GSK (GSK) licensor Hansoh Pharmaceutical reported Sunday that a phase 3 trial evaluating risvutatug rezetecan, or Ris-Rez, against commonly used topotecan in patients with relapsed small-cell lung cancer met its primary endpoint.

Results of the trial showed the drug conjugate cut risk of death by 54% versus topotecan, the company said.

Patients treated with Ris-Rez lived a median of 18.5 months compared with 10.3 months for those treated with topotecan, the company added.

GSK retains exclusive rights to develop and commercialize Ris-Rez outside mainland China, Hong Kong, Macau and Taiwan, the company said.