The United States Food and Drug Administration has granted Fast Track Designation for China-based RemeGen‘s RC88, a mesothelin (MSLN)-targeting antibody-drug conjugate (ADC). The investigational drug is intended for the treatment of patients diagnosed with platinum-resistant recurrent epithelial ovarian, fallopian tube, and primary peritoneal cancers.
The FDA’s Fast Track Designation is a process to facilitate the development of novel therapeutics, and expedite the review of of these agents to treat serious conditions and fill an unmet medical need. The goal of this approach is to get important new drugs to the patient earlier.
“The FDA’s Fast Track Designation accelerates the development and review process of RC88, which affirms our commitment to pioneering treatments that address the urgent needs of those facing challenging disease. Moving forward, RemeGen will continue to accelerate the development of its ADC products, with the aim of bringing more and better solutions to patients globally,” said Jianmin Fang, Ph.D., the Chief Executive Officer of RemeGen,
The regulatory decision marks another significant development following an earlier FDA approval to RC88’s international multicenter Phase 2 clinical trials.
RC88 is a novel antibody drug conjugate (ADC) independently developed by RemeGen targeting mesothelin (MSLN).
Mesothelin (MSLN) is an attractive therapeutic target for antibody drug conjugates (ADC) because of significant differences in expression pattern between diseased and normal tissues.
Epithelial ovarian cancer (EOC) is the leading cause of cancer-related deaths in women, often diagnosed late and prone to relapse within two years, with their disease evolving from platinum-sensitive to resistant. The later the stage and the more aggressive the ovarian cancer, the higher the expression rate of MSLN, and current treatment options are limited. RC88 uniquely targets MSLN, offering a novel approach to this challenging medical condition.
RC88 uses RemeGen’s independently developed innovative bridging technology to connect antibodies and drugs. The structure includes MSLN-targeting antibodies, cleavable connections and the microtubule inhibitor monomethyl auristatin E (MMAE). The ADC can mediate the endocytosis of antibodies by binding to MSLN-positive tumor cells, thereby effectively delivering cytotoxins to cancer cells and achieving improved tumor killing effects.
An integrated analysis of results from preclinical studies showed that RC88 has an acceptable safety profile and provided an improved treatment window. Based on these results further investigation of RC88 in humans is scheduled. 
RemeGen will initiate international multicenter phase 2 clinical studies across the United States, China, the European Union, and other regions, aiming to further clarify the optimal dosage, effectiveness, and safety of RC88 monotherapy.
A Study to Assess the Safety and Tolerability of RC88 for Patients With Advanced Solid Tumors – ClinicalTrials.gov ID NCT05508334
A Study of RC88 Combined With JS001 for Advanced Solid Tumours
ClinicalTrials.gov ID NCT05804526
RC88 in Platinum-Resistant Recurrent Epithelial Ovarian Cancer, Fallopian Tube Cancer, and Primary Peritoneal Cancer
ClinicalTrials.gov ID NCT06173037
A Phase I /IIa Study of RC88-ADC in Subjects With Advanced Malignant Solid Tumors
ClinicalTrials.gov ID NCT04175847
 Jiang J, Li S, Tang N, Wang L, Xin W, Li S. Preclinical safety profile of RC88-ADC：a novel mesothelin-targeted antibody conjugated with Monomethyl auristatin E. Drug Chem Toxicol. 2023 Jan;46(1):24-34. doi: 10.1080/01480545.2021.2005085. Epub 2021 Nov 28. PMID: 34839761.
 Li Q, Wang L, Zhang J, Zhao G, Liu Z, Ma X, Jiang J. Translation of the efficacy of antibody-drug conjugates from preclinical to clinical using a semimechanistic PK/PD model: A case study with RC88. Clin Transl Sci. 2023 Jul;16(7):1232-1242. doi: 10.1111/cts.13526. Epub 2023 May 31. PMID: 37259689; PMCID: PMC10339704.
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