Rinn, Kristine

TPS1138 Background: The SV-BR-1-GM breast cancer cell line activates anti-tumor immunity by expressing tumor associated antigens and secreting GM-CSF which enhances dendritic cell activation and promotes adaptive (T-cell mediated) and innate (dendritic and NK cell) immune responses. The cells are also engineered to optimize immune recognition through pt specific HLA antigen matching. SV-BR-1-GM acts through direct antigen presentation and CD4+ T-cell activation and, when combined w/ checkpoint inhibitors (CPIs), has demonstrated clinical benefit in 54 heavily pretreated metastatic breast cancer (MBC) pts. In pts w/ disease progression following CPI therapy, similar or improved progression free survival (PFS) compared to their prior treatment regimen. Disease control following antibody drug conjugates was observed in 40%of pts. Clinical benefit was seen in 5 out of 8 pts w/ untreated intracranial metastases. CD8+ Immuno-PET imaging suggests systemic activation, w/ increased CD8+ tumor infiltrating lymphocytes at both primary and metastatic tumor sites, as well as lymphoid organs. Optimized sequencing of CPI w/ SV-BR-1-GM and its latest phase 3 formulation have shown enhanced clinical outcomes, including improved overall survival (OS) (median 13.4 mos), PFS (3.6 mos), and clinical benefit rate (CBR; 61%).These findings have informed refinements to the ongoing pivotal, registration enabling Phase 3 trial, designed to optimize pt selection and treatment sequencing strategies. Methods: This ongoing multicenter, randomized, open label Phase 3 trial evaluates Bria-IMT + CPI vs. Treatment of Physician’s Choice (TPC) in MBC pts lacking approved curative therapies. Pts are randomized 1:1:1 to Bria-IMT + CPI, TPC, or Bria-IMT monotherapy (discontinued after 150 enrollments to prioritize combination arms). The Bria-IMT regimen consists of: Day -2: Cyclophosphamide 300 mg/m², Day 0: 20M irradiated SV-BR-1-GM cells, Day 2/3: 0.1 mcg pegylated α interferon at each inoculation site. CPI infusion is administered Day -3 to 3. Cycles q3w. TPC regimens follow site specific SOC. Imaging q6w (first 2 cycles), then q8w. Eligibility includes all MBC subtypes, including CNS mets, and permits prior CPI therapy ( >21 days pre-treatment). There will be 100 sites across the U.S., Canada, and ex-North America w/ an enrollment target of 404. The trial is currently active at 59 sites with 217 sub investigators. To date, 67 pts screened: 46 randomized (median age 56 yrs [34–83], median 6 [2–13] prior lines of therapy. The primary endpoint is OS, with an interim analysis at 144 events targeting a hazard ratio of 0.6. Secondary endpoints: PFS, overall response rate, CBR, CNS event free survival, and TWiST. Safety analyses ongoing; pt reported outcomes assess subjective treatment impact. Clinical trial information: NCT03328026 .

CRA1008 The full, final text of this abstract will be available at abstract.asco.org at 7:30 AM (EDT) on Monday, June, 3, 2013, and in the Annual Meeting Proceedings online supplement to the June 20, 2013, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

521 Background: S0221 investigated weekly vs q 2 week dosing of doxorubicin/cyclophosphamide (AC) and paclitaxel (P) in patients (pts) with high risk early breast cancer as previously reported (JCO 33:58-64, 2015). After enrollment of 2716 pts randomization to the two AC arms was stopped for futility and an additional 578 pts received 4 cycles of q 2 week AC and were randomized to P weekly (Pw) or P q 2 weeks (P2). We report updated results of the original trial design and the first report of the 578 pts treated with AC x 4 and Pw x 12 or P2 x 6. Methods: Between December 2003 and November 2010, 2716 pts were randomized in a 2x2 factorial design to 1) 15 weeks of weekly AC (A 24 mg/m2/week and C 60 mg/m2/day po) vs 6 cycles of q 2 week AC (A 60 mg/m2 and C 600 mg/m2) and 2) Pw (paclitaxel 80 mg/m2/week x 12) vs P2 (paclitaxel 175 mg/m2 q 2 weeks x 6), with growth factor support as previously described. After study amendment 578 patients received 4 cycles of q 2 week AC followed by Pw or P2. Updated survival was assessed using log-rank tests and Cox regression models. Results: At a median follow-up of 8.5 years, among the pts treated in the original protocol, there were no significant differences among the four treatments for DFS (p=0.21) or OS (p=0.08). The triple-negative subset had worse DFS (P<0.001) than the HER2-positive or ER/PR+/HER2- subsets, with 5 year DFS of 75% vs 83% and 84%, respectively. While we previously found in the triple negative subset that the arm using q 2 weeks for both AC and paclitaxel was marginally superior, the differences among the arms are no longer significant for DFS (p=0.12) or OS (p=0.11). Among the 578 pts assigned ACx4 and randomized to Pw v P2 there were no overall differences in DFS (p=0.70) or OS (p=0.63) after 4.4 years median follow-up. Conclusions: There were no significant differences in DFS or OS between any of the schedules with extended follow-up in the original cohort and no difference in outcome by paclitaxel schedule for the 578 additional patients in the revised protocol. Either paclitaxel schedule may be recommended, with selection based on toxicity, cost, or patient preference rather than efficacy. Support: NCI grants CA32102, CA38926, CA21115, CA21076, CA77597, CA25224, CA77202, CCSRI15469, and Amgen, Inc. Clinical trial information: NCT00070564.

