Why were the early JMT108 data a positive surprise?

  • Morgan Stanley rated the first-in-human trial results for the PD-1/IL-15 drug JMT108 as slightly better than expected. Among patients with hepatocellular carcinoma receiving second-line or later treatment, the objective response rate in the efficacy analysis set was 40% (4/10); among patients previously treated with immunotherapy, it was 33.3% (3/9).
  • The objective response rate among patients with colorectal cancer receiving second-line or later treatment was 21.1% (4/19); among those with liver metastases, 4 of 17 patients achieved a response. The bank believes the data suggest the drug has the potential to restore antitumor activity in patients who have developed resistance to immunotherapy.
  • The company has initiated phase Ib/II studies in China for colorectal cancer and hepatocellular carcinoma, and the colorectal cancer indication has received breakthrough therapy designation from the US FDA.

What limitations remain in the safety and dose data?

  • IL-15-related adverse reactions, a focus for investors, were generally manageable. The incidence of grade 3 or higher treatment-related adverse events was 8.3% and 23.1% in the 0.3 mg/kg and 1 mg/kg dose groups, respectively; in the 1 mg/kg group, individual patients experienced grade 3 or higher IL-15-related events, such as elevated liver enzymes or rash.
  • In the 2 mg/kg group, 1 patient discontinued treatment because of a grade 3 or higher immune-related adverse event. Small sample sizes and differing patient baseline characteristics across dose groups, together with heavier prior treatment in the 1 mg/kg group, complicate comparisons between doses; duration of efficacy and long-term safety data will affect the assessment of competitiveness.

How are the two breast cancer regimens progressing?

  • Breast cancer data for the B7H3 ADC SYS6043 met Morgan Stanley’s expectations. In the triple-negative breast cancer cohort of 32 patients, the objective response rate was 75%, median progression-free survival was 7.2 months, and median duration of response was 5.5 months; the company has initiated a phase III trial in first-line triple-negative breast cancer.
  • An interim analysis of a phase III trial of the HER2 bispecific antibody Anbenitamab plus HB1801 in first-line HER2-positive breast cancer showed that independently reviewed median progression-free survival had not been reached, versus 14.3 months in the control group, with a hazard ratio of 0.46. The investigator-assessed hazard ratio was 0.52, and the final progression-free survival analysis is expected to be published between the end of 2027 and early 2028.
  • The bank believes this hazard ratio is competitive in cross-trial comparisons, but differences in the control group’s performance, use of endocrine therapy and statistical methods in another trial limit direct comparison. The supplemental marketing application for this breast cancer indication was accepted and granted priority review in August 2026.