+ mo). 155/181 (85.6%) of sbj with ≥1 postbaseline scan (ps) experienced tumor shrinkage (92.3% of them at 1st ps at 6 ...

We evaluated the efficacy and safety of patient-specific immunotherapy with mitumprotimut-T idiotype keyhole limpet hemocyanin and granulocyte-monocyte colony-stimulating factor (GM-CSF) following rituximab in patients with follicular B-cell lymphoma. Patients with previously untreated or relapsed/refractory CD20+ follicular lymphoma received 4 weekly infusions of rituximab and those with a complete response (CR), partial response (PR), or stable disease received mitumprotimut-T and GM-CSF injections subcutaneously. Courses were given monthly for 6 doses, every 2 months for 6 doses, and then every 3 months until disease progression. Computed tomography scans were obtained every 3 to 6 months and reviewed centrally. The primary endpoint was event-free survival (EFS). Among 103 patients treated with rituximab, 92 (54 relapsed/refractory and 38 previously untreated) received mitumprotimut-T/GM-CSF; median age was 53 years, 91% had stage III to IV disease, and 59% had failed earlier therapy. The premitumprotimut-T objective response rate was 47% (2 CRs, 41 PRs). During the mitumprotimut-T treatment phase, 16 patients converted to CR resulting in an overall objective response rate of 60% (18 CRs, 37 PRs). Median EFS was 15.2, 20.8, and 13.5 months for all, treatment-naive, and relapsed/refractory disease patients, respectively. Anti-Id cellular immune responses were detected in 13 of 18 (72%) patients and humoral immune responses in 17 of 83 (20%) patients. Adverse events were usually mild-to-moderate. The most common adverse event was injection site reactions. Mitumprotimut-T/GM-CSF-induced anti-Id cellular immune responses in most patients. The occurrence of late CRs and favorable EFS suggested a clinical benefit of active immunotherapy and led to a placebo-controlled phase 3 trial.

Purpose To compare the safety and activity of DN-101, a new high-dose oral formulation of calcitriol designed for cancer therapy, and docetaxel with placebo and docetaxel. Patients and Methods Patients with progressive metastatic androgen-independent prostate cancer and adequate organ function received weekly docetaxel 36 mg/m2 intravenously for 3 weeks of a 4-week cycle combined with either 45 μg DN-101 or placebo taken orally 1 day before docetaxel. The primary end point was prostate-specific antigen (PSA) response within 6 months of enrollment, defined as a 50% reduction confirmed at least 4 weeks later. Results Two hundred fifty patients were randomly assigned. Baseline characteristics were similar in both arms. Within 6 months, PSA responses were seen in 58% in DN-101 patients and 49% in placebo patients (P = .16). Overall, PSA response rates were 63% (DN-101) and 52% (placebo), P = .07. Patients in the DN-101 group had a hazard ratio for death of 0.67 (P = .04) in a multivariate analysis that included baseline hemoglobin and performance status. Median survival has not been reached for the DN-101 arm and is estimated to be 24.5 months using the hazard ratio, compared with 16.4 months for placebo. Grade 3/4 adverse events occurred in 58% of DN-101 patients and in 70% of placebo-treated patients (P = .07). Most common grade 3/4 toxicities for DN-101 versus placebo were neutropenia (10% v 8%), fatigue (8% v 16%), infection (8% v 13%), and hyperglycemia (6% v 12%). Conclusion This study suggests that DN-101 treatment was associated with improved survival, but this will require confirmation because survival was not a primary end point. The addition of weekly DN-101 did not increase the toxicity of weekly docetaxel.

Purpose To evaluate idiotype (Id) vaccination as a single agent in previously treated patients with indolent non-Hodgkin’s lymphoma. Patients and Methods Patients underwent biopsy for determination of their lymphoma-specific Id sequence. Recombinant Id protein was manufactured and covalently linked with keyhole limpet hemocyanin (KLH) to generate Id/KLH. Patients received Id/KLH 1 mg on day 1 subcutaneously, with granulocyte-macrophage colony-stimulating factor 250 μg on days 1 to 4, monthly for 6 months. Booster injections were administered until progression. Both clinical and immune responses were evaluated. Results Thirty-two previously treated patients received at least one injection of Id/KLH, and 31 were assessed for efficacy. Responses were observed in four patients (one complete response and three partial responses). Median time to onset of response was 5.9 months (range, 2.3 to 14.1 months). Median duration of response has not been reached but should be at least 19.4 months (range, 10.4 to 27.2+ months). Median time to progression is 13.5 months. The most common adverse events were mild to moderate injection site reactions. Six (67%) of nine patients tested demonstrated a cellular immune response, and four (20%) of 20 patients demonstrated an antibody response against their Id. Conclusion This trial demonstrates that Id/KLH alone can induce tumor regression and durable objective responses. Further study of Id/KLH is recommended in other settings where efficacy may be further enhanced as in first-line therapy or after cytoreductive therapy.

