On April 11, Shanghai Junshi Biosciences (Junshi) provided a brief interim update on the Phase III FLAMES trial (NCT04169997) for its poly (ADP-ribose) polymerase inhibitor (PARPi) senaparib.

Targeting patients with stage III/IV ovarian carcinoma, fallopian tube cancer or primary peritoneal cancer who achieved a complete response or partial response to first-line, platinum-based chemotherapy, senaparib as a maintenance therapy improved progression-free survival compared to placebo, with the primary endpoint of meeting the predefined efficacy boundary for the FLAMES trial. Detailed clinical data had not yet been provided in the current announcement.

PARPi as targeted therapy has been the only targeted therapy drug class positioned as maintenance therapy following platinum-based chemotherapy. Domestically developed in China, senaparib is on track to becoming the latest Chinese PARPi in this setting with a competitive price tag. The new agent is unlikely to disrupt markets outside of China as the joint venture agreement Junshi has with IMPACT Therapeutics aims for the R&D and commercialisation of the asset within mainland China, Hong Kong and Macau. Also, Chinese patients are the only patient population enrolled in the FLAMES trial, giving rise to a regulatory obstacle in the lack of racial diversity when the new agent is filed for approvals in foreign markets.

According to GlobalData’s Pharma Intelligence Center, there are four National Medical Products Administration-approved PARPi for ovarian cancer (OC) maintenance in the Chinese market, with two overseas-originated players—GSK’s Zejula (niraparib) and AstraZeneca’s Lynparza (olaparib) and two domestic players—Hengrui’s AiRuiYi (fuzuloparib) and Beigene’s Partruvix (pamiparib). All four PARPi are currently listed on the 2022 National Drug Reimbursement List (NRDL). Senaparib is likely to see difficult competition with entrenched OC competitors, especially when the first mover Zejula, which was approved in first-line maintenance in late 2020, has a three-year head start propelled by GSK’s commercialisation partner Zai Lab in the country.

With the commoditisation of PARPi in the space, Junshi will have to provide superior efficacy or safety data to create a meaningful differentiation from existing players. Combination therapy might be a strategy for the pipeline agent to penetrate the OC market, yet the candidate is lagging with one early trial (Phase I/II, NCT05269316) compared to senaparib, which is being evaluated in combination with a novel ATR inhibitor, IMP-9064, in patients with advanced solid tumours.

Addressing the Chinese physician and patient community could be a winning strategy for Junshi. The underutilisation of OC maintenance therapy in China was illustrated in the 2022 white paper on China’s OC treatment landscape, which was jointly published by the Chinese Gynecologic Cancer Society (CGCS) and Beijing Life Oasis Public Service Center. The adoption of maintenance was limited by the lack of insurance coverage on PARPi and inadequate community awareness, resulting in only 38% of first-line patients receiving the therapy. In contrast, 93% of first-line patients who responded to the white paper’s survey will consider using maintenance therapy if available.

Ultimately, senaparib’s NRDL inclusion will be instrumental to its greater market penetration, as well as increasing education for local healthcare professionals and OC patients via medical conferences, awareness campaigns and patient guidelines, all of which will prove useful to the promotion of the latest inhibitor. Collaboration with advocacy groups like the CGCS, as well as omnichannel marketing, will help catalyse the process of community education on the importance of maintenance therapy. Targeting key leverage points will be important to counteract the commoditisation of the PARPi market.