SUZHOU and SHANGHAI China, Jul 10, 2025 - Forlong Biotechnology, a clinical stage biotech dedicated to developing next-generation cytokine therapeutics, today announced that CDE has approved the Phase Ib/II IND application of FL115 (IV) Plus PD-1(Sintilimab) in patients with advanced solid tumors. The Phase Ib/II clinical study, launched under the clinical collaboration signed with Innovent Biologics in December 2024, is also the fourth clinical trial of FL115. In the early clinical trials, FL115 monotherapy has already shown preliminary efficacy.

IL-15 possesses the ability to activate NK cells and T cells, and its mechanism of action is highly synergistic with PD-1 antibodies. The clinical potential of such combination therapy has been demonstrated. At the 2024 WCLC, data from the Phase 2 QUILT 3.055 trial showed that IL-15 plus CPI therapy in 2nd line or greater NSCLC demonstrated long-term median OS, independent of PDL1 status, and independent of prior lines of therapy in patients with acquired resistance to CPI. These findings support the novel mechanism of action of IL-15 to rescue CPI activity through the activation of NK and T cells, driving long-term memory, with median OS ongoing survival of 33% and 30% at 18 and 21 months respectively, exceeding the standard of care. Pre-clinical studies have shown synergistic NK- and T-cell activation when combined with sintilimab.

With cytokine therapeutics poised to become a cornerstone of next-generation immuno-oncology, Forlong will leverage its deep cytokine engineering expertise to expand a pipeline of multi-functional immune-cell-activating agents and deliver accessible treatment options for cancer patients.

About FL115

FL115, a fusion protein composed of IL-15, IL-15Rα, and Fbody, is a super agonist of interleukin-15 (IL-15) that can activate natural killer (NK) cells and memory T cells. FL115 has demonstrated superior safety and tumor-killing ability to Anktiva® in multiple pre-clinical models with expanding the therapeutic window.Currently, multiple clinical trials of FL115 are ongoing in China and the United States. As a monotherapy, it has shown good safety and initial clinical efficacy in patients with advanced solid tumors. It is the only IL-15 super agonist to achieve partial response (PR) as a monotherapy and has the potential to be the best-in-class globally.

About Forlong Biotechnology

Forlong Biotechnology is a clinical stage biotechnology company dedicated to developing next-generation cytokine therapeutics. Based on synthetic immunology, the company has established four core technology platforms, committed to overcoming the challenges of developing cytokine drugs.

Focusing on tumor immunology, Forlong develops engineering therapeutic cytokine combinations that act at distinct steps of the cancer–immunity cycle to treat cancer.