A Phase 2 study examining the efficacy of patezolizumab and bevacizumab combined for malignant peritoneal mesothelioma (MPM) patients has just been published in the journal Cancer Discovery. The results demonstrated that this combination treatment was efficacious and well-tolerated for this patient population. The responses were both durable and robust.

Researchers are so excited about these findings because it means this combination treatment could fulfill an unmet therapeutic need for MPM. Despite the fact that some patients find optimal cytoreductive surgery, hyperthermic intraoperative peritoneal perfusion, and chemotherapy successful, many patients do not. Further, those who are unresponsive to this therapy typically face limited survival.

Additionally, despite the general recommendation of chemotherapy, there is unfortunately no currently approved first-line, standard therapy.

The Study

This study was conducted by a team from the University of Texas, and it included a wide array of rare cancers. You can read full details of the recent Phase 2 investigation here.

There were a total of 20 MPM patients (advanced and unresectable). All patients had experienced either an intolerance to the chemotherapy or disease progression. The patients’ average age was 63, and 60% were female. Most reported no exposures to asbestos.

The primary endpoint of this trial was objective response rate.

All patients were given atezolizumab at 1200mg and 15mg/kg of bevacizumab by IV once every 21 days. The treatment was stopped if the disease progressed or there were unacceptable levels of toxicity.

8 of the 20 patients met the primary endpoint. Their median response duration was 12.8 months. 6 of these patients had a response lasting longer than 10 months. Further, prior chemotherapy treatment did not have an impact on the patient’s response to the combination therapy.

The one-year overall survival rate was 85%. The median progression-free survival was 17.6 months.

Anemia and hypertension were the most commonly experienced grade 3 adverse events, occurring in 10 patients. However, no grade 4 or grade 5 adverse events were reported.

The researchers also noted that a high EMT gene expression score was correlated with a poorer overall response rate.

Ultimately, the researchers are hopeful for the future of this therapy in MPM based on the results of this study. You can read more of the details of this investigation and what its findings could mean for patients here.