CRA1008 Background: S0221 is a SWOG-coordinated phase III adjuvant chemotherapy intergroup trial in node-positive and high-risk node-negative operable breast cancer which hypothesized that 1) the weekly AC+G regimen is superior to ddAC x 6 and 2) 12 weeks of weekly paclitaxel (wP) is superior to q 2 week paclitaxel x 6 (ddP). Methods: Between December 2003 and November 2010, 2,716 patients were randomized in a 2 x 2 factorial design to 1) AC+G vs ddAC and 2) P 80 mg/m2/week x 12 vs P 175 mg/m2 q 2 weeks x 6. If there was no significant interaction between the factors, the trial was powered to find a disease-free survival hazard ratio (HR) ≤ 0.82 for weekly vs q 2 week for each factor. At the first interim analysis, the AC randomization was halted for futility, and S0221 was closed to accrual 10 November 2010. S0221 reopened 15 December 2010, after which time all patients received 4 cycles of ddAC and randomization to P weekly x 12 and ddP x 6 continued. Accrual halted at a total of 3,294 in January 2012. Results: By September 7, 2012, 487 events and 340 deaths had occurred, prompting the third planned interim analysis. The Data Safety and Monitoring Committee recommended reporting the results since the futility boundary was crossed. A Cox model adjusting for the AC arms had a HR = 1.08 (95% CI 0.90-1.28; p=0.42), with the 99.5% CI excluding the original alternative hypothesis that the HR=0.82. There was no significant interaction of the two factors. Estimated 5-year progression-free survivals were 82% for weekly P and 81% for ddP. Toxicity data were available for 1,385 patients treated with ddP and 1,367 treated with weekly P. Grade 5 toxicity occurred in 4 patients on ddP and 2 on weekly P. Percent grade 3-4 toxicity per arm are shown in the Table. Conclusions: Either ddPx6 or weekly P x 12 are acceptable schedules of P administration. The differences in leukopenia likely reflect ascertainment bias against weekly P. If this is accepted, weekly P x 12 produces less overall toxicity than 6 cycles of ddP. Support: NCI grants CA32102, CA38926, CA21115, CA21076, CA77597, CA25224, CA77202, CCSRI15469, and Amgen, Inc. Clinical trial information: NCT00070564. [Table: see text]

Purpose To determine the optimal dose and schedule of anthracycline and taxane administration as adjuvant therapy for early-stage breast cancer. Patients and Methods A 2 × 2 factorial design was used to test two hypotheses: (1) that a novel continuous schedule of doxorubicin-cyclophosphamide was superior to six cycles of doxorubicin-cyclophosphamide once every 2 weeks and (2) that paclitaxel once per week was superior to six cycles of paclitaxel once every 2 weeks in patients with node-positive or high-risk node-negative early-stage breast cancer. With 3,250 patients, a disease-free survival (DFS) hazard ratio of 0.82 for each randomization could be detected with 90% power with two-sided α = .05. Overall survival (OS) was a secondary outcome. Results Interim analyses crossed the futility boundaries for demonstrating superiority of both once-per-week regimens and once-every-2-weeks regimens. After a median follow-up of 6 years, a significant interaction developed between the two randomization factors (DFS P = .024; OS P = .010) in the 2,716 patients randomly assigned in the original design, which precluded interpretation of the two factors separately. Comparing all four arms showed a significant difference in OS (P = .040) but not in DFS (P = .11), with all treatments given once every 2 weeks associated with the highest OS. This difference in OS seemed confined to patients with hormone receptor–negative/human epidermal growth factor receptor 2 (HER2) –negative tumors (P = .067), with no differences seen with hormone receptor–positive/HER2-negative (P = .90) or HER2-positive tumors (P = .40). Conclusion Patients achieved a similar DFS with any of these regimens. Subset analysis suggests the hypothesis that once-every-2-weeks dosing may be best for patients with hormone receptor–negative/HER2-negative tumors.

AbstractPurpose: This study aimed to evaluate the safety of, immune response induced by, and efficacy of treatment with lapuleucel-T (APC8024) in patients with HER-2/neu–expressing tumors. Lapuleucel-T is an investigational active immunotherapy product consisting of autologous peripheral blood mononuclear cells, including antigen presenting cells, which are cultured ex vivo with BA7072, a recombinant fusion antigen consisting of portions of the intracellular and extracellular regions of HER-2/neu linked to granulocyte-macrophage colony-stimulating factor.Experimental Design: Patients with metastatic breast, ovarian, or colorectal cancer whose tumors expressed HER-2 were eligible. Patients underwent leukapheresis in week 0 and received lapuleucel-T infusions in weeks 0, 2, and 4. Patients who achieved a partial response or had stable disease through week 48 were eligible for re-treatment using the same protocol and dose as their initial treatment.Results: Eighteen patients were enrolled and treated. Patients showed an immune response to the immunizing antigen (BA7072) at week 8 compared with week 0 as measured by T lymphocyte proliferation and IFN-γ enzyme-linked immunospot assay. Therapy was well tolerated. The majority (94.7%) of adverse events associated with treatment were grade 1 or 2. Two patients experienced stable disease lasting &gt;48 weeks.Conclusions: Autologous active cellular immunotherapy with lapuleucel-T stimulated an immune response specific to the immunizing antigen and seemed to be well tolerated. Further clinical studies to assess the clinical benefit for patients with HER/2-neu–expressing breast, ovarian, and colorectal cancer are warranted. (Clin Cancer Res 2009;15(18):5937–44)