Positive Phase 3 Data Still May Not Win FDA Approval
China now hosts many of the world’s clinical trials, and cancer therapies increasingly enter development there first. This reverses the traditional West-to-Asia bridging model. However, FDA approval depends on more than statistical success. Regulators examine whether population differences could change efficacy, safety or dose response. Therefore, sponsors must show that a positive result reflects the drug’s effect rather than the characteristics of one regional population.
China-First Cancer Drugs Face a Global Evidence Problem
A trial conducted in one country may include a homogeneous population. In contrast, a global study includes more variation in age, genetics, disease biology, smoking history and post-trial care.
That variability can change the treatment effect. For example, HARMONi-6 included many Chinese patients with squamous non-small cell lung cancer who had never smoked. That profile appears less often in U.S. practice. As a result, regulators and analysts question whether ivonescimab can deliver the same benefit across Western populations.
Sintilimab Had Phase 3 Data So Why Did FDA Still Say No?
The FDA signaled this concern in 2022 when it rejected Eli Lilly and Innovent Biologics’ sintilimab application for lung cancer. The pivotal Phase 3 study enrolled patients only in China.
Although the drug lacked a clear advantage over available PD-1 therapies, the FDA recommended another multiregional study. The decision showed that positive single-country data may not support approval when regulators cannot confirm global relevance. It demonstrated how late evidence gaps can delay or end a development program.
Can Bridging Studies Save China-First Drugs From FDA Delays?
Sponsors do not always need to repeat a global Phase 3 trial. Instead, the FDA may consider a bridging study, limited U.S. data or substantial post-marketing requirements when a therapy shows a transformative benefit.
However, companies must discuss these options early. A bridging strategy can test whether regional efficacy translates to U.S. patients without repeating a four-to-six-year program. In addition, early FDA engagement helps sponsors define acceptable populations, control arms and evidence standards before completing development.
Summit and Merck Now Face the FDA’s Toughest Evidence Test
Summit and Akeso are collecting multiregional evidence through HARMONi-3, while Merck and Kelun-Biotech are evaluating sacituzumab tirumotecan in several global Phase 3 studies. These programs may determine whether China-first cancer assets can cross the regulatory divide.
The central lesson remains clear. Positive Phase 3 results can establish promise, but they do not guarantee FDA approval. Sponsors must prove that the data remain reliable across populations, regions and standards of care. Without that bridge, even a successful cancer drug may face delay, additional trials or rejection.
As global development programs face closer regulatory scrutiny, pharmaceutical teams also need robust validation frameworks to keep regulated systems and supporting data reliable throughout the lifecycle. Explore Zamann Pharma’s Qualification and Validation for GMP-Regulated Systems service to strengthen compliant, consistent, and inspection-ready validation practices.
Source: Biospace.Com