PORTLAND, Ore.—As Galena Biopharma Inc. seeks to advance NeuVax, its leading cancer immunotherapy candidate, the company reached an important clinical milestone this week: the company has enrolled the 700th patient in its NeuVax (nelipepimut-S) Phase 3 PRESENT (Prevention of Recurrence in Early-Stage, Node-Positive Breast Cancer with Low to Intermediate HER2 Expression with NeuVax Treatment) clinical trial.
The 700-patient milestone is the enrollment target as defined by the trial's protocol. The PRESENT trial received a Special Protocol Assessment from the U.S. Food and Drug Administration (FDA) that certified the agreement with the FDA with regards to the study's endpoints, design and its statistical assumptions. Completion of final enrollment for this trial expected near the end of the first quarter of 2015.
The trial is a randomized, double-blind, placebo-controlled, international Phase 3 study currently running in 13 countries at more than 140 sites. The target population for the study is the roughly 50 to 60 percent of women with breast cancer who are low to intermediate (immunohistochemistry [IHC] 1+/2+ or fluorescence in-situ hybridization [FISH] < 2.0) HER2 expression and achieved no evidence of disease with current standard-of-care treatment. The patients in this trial all have stage IIa to IIIa breast cancer.
Once trial patients have completed their current standard-of-care treatment, they receive an injection once a month for six months, followed by five booster injections once every six months, for a total of 11 injections over the course of three years. Galena expects to reach the final endpoint in 2018, after the last patient dosed reaches their 36th month of treatment, or 141 events (recurrence or death), whichever comes later.
Galena's NeuVax is a first-in-class, HER2-directed cancer immunotherapy being evaluated as a means of preventing breast cancer recurrence after standard-of-care treatment in the adjuvant setting. Galena's vaccines are delivered with the immune adjuvant recombinant human granulocyte macrophage-colony stimulating factor.
"Reaching enrollment of our 700th patient is a significant milestone for the PRESENT trial and for our NeuVax cancer immunotherapy franchise," Dr. Mark W. Schwartz, president and CEO, noted in a press release. "We are grateful to all the women who volunteered to participate in our study, and we now look forward to completing enrollment near the end of this quarter and reaching our event-driven, interim analysis, which we anticipate occurring at the end of 2015/early 2016 timeframe. Next year, we also expect several key milestones from our portfolio of NeuVax trials, including our ongoing Phase 2b trial with NeuVax in combination with Herceptin."
NeuVax is a cancer immunotherapy for adjuvant treatment, the immunodominant peptide derived from the extracellular domain of the HER2 protein. The nelipepimut-S sequence stimulates specific CD8+ cytotoxic T lymphocytes after binding to HLA-A2/A3 molecules on antigen-presenting cells. The activated specific cytotoxic T lymphocytes recognize, neutralize and destroy HER2-expressing cancer cells, and can also generate cytotoxic T lymphocytes to other immunogenic peptides through inter- and intra-antigenic epitope spreading.
Galena notes on its website that approximately 25 percent of resectable node-positive breast cancer patients will relapse in three years, even with no evidence of disease after surgery and chemo/radiation therapy. So far, in preliminary Phase 1 and Phase 2 trials, NeuVax has demonstrated an initial dose response, with evidence that boosters may have an effect on efficacy, and a statistically significant increase in disease-free survival. In addition, NeuVax plus sargramostim seems to be well tolerated and effectively raise HER2 immunity.
Galena is also evaluating NeuVax in two additional breast cancer studies in combination with Herceptin: a Phase 2b trial in node positive and triple negative HER2 IHC 1+/2+, and a Phase 2 trial in neoadjuvant node positive and negative HER2 IHC 3+ patients.