ESMO 2026 Takeaways: Updated Mo-Rez Phase Ib PROC data looks encouraging on efficacy, minor positive

This weekend, we attended the ESMO 2026 Conference, where we saw data updates for GSK's Mo-Rez (B7H4 ADC) and a safety analysis for Ris-Rez (B7H3 ADC) and the AZUR-1 data for Jemperli. The Mo-Rez updated Phase Ib BEHOLD-1 global data confirmed the strong ORR shown earlier this year in a larger, more robust sample size (n=130 vs. 34 previously) and also showed a strong duration of response of 12.2 months and median PFS of 11 months, with the totality of the efficacy data described as "excellent" by the discussant. On tolerability, treatment discontinuation rates were low at the selected 5.8mg/kg dose at 2%, but higher at the middle dose at 7%. While further data will be needed to assess the competitive positioning of Mo-Rez in the rapidly evolving PROC landscape, where Genmab's Rina-S demonstrated a strong 71% PFS benefit in Phase III, we see the updated BEHOLD-01 trial as encouraging for the ongoing Phase III, where GSK have guided for submission in 2029+. We forecast a 50% probability