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Background: The SAKK 22/99 is a phase III randomized clinical trial launched by the Swiss Group for Clinical Cancer Research and the European Institute of Oncology in Milan in 99 for women with HER2-positive advanced breast cancer (ABC). 175 patients were randomized 1:1 from Sept 99 to Jan 2013 to receive first-line trastuzumab (T) alone followed at disease progression by the combination with chemo (Arm A) vs the upfront combination of T and chemo (Arm B). The results were published in 2017 (O. Pagani et al Ann Onc 28: 305–312, 2017). The outcome was similar for sequential T-chemo or upfront combination The patients’ treatment and FU continued until March 2022 and we now report the safety data after 135.2 months of median FU. Patients and methods: at the time of study termination 1 patient with SD was still receiving T alone in the study and T was continued after trial closure. The safety analyses include 86 pts allocated to arm A and 88 to arm B. 1 pt did not receive any trial treatment and was excluded from this analyses. 19 of the 86 patients in arm A stopped trial treatment after T alone, 67 continued with T+ chemo. Baseline characteristics were well balanced and are summarized in Table 1. Treatment The T loading dose of 4 mg/kg/iv was followed by 2 mg/kg/iv weekly. In the 1st-line population (84) chemo was weekly paclitaxel (90 mg/m2/iv-3/4 weeks). After amendment 1 chemo was at investigator’s choice (taxanes, vinorelbine, platin) according to label indications and could be stopped after 24 weeks (6–8 cycles) in responding patients or after unacceptable toxicity. Results: 7 patients in arm A (8%) and 11 in arm B (13%) stopped trial treatment due to toxicities (Fisher’s exact test, p=0.46). 3 of the 7 patients in arm A stopped under T alone and 4 under T+chemo (all paclitaxel weekly) Treatment durations of these 7 and 11 patients were 7.7 months (range 0.5 – 49) in arm A and 5.5 months (range 0.6 – 31 months) in arm B, respectively. Cardiovascular toxicities: The most common toxicities were thromboembolic events, blood pressure disorders and arrhythmia. 6 patients (7%) in arm A and 10 (11%) in arm B had cardiac events (Fisher’s exact test, p=0.43). G1-3 toxicities occurred in 2 (2%), 2 (2%) and 2 (2%) patients of arm A and in 5 (7%), 2 (2%) and 3 (3%) of arm B. We observed no grade 4 events. Split by treatment phase in arm A, G1-3 toxicities were seen in in 1 (1%), 2 (2%) and 1 (1%) patient under T alone (N=86) and in 1 (1%), 0 (0%) and 2 (3%) under T+chemo (N=67). LVEF-decline: 78 patients in arm A and 74 in arm B had sequential LVEF measurements. A decline ≥ 10% was found in 35 patients (45%) in arm A and in 20 (27%) in arm B (Fisher’s exact test, p=0.028). Among the 35 patients in arm A, 12 had the decline under T alone, 14 under T+chemo, and 9 under both T alone and T+chemo. A decline ≥ 20% was found in 10 patients (13%) in arm A and in 3 (4%) in arm B (Fisher’s exact test, p=0.08). Among the 10 patients in arm A, 7 had the decline under T alone, 3 under T+chemo. Sensory neuropathy 43 patients (50%) in arm A and 48 (54%) in arm B had neuropathy (Fisher’s exact test, p=0.65). G1-3 toxicity in arm A was developed by 26 (30%), 11 (13%) and 6 (7%) patients, respectively; in arm B 30 (34%), 12 (14%) and 6 (7%). No grades 4 events occurred. Conclusion: After more than 11 years of follow-up, no relevant toxicities were found in these patients receiving T for ABC. In particular, the incidence and grade of cardiac toxicity was low. The decline in LVEF was numerically higher in the arm A and in particular in the T alone group, but was not clinically relevant. Our data potentially suggest that T+chemo followed by T maintenance could have less cardiotoxicity than T followed by T+chemo. The possible causes for the difference in LVEF decline between the two arms are unclear, but could be related to treatment duration. The women in Arm A shows a trend to longer therapy: Median treatment duration (months) in Arm A was 7.92 (0.46 - 135.98) vs 6.62 (0.56 - 71.28) in Arm B. This long-term analysis confirms the favorable safety and good tolerability of the reported regimes. Table 2: Treatment duration Citation Format: Manuela Rabaglio, Daniel Dietrich, Bernhard Scheibe, Thomas Ruhstaller, Franco Nole, Serenella Eppenberger, Christian Oehlschlegel, Dagmar Hess, Christoph Mamot, Elisabetta Munzone, Bernhard Pestalozzi, Stefan Aebi, Marcus Vetter, Beat Thuerlimann, Roger von Moos, Khalil Zaman, Olivia Pagani. Safety analysis after 11 years of follow-up of the randomized phase III trial SAKK22/99: upfront chemotherapy in advanced HER2 positive breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-25.

