Forlong Biotechnology, a clinical-stage biotech company focused on developing transformative cytokine therapies for patients with severe unmet needs, today announced that its manufacturing partner, JOINN Biologics, has successfully completed production of the FL115 pivotal batch, which will support the company’s upcoming Phase III clinical trial in non-muscle invasive bladder cancer (NMIBC).

FL115 is an engineered IL-15/IL-15Rα-Fbody^® fusion protein. Fbody^® is a single-chain Fc engineered to preserve FcRn affinity while eliminating binding to FcγRs and complement systems, with the goal of optimizing protein half-life and biodistribution. FL115 drug substance and drug product have demonstrated excellent stability and solubility at concentrations up to 20 mg/mL, supported by a robust, low-cost GMP manufacturing process.

A clinical study of FL115 (NCT07122414) in BCG-unresponsive NMIBC is ongoing. Following the first patient dosing in August 2024, 10 patients have been dosed with FL115 alone and 52 patients have been dosed with FL115 at 3 dose levels in combination with BCG, all via intravesical delivery.

“FL115 in combination with BCG has shown impressive safety and efficacy data in patients with BCG-unresponsive NMIBC, with the potential to be the best-in-disease therapy,” said Dong Wei, Ph.D., Chief Executive Officer of Forlong Biotechnology. “Successfully manufacturing and releasing the pivotal batch is an important milestone for the FL115 program, and we greatly appreciate the professional expertise and diligent effort of JOINN Biologics as our manufacturing partner. Together, we will advance FL115 into the pivotal Phase III clinical trial for NMIBC in 2027.”