China-First Cancer Drugs Face New FDA Regulatory Hurdles

Summit, Merck Face Heightened FDA Scrutiny as China-First Oncology Trials Reshape Drug Approval Landscape 

NEW YORK, United States — July 27, 2026 — Summit Therapeutics and Merck & Co. are confronting a rapidly evolving regulatory environment as China-originated clinical trial data for cancer drug candidates — including the PD-1/VEGF-targeting antibody ivonescimab and the antibody-drug conjugate sacituzumab tirumotecan — face intensified scrutiny from the U.S. Food and Drug Administration, raising fundamental questions about the translatability of single-country oncology data to Western patient populations and reshaping the global cancer therapeutics development landscape. 

Summit Therapeutics and its China-based partner Akeso last week released two-year follow-up data from the global Phase 3 HARMONi study, demonstrating that ivonescimab's efficacy in North American and European patients is consistent with results previously observed in Chinese populations. The development is being viewed by analysts as a meaningful counter to persistent concerns that China-derived oncology data may not translate to Western patient cohorts. 

Ivonescimab, a bispecific antibody targeting both PD-1 and VEGF, previously demonstrated a 49% reduction in the risk of disease progression or death compared to Merck's blockbuster checkpoint inhibitor Keytruda in a Phase 3 non-small cell lung cancer (NSCLC) trial conducted exclusively in China. Akeso subsequently presented Phase 3 HARMONi-6 overall survival data at the American Society of Clinical Oncology (ASCO) annual meeting in May 2026, reporting a 34% reduction in the risk of death among Chinese patients. 

Despite these results, regulatory and scientific uncertainty has persisted. "The risk that China data would not translate has been a lingering bear argument," Stifel analysts wrote in a July 22 note, describing the new Western follow-up data as "a strong counter to that pushback." 

The FDA is expected to render a decision on ivonescimab by November 14, 2026. Summit and Akeso are also awaiting results from the multiregional HARMONi-3 trial (NCT05899608), which compares ivonescimab plus chemotherapy against Keytruda plus chemotherapy in first-line NSCLC across approximately 1,600 patients, with a data readout anticipated in December 2028. 

Merck faces a parallel challenge with sacituzumab tirumotecan (sac-TMT), an ADC developed in partnership with China's Kelun-Biotech. Phase 3 data released earlier this month indicated that sac-TMT combined with Keytruda has the potential to replace platinum-based chemotherapy in first-line NSCLC — but those results were also generated in China. Merck is currently evaluating sac-TMT in five global multicenter Phase 3 studies to generate the multiregional evidence required for FDA consideration. 

China now hosts more clinical trials than the United States or any other country, and the gap is widening. Harpreet Singh, Chief Medical Officer at Precision for Medicine and former Division Director of Oncology at the FDA, noted that many of the assets being tested in China are "quite novel and innovative therapies that are not necessarily follow-on drugs," underscoring the strategic importance of resolving the regulatory pathway for China-first oncology assets. 

The FDA has outlined two primary options for sponsors seeking approval based on single-country data: granting approval tied to substantial post-marketing requirements to confirm efficacy in U.S. patients, or requiring a bridging study — a smaller, targeted trial in a multiregional or U.S.-only population — to demonstrate that results translate across geographies. The agency has encouraged sponsors to engage in pre-submission meetings when approval based solely on foreign data is being sought. 

Key Highlights: 

• Summit Therapeutics and Akeso released two-year Western follow-up data from the global Phase 3 HARMONi study on July 22, 2026, showing ivonescimab's efficacy is consistent across North American and European patient populations. 

• The FDA is expected to issue a regulatory decision on ivonescimab by November 14, 2026, with the multiregional HARMONi-3 trial data anticipated in December 2028. 

• Merck and Kelun-Biotech's ADC sacituzumab tirumotecan demonstrated Phase 3 efficacy in first-line NSCLC in China; Merck is now running five global Phase 3 studies to support a potential FDA submission. 

Analyst Insight: 

According to analysts at Next Move Strategy Consulting, the regulatory complexity surrounding China-first oncology assets reflects a structural shift in global drug development that carries significant implications for the broader cancer therapeutics market. NMSC analysts note that as China continues to expand its share of global clinical trial activity — now surpassing the United States in trial volume — pharmaceutical companies pursuing FDA approval for China-originated assets will face increasing pressure to design multiregional studies from the outset of development. The ability to demonstrate cross-population efficacy will become a defining competitive differentiator, particularly in high-value oncology segments such as NSCLC, where multiple next-generation immunotherapy and ADC candidates are converging on the same patient populations. 

Industry Outlook: 

The regulatory terrain for China-first cancer therapeutics is expected to grow more defined as landmark decisions — including the FDA's anticipated ruling on ivonescimab by November 14, 2026 — establish precedent for how single-country oncology data will be evaluated in Western markets. As the global cancer therapeutics market advances toward USD 326.05 billion by 2030, the capacity of transnational pharmaceutical partnerships to navigate divergent regulatory frameworks will increasingly determine which next-generation oncology assets reach patients in the United States and Europe, and on what timeline. 

Source: BioSpace 

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Prepared By: Sanyukta Deb