In advanced HER2+ breast cancer the impact of combining Trastuzumab (T) and chemotherapy (chemo) versus T alone followed by the addition of chemo at disease progression has not been properly studied. Study design The trial compared efficacy, toxicity and quality of life of sequential administration of T followed, at progression, by combination with chemo (T>TChemo) versus the upfront combination of T and chemo (TChemo) in patients with HER2+ advanced breast cancer. Materials and methods Eligibility: measurable/evaluable HER2+ advanced disease; ≤2 previous chemo; ECOG performance status The estimated median TTP-TChemo in the control arm (TChemo) was 5-6 months. A 3 months’ increase in the experimental T>TChemo arm was considered meaningful. The chemo backbone was at investigator’s choice (taxanes, vinorelbine, cisplatin) and could be stopped after 6 cycles in responding patients. T was continued until progression. Treatment after progression under TChemo was by investigators’ decision. Patients’ characteristics From Sept 1999–Jan 2013, 175 patients were enrolled. The trial was stopped prematurely due to insufficient accrual. Baseline characteristics were well balanced between arms: median age 55 years (32–79), ER and/or progesterone receptor positive 63%, ≥2 disease sites 91%, dominant bone 36% or dominant visceral disease 66%, 1stline therapy 72%. Results At the cutoff date (May 2014) 173 patients were evaluable: median follow up 77.7 months, 29 patients (17%) censored when receiving, at chemo stop, off-protocol treatment before progression (maintenance metronomic chemotherapy or endocrine therapy), 11 patients (6%) had no event at the end of follow-up. TTP-TChemo was longer than expected in both arms (12.7 months T>TChemo, 10.3 months TChemo) and not significantly different (HR=0.7; 95% CI, 0.5–1.0; p=0.08). In the T>TChemo arm, median TTP before introduction of chemo was 3.7 months (95% CI 2.3–5.1). Overall survival was not significantly different, 35.6 months versus 36.3 months (HR=0.9; 95% CI, 0.6–1.3; p=0.50). Toxicity was mainly chemo related, consistent with the chosen regimen. Cardiac toxicity was mild (no grade 4, 1 cardiac failure NYHA III in the T>TChemo arm). No treatment-related death was reported. Conclusions The sequential administration of T and chemo showed a non-significant trend to longer TTP-TChemo compared to upfront combination therapy: it allows to delay chemo use and its toxicity and seems a reasonable approach. TTP-TChemo was better than projected in both arms. The sequential strategy with double anti-HER2 targeting (T/Pertuzumab) is now under evaluation in 1st-line patients in the SAKK 22/10 trial. Citation Format: Olivia Pagani, Dirk Klingbiel, Thomas Ruhstaller, Franco Nolè, Serenella Eppenberger, Christian Oehlschlegel, Jürg Bernhard, Peter Brauchli, Dagmar Hess, Christoph Mamot, Elisabetta Munzone, Bernhard Pestalozzi, Manuela Rabaglio, Karin Ribi, Christoph Rochlitz, Karin Rothgiesser, Beat Thürlimann, Roger von Moos, Khalil Zaman, Aron Goldhirsch. Advanced HER2 positive breast cancer treated with trastuzumab: Is combination with chemotherapy always needed? Randomized phase III trial SAKK 22/99 [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-15-11.

