Comparative Phase 3 Study of GSK5764227, a B7-H3 Antibody-Drug Conjugate, Versus Topotecan in Relapsed Small Cell Lung Cancer Patients

The primary objective is to compare the antitumor activity of GSK5764227, a B7-H3 antibody drug conjugate, against topotecan in patients diagnosed with relapsed small cell lung cancer. This evaluation is critical for determining the comparative therapeutic efficacy of the novel agent in a refractory setting. 5, 4, 6, 7.

The study involves a total of 139 participants diagnosed with small cell lung cancer. The population includes both male and female patients. The age range of the participants corresponds to categories 3 and 4. Eligible subjects must have histologically or cytologically confirmed extensive stage small cell lung cancer. Prior treatment must include exactly one platinum-based systemic therapy administered for at least two cycles in combination with a PD-(L)1 inhibitor. Participants are required to have at least one non-brain target lesion according to RECIST 1.1. Additionally, an ECOG performance status of 0 or 1 is mandatory, alongside the presence of adequate organ function.

This Phase 3, multicenter, randomized, open-label clinical study is designed to compare the antitumor activity of GSK5764227, a B7-H3 antibody drug conjugate, against topotecan in participants with relapsed small cell lung cancer. The study methodology aims to evaluate efficacy through two primary endpoints: objective response rate and overall survival. The trial sequence begins with a screening visit to confirm histological or cytological evidence of extensive-stage small cell lung cancer, ensure adequate organ function, and verify a performance status of 0 or 1 according to ECOG criteria. Following successful screening, participants undergo randomization to receive either the investigational product or the comparator via intravenous use. The trial period is estimated to conclude by September 2028.

The experimental treatment consists of GSK5764227, an antibody-drug conjugate administered as a powder for solution for infusion. The dosage is 8 mg/kg via intravenous use.

The comparator treatment is topotecan, provided as a solution for infusion. This medication is administered via intravenous use at a dose of 1.5 mg/m² for participants with relapsed small cell lung cancer.

The antitumor activity of GSK5764227 will be evaluated in participants with relapsed small cell lung cancer. The primary efficacy endpoints include overall response rate (ORR) and overall survival (OS).

ORR is defined as the percentage of participants achieving a confirmed complete response (CR) or a confirmed partial response (PR) according to RECIST 1.1. This assessment will be conducted via blinded independent central review (BICR). OS is defined as the duration from the date of randomization to the date of death from any cause.