TPS389 Background: Recent data have shown that up to 25% of patients with advanced prostate cancer, including mCRPC, have a deleterious germline or somatic mutation in BRCA1, BRCA2, ATM, or another homologous recombination DNA repair gene. Such mutations can be used as a molecular marker to select patients for targeted treatment with poly(ADP-ribose) polymerase inhibitors (PARPis), which are lethal to cells with HRD. Treatment with PARPis has shown preliminary evidence of antitumor activity in patients with mCRPC and a mutation in a homologous recombination DNA repair gene (Mateo et al. N Engl J Med. 2015;373:1697-708). These data provide a compelling rationale for evaluating rucaparib, a potent inhibitor of PARP1, PARP2, and PARP3, in patients with mCRPC associated with HRD. Methods: TRITON3 (NCT02975934) is a randomized, phase 3 study evaluating rucaparib 600 mg BID vs physician’s choice of abiraterone, enzalutamide, or docetaxel in patients with mCRPC and a deleterious germline or somatic BRCA1, BRCA2, or ATM mutation (identified by prior local testing or central testing during screening). Patients must have progressed on androgen receptor signaling–directed therapy in the mCRPC setting; prior PARPi treatment or chemotherapy for mCRPC are exclusion criteria. Patients will be randomly assigned in a 2:1 ratio to either rucaparib or physician’s choice, with the possibility for cross over from the comparator treatment to rucaparib upon radiographic progression confirmed by independent radiology review. The primary endpoint is radiographic progression-free survival (modified RECIST v1.1/PCWG3 criteria) assessed by independent radiology review. Secondary endpoints include objective response rate, duration of response, patient-reported outcomes, overall survival, and safety. Pretreatment blood samples collected from all patients will enable development of a noninvasive plasma-based companion diagnostic to select patients who may benefit from rucaparib treatment. Patients (≈400) will be enrolled at > 100 sites worldwide. Clinical trial information: NCT02975934.

The objective of this study was to evaluate the potential for a pharmacokinetic (PK) drug-drug interaction (DDI) between trastuzumab and carboplatin and to evaluate the potential effect of trastuzumab on the electrocardiogram QT interval. Here, we report the results of the PK DDI assessment and an interim safety analysis. Patients with metastatic or locally advanced, inoperable, human epidermal growth factor receptor 2-positive cancer received docetaxel and carboplatin on cycle 1, day 1 and then on day 1 of each subsequent 3-weekly treatment cycle. Trastuzumab was administered by intravenous infusion, with an accelerated loading dose on cycle 1, day 2 and cycle 1, day 8, and then a maintenance dose on day 1 of each subsequent 3-weekly treatment cycle. Blood was collected at various time points to assess free (unbound) plasma carboplatin and serum trastuzumab PK. The study enrolled 59 patients. Carboplatin concentrations in the presence and absence of trastuzumab were similar, as demonstrated by the geometric mean ratios for PK parameters, which were close to 1.0 (no effect). The observed trastuzumab concentrations were similar to the values predicted by population PK modelling on the basis of a prediction-corrected visual predictive check, computed using the actual sampling time. In this interim safety analysis, 84.5% of patients had experienced adverse events of grade three or higher, the most common of which were hematologic and as expected. The results suggest that there is no clinically relevant PK DDI between carboplatin and trastuzumab. The safety profile of trastuzumab plus carboplatin and docetaxel was consistent with the known safety profile of this combination.

108 Background: Human epidermal growth factor 2 (HER2) is a potential strong tumor driver for breast (BC) and gastric cancer (GC) as well as other HER2 expressing tumors. Antibody-drug conjugates (ADC) provide wider therapeutic window by more efficient and specific drug delivery. DS-8201a is a HER2 targeting ADC of high drug to antibody ratio (7 to 8) with a novel topoisomerase I inhibitor. In preclinical studies, DS-8201a showed a broader antitumor spectrum than T-DM1, including efficacy against low HER2 expressing tumors. Current trial includes dose escalation (Part 1) and expansion (Part 2) focusing on HER2 expressing solid tumors (NCT02564900). Methods: Part 1 used a modified continuous reassessment method to identify the expansion dose in patients (pts) with BC or GC. Part 2 was designed to evaluate the safety and efficacy in 4 expansion cohorts: T-DM1 treated HER2+ BC, trastuzumab treated HER2+ GC, BC with low HER2 expressing and other HER2 expressing solid tumors. Adverse events (AEs), objective response rate (ORR) and durability of responses were assessed. Results: 89 pts were administered in total: 24 pts in Part 1 and 65 pts (BC, GC, colorectal, salivary and non-small cell lung cancer) in Part 2 with median prior therapies of 4. DS-8201a was administered up to 8.0 mg/kg in Part 1, and dose levels of 6.4 and 5.4 mg/kg IV every 3 weeks were chosen for Part 2. There was no dose limiting toxicity, and maximum tolerated dose was not reached in Part 1. The most common AEs in Part 1 and Part 2 were nausea (62%), anorexia (56%) and platelet count decreased (28%). 29% pts experienced ≥ Gr3 AEs (Gr3: 25% Gr4: 4%). The ORR and disease control rate (DCR: CR + PR + SD) are shown in the table. ORR and DCR were 40% and 90%, respectively in evaluable 73 pts including 14 low HER2 expression. One T-DM1 treated BC pt achieved CR. 4 PRs were achieved in pts with low HER2 expression. 63 pts in total are currently being treated. Median duration of treatment was ≥27 weeks in Part 1 and not reached in Part 2. Conclusions: DS-8201a was well tolerated and is remarkably active in heavily pretreated HER2 expressing cancers. Clinical trial information: NCT02564900. [Table: see text]

Cardiomyopathy is a major cause of morbidity and mortality. Ventricular conduction delay, as shown by prolonged deflections in the electrocardiogram caused by delayed ventricular contraction (wide QRS complex), is a common feature of cardiomyopathy and is associated with a poor prognosis. Although the G i -signaling pathway is up-regulated in certain cardiomyopathies, previous studies suggested this up-regulation was compensatory rather than a potential cause of the disease. Using the tetracycline transactivator system and a modified G i -coupled receptor (Ro1), we provide evidence that increased G i signaling in mice can result in a lethal cardiomyopathy associated with a wide QRS complex arrhythmia. Induced expression of Ro1 in adult mice resulted in a >90% mortality rate at 16 wk, whereas suppression of Ro1 expression after 8 wk protected mice from further mortality and allowed partial improvement in systolic function. Results of DNA-array analysis of over 6,000 genes from hearts expressing Ro1 are consistent with hyperactive G i signaling. DNA-array analysis also identified known markers of cardiomyopathy and hundreds of previously unknown potential diagnostic markers and therapeutic targets for this syndrome. Our system allows cardiomyopathy to be induced and reversed in adult mice, providing an unprecedented opportunity to dissect the role of G i signaling in causing cardiac pathology.