Background: Mitogen-activated protein kinase (MAPK) pathway is one of the major signaling cascades responsible for resistance to endocrine therapy by promoting estrogen-independent tumor growth. Sel is a potent selective MEK1 and MEK2 inhibitor active in melanoma, ovarian, colorectal and non-small cell lung cancers. Fulvestrant (Fulv) is a pure antagonist and downregulator of nuclear and membranous/cytoplasmic estrogen receptor (ER). The combination of a MEK inhibitor with Fulv may improve the efficacy of endocrine therapy by reversing and/or delaying the development of resistance. Material and methods: Postmenopausal patients with advanced stage endocrine-sensitive (ER and/or progesterone receptors ≥10%) breast cancer progressing after aromatase inhibitor were randomized to intramuscular Fulv 500 mg (day 1, 15, 29 then every 28±2 days) combined with either oral Sel 75 mg bid or placebo bid. The primary endpoint was disease control (DC = CR + PR + stable disease ≥ 24 weeks). Sample size was calculated according to Simon's optimal two-stage design. A DC rate of ≤30% in the experimental arm was considered as not interesting and ≥50% as promising. Using a 5% significance level and 80% power, 46 patients were needed, 15 in the first stage and 31 in the second stage. In the control arm a total of 43 patients was needed to estimate the DC rate with a confidence interval width of ≤30%. An interim efficacy analysis was planned according to Herndon's modification of Simon's optimal two-stage design. Results: Forty-six patients were included (23 per arm). Seventy percent of the patients in the experimental arm had measurable disease and 57% had visceral metastases. Patients had received AI in the metastatic (61%) or adjuvant (39%) setting (65% had also prior tamoxifen). Five of 23 patients (22%) reached DC in the experimental arm. DC rate being inferior to the statistical hypothesis the study was terminated following the planned interim efficacy analysis. Most frequently reported adverse events (AEs) were rash and other skin disorders, fatigue, diarrhea, hypertension, edema, nausea/vomiting, anorexia, musculoskeletal symptoms, dry mouth and paresthesia. AEs were mainly grade 1 and 2 (NCI-CTCAE v4.0), but they often precluded treatment continuation. Most of the first patients exposed to Sel 75 mg bid stopped treatment before disease progression. Seven of the 23 patients (30%) were exposed to Sel for only 1 cycle or less. After an amendment facilitating early dose-reduction, patients decreasing to 75 mg qd had much better tolerance and improved treatment duration with Sel. Four out of the 5 patients reaching DC had Sel dose reduction. Conclusion: The combination of Sel with fulvestrant did not reach the prespecified disease control rate. The toxicity of Sel 75 mg bid led to frequent treatment interruptions/dose reductions and poor exposure to the drug. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-16-19.

Background: The anti-angiogenic drug, bevacizumab (Bv), is currently used in the treatment of different malignancies including breast cancer. Many angiogenesis-associated molecules are found in the circulation of cancer patients. Until now, there are no prognostic or predictive factors identified in breast cancer patients treated with Bv. We present here the first results of the prospective monitoring of 6 angiogenesis-related molecules in the peripheral blood of breast cancer patients treated with a combination of Bv and PLD in the phase II trial, SAKK 24/06. Methods: Patients were treated with PLD (20 mg/m2) and Bv (10 mg/kg) on days 1 and 15 of each 4-week cycle for a maximum of 6 cycles, followed by Bv monotherapy maintenance (10 mg/m2 q2 weeks) until progression or severe toxicity. Plasma and serum samples were collected at baseline, after 2 months of therapy, then every 3 months and at treatment discontinuation. Enzyme-linked immunosorbent assays (Quantikine, R&D Systems and Reliatech) were used to measure the expression levels of human vascular endothelial growth factor (hVEGF), placental growth factor (hPlGF), matrix metalloproteinase 9 (hMMP9) and soluble VEGF receptors hsVEGFR-1, hsVEGFR-2 and hsVEGFR-3. The log-transformed data (to reduce the skewness) for each marker was analyzed using an analysis of variance (ANOVA) model to determine if there was a difference between the mean of the subgroups of interest (where α = 0.05). The untransformed data was also analyzed in the same manner as a “sensitivity” check. Results: 132 blood samples were collected in 41 out of 43 enrolled patients. Baseline levels of the molecules were compared to disease status according to RECIST. There was a statistically significant difference in the mean of the log-transformed levels of hMMP9 between responders [CR+PR] versus the mean in patients with PD (p-value=0.0004, log fold change=0.7536), and between patients with disease control [CR+PR+SD] and those with PD (p-value= Conclusions: Our results suggest that baseline plasma level of the matrix metalloproteinase, hMMP9, could predict tumor response and PFS in patients treated with a combination of Bv and PLD. These data justify further investigation in breast cancer patients treated with anti-angiogenic therapy. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-16-07.

