Forlong's $17.5M Boosts Next-Gen Cytokine Cancer Therapies

SHANGHAI & SUZHOU, China – May 19, 2026 – Forlong Biotechnology, a clinical-stage company developing a new class of cancer treatments, has secured RMB 120 million (approximately USD 17.5 million) in a Series Pre-B financing round. The funding, co-led by Fudan Capital and an undisclosed fund, is set to accelerate the development of the company's promising cytokine-based therapies, positioning it as a key player in the next wave of immuno-oncology.

The capital infusion will be primarily directed toward advancing two lead candidates: FL115, an IL-15 superagonist, and FL116, a novel PD-1/IL-18 bispecific antibody. This move signals strong investor confidence in Forlong's approach to tackling some of the most challenging cancers, including those that have become resistant to current treatments.

A Vote of Confidence in Cytokine Innovation

This latest financing round, which also saw participation from Changshu Guofa Venture and Kunsheng Relay Fund, builds on the momentum from a RMB 110 million (approx. $16.2 million) raise in February 2023. The continued support underscores a belief in Forlong's strategy and its proprietary technology platforms, which are designed to engineer safer and more effective versions of cytokines—powerful signaling proteins that regulate the immune system.

Investors have taken note of the company's progress. Fudan Capital stated, “We are confident in Forlong Biotechnology’s leadership position in the cytokine therapeutics space. The company has established globally leading technology platforms including Fbody® and Syntokine®, validated through R&D collaborations with top-tier pharmaceutical companies such as Innovent and Henlius.”

The investor's statement further highlighted the potential of the company's lead asset, FL115, noting it has “demonstrated global best-in-class potential in Phase I clinical trials... underscoring a high probability of successful commercialization.” Fudan Capital believes FL115 could become a “benchmark in tumor immunotherapy in the post-PD-1 era,” referring to the need for new options for patients whose cancers no longer respond to blockbuster PD-1 checkpoint inhibitors.

The Science Driving the Pipeline

At the heart of Forlong's strategy are its two lead drug candidates, which leverage distinct but complementary immune-activating mechanisms.

FL115 is an IL-15 superagonist designed to potently activate and expand two critical types of immune cells: Natural Killer (NK) cells and CD8+ T cells, both of which are essential for finding and destroying cancer cells. In early clinical trials involving 95 patients with advanced solid tumors or non-muscle invasive bladder cancer (NMIBC), FL115 has shown a promising safety profile and early signs of efficacy. Notably, the company reports that FL115 is the only IL-15 superagonist to have achieved a partial response in a patient when used as a standalone monotherapy. For NMIBC patients, four out of six treated with FL115 alone achieved responses lasting over three months.

FL116 represents a different, more targeted approach. It is a bispecific antibody that combines a PD-1 inhibitor with a modified version of the cytokine IL-18. This dual-action molecule is designed to block the PD-1 "off switch" on T cells while simultaneously delivering a powerful IL-18 "on switch" directly to the tumor microenvironment. A key innovation in FL116 is its ability to evade the naturally occurring IL-18 binding protein (IL-18BP), a decoy protein that can neutralize the effects of IL-18. Preclinical studies have shown that FL116 can induce potent tumor-killing in models resistant to standard checkpoint inhibitors, with a safety profile supported by initial studies in non-human primates.

The company plans to share more detailed clinical data at upcoming major scientific conferences, including the Society for Immunotherapy of Cancer (SITC) 2025 Annual Meeting and the 2026 ASCO Annual Meeting.

Navigating a Competitive Therapeutic Landscape

Forlong is entering a dynamic and increasingly competitive field. The approval of ImmunityBio’s Anktiva (N-803) in April 2024 as the first IL-15-based therapy for BCG-unresponsive NMIBC validated this therapeutic class and set a benchmark. Several other major pharmaceutical companies, including Sanofi and BeiGene, are also developing their own IL-15 agonists.

However, Forlong believes FL115 is differentiated. Its unique engineering, based on the company's Fbody® platform, aims for a better safety profile and superior tumor penetration. The company's claim of achieving a partial response with monotherapy in a solid tumor patient, if substantiated in larger trials, could set it apart from competitors that have primarily shown efficacy in combination with other agents.

The landscape for IL-18 therapies like FL116 appears less crowded, particularly for bispecific antibodies targeting both PD-1 and IL-18. By designing a molecule that overcomes the natural inhibition of IL-18 by its binding protein, Forlong may have carved out a unique niche with the potential to treat a broad range of tumors, especially those that have proven difficult for current immunotherapies.

Addressing Critical Unmet Needs in Cancer Care

The ultimate goal of this research and investment is to provide new hope for patients with hard-to-treat cancers. BCG-unresponsive NMIBC, for example, is a condition where the standard-of-care immunotherapy fails, often leaving radical bladder removal as the only option. An effective, bladder-sparing alternative is a significant unmet need.

“Exciting progress in the past 3 years have validated our cytokine-based portfolio strategy, R&D capability and efficiency,” said Dong Wei, Ph.D., CEO of Forlong Biotechnology. “This round of financing will enable us to strengthen operational readiness and accelerate clinical development momentum to advance FL115 into Phase 3 pivotal study for BCG-unresponsive NMIBC, and FL115 as well as FL116 into Phase 2a definitive studies for solid tumors in 2027.”

The company’s focus also extends to the large population of patients with advanced solid tumors who do not respond to or relapse after treatment with PD-1 inhibitors. By activating the immune system through different pathways with FL115 and FL116, Forlong aims to overcome this resistance and offer durable benefits.

“Cytokine therapeutics have demonstrated breakthrough potential across multiple areas of significant unmet medical needs,” stated Mr. En Ji, Co-founder of Forlong Biotechnology. He emphasized the company's commitment to "synthetic immunology-driven original innovation" and its goal to "bring safer and more effective cytokine therapies to patients." The new funding is a critical step in turning that commitment into clinical reality, moving these promising therapies from the laboratory bench to the patient’s bedside.