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# Sellas Nelipepimut-S Phase 3 Study in Breast Cancer
- URL: https://www.fdaweb.com/sellas-nelipepimut-s-phase-3-study-in-breast-cancer/
- Published: 2020-02-14T12:00:00.000Z
- Updated: 2026-09-14T16:03:13.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5146097

After recently meeting with FDA in a Type C meeting, Sellas Life Sciences Group says it has finalized the design and plan for a Phase 3 study of nelipepimut-S (NPS) vaccine in combination with trastuzumab (Genentech’s Herceptin) for treating patients with triple negative breast cancer in the adjuvant setting after standard treatment. If successful, the study is likely to support BLA submission, it says.

Sellas describes the planned Phase 3 study as a 1:1 randomized, blinded two-arm study to evaluate the NPS vaccine (NPS plus granulocyte macrophage-colony stimulating factor (GM-CSF)) in combination with trastuzumab vs. GM-CSF alone as maintenance treatment in the adjuvant setting following standard-of-care therapy in patients with triple negative breast cancer. It says feedback from FDA stated that there is adequate safety information to support the use of NPS in combination with trastuzumab.

Sellas previously reported the final efficacy and safety results from a Phase 2b study of NPS in combination with trastuzumab in TNBC patients (n=97). The disease-free survival rate at 24 months was 92.6% for the combination arm vs. 70.2% for the trastuzumab alone arm, the company says.