To control G protein signaling in vivo, we have modified G protein-coupled receptors to respond exclusively to synthetic small molecule agonists and not to their natural agonist(s). These engineered receptors are designated RASSLs (receptor activated solely by a synthetic ligand). A prototype RASSL (Ro1) based on the Gi-coupled K opioid receptor was expressed in transgenic mice under the control of the tetracycline transactivator (tet) system. Activation of Ro1 expressed in the heart decreased heart rate by up to 80%, an expected effect of increased Gi signaling. Maximal heart rate changes occurred in less than 1 min, demonstrating the speed of this inducible signaling system. This Ro1-mediated slowing of heart rate was also subject to desensitization, which lasted more than 24 h. Both the initial effect on heart rate and the desensitization occurred, even though Ro1 is derived from a human opioid receptor not normally involved in heart rate control. In addition, the tet system was used to induce Ro1 expression in hepatocytes and salivary gland, where Gi signaling is known to control physiologic events such as proliferation and secretion. These studies demonstrate that a RASSL can be inducibly expressed in several mouse tissues and used in vivo to activate G protein signaling in a controllable fashion.

190 Background: The optimal sequence and combination of life-extending anticancer therapies in mCRPC pts remains unknown. Sipuleucel-T (sip-T), an autologous cellular immunotherapy approved for the therapy of asymptomatic or minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC) pts, was evaluated in combination with abiraterone acetate and prednisone (abi) in the phase II STAMP trial (NCT01487863), with pts randomly assigned to receive CON sip-T + abi or SEQ sip-T followed by abi. The combination was well-tolerated and did not alter the immune response parameters that correlate with overall survival (OS) (Small Clin Can Res 2015). Here, we present long-term follow-up of clinical outcomes, including OS. Methods: mCRPC pts were randomized 1:1 to CON or SEQ therapy with sip-T and abi. Abi began 1 day after (CON) or at wk 10 (SEQ) after the first sip-T infusion and continued for 26 wk of therapy, after which continued abi therapy was permitted. Long-term clinical outcomes included OS, disease-specific death (DSS), progressive disease (PD), time to first anticancer intervention (tACI), and safety. Results: 69 pts were enrolled (35 CON; 34 SEQ). Median OS was 34.0 mo (95% CI, 24.4-not estimable [NE]; 30.0 mo CON; 34.2 mo SEQ; p = 0.921), and median time to DSS was not reached (CON vs SEQ; p = 0.733). Median time to PD was 17.3 mo (95% CI, 9.7–NE; 17.7 mo CON vs 13.9 mo SEQ; p = 0.914; consistent with higher rates of abi discontinuation due to PD in SEQ [26.5% vs 14.3% in CON]). tACI was similar between arms at 15.4 mo (95% CI, 11.0–19.9). No new safety signals were observed with the combination, and no discernable difference in clinical outcomes was observed with CON or SEQ treatments. Conclusions: Long-term follow-up data confirm that sip-T + CON or SEQ abi is well-tolerated, with no new safety signals. No clear differences were observed in clinical outcomes between arms, although the study was not powered to detect these differences. Future and more appropriately powered studies on the effect of sip-T + continuous abi for responding pts may provide further insights on the benefit of combination therapy. Clinical trial information: NCT01487863.

9036Background: Avelumab* is a fully human anti-PD-L1 IgG1 antibody under clinical investigation in multiple cancers. We report safety and clinical activity of avelumab as 1st-line therapy in patie...

Purpose Sipuleucel-T (APC8015) is an investigational immunotherapy product designed to stimulate T-cell immunity against prostatic acid phosphatase. A phase III study was undertaken to evaluate the safety and efficacy of sipuleucel-T in a placebo-controlled study. Patients and Methods A total of 127 patients with asymptomatic metastatic hormone refractory prostate cancer (HRPC) were randomly assigned in a 2:1 ratio to receive three infusions of sipuleucel-T (n = 82) or placebo (n = 45) every 2 weeks. On disease progression, placebo patients could receive APC8015F, a product made with frozen leukapheresis cells. Results Of the 127 patients, 115 patients had progressive disease at the time of data analysis, and all patients were followed for survival for 36 months. The median for time to disease progression (TTP) for sipuleucel-T was 11.7 weeks compared with 10.0 weeks for placebo (P = .052, log-rank; hazard ratio [HR], 1.45; 95%CI, 0.99 to 2.11). Median survival was 25.9 months for sipuleucel-T and 21.4 months for placebo (P = .01, log-rank; HR, 1.70; 95%CI, 1.13 to 2.56). Treatment remained a strong independent predictor of overall survival after adjusting for prognostic factors using a Cox multivariable regression model (P = .002, Wald test; HR, 2.12; 95%CI, 1.31 to 3.44). The median ratio of T-cell stimulation at 8 weeks to pretreatment was eight-fold higher in sipuleucel-T-treated patients (16.9 v 1.99; P < .001). Sipuleucel-T therapy was well tolerated. Conclusion While the improvement in the primary end point TTP did not achieve statistical significance, this study suggests that sipuleucel-T may provide a survival advantage to asymptomatic HRPC patients. Supportive studies are underway.

