GSK's risvutatug rezetecan shows 18.5-month
GSK and Hansoh Pharma's antibody-drug conjugate risvutatug rezetecan achieved a median overall survival of 18.5 months in a phase 3 trial for relapsed
GSK's antibody-drug conjugate risvutatug rezetecan (ris-rez) posted a median overall survival of 18.5 months in a phase 3 trial for small cell lung cancer. The result compares to 10.3 months for patients on the chemotherapy drug topotecan.
Hansoh Pharma's phase 3 trial enrolled 461 patients with small cell lung cancer (SCLC) at sites in China. All participants had relapsed after initial treatment with platinum-based therapy. They received either the B7-H3-targeting ADC ris-rez or topotecan via intravenous infusion every three weeks.
The 18.5-month median overall survival result was statistically significant, meeting the trial's primary goal. This outcome suggests ris-rez could be a strong contender in the second-line SCLC treatment landscape, where other new drugs have shown shorter survival times.
Comparative survival data
Data from recent trials for other second-line SCLC therapies show varied results. The following table compares median overall survival figures from different studies.
| Therapy (Company) | Trial Phase | Median Overall Survival (Months) | Comparator Arm Survival (Months) |
|---|---|---|---|
| risvutatug rezetecan (GSK/Hansoh) | 3 | 18.5 | 10.3 (topotecan) |
| Imdelltra (Amgen) | 3 | 13.6 | 8.3 (chemotherapy) |
| ifinatamab deruxtecan (Merck/Daiichi) | 2 | 12.0 | Not reported |
Direct comparisons are complicated by differences in trial design. A key distinction is that the ris-rez trial was conducted solely in China, while the studies for Imdelltra and ifinatamab deruxtecan were global.
Questions over global translation
Western drugmakers increasingly seek cancer drugs from China, raising questions about whether clinical data from Chinese trials will hold up in global populations. Hesham Abdullah, M.D., global head of oncology R&D at GSK, addressed this on a media call.
Abdullah cited consistent data for another Hansoh-partnered ADC, mocertatug rezetecan, in Chinese and global studies as a reason for confidence. He stated that treatment pathways for patients before receiving ris-rez are similar in China and globally. This parallel development provides GSK with "two independent data sets that are being replicated" to help prioritize which cancer types to target.
Safety profile and development timeline
GSK began a global phase 3 trial of ris-rez in relapsed SCLC last year, with key data expected in 2027. This timeline puts GSK behind rivals, but Abdullah suggested safety could be a differentiator.
He noted that interstitial lung disease (ILD) is linked to some other drug platforms. Daiichi Sankyo and Merck reported two fatal treatment-related ILD events in their mid-phase trial for ifinatamab deruxtecan. In contrast, Hansoh reported no grade 4 or 5 ILD events in its phase 3 ris-rez trial. The rate of grade 3 ILD events was 3.9% for ris-rez, similar to the rate seen in the ifinatamab deruxtecan study.
The absence of fatal ILD events in the Hansoh trial may give the GSK-partnered ADC a potential edge. Despite the strong phase 3 data, investor enthusiasm for ris-rez has been muted. Analysts at Guggenheim Securities said in a July note that the drug's differentiation was "unclear to us at the moment," assigning limited risk-adjusted sales potential to it and GSK's broader ADC portfolio.
