What has the global phase III trial changed?

  • The TROP2 antibody-drug conjugate sac-TMT, jointly developed by Kelun-Biotech and Merck & Co., was evaluated in previously treated patients with advanced or recurrent endometrial cancer in the global phase III TroFuse-005 trial. Bernstein views this as an important test of whether earlier Chinese trial data can translate to the global population.
  • At a median follow-up of 14 months, median progression-free survival was 7.2 months in the sac-TMT group and 3.9 months in the physician’s choice of treatment group; the risk of disease progression or death was reduced by 41%. Median overall survival was 19.0 months and 12.1 months, respectively, with the risk of death reduced by 32%; both improvements were statistically significant.
  • The treatment need arises from limited later-line options: for patients whose disease continues to progress after platinum-based chemotherapy and PD-(L)1 therapy, single-agent chemotherapy remains among the main treatment options.

How does its efficacy compare with other ADCs?

  • Bernstein believes that, although patients in the sac-TMT trial had received more prior treatment, its efficacy signal remains competitive among ADCs in the same class. Its median progression-free survival of 7.2 months is comparable to data for AstraZeneca’s puxi-sam, although the latter was studied in patients at earlier lines of treatment who were B7-H4 positive.
  • The median overall survival of 19.0 months for sac-TMT is numerically higher than the approximately 15.0 months reported for Gilead’s Trodelvy; overall survival data for most competing ADC programs are not yet mature. The populations and stages differ across trials, making these figures a cross-trial comparison.

What constraints could limit broader use?

  • The incidence of grade 3 or higher treatment-related adverse events in the sac-TMT group was 54.4%, higher than the 41.4% in the physician’s choice of treatment group. Stomatitis warrants attention: its incidence at any grade was 55%, with approximately 10% reaching grade 3 or higher.
  • The dose interruption rate in the trial was 44.5%. Preventive use of steroid mouthwash has significantly reduced the incidence of stomatitis; Bernstein believes targeted interventions and better adverse event management are important for broader clinical use.

What is the regulatory progress and institutional assessment?

  • Based on these data, the US FDA has accepted the biologics license application for sac-TMT in this indication and granted it priority review, with a target review date of 15 June 2027.
  • Bernstein rates Kelun-Biotech “Outperform” with a target price of HK$526, implying approximately 10% upside from the closing price of HK$480.20 on 26 October 2026. The firm also lists downside risks including trial results falling short of expectations, a slower-than-expected ramp-up in domestic sales, and global licensing revenue failing to materialize.