RemeGen Co., Ltd., a leader in biopharmaceutical innovation based in China, has unveiled promising results from its Phase I/II clinical study of RC88, a first-in-class antibody-drug conjugate (ADC), at the American Society of Clinical Oncology Annual Meeting (ASCO 2024) in Chicago. The study focuses on the efficacy and safety of RC88 in treating advanced solid tumors expressing mesothelin (MSLN), with significant findings in ovarian, non-squamous non-small cell lung, and cervical cancers.

Overview of Clinical Study Results

The Phase I/II study, an open-label, multi-center trial, evaluated the effects of RC88 in patients who had previously failed standard therapies. RC88 targets MSLN, a protein overexpressed in many solid tumors, using a monomethyl auristatin E (MMAE) payload to inhibit microtubule function, leading to cancer cell death. As of the latest data cutoff on February 21, 2024, 170 patients had been enrolled, with dosages of 2.0 mg/kg and 2.5 mg/kg expanded into the Phase II part of the study.

In the ovarian cancer cohort, an overall response rate (ORR) of 41.9% was observed, significantly surpassing the ORR for standard chemotherapy, which stands at approximately 12%. In the non-squamous non-small cell lung cancer (NSCLC) cohort, patients with high MSLN expression showed an ORR of 41.7%, with a median progression-free survival (PFS) of 6.87 months and median duration of response (DoR) of 9.13 months. The cervical cancer cohort also demonstrated encouraging results, with an ORR of 33.3% among patients who had progressed on previous systemic therapies.

Safety and Efficacy

RC88 has shown a manageable safety profile consistent with the known effects of MMAE, including potential infusion reactions and transient increases in liver enzymes. The study’s findings indicate that RC88 could be a potent new treatment option for patients with MSLN-expressing tumors, offering a novel mechanism of action compared to traditional chemotherapy.

Expert Commentary

Dr. Fang Jianmin, CEO of RemeGen, highlighted the significance of these results, stating, “The promising results of 41.9% ORR from this study underscore the potential of RC88 to significantly improve outcomes for patients with MSLN-expressing advanced solid tumors. We are committed to advancing our innovative therapies to address these huge unmet medical needs and enhance patient care.”

Future Directions

With ongoing recruitment and further data collection, RemeGen expects to provide additional updates on the efficacy and safety of RC88 in the second half of 2024. The continued positive results could pave the way for RC88 to become a vital component in the treatment regimens for various advanced solid tumors, particularly those resistant to conventional therapies.

  Advanced solid tumors, ASCO 2024, cancer treatment innovations, clinical trials, RC88, RemeGen