Although liposomes have been used as a vehicle for delivery of therapeutic agents in oncology, their efficacy in targeting brain tumors has been limited due to poor penetration through the blood-brain barrier. Because convection-enhanced delivery (CED) of liposomes may improve the therapeutic index for targeting brain tumors, we conducted a three-stage study: stage 1 established the feasibility of using in vivo magnetic resonance imaging (MRI) to confirm adequate liposomal distribution within targeted regions in normal rat brain. Liposomes colabeled with gadolinium (Gd) and a fluorescent indicator, 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine-5,5′-disulfonic acid [DiI-DS; formally DiIC18(3)-DS], were administered by CED into striatal regions. The minimum concentration of Gd needed for monitoring, correlation of infused volume with distribution volume, clearance of infused liposome containing Gd and DiI-DS (Lip/Gd/DiI-DS), and potential local toxicity were evaluated. After determination of adequate conditions for MRI detection in normal brain, stage 2 evaluated the feasibility of in vivo MRI monitoring of liposomal distribution in C6 and 9L-2 rat glioma models. In both models, the distribution of Lip/Gd/DiI-DS covering the tumor mass was well defined and monitored with MRI. Stage 3 was designed to develop a clinically relevant treatment strategy in the 9L-2 model by infusing liposome containing Gd (Lip/Gd), prepared in the same size as Lip/Gd/DiI-DS, with Doxil, a liposomal drug of similar size used to treat several cancers. MRI detection of Lip/Gd coadministered with Doxil provided optimum CED parameters for complete coverage of 9L-2 tumors. By permitting in vivo monitoring of therapeutic distribution in brain tumors, this technique optimizes local drug delivery and may provide a basis for clinical applications in the treatment of malignant glioma.

We previously reported the development of epidermal growth factor receptor (EGFR)–targeted immunoliposomes that bind and internalize in tumor cells which overexpress EGFR and/or mutant EGFR variant III (EGFRvIII), enabling intracellular delivery of potent anticancer agents in vitro. We now describe in vivo proof-of-concept for this approach for the delivery of multiple anticancer drugs in EGFR-overexpressing tumor models. Anti-EGFR immunoliposomes were constructed modularly with Fab′ fragments of cetuximab (IMC-C225), covalently linked to liposomes containing probes and/or anticancer drugs. Pharmacokinetic and biodistribution studies confirmed long circulation times (t1/2 = 21 hours) and efficient accumulation in tumors (up to 15% ID/g) irrespective of the presence of the targeting ligand. Although total accumulations of anti-EGFR immunoliposomes and nontargeted liposomes in EGFR-overexpressing tumors were comparable, only immunoliposomes internalized extensively within tumor cells (92% of analyzed cells versus

We hypothesized that immunoliposomes (ILs) that target epidermal growth factor receptor (EGFR) and/or its truncated variant EGFRvIII can be constructed to provide efficient intracellular drug delivery in tumor cells overexpressing these receptors. Monoclonal antibody fragments included Fab' fragments derived from C225, which binds both EGFR and EGFRvIII, or novel anti-EGFR scFv C10, which binds EGFR only. Monoclonal antibody fragments were covalently linked to liposomes containing various reporters or drugs. ILs were evaluated for specific binding, internalization, and cytotoxicity in EGFR/EGFRvIII-overexpressing cell lines in vitro. Flow cytometry and fluorescence microscopy showed that EGFR-targeted ILs, but not nontargeted liposomes or irrelevant ILs, were efficiently bound and internalized by EGFR-overexpressing cells, including glioma cells (U-87), carcinoma cells (A-431 and MDA-MB-468), and EGFRvIII stable transfectants (NR-6M). Furthermore, EGFR-targeted ILs did not bind to non-EGFR-overexpressing cells (MCF-7 and parental NR-6). ILs showed 3 orders of magnitude greater accumulation in NR-6-EGFRvIII stable transfectants versus parental NR-6 cells. Quantitative internalization studies indicated binding of EGFR-targeted ILs to target cells within 5 min, followed by intracellular accumulation beginning at 15 min; total uptake reached approximately 13,000 ILs/cell. ILs were used to deliver cytotoxic drugs doxorubicin, vinorelbine, or methotrexate to EGFR/EGFRvIII-overexpressing target cells in vitro. In each case, the IL agent was significantly more cytotoxic than the corresponding nontargeted liposomal drug in target cells, whereas it was equivalent in cells lacking EGFR/EGFRvIII overexpression. We conclude that EGFR-targeted ILs provide efficient and targeted delivery of anticancer drugs in cells overexpressing EGFR or EGFRvIII.

