Swaby, Ramona F.

6025 Background: Blinding patients to treatment regimen is an important component of high quality randomized clinical trials although concern exists about how receipt of a placebo will impact participants’ views. In ECOG5103, patients were randomized to receive adjuvant chemotherapy for breast cancer with either placebo (arm A) or bevacizumab (arms B and C) and treatment assignment was unblinded by 24 weeks. We sought to determine if unblinding was associated with differential changes in participants’ views. Methods: The Decision-Making/Quality of Life component (DM-QOL) included all patients enrolling on E5103 between 1/5- 6/8/10. Women were surveyed pretreatment and after unblinding. Wilcoxon rank sum testing was used to examine differences. Results: 572 patients on DM-QOL started protocol therapy; 118 on arm A, 454 on arm B/C; the two groups (arm A vs. B/C) were well balanced. 516 patients participated in pretreatment, 514 in unblinding survey. Pretreatment, 32% reported >moderate chance of recurrence in 5 years, 27% >moderate chance of serious problem from treatment, 99% feeling at least somewhat informed, 98% at least somewhat confident in study participation, most “extremely” confident. Overall, median response scores did not change over time, with no statistically significant differences between the groups in changes in perceptions of: recurrence risk (p=0.45); chances of a serious problem (p=0.12), feeling informed (p=0.99). However, they differed in confidence about study participation (p=0.04): after unblinding, a higher % of placebo-treated patients had increased confidence (38% vs. 25%), and a higher % of bevacizumab-treated patients had decreased confidence (29% vs. 22%), although 44% across all arms had no change. Conclusions: In a placebo-controlled, double-blinded RCT, unblinding did not significantly affect most participants’ views, regardless of receipt of placebo or experimental drug. However, confidence in study participation may have been affected by knowledge of receipt of bevacizumab; publicity surrounding this experimental therapy may have affected results.

605 Background: Pre-clinical and nonrandomized clinical data support synergy of the combination of bevacizumab and trastuzumab. We conducted a randomized double-blinded phase III trial of chemotherapy/trastuzumab ± bevacizumab to evaluate efficacy (PFS after treatment initiation) of the addition of bevacizumab in first-line treatment of HER2+ MBC. Methods: Days 1, 8 and 15 paclitaxel ± carboplatin were administered with trastuzumab and either placebo or bevacizumab 10 mg/kg every 2 weeks for a total of 6 months. Antibody therapy was then continued without chemo every 3 weeks, until disease progression or unacceptable toxicity. Disease assessments were performed every 3 months. Results: Ninety-six of the planned 489 analyzable patients (pts) were accrued between 2007 and 2009, at which time the study terminated due to poor accrual. Seventy % of pts were post-menopausal, 60% had ER+/HER2+ BC. Median age was 55 years (28-80). Outcomes and toxicities are summarized on the tables below. Median follow-up was 30 months. Conclusions: The combination of chemotherapy, trastuzumab, and bevacizumab did not significantly increased toxicity, and was overall safe and well tolerated. No significant differences in clinical benefit were observed between both treatment arms. Data on CTCs and Quality of Life will be presented at the meeting. This study was conducted by the Eastern Cooperative Oncology Group (Robert L. Comis, MD, Chair) and supported in part by Public Health Service Grants CA23318, CA66636, CA21115, CA32291, CA31946, CA49957, CA27525, CA14548, CA17145, CA32102, CA25224, CA49. [Table: see text] [Table: see text]

Abstract Abstract #404 Background: The oral HDACi vorinostat (V) sensitizes breast cancer cells to tubulin polymerizing agents and anti-VEGF directed therapies in vitro. We sought to determine the safety and efficacy of V plus paclitaxel (P) and bevacizumab (B) as first-line therapy for MBC.
 Methods: Eligible patients (pts) with measurable disease, ECOG PS 0 or 1, and no prior chemotherapy for MBC, received P (90mg/m2) on days 1, 8, 15 and B (10mg/kg) on days 1,15 every 28 days, plus V 200 mg (N=3) or 300 mg (N=28) BID orally for 3 days given the day before, day of, and day after each P dose. Response was assessed after every 3 cycles (RECIST). The trial was designed to distinguish between a response rate of < 40% vs. > 60% (alpha=0.10, beta=0.10) using Simon's optimal 2-stage design. At least 12 responses were required in the first 28 evaluable pts in the 1st stage and 21 of 41 in the 2nd stage.
 Results: There were no dose-limiting toxicities among the first 6 pts treated at the 1st (200 mg BID; N=3) and 2nd (300 mg BID; N=3) dose levels. Among the 26 evaluable pts treated at the recommended phase II dose of 300mg bid in the 1st stage, 14 patients had a partial response (PR-54%; 90% confidence interval [C.I.] 36%-71%), 6 had stable disease (SD) at 3 months and remain on treatment, 2 had SD as the best response with progressive disease (PD) at 11.8 and 15 months, and 4 had PD as their best response. Additionally, 2 of 3 pts treated at the first V dose level had a PR, indicating PR in 16 of 29 overall (55%, 90% C.I 38%-71%). Only 11 of 29 evaluable pts (38%) have progressed after a median followup of 10.5 months (R-2.3-14.9). Two pts had tumor biopsies and peripheral blood mononuclear cells (PBMC) collected before and 4 hours after the 3rd V dose (300 mg BID) which showed increased acetylation of K69 lysine residue of the chaperone protein Hsp 90, upregulation of Hsp70, and downregulation of AKT by Western Blot, providing evidence of Hsp90 inhibition in tumor and PBMC.
 
 Gr 3-4 toxicities included neutropenia (26%), neuropathy (23%), fatigue (16%), thrombosis (10%), vomiting (6%), hypertension (3%), and diarrhea (3%).
 Conclusions: Our preliminary findings indicate that the HDACi V inhibits Hsp90 and downregulates AKT in breast cancer in vivo, and enhances the effectiveness of P plus B in MBC. Accrual is nearly complete and the final efficacy analysis will be presented. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 404.

Abstract Germ line inactivating mutations in BRCA1 confer susceptibility for breast and ovarian cancer. However, the relevance of the many missense changes in the gene for which the effect on protein function is unknown remains unclear. Determination of which variants are causally associated with cancer is important for assessment of individual risk. We used a functional assay that measures the transactivation activity of BRCA1 in combination with analysis of protein modeling based on the structure of BRCA1 BRCT domains. In addition, the information generated was interpreted in light of genetic data. We determined the predicted cancer association of 22 BRCA1 variants and verified that the common polymorphism S1613G has no effect on BRCA1 function, even when combined with other rare variants. We estimated the specificity and sensitivity of the assay, and by meta-analysis of 47 variants, we show that variants with <45% of wild-type activity can be classified as deleterious whereas variants with >50% can be classified as neutral. In conclusion, we did functional and structure-based analyses on a large series of BRCA1 missense variants and defined a tentative threshold activity for the classification missense variants. By interpreting the validated functional data in light of additional clinical and structural evidence, we conclude that it is possible to classify all missense variants in the BRCA1 COOH-terminal region. These results bring functional assays for BRCA1 closer to clinical applicability. [Cancer Res 2007;67(4):1494–501]