FDA rejected Eli Lilly and Innovent Biologics’ PD-1 inhibitor sintilimab in 2022 with a Complete Response Letter that primarily cited the drug’s failure to show a significant advantage over existing PD-1 inhibitors like Keytruda and Opdivo; the FDA also recommended an additional multiregional trial if Lilly wanted to resubmit. Lilly walked away from the drug’s ex-U.S. rights that same year.
Summit Therapeutics and Chinese partner Akeso are staring down the same fork. On July 22, Summit released a two-year follow-up from its global HARMONi trial showing the overall survival hazard ratio in Western patients improved to 0.76, catching up to results seen in Asian patients. That’s a sharp turn from 0.98 at the April 2025 primary analysis, the number that had analysts worried Chinese efficacy wouldn’t hold up abroad.
The stakes: FDA’s decision on ivonescimab, a PD-1/VEGF bispecific that beat Keytruda outright in a China-run trial, is due Nov. 14.
Merck faces its own version of this test. Its China-based partner Kelun-Biotech’s OptiTROP-Lung06 trial hit its primary endpoint on July 14 for antibody-drug conjugate sac-TMT paired with Keytruda, in a trial conducted in China.
Sintilimab is the cautionary tale everyone in oncology cites informally now. Summit and Merck are both threading the needle Lilly missed, backing single-country wins with multiregional data instead of resubmitting and hoping the numbers translate. One of them will find out first whether that’s enough.
Summit’s own multiregional trial, HARMONi-3, isn’t due to read out until December 2028. Long wait.
— Sarah Chen