MENLO PARK, CA, USA I October 28, 2021 I Synthekine Inc., an engineered cytokine therapeutics company, today announced it is advancing its IL-2 partial agonist, STK-012, into clinical investigation following clearance of its investigational new drug (IND) application by the U.S. Food and Drug Administration (FDA).

Synthekine will evaluate STK-012 in a Phase 1a/1b, open-label, multi-center, dose escalation study. The study will investigate STK-012 both as a monotherapy and in combination with an immune checkpoint inhibitor in individuals with advanced solid tumors.

“IL-2 is a cytokine with proven benefit as an anti-cancer therapy. However, the indiscriminate activity of IL-2 can cause severe toxicities, limiting its clinical application,” said Naiyer Rizvi, M.D., chief medical officer of Synthekine. “We have designed STK-012 to uncouple the efficacy and toxicity of IL