Summit Therapeutics and its China-based partner Akeso revealed new data last week indicating that their PD-1/VEGF-targeting antibody ivonescimab shows efficacy across different geographic populations, a development that could help them in seeking U.S. Food and Drug Administration approval. Traditionally, cancer therapies developed in China must demonstrate efficacy in U.S. or global trials to secure FDA approval.
Daina Graybosch, senior managing director of immuno-oncology at Leerink Partners, said, “Probably the biggest thing to keep in mind is this is just a flip of a process that has existed for, I don’t know, the last 20 years in drug development. It used to be that global studies were bridged to Asian countries.” She cited Merck’s Keytruda as an example where bridging studies were conducted specifically for Chinese regulators after global trials.
China now hosts more clinical trials than any other country, with many novel therapies being tested there first. Harpreet Singh, chief medical officer at Precision for Medicine and former division director of Oncology at FDA, said these are “quite novel and innovative therapies that are not necessarily follow-on drugs.” Ivonescimab notably outperformed Keytruda in a Phase 3 trial hosted in China by reducing the risk of disease progression or death by 49%. However, questions remain about whether these results will translate to American patients.
Stifel analysts wrote on July 22 that new data from North American and European patients provide “a strong counter” to concerns about translatability, but noted further details on statistical significance have yet to be shared. Other companies face similar challenges; Merck’s partnership with Kelun-Biotech also produced positive results from Chinese trials but must replicate them globally for Western approvals.
The FDA previously rejected Eli Lilly’s PD-1 inhibitor sintilimab because its Phase 3 study was conducted only in China without offering significant advantages over existing treatments like Keytruda or Opdivo. The agency recommended an additional multiregional trial if Lilly wanted to resubmit.
Graybosch emphasized the complexities introduced by moving from homogeneous populations like those found in single-country studies into more diverse global settings: “Whenever you do any sort of clinical experiment in humans, variability creates noise,” she said. She also highlighted factors such as genetics and socioeconomic differences among trial participants as potential contributors to varying outcomes between regions.
Both Summit/Akeso and Merck/Kelun are planning or conducting multiregional trials expected to yield further data later this year or beyond. The FDA encourages early engagement with sponsors considering approval based solely on foreign data through presubmission meetings.
