Suzhou-based Forlong Biotechnology has closed a Series Pre-B financing round of approximately RMB 120 million (USD 17.5 million) to advance its IL-15 and IL-18 pipeline, bringing total disclosed funding to roughly USD 33.7 million since the company's founding.
The round was co-led by Fudan Capital and an undisclosed fund, with participation from Changshu Guofa Venture, Kunsheng Relay Fund, and additional unnamed investors. The company said proceeds will be used to advance FL115, an IL-15 superagonist, toward a pivotal Phase III study in BCG-unresponsive non-muscle invasive bladder cancer (NMIBC), and to bring FL116, a PD-1/IL-18 bispecific antibody, into clinical testing. The company previously raised approximately RMB 110 million in February 2023, a round that funded FL115's entry into human trials and the dosing of 95 patients across advanced solid tumors and NMIBC.
FL115 and the IL-15 IL-18 pipeline
FL115 is Forlong's lead asset and the most clinically advanced program in its cytokine therapies portfolio. The molecule is an engineered IL-15 superagonist built on the IL-15[N72D]/IL-15Rα-sFc construct, designed to extend circulating half-life through FcRn-mediated recycling while silencing FcγR and complement binding to reduce off-target immune activation. The company has conducted Phase I trials in advanced solid tumors and is also evaluating FL115 in combination with a PD-1 antibody in the same setting. A separate study is examining intravesical FL115 alone or with BCG in NMIBC. BCG-unresponsive NMIBC is the stated lead pivotal indication, with a Phase III study planned as a primary use of the current financing.
FL116, the company's second disclosed asset, is a bispecific antibody targeting PD-1 and IL-18. Forlong said the molecule has shown tumor-killing activity across multiple in vivo models and that a pilot non-human primate toxicology study produced results supportive of safety. The company plans to advance FL116 into Phase IIa studies for solid tumors in 2027, alongside FL115.