This phase 1 clinical trial was conducted to evaluate the safety and to determine the maximum tolerated dose (MTD) of the immunocytokine EMD 273066 huKS-IL2 and, secondarily, to assess its pharmacokinetics, immunogenic potential, and immunologic activity in patients with androgen-independent prostate cancer (n = 22). EMD 273066 was administered in 3-day cycles (separated by 4 weeks) of once-daily, 4-hour intravenous infusions at a dose determined by an escalation protocol (0.4, 0.7, 1.4, 2.8, 4.3, 6.4, or 8.5 mg/m/d). Approximately 2/3 of patients received a second cycle of treatment. The results show that the MTD of EMD 273066 [ie, one dose level below that producing dose-limiting toxicity (DLT) in at least 33% of patients in a dosing group] was 6.4 mg/m/d. EMD 273066 was generally well tolerated up to a dose of 4.3 mg/m/d. No DLTs, defined as drug-related toxicities >OR= Grade 3 occurring during the first treatment cycle, were observed among patients in the 0.4-, 0.7-, 1.4-, or 4.3-mg/m/d dosing groups. Four patients treated with 2.8, 6.4, or 8.5 mg/m/d EMD 273066 experienced DLTs. Titers of both antiimmunocytokine and anti-FcIL-2 antibody responses were observed after the first dose cycle and either decreased or remained stable during a second course of treatment. No hypersensitivity reactions were observed. EMD 273066 exhibited immunologic activity as demonstrated by increases in lymphocyte counts, natural killer cell number and specific activity, and antibody-dependent cellular cytotoxicity activity. On average, Cmax, which was dose-dependent, was achieved within 1 hour after infusion. Mean t(1/2) which was independent of dose, ranged from 4.0 to 6.7 hours across doses. A zero-compartment body model with one-order kinetics best described the concentration-time profiles. These data demonstrate that the novel immunocytokine EMD 273066 is well tolerated at doses above a level of observed systemic biologic activity in patients with androgen-independent prostate cancer.

Publisher Summary The diversity of G protein-coupled receptors (GPCRs) presents a challenge to understanding the connection between a single receptor signaling pathway and a specific physiological or pathological response. Receptors activated solely by synthetic ligands (RASSLs) offer control over the location, timing, and specificity of a G protein signal in vivo. These novel, reversible switches for G protein signaling have clarified the role of Gi signaling in cardiac physiology and are now being used to probe sensory transduction and complex neurobehavioral responses. This chapter summarizes the design of RASSLs and their first use in vivo. Existing RASSLs will allow study of the effects of Gi signaling in specific tissues under specific circumstances. New RASSLs can be developed by using many of the same principles used to develop the existing Gi-coupled RASSLs. The ideal RASSL activator should be a small molecule drug that is readily available from commercial sources. Its binding site should be well characterized. It must be highly specific for a single receptor subtype to minimize effects of the drug at non-RASSL receptors. Ideally, this could be a synthetic system in which the ligand would not activate endogenous receptors.

The functional and molecular diversity of G-protein-coupled receptors presents a significant challenge to understanding the connection between a single receptor signaling pathway and a specific physiological or pathological response. To gain control over the timing and specificity of a G-protein signal, receptors activated solely by synthetic ligands (RASSLs) have been developed. These engineered receptors no longer respond to endogenous peptides, but can still be activated by a specific small-molecule drug. Further control over the location of the signal can be achieved by using RASSLs in conjunction with tissue-specific expression systems in vivo. Existing RASSLs have clarified the role of G(i) signaling in cardiac physiology and are currently being used to study cardiomyopathy, muscle remodeling, sensory transduction and complex neurobehavioral responses.

Although increased Gi signaling has been associated with dilated cardiomyopathy in humans, its role is not clear. Our goal was to determine the effects of chronically increased Gi signaling on myocardial function. We studied transgenic mice that expressed a Gi-coupled receptor (Ro1) that was targeted to the heart and regulated by a tetracycline-controlled expression system. Ro1 expression for 8 wk resulted in abnormal contractions of right ventricular muscle strips in vitro. Ro1 expression reduced myocardial force by >60% (from 35 ± 3 to 13 ± 2 mN/mm2, P < 0.001). Nevertheless, sensitivity to extracellular Ca2+ was enhanced. The extracellular [Ca2+] resulting in half-maximal force was lower with Ro1 expression compared with control (0.41 ± 0.05 vs. 0.88 ± 0.05 mM, P < 0.001). Ro1 expression slowed both contraction and relaxation kinetics, increasing the twitch time to peak (143 ± 6 vs. 100 ± 4 ms in control, P < 0.001) and the time to half relaxation (124 ± 6 vs. 75 ± 6 ms in control, P < 0.001). Increased pacing frequency increased contractile force threefold in control myocardium ( P < 0.001) but caused no increase of force in Ro1-expressing myocardium. When stimulation was interrupted with rests, postrest force increased in control myocardium, but there was postrest decay of force in Ro1-expressing myocardium. These results suggest that defects in contractility mediated by Gi signaling may contribute to the development of dilated cardiomyopathy.

