Philips, Prejesh

Background Most patients with advanced melanomas relapse after checkpoint blockade therapy. Thus, immunotherapies are needed that can be applied safely early, in the adjuvant setting. Seviprotimut-L is a vaccine containing human melanoma antigens, plus alum. To assess the efficacy of seviprotimut-L, the Melanoma Antigen Vaccine Immunotherapy Study (MAVIS) was initiated as a three-part multicenter, double-blind, placebo-controlled phase III trial. Results from part B1 are reported here. Methods Patients with AJCC V.7 stage IIB-III cutaneous melanoma after resection were randomized 2:1, with stage stratification (IIB/C, IIIA, IIIB/C), to seviprotimut-L 40 mcg or placebo. Recurrence-free survival (RFS) was the primary endpoint. For an hypothesized HR of 0.625, one-sided alpha of 0.10, and power 80%, target enrollment was 325 patients. Results For randomized patients (n=347), arms were well-balanced, and treatment-emergent adverse events were similar for seviprotimut-L and placebo. For the primary intent-to-treat endpoint of RFS, the estimated HR was 0.881 (95% CI: 0.629 to 1.233), with stratified logrank p=0.46. However, estimated HRs were not uniform over the stage randomized strata, with HRs (95% CIs) for stages IIB/IIC, IIIA, IIIB/IIIC of 0.67 (95% CI: 0.37 to 1.19), 0.72 (95% CI: 0.35 to 1.50), and 1.19 (95% CI: 0.72 to 1.97), respectively. In the stage IIB/IIC stratum, the effect on RFS was greatest for patients <60 years old (HR=0.324 (95% CI: 0.121 to 0.864)) and those with ulcerated primary melanomas (HR=0.493 (95% CI: 0.255 to 0.952)). Conclusions Seviprotimut-L is very well tolerated. Exploratory efficacy model estimation supports further study in stage IIB/IIC patients, especially younger patients and those with ulcerated melanomas. Trial registration number NCT01546571.

10017 Background: Seviprotimut-L is a vaccine prepared from antigens of 3 human melanoma cell lines, administered with alum. Prior formulations induced T cell and antibody responses and improved survival in a small phase II clinical trial. Part B1 of MAVIS (Melanoma Antigen Vaccine Immunotherapy Study, a three part, Phase III clinical program), was a multicenter, double-blind, placebo-controlled trial to assess efficacy of seviprotimut-L, with the primary endpoint of relapse-free survival (RFS). The goal of Part B1 was to guide design of the pivotal Part B2. Methods: Patients with AJCC v7 stage IIB-III cutaneous melanoma, after surgical resection, age 18-75, ECOG PS 0-1, were randomized 2:1 to seviprotimut-L 40 mcg or placebo, injected subcutaneously every 2 weeks x 5, then monthly x 4, then every 3 months x 9. Patients were stratified by stage (IIB/C, IIIA, IIIB/C). Target enrollment was 325. The study was powered for assessment of RFS, with target hazard ratio (HR) of 0.625, one-sided alpha of 0.10, and power 80%. Final data are presented. Results: 347 patients were randomized. Arms were well-balanced. Treatment-related adverse events (AEs) led to discontinuation in 0.4% and 0%, respectively, for vaccine and placebo arms. There were no treatment-related SAEs. By intent-to-treat (ITT) analysis, RFS was not significantly longer for seviprotimut-L in the full study population but trended toward benefit (HR 0.88). Subgroup analysis based on planned stratification revealed the hazard ratio (HR) for the Stage IIB/IIC subset (randomization stratum, n=111) to be 0.65 (95% CI [0.37, 1.17]), favoring seviprotimut-L. Age can decrease immune competence: RFS was longer with vaccine for patients age <60 overall (N = 191, HR = 0.64 [0.38, 1.08]) and among Stage IIB/C patients (N = 52, HR = 0.32 [0.12, 0.86]). The effect modification interaction p value for age for stage IIB/IIC patients was 0.056. In a multivariable RFS model, for IIB/IIC patients <60 with ulceration (n=38), HR = 0.209 [0.07,0.61]. For overall survival, for patients < 60, HR = 0.41 [0.33,1.14] (n=191, 19 deaths) and for those ≥60, HR = 0.92 [0.39,2.12] (n = 156, 24 deaths). Conclusions: Seviprotimut-L is very well-tolerated. Subgroup efficacy analyses identified populations who may benefit from Seviprotimut-L: those with Stage IIB/IIC melanoma and those under age 60. These data support design of the definitive part B2 of the MAVIS phase III trial to test seviprotimut-L for stage IIB/C patients, with stratification by age and ulceration. Clinical trial information: NCT01546571.

Abstract Background. Third generation aromatase inhibitors (AIs) have been shown to be superior to tamoxifen in multiple randomized clinical trials and become the new standard of treatment for postmenopausal women with early or advanced endocrine-sensitive breast cancer. It is thus important to identify biomarkers predicting resistance to AIs so that alternative therapeutic options can be employed. A two gene expression index, HOXB13:IL17BR, and HOXB13 in particular, has been shown to be a negative predictor of clinical benefit from tamoxifen. It is unclear whether HOXB13:IL17BR or HOXB13 is also predictive of AI therapy.Methods. We performed a retrospective analysis of a phase II randomized neoadjuvant study of everolimus+letrozole vs. placebo+letrozole in patients with estrogen receptor-positive breast cancer. Total RNA was extracted from frozen tissue biopsies taken either prior to treatment or after 15 days of treatment. HOXB13:IL13BR and a molecular grade index (MGI) were measured in 107 pre-treatment samples and 111 samples after 15 days of treatment. Antiproliferative response as defined by a ln[Ki767] &lt;1 at day 15 in the samples analyzed was correlated with these gene expression indices.Results. In the placebo+letrozole treatment arm, the antiproliferative response rate was 30% (14/47). Using a pre-specified cutpoint of 0.06, the response rate was 40% for low HOXB13:IL17BR patients, compared to 12% for high HOXB13:IL17BR patients (p=0.05). In the everolimus+letrozole arm, the antiproliferative response rate in the samples analyzed was 55% (33/60), and the response rates for low and high HOXB13:Il17BR patients were 70% and 37% (p=0.02), respectively. When examined separately, high HOXB13 expression was significantly associated with nonresponse to therapy (everolimus+letrozole arm, p=0.02; placebo+letrozle arm, p=0.03), but IL17BR was not (everolimus+letrozole arm, p=0.6; placebo+letrozle arm, p=0.88). As expected, we observed a significant correlation between MGI and Ki67 staining (Spearman r=0.67, p&lt;0.0001).Conclusions. High HOXB13:IL17BR index and high HOXB13 expression may identify a possible subset of patients with estrogen receptor-positive tumor that could be less responsive to aromatase inhibitors such as letrozole. Furthermore, use of MGI may enable rapid assessment of antiproliferative response by fine needle aspiration. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2120.