Neuroendocrine tumors are well vascularized and express specific cell surface markers, such as somatostatin receptors and glucagon-like peptide-1 receptors (GLP-1R). Using the Rip1Tag2 transgenic mouse model of pancreatic neuroendocrine tumors, we have investigated the potential benefit of a combination of anti-angiogenic treatment with targeted internal radiotherapy. To this end, [Lys40(Ahx-DTPA-111In)NH2]-Exendin-4, a radiopeptide that selectively binds to GLP-1R expressed on insulinoma and other neuroendocrine tumor cells, was co-administered with PTK787, an inhibitor of vascular endothelial growth factors (VEGFR). For biodistribution, Rip1Tag2 mice were pre-treated with PTK787 for 0, 3, 5 or 7 days. Subsequently, [Lys40(Ahx-DTPA-111In)NH2]-Exendin-4 was administered and the biodistribution assessed after 4 hours. For therapy, mice were injected with 1.1 MBq [Lys40(Ahx-DTPA-111In)NH2]-Exendin-4 and treated with PTK787 orally for another 7 days. Tumor volume, tumor cell apoptosis and proliferation, and microvessel density were quantified. Combination of [Lys40(Ahx-DTPA-111In)NH2]-Exendin-4 and PTK787 was significantly more effective than single treatments (p Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5714. doi:1538-7445.AM2012-5714

Angiogenesis is a key process in tumor progression. Angiogenic sprouting involves specification of subpopulations of endothelial cells into tip cells that respond to vascular endothelial growth factor (VEGF) guidance cues, and stalk cells that proliferate to form the vascular network. While angiogenic stalk cells mainly express VEGFR-2, the tip cells express VEGFR-3. Up to now, therapeutic approaches have mainly been aimed against VEGFR-2 activity. Bevacizumab, a monoclonal antibody against VEGF-A, has been used with some success in different treatment regimens of metastatic bowel and breast cancer. However, it remains unclear to which extend VEGFR-2 expressing stalk and VEGFR-3 expressing tip cells contribute to tumor-associated angiogenesis in vivo. While anti-VEGF-A antibodies inhibit angiogenesis by blocking VEGFR-2 expressing stalk cells, they do not interfere with VEGFR-3 signalling. Until recently, it was not possible to directly target different populations of endothelial cells involved in neoangiogenesis. This has changed since new technologies based on liposomes allow for the transport of pharmacological compounds to selected cells in vivo. In our lab we have established a method of transportation based on immunoliposomes (ILs), i.e., liposomes coated with antibodies directed against cell surface antigens. DC101 anti-mouse VEGFR-2 and AFL4 anti-mouse VEGFR-3 antibodies were utilized to target liposomes to VEGFR-2 or -3 expressing endothelial cells in vivo. Using this technology, we are able to selectively deplete VEGFR-2 or VEGFR-3 expressing cells from the angiogenic endothelial cell pool and thereby study the functional role of these cell populations. In this study we have investigated doxorubicin-containing ILs coated with anti-VEGFR-2 or anti-VEGFR-3 antibodies in two transgenic mouse models (the Rip1Tag2 model of human insulinoma and the MMTV-PyMT model of human breast cancer) and one xenograft model (the human colon cancer cell line HT29 in nude mice). In all three models, doxorubicin-containing ILs against VEGFR-2- or VEGFR-3-positive cells were effective in suppressing tumor growth. Both were more powerful than untargeted liposomes containing the same dose of doxorubicin. Combined anti-VEGFR-2 and -3 therapy was significantly more potent than targeting anti-VEGFR-2 expressing endothelial cells alone. In the Rip1Tag2 model, tumor burden after 2 weeks of therapy was 14.4 ± 7.9 mm3 (mean ± standard deviation) in the empty liposome group, 5.4 ± 4.7 mm3 in the untargeted liposomal doxorubicin group, 2.1 ± 2.5 mm3 in the anti-VEGFR-2 ILs group, 1.1 ± 1.5 mm3 in the anti-VEGFR-3 ILs and 0.3 ± 0.4 mm3 in the combined anti-VEGFR-2 and -3 ILs group. Thus, delivery of cytotoxic drugs to different angiogenic tumor-associated cells is feasible and may be more promising than focusing on a single entity of endothelial cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3634. doi:10.1158/1538-7445.AM2011-3634