5047^ Background: Sipuleucel-T and AA + P are FDA-approved for asymptomatic/minimally symptomatic mCRPC. Suppression of the androgen axis can be immunostimulatory and AA suppresses circulating androgen levels; AA plus sipuleucel-T may therefore be synergistic. However P used with AA, which may be immunosuppressive, has not been studied with concurrent sipuleucelET and could impair sipuleucel-T production and/or immunologic response. P11-3 (NCT01487863) is the 1st study to evaluate the combination of sipuleucel-T and AA + P Methods: Patients (pts) with asymptomatic/minimally symptomatic mCRPC were randomized (1:1) to sipuleucel-T (3 infusions at approx 2-wk intervals) with up to 26 wks of AA + P (AA 1000mg QD + P 5mg BID) starting 1 day after the 1st sipuleucel-T infusion (concurrent, arm A) or at 10 wks following the 1st sipuleucel-T infusion (sequential, arm B). Endpoints included the effect of AA + P on product (sipuleucel-T) characteristics eg antigen presenting cell (APC) activation, measured as CD54 upregulation (primary endpoint), APC (measured as CD54+ cells) and total nucleated cell (TNC) counts, as well as safety and immunologic responses. Results: 31 pts in arm A and 32 pts in arm B completed sipuleucel-T treatment by the interim analysis (Nov 2012). Baseline characteristics were similar in the 2 arms. 60/63 pts received all 3 infusions of sipuleucel-T. No significant differences in median cumulative APC activation, APC count or TNC count were seen between the arms. Increased CD54 upregulation with the 2nd and 3rd treatments were indicative of a prime boost effect in both arms. Similar profiles of antigen-specific humoral and cellular immune responses were generated with no difference in magnitude of response between the arms (p>0.05). The incidence of adverse events (AEs) and serious AEs was similar in both arms. Conclusions: These data suggest sipuleucel-T can be successfully manufactured during concurrent AA + P. Product potency and prime boost effect were similar to sipuleucel-T alone. Immune responses and AEs were similar in both arms. It is not known if sipuleucel-T will provide similar efficacy with concurrent or sequential AA + P. Clinical trial information: NCT01487863.

114 Background: Sipuleucel-T and AA are both FDA approved for mCRPC. Given that androgen deprivation therapy is immunostimulatory, increased suppression of the androgen axis with AA could provide synergy in combination with sipuleucel-T; however, AA is given with prednisone (P), which may be immunosuppressive. In order to evaluate the impact of concurrent AA + P on product characteristics, a study of sipuleucel-T with concurrent or sequential AA + P was undertaken. Methods: Pts aged ≥18 yrs with asymptomatic or minimally symptomatic mCRPC, and ECOG PS 0/1 were randomized (1:1) to sipuleucel-T (3 infusions at approx 2-week intervals) with up to 26 weeks of AA + P (AA 1000mg QD + P 5mg BID) starting 1 day after the first sipuleucel-T infusion (concurrent arm) or at week 10 (sequential arm). The primary endpoint was cumulative CD54 upregulation (measure of antigen presenting cell activation); secondary and tertiary endpoints included CD54+cell and total nucleated cell (TNC) counts (measures of product potency), safety and efficacy. Results: 29 pts have been enrolled. 16 pts in the concurrent arm (A) and 13 pts in the sequential arm (B) have completed sipuleucel-T treatment at the time of this interim analysis (7 Sept 2012). 27/29 pts received all 3 infusions of sipuleucel-T; 2 pts (both arm A) received only 1 infusion due to insufficient TNC count (n=1) and disease progression 8 days after randomization (n=1). No significant differences in median cumulative CD54 upregulation (31.6 vs 36.6) and CD54+ count (1.9 vs 2.1 x109) were observed between arms A and B, respectively. Increased CD54 upregulation with the 2nd and 3rd treatments were indicative of a prime boost effect in both arms. Similarly, the TNC profile over time was similar for both arms. The overall incidence of adverse events (AEs) was similar in arms A (81%) and B (77%). Common all-grade AEs included muscle spasms (31% vs 23%), oral paresthesia (19% vs 31%), chills (31% vs 8%) and cough (19% vs 15%). Conclusions: These data suggest that sipuleucel-T can be manufactured during treatment with AA + P with product potency and prime boost similar to that of sipuleucel-T alone. Clinical trial information: NCT01487863.

TPS4697 Background: ARN-509 is a novel small molecule androgen signaling inhibitor that impairs AR nuclear translocation and binding to DNA, inhibiting tumor growth and promoting apoptosis, with no partial agonist activity. Preclinical data suggests that the maximal therapeutic index of ARN-509 can be achieved at low steady state plasma levels with minimal toxicity (Clegg et al, 2012). Enrollment in the Phase 1 dose escalation study of ARN-509 in patients with progressive CRPC with and without prior chemotherapy was completed in January 2012. The recommended Phase 2 dose of 240 mg was determined based on safety, PSA kinetics, and pharmacokinetic and pharmacodynamic analysis (Rathkopf et al, GU ASCO, 2012). Methods: The primary objective of this Phase 2 study is to determine the PSA response at 12 weeks according to Prostate Cancer Working Group 2 (PCWG2) Criteria (Scher et al, 2008). Three expansion cohorts will enroll a total of 80-90 patients for treatment with 240 mg continuous oral ARN-509 daily. These cohorts include: 1) non-metastatic treatment-naïve CRPC (50 patients); 2) chemotherapy-naïve metastatic (m) CRPC (20 patients); and 3) chemotherapy-naïve, post abiraterone mCRPC (10-20 patients). The effect of food on the PK of ARN-509 and the effect of ARN-509 on ventricular repolarization will also be evaluated. Phase 2 enrollment is ongoing. DOD/PCF PCCTC trial sponsored by Aragon Pharmaceuticals. NCT01171898.

4550 Background: Sipuleucel-T is an investigational autologous active cellular immunotherapy for treatment of metastatic castration resistant prostate cancer. Reported here is an analysis of the ho...

