Per the agreement, Oncologie will conduct a phase II single-arm, open-label study to evaluate the efficacy and safety of its Bavituximab, an antibody that blocks the activity of phosphatidylserine (PS), with Merck’s, known as MSD outside North America, blockbuster Keytruda (pembrolizumab) in patients with advanced gastric or gastroesophageal cancer. Merck will supply Keytruda for the expected 80 patients that will be enrolled in this trial through the companies’ agreement.
Merck’s anti-PD-1 therapy targets proteins found on the body’s immune and cancer cells and blocks the cellular pathway potentially helping the body’s immune system fight. The drug has been approved for a number of indications by both the US FDA and the European Medicines Agency (EMA) including the use of the drug as an adjuvant therapy.
Bavituximab is an investigational chimeric monoclonal antibody (mAb) that targets PS and is believed to reverse PS-mediated immunosuppression by blocking the engagement of PS with its receptors.
According to Oncologie, PS-targeting antibodies have been shown to shift the functions of immune cells in tumors, resulting in signs of immune activation and anti-tumor immune responses, enabling other cancer therapies to more effectively attack tumors by reversing immunosuppression that limits the impact of those treatments.
A spokesperson for Oncologie told us that Bavituximab was investigated in a Phase III study comparing its use with chemotherapy to chemotherapy and placebo and the study did not meet its primary endpoint of overall survival. Yet, a subset analysis of over 90 patients in the study that were treated within a couple of weeks with anti-PD-1 that had been previously treated with Bavituximab showed improved overall survival.
They added that the upcoming study of Bavituximab in combination with Keytruda aims to further test the hypothesis that Bavituximab improves responsiveness to anti-PD-1 in gastric cancer. In the gastric cancer setting, according to the spokesperson, there is an unmet need and relatively low efficacy for anti-PD-1.
The study is expected to enroll approximately patients in the US, UK, Korea, and Taiwan with recruitment beginning in the second half of 2019.
In 2019 sales of Keytruda were up by 58% year-on-year, which led Merck to a sales increase of 12% overall compared to 2018. The drug is on track to bring in revenues of above $10bn (€8.9bn).