Hansoh Pharma - H: Read-through from Merck/Daiichi B7-H3 ADC BLA Withdrawal

J.P. Morgan comments on Hansoh Pharma (3692.HK, Overweight). We think Merck/Daiichi's voluntary withdrawal of the U.S. BLA for their B7-H3 ADC ifinatamab deruxtecan (I-DXd) in previously treated ES-SCLC—after FDA discussions that the supporting data, including Ph2 IDeate-Lung01, did not meet requirements for accelerated approval—is incrementally positive for Hansoh/GSK's Ris-Rez (GSK, UW) from a competitive-timing perspective. The withdrawn BLA had priority review with an Oct. 10, 2026 PDUFA date; I-DXd's future U.S. filing now likely depends on the ongoing Ph3 IDeate-Lung02 (completion early 2028), so a new BLA might be filed in early 2028. Ris-Rez already reported positive randomized Ph3 OS data in ES-SCLC in China and is being evaluated in GSK's global Ph3 EMBOLD SCLC-301, whose potential U.S. filing could occur in 2028. In China Ph3 ARTEMIS-008 for 2L+ ES-SCLC, Ris-Rez delivered mOS of 18.5 vs 10.3 months vs topotecan (HR 0.46), mPFS 7.2 vs 3.0 months and ORR 58.3% vs 12.6%;