Background: We have previously reported results from a Phase 2 trial in which both treatment naïve (TN) and relapsed/refractory (R/R) pts with stable disease (SD) or a clinical response (PR or CR/CRu) following 4 weekly doses of rituximab received mitumprotimut-T active immunotherapy (Koc et al, Blood2006; 108: #691). We report here 4-year follow up of conversion of pts into complete remission (CR/CRu) and an assessment of the DUR in this population. Treatment: Pts received rituximab (375mg/m2 iv weekly x 4) and those with ≥SD assessed at Week 11 received mitumprotimut-T, 1 mg sq every month (mo) x 6 starting on Week 12 along with Leukine (sargramostim, GM-CSF), 250 mcg, sq on Days 1–4. Pts continued to receive booster injections on a reduced schedule (every 2 mos x 6, then quarterly) until disease progression. Radiological scans were performed every 3 mos for the first 2 years then every 6 mos, and reviewed centrally. Objective response and progression were assessed using modified IWG criteria. Results: 89 pts (54 RR, 35 TN) had ≥SD following rituximab received mitumprotimut-T + Leukine. Two pts (RR) achieved a CR following rituximab and prior to receiving mitumprotimut-T. As shown in Fig. 1, an additional 16 pts (9 TN, 7 RR) converted to CR/CRu over the next 31 mos. At a median follow-up of 42 mos, only 6 (3 TN, 3 RR) of the 18 CR pts have relapsed (Fig. 2). Discussion: Long-term follow-up has shown a continuing conversion of pts into CR occurring as late as 31 mos. These data suggest clinical activity of mitumprotimut-T in these pts as determined by the increasing CR rate and the durability of this response. These data are of particular interest since a blinded interim analysis of best response in an ongoing controlled Phase 3 study of single agent rituximab vs. rituximab followed by mitumprotimut-T showed 47% of pts in this study to be in CR/CRu with 12–18 mos of follow-up (Freedman et al, Blood2006; 108: #2756). Figure Figure Figure Figure

Background: We report here PFS with a 4-year follow-up of previously reported results from a Ph 2 trial in which both treatment-naive (TN) and relapsed/refractory (R/R) pts with FL with stable disease (SD) or a clinical response (PR or CR/CRu) following 4 weekly doses of rituximab received mitumprotimut-T active immunotherapy (Koc et al, Blood, 2006; 108: #691). Treatment: Pts received rituximab (375 mg/m2 i.v. weekly × 4) and those with stable or responding disease assessed at Week 11 received mitumprotimut-T (1 mg sq monthly × 6) starting on Week 12 along with Leukine® (sargramostim, GM-CSF, 250 mcg, sq) on days 1-4. Pts continued to receive booster injections on a reduced schedule (every 2 months (mos) × 6, then quarterly) until disease progression. Radiological scans were performed every 3 mos for the first 2 years on study, then every 6 mos thereafter and reviewed centrally. Objective response and disease progression were assessed using modified IWG criteria. Results: 89 pts had ≥SD following rituximab and received mitumprotimut-T + Leukine, 54 R/R and 35 TN. There were 2 CRs and 40 PRs following rituximab for a pre mitumprotimut-T objective response rate (ORR) of 47%. The overall response for the combined treatment was 63% (18 CR, 38 PR). During the mitumprotimut-T treatment phase, 16 pts (9 TN, 7 RR) converted to CR/CRu. The following table presents PFS for all pts and patient subsets. Conclusion: These data show that 43% of all rituximab responders and 51% of TN rituximab responders remain in remission with 42 mos follow up. These results appear favorable when compared to published results of single-agent rituximab studies in pts with TN FL, where the reported 3-yr PFS are ∼20%, and suggest a clinical benefit to adding mitumprotimut-T to rituximab therapy. This hypothesis is being tested in an ongoing Ph 3 study of rituximab single agent vs. rituximab followed by mitumprotimut-T + GM-CSF. A total of 349 pts have been randomized and 78% are TN. An interim blinded analysis of response in the first 226 randomized pts showed an ORR of 70% with 47% of pts in CR/CRu (Freedman et al, Blood 2006; 108:#2756). | | Subjects Progression-Free at: | |:-------------------------------:| ----------------------------- | ------ | | Group | n | 12 mos | 24 mos | 36 mos | 42 mos | | All Efficacy-Evaluable Subjects | 89 | 61% | 38% | 31% | 29% | | Relapsed/Refractory Subjects | 54 | 57% | 31% | 22% | 19% | | Treatment-Naive Subjects | 35 | 67% | 48% | 44% | 44% | | All rituximab Responders | 43 | 70% | 50% | 43% | 43% | | Relapsed/Refractory Responders | 19 | 63% | 41% | 33% | 33% | | Treatment-Naive Responders | 24 | 75% | 57% | 51% | 51%

