Celldex Therapeutics Terminates Phase III Clinical Trial For Brain Cancer Vaccine

On Monday, biotech company Celldex Therapeutics announced they would be prematurely ending the Phase III clinical trial for their glioblastoma vaccine, Rintega. The decision was based on an independent review by the Data Safety and Monitoring Board (DSMB), who found that the vaccine was likely to fail its primary endpoint of improving patient survival, over traditional chemotherapy.

The immunotherapy-based vaccine was being investigated for its effectiveness in treating glioblastoma multiforme, a common and very aggressive type of brain cancer. Participants in the Phase III clinical trial for Rintega – called ACT IV – were patients who had been recently diagnosed with EGFRvIII-positive glioblastoma.

Following the announcement, shares in the biotech dropped by 66 percent. The news was disappointing to some analysts that had previously predicted that Rintega could be the second cancer vaccine to be approved in the US. Currently Provenge – an immunotherapy used to treat prostate cancer – is the only cancer vaccine on the US market, but the product has had disappointing sales since its approval in 2010.

Rintega showed promising results in a Phase II clinical trial, which found that the vaccine performed better on a measure of progression-free survival, compared to the control. The vaccine – whose common name is rindopepimut – was designed to target EGFRvIII, a mutated receptor found in one third of all cases of glioblastoma multiforme.

Approximately 4,000 patients in the US have EGFRvIII-positive glioblastoma. According to the American Cancer Society, there is no cure for glioblastoma multiforme and most patients with this form of brain cancer die within 15 months of diagnosis.

“We are extremely disappointed for patients that the ACT IV study was not successful,” said Anthony Marucci, CEO of Celldex Therapeutics. “On behalf of Celldex, I want to express our gratitude to the ACT IV investigators, patients and families who participated in this trial. While this is certainly not the desired outcome, we remain steadfast believers in the power of immunotherapy to transform the future of cancer treatment.”

According to Celldex, the company currently has no plans to further develop Rintega. The company will, however, continue to offer the treatment to patients who received rindopepimut in the clinical trial and for those who were given access to the immunotherapy for compassionate reasons.