DPX-Survivac Treatment Continues to Show Promise in Women with Advanced Ovarian Cancer, Early Data Show

Treatment with DPX-Survivac plus intermittent low-dose cyclophosphamide continues to show promise in women with advanced recurrent ovarian cancer, the second part of a Phase 1/2 trial shows.

Interim data from the first six patients revealed that five patients (83%) achieved stable disease, including two tumor regressions — although it was not enough to be called a partial response.

Among these five patients, four (80%) had smaller tumors — five centimeters or less — at the study’s start, confirming earlier Phase 1 findings that smaller tumors led to better responses to treatment.

“We are encouraged by these early initial results and are committed to advancing this program quickly with the goal of providing an additional treatment option to patients with advanced ovarian cancer,” Frederic Ors, CEO of IMV, said in a press release.

DPX-Survivac consists of small fractions of the survivin protein, which is broadly over-activated in most cancer types and promotes tumor growth, according to IMV. Survivin plays an essential role in supporting tumor blood vessel growth and promoting resistance to anti-cancer therapies.

The therapy, administered as an injection under the skin, works by triggering a strong immune response against cancer cells producing the survivin protein, causing them to die.

The DECIDE1 Phase 1/2 trial (NCT02785250) was initially planned to test a combination of DPX-Survivac, epacadostat, and low-dose cyclophosphamide in ovarian cancer patients who had received surgery and at least one chemotherapy regimen.

Incyte‘s epacadostat is a potent, selective oral IDO1 inhibitor that belongs to the growing class of checkpoint inhibitors, such as CTLA-4, PD-1, and PD-L1 antibodies. It is meant to restore the immune system’s ability to recognize and fight cancer.

But results from the Phase 1b portion showed that a lower dose of 100 mg ecapadostat resulted in better responses than a 300 mg dose, leading IMV and Incyte to stop dosing patients with epacadostat but continue studying a combination of DPX-Survivac and cyclophosphamide in the Phase 2 trial.

The Phase 1b part included 53 patients, and showed that the treatments were well-tolerated and induced the expansion of survivin-specific T-cells, meeting the trial’s main goal for this part.

Researchers found that durable responses correlated with the amount of T-cells within tumors and that those with smaller tumors had better responses to treatment: 67% of patients with non-bulky disease at the study’s start — meaning their tumors were no more than five cm — experienced a reduction of at least 30% in their tumors, compared with 15% of those with bigger tumors.

The initial Phase 2 data “confirms the earlier trends we saw in the phase 1b portion of the study,” Ors said. “It supports the potential of DPX-Survivac as a monotherapy and the use of our patient selection strategy.”

In earlier stages of DECIDE1, the researchers noted that durable clinical responses occurred after 140 days of treatment, which have now lasted for 20 months or more. Clinical results from the Phase 2 portion covering the 140-day mark are expected to be available by mid-2019.

Thirteen patients had been enrolled in the Phase 2 portion of the trial by March 2019. The study is now expected to enroll 16 additional patients with a lower tumor burden across multiple sites in the Unites States and Canada.

For more information about the trial, including locations and contacts, visit the webpage here.