Background: Studies of Id/KLH immunotherapy in treatment naïve (TN) fNHL pts following first remission from chemotherapy have demonstrated a prolonged duration of remission. We expanded this approach in a PhII trial to include TN and relapsed/refractory (R/R) pts with stable disease (SD) or PR or CR/CRu following 4 wkly doses of rituximab. We report here long term follow up of RRI, defined as the % of pts who converted from SD to PR or PR to CR/CRu following initiation of Id/KLH treatment, and analysis of disease progression. Treatment: Pts received rituximab (375mg/m2 i.v. wkly x 4 during wk1–4) and those with stable or responsive disease received Id/KLH (1 mg s.q. mo x 6) starting on wk 12 along with GM-CSF (250 mcg, s.q.) on days 1–4. Pts continued to receive booster injections on a reduced schedule until disease progression. Radiological scans, performed every 3 mos, were reviewed centrally. Disease progression and response were assessed using modified Cheson criteria. This data analysis was performed 32 mo from end of enrollment. Results: 103 pts were enrolled and received rituximab; 89 pts had ≥SD and received Id/KLH + GM-CSF of whom, 54 were R/R, and 35 were TN. The overall response rate (ORR) was 47% (42/89) at mo 3. After the initiation of Id/KLH dosing, ORR improved to 63% (56/89). In RRI pts, median time to best response was 9.1 mos from start of rituximab treatment (5.2 – 29.6 mos). 12 of 39 PR pts (31%) converted to CR/Cru. 14 of 43 SD pts (33%) converted to PR. Pt Groups # of Pts % Prog Free Median TTP Est by K-M (mo) Pts w/RRI 26 69% 37.9 TN rituximab responders 23 70% Not Reached (NR) Rituximab responders (All) 42 60% NR Non Responders (All) 47 36% 14.9 All Pts 89 47% 18.2 TN Pts (All) 35 66% NR Relapsed Pts (All) 54 37% 16.8 Conclusion: RRI following FavId is seen in nearly one third of pts. The magnitude of this improvement, the number of conversions to CR/CRu and median time to best response (9 mo and as late as 29.6 mo) suggests this is likely to be a FavId effect rather than late response to rituximab. Responders and TN pts show more durable responses compared to previously published data for rituximab therapy. FavId may also confer a benefit for nonresponders and R/R pts relative to rituximab alone. To confirm benefit of FavId following rituximab induction, a placebo controlled PhIII study was initiated; it completed enrollment in Jan 06. RRI data from this study is expected to be available in Nov 06.

Background: Idiotype vaccination (Id/KLH) is a promising approach to the treatment of patients (pts) with B-cell malignancies. Our experience suggests that Id/KLH may function best in pts with lower tumor burden who are less heavily pretreated. We have conducted a phase II trial of Id/KLH following cytoreduction with rituximab in patients with treatment naive (TN) or relapsed/refractory (R/R) follicular NHL (FL). Treatment: Pts received rituximab, 375mg/m2, IV, weekly x 4, wk 1–4. Pts with without progression received Id/KLH, 1 mg, SQ, monthly x 6, starting on wk 12, with GM-CSF, 250 mcg, SQ, on days 1–4. Pts could receive booster Id/KLH on a reduced schedule until disease progression. Results: One hundred three pts were enrolled and received rituximab; 89 pts received Id/KLH. The last patient was registered in Dec 2003. Among these 89 evaluable pts, 55 were R/R to prior therapy, and 34 were TN. The overall response rate (ORR) following rituximab (assessed at month 3 based on a centralized read of CT scans) was 49% (44/89). Following Id/KLH, the ORR improved to 64% (57/89). The median time for improved response following initiation of Id/KLH treatment was 6.6 months (range 5.8 – 23.4 months) which was consistent with the time required to demonstrate an immune response in those pts tested. Prognostic factors for time to tumor progression (TTP) were evaluated and demonstrated a significant negative relationship for liver involvement (hazard ratio; HR = 9.3, p=0.0017) and 3 or more prior regimens (HR=4.7, p=0.0035). Median TTP has not been reached in the TN group (N=34) and in pts who relapsed after prior chemotherapy (N=26), with an actuarial 18 month progression free survival rate of 69% and 70%, respectively. The group of pts who would be eligible for the ongoing phase 3 randomized registration study (N=71) of rituximab followed by Id/KLH have also not reached median TTP. T-cell responses to both Id and KLH were observed in 80% and 86% of pts respectively (N=15) and were seen after a median of 2 doses of Id/KLH. Likewise, antibody responses to Id and KLH were seen in 13% and 69% respectively (N=23) and developed after a median of 5 to 6 doses of Id/KLH. Conclusion: Id/KLH, administered following rituximab to pts with FL, appears to result in an increase in the response rate and TTP compared to that reported for rituximab alone. We also observed a high rate of cellular immunity against idiotype following Id/KLH. These data support the design of an ongoing PIII clinical study of Id/KLH following rituximab which excluded pts with poor prognostic indicators.

2510 Background: Infusion of activated & expanded autologous T lymphocytes (Xcellerated T Cells [XTC]) leads to reduction in lymphadenopathy and splenomegaly in chronic lymphocytic leukemia (Castro...

Background: Id/KLH vaccine (FavId) administered as a single agent has been associated with tumor regressions in patients with relapsed/refractory (RR) FL. B-cell depletion has been demonstrated to augment the T-cell immune response to subsequent vaccine administration in mice (Qin 1998 Nat Med 4:627). Objective: To evaluate the efficacy and safety of Id-KLH administered during the period of rituximab induced B-cell depletion. Eligibility: FL pts who were: treatment naïve (TN); RR following chemotherapy; or relapsed following rituximab. Treatment: Following rituximab (375mg/m2 i.v. weekly x 4) pts received Id-KLH (1 mg s.q. monthly x 6) starting on week 12. GM-CSF, 250 mcg, was administered s.q. at the Id-KLH injection site on days 1–4. Pts could continue Id-KLH until progression. Results: 103 pts received rituximab. Response to rituximab at month 3 was 35% (3-CR; 33-PR). Eleven (11) pts were PD following rituximab (11%). Id/KLH could not be made for 4 pts (4%). Eighty-eight (88) pts were begun on Id-KLH. Among the 45 RR pts, 32 (72%) have not progressed at a median follow-up of 12 months compared with 40% of historical control pts treated with rituximab alone (Witzig 2002 JCO 20:2453). Among the 43 TN pts, 82% have not progressed after a median follow-up of 9 months. RRI (SD to PR, PR to CR after month 3) was observed in 21 pts (12-SD to PR; 9-PR to CR). Robust T-cell responses to both Id and KLH were observed (3 of 3 pts tested). Anti-KLH antibody responses were generally not seen until B-cell recovery. The most frequent adverse event was an injection site reaction. A flu-like syndrome was also observed consistent with GM-CSF administration. Conclusion: Id/KLH vaccine (FavId), administered to pts with FL during a period of B-cell depletion induced by rituximab, can result in an anti-Id T-cell response, and appears to result in an RRI and an increased TTP compared to historical controls. A randomized, double-blind, placebo-controlled, Phase 3 trial of rituximab + FavId has been initiated.

