NeuVax (nelipepimut-S) is an investigational immunotherapy being developed by Sellas Life Sciences Group to treat human epidermal growth factor 2 (HER2)-associated breast cancers. The treatment was initially developed by Galena Biopharma, which became part of Sellas in 2017.

How NeuVax works

NeuVax is a cancer vaccine, meaning that it acts to “educate” the immune system to recognize and mount a response against specific tumor-associated antigens (TAAs). Antigens are substances that are associated with a disease and not normally found in the body.

Many breast cancer cells produce a protein called HER2, which promotes cell growth. NeuVax contains peptides, or small parts of a protein, derived from HER2. These are called E75.

When NeuVax is injected into a patient’s body, the immune system recognizes these peptides as an antigen. This stimulates the production of a type of “killer” immune cells called cytotoxic T lymphocytes (CTLs), which are designed to identify and destroy tumor cells expressing the HER2 antigen.

NeuVax is given alongside Leukine (sargramostim or GM-CSF), which can boost the number of immune cells in the body and increase the anti-tumor activity of the vaccine.

NeuVax in clinical trials

An initial Phase 1/2 clinical trial (NCT00841399) to assess the safety, maximum tolerated dose, and immune response associated with NeuVax was carried out in 100 patients with breast cancer in the United States. The results were published in the scientific journal Annals of Oncology, alongside data from a second trial in 95 patients. The most common side effects associated with the treatment were mild injection-site reactions, fatigue, bone pain, and flu-like symptoms.

A Phase 3 trial (NCT01479244) assessing the safety and effectiveness of NeuVax plus Leukine in early-stage breast cancer patients with low to intermediate HER2 was discontinued in 2016, based on a recommendation from the Independent Data Monitoring Committee during a planned interim futility analysis. NeuVax continues to be investigated in other indications and in combination with other therapies.

Two Phase 2 clinical trials were carried out by Cancer Insight in collaboration with Sellas and Genentech. These trials aim to assess the safety and effectiveness of NeoVax with Leukine alongside Genentech’s Herceptin (trastuzumab) compared to Herceptin and Leukine alone.

The first Phase 2 trial (NCT01570036) recruited 275 patients with HER2 1+/2+ breast cancer at 32 sites across the U.S. Patients were randomly assigned to receive either Neuvax, Leukine, and Herceptin or Leukine and Herceptin alone. Patients were treated every three weeks for one year, and survival data were collected for three years from the start of treatment.

No significant differences in safety were observed between the two treatment groups. At 24 months, disease-free survival was slightly improved in the group that received Neuvax (89.8 percent compared with 83.8 percent for the control group).

A total of 97 patients with triple-negative breast cancer (TNBC) were randomly assigned to either treatment group as well. The disease-free survival rate for patients receiving Neuvax was 92.6 percent compared with 71.9 percent for the control group. Based on these findings, Sellas is continuing discussions with the U.S. Food and Drug Administration (FDA) for Neuvax in treating breast cancer.

The second Phase 2 trial (NCT02297698) has recruited 100 high-risk HER2 3+ breast cancer patients at 26 sites across the U.S. Results from an interim analysis were announced in April 2017, suggesting that NeuVax was well-tolerated and no significant difference in the level of side effects has been observed between the two treatment groups. The study is scheduled to be completed by October.

A Phase 2 trial (NCT02636582) called VADIS is assessing NeuVax alongside Leukine as a treatment for ductal carcinoma in situ (DCIS). The trial is being carried out by the National Cancer Institute (NCI). A total of 13 participants have been randomly assigned to receive either Neuvax and Leukine or Leukine alone as two injections two weeks apart prior to breast cancer surgery. Patients’ blood will be examined for an immune response against NeuVax before the first vaccination to six months after the last vaccination.

Secondary outcome measures will include toxicity and allergic reactions to the vaccine. 


Last updated: Aug. 20, 2019


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