On March 4, 2019 SELLAS Life Sciences Group, Inc. (Nasdaq: SLS) ("SELLAS" or the "Company"), a clinical-stage biopharmaceutical company focused on the development of novel cancer immunotherapies for a broad range of cancer indications, reported final results from the efficacy and safety data analysis of the prospective, randomized, single-blinded, controlled Phase 2b independent investigator-sponsored clinical trial of the combination of trastuzumab (Herceptin) +/- nelipepimut-S (NeuVax, NPS) targeting HER2 low-expressing breast cancer patient cohorts, including triple-negative breast cancer (TNBC) patients, which were presented at the 2019 ASCO (Free ASCO Whitepaper)-SITC Clinical Immuno-Oncology Symposium in San Francisco, CA (Press release, Sellas Life Sciences, MAR 4, 2019, View Source [SID1234533923]).

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The comprehensive findings are based on the final analysis of the full data-set from the clinical trial, and at a median follow-up of 25.7 months from the time of randomization. In the clinical trial, 275 patients were randomized to either placebo with granulocyte-macrophage colony-stimulating factor (GM-CSF) (n=139) or NPS with GM-CSF (n=136), while all received trastuzumab every 3 weeks for one year. No safety-related statistically significant differences were seen between the treatment and control arms in the rate of grade 1-3 adverse events of either local or systemic nature, while no grade 4/5 toxicities were observed in either arm. Also, there was no statistically significant difference between the treatment arms in the cardiac ejection fraction measured at baseline, as well as at four additional time-points up to 24 months post-randomization.

In the intent-to-treat (ITT) population (all HER2 low-expressing breast cancer patients; n=275), and over the 24-month post-randomization follow-up period, the disease-free survival (DFS) landmark rate was in favor of the combination (NPS plus trastuzumab) arm (89.8%) versus trastuzumab alone (83.8%), as shown in the graph below:

In the 97-patient TNBC cohort, the DFS landmark rate at 24 months for patients treated with NPS plus trastuzumab (n=53) was 92.6% compared to 70.2% for those treated with trastuzumab alone (n=44), a clinically and statistically significant improvement, as shown in the graph below:

In the TNBC cohort, there was a statistically significant reduction of 71.9% (p=0.01) in the frequency of clinically detected recurrences in those patients treated with the combination (NPS plus trastuzumab) versus trastuzumab alone.

"This final analysis of the study database establishes a clinically meaningful and statistically significant prolongation in DFS, a validated surrogate marker of overall survival for TNBC – by both hazard ratios and 24-month event rates – and a meaningful decrease in the frequency of relapses identified by standard clinical follow-up in favor of NPS plus trastuzumab given in the adjuvant setting in TNBC patients," commented Elizabeth A. Mittendorf, MD, PhD, Rob and Karen Hale Distinguished Chair in Surgical Oncology, Director of Research, Breast Surgical Oncology Brigham and Women’s Hospital, Director, Breast Immuno-Oncology Program Dana-Farber/Brigham and Women’s Cancer Center, and the Principal Investigator of the Phase 2b study.

Nicholas J. Sarlis, MD, PhD, Executive Vice President and Chief Medical Officer of SELLAS, further commented that "These definitive results provide us with an enhanced understanding of the clinical effect and safety profile of the combination therapy in this trial, with positive efficacy outcomes being essentially confined to TNBC patients, and continue to encourage us and support our ongoing discussions with the U.S. Food and Drug Administration on the most appropriate registration-enabling development path for NPS in TNBC."

The abstract text can be accessed at: View Source

Herceptin is a registered trademark of Genentech, Inc. and is not a trademark of SELLAS. The manufacturer of this brand is not affiliated with and does not endorse SELLAS or its products