Background: T cells can be activated and expanded ex vivo using the Xcellerate™ Process, in which peripheral blood mononuclear cells (PBMC) are incubated with anti-CD3 and anti-CD28 antibody-coated magnetic beads (Xcyte™-Dynabeads®). In an ongoing trial of Xcellerated T Cells in subjects with chronic lymphocytic leukemia, marked and sustained reductions in lymphadenopathy and splenomegaly were observed (Wierda et al., ASCO 2004). Increases in neutrophil, platelet and NK cell counts were also documented. This study is designed to determine if similar effects can be observed in subjects with indolent non-Hodgkin’s lymphoma (NHL). Methods: Subjects must have indolent NHL (follicular, small lymphocytic, marginal zone, or mantle cell lymphoma), have relapsed or refractory disease, and have received at least 1 but not more than 4 prior treatment regimens. PBMC are collected by leukapheresis for the Xcellerate Process, and subjects subsequently receive two infusions of 20–60 x 109 Xcellerated T Cells separated by 6–8 weeks. Approximately 40 subjects will be treated. Results: Seven subjects have been enrolled and Xcellerated T Cells have been manufactured in 5 subjects to date. T cells expanded 181.8 ± 88.5 fold and the final product was >99.0 ± 0.0% T cells (mean + SD). One subject with small lymphocytic lymphoma has been treated with two infusions of 38.6 x 109 Xcellerated T Cells. There have been no serious adverse events to date. Following the first treatment, the lymphocyte count increased from 1.8 x 109/L to 2.9 x 109/L on Day 28. The neutrophil count also increased from 2.9 x 109/L to 5.5 x 109/L six weeks following infusion. The subject had a significant reduction in cervical lymphadenopathy and a slight decrease in bulky mesenteric lymphadenopathy six weeks following the first infusion. Conclusions: Xcellerated T Cells can be manufactured in subjects with indolent NHL. Treatment leads to significant increases in T cell and neutrophil counts. Preliminary data suggest a reduction in peripheral lymphadenopathy. Data on additional subjects will be presented.

2520 Background: Active immunotherapy of FL is a promising therapeutic strategy. Anti-idiotype (Id) antibody and T-cell responses to Id-KLH have been correlated with responses in patients with FL. In a phase II trial, we evaluated the efficacy of Id-KLH vaccination in patients with FL, after cytoreduction with rituximab and during B-lymphopenia. Anti-Id responses were measured and the TTP was compared to historical data for rituximab alone. Methods: Pts with gr 1,2 FL who were treatment naive; relapsed/refractory to chemo or relapsed after rituximab were eligible. Rituximab (375mg/m2 weekly x4) was followed by response assessment at wk10. Pts with at least SD (CR/PR/SD) started Id-KLH (1 mg s.q. monthly x 6) 12 wks after the first dose of rituximab. GM-CSF 250 mcg was given s.q. at the Id-KLH injection site on days 1–4. Pts with at least SD after 6 doses of Id-KLH could continue receiving the immunotherapy until progression. 123 pts were biopsied and 95 were eligible. Prior trerapy (in 60 of 95) was chemo...

037 A Critical Period of Vulnerability to Hyperactive Gq Signaling Revealed by Inducible and Heart-Specific Expression of Gq* in Transgenic Mice Nathalie Cotte, 1 Charles H. Redfern, 1'2 Peter Mikus, 1 Nathan Salomonis, 1 Michael Y. Degtyarev] Peter S. Coward, 1 Andrew Kwa, 1 Tetsuo Shioi, 4 Nila Shah, 5 Tim McKinsey, 3 Eric Olson, s Seigo Izumo, a Janet Wartington, s Anthony J. Baker, 2 Brace R. Conklin~'2; 1Gladstone Institute of Cardiovascular Disease, Gladstone Institute of Neurological Disease, 2Department of Medicine, University of California, San Francisco, CA, 3Hamon Center for Basic Research in Cancer, University of Texas Southwestern Medical Center, Dallas, TX, 4Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, SAffymetrix Inc, Santa Clara, CA

An in vitro test of cell sensitivity to drugs that indicates in vivo response is an important need in cancer therapy and cancer drug development. Toward this end, we previously developed a collagen gel-supported culture system for growth of human tumors. This three-dimensional culture system is general and grows tumors at high frequency directly from surgery or biopsy that maintain important in vivo properties in vitro, including tissue architecture. We report here that with autoradiographic techniques measuring cellular DNA synthesis the drug responses of individual cells within the tissue structure of in vitro-grown tumors can be determined. Twenty tumor classes, including all the major ones, have been measured in toto at greater than 50% frequency. Quantitative and qualitative results show increasing cell kill with rising cytotoxic drug concentration, differential drug sensitivities of multiple cell types within individual cultured tumors, differential sensitivities of a series of tumors of the same histopathological classification to a single drug, differential sensitivities of individual tumors to a series of drugs, and sensitivity patterns of various tumor types similar to the sensitivities found in vivo. Therefore, the results indicate that potentially important therapeutic data can be obtained from tumor specimens growing in vitro for the individual cancer patient as well as for rational and relevant screening for new agents active against human solid tumors.