Novel Immunotherapy Receives Breakthrough Designation in Advanced Melanoma

The therapy is a modified poliovirus vaccine that not only kills cancer cells but also can trigger long-term immune memory.

The FDA has granted fast track designation for Pvsripo for the improved survival in patients with advanced melanoma who have disease progression after anti-PD-1/anti-PD-L1 therapy. Pvsripo, developed by Istari Oncology in Durham, North Carolina, is a novel viral immunotherapy in development in combination with anti-PD-1/L1 therapies.

“We strategically prioritized the clinical trials program for melanoma given the lack of effective options for patients whose cancer can’t be surgically resected and who failed other treatments,” Matt Stober, president and chief executive officer at Istari Oncology, said in a statement.

Istari oncology is recruiting for a phase 2 open-label, randomized trial in patients with advanced, unresectable melanoma who previously failed anti-PD-1 therapy. A phase 1 monotherapy study of Pvsripo in anti-PD1 refractory advanced melanoma found that patients who received three Pvsripo injections (6/12) had an overall response rate of 67% (4/6).

Pvsripo is an immunotherapy based on the live attenuated Sabin type 1 poliovirus vaccine that has been genetically modified. It targets CD155, which is expressed on many solid tumors. It activates a patient’s innate and adaptive immune system to kill cancer cells and establish a long-term immunologic memory to kill cancer if it returns.

Earlier this year, the FDA granted Pvsripo orphan drug designation for treatment of advanced melanoma. Preclinical data of Pvsripo in combination with an immune checkpoint inhibitor in advanced melanoma was presented at the American Society of Clinical Oncology (ASCO) in June 2021.

Additionally, the FDA granted breakthrough therapy designation and orphan status to Pvsripo in recurrent glioblastoma. At ASCO, the company presented the study design for a phase 2, multicenter, open-label, single-arm study of intratumoral infusion of Pvsripo in combination with pembrolizumab (Keytruda) in patients with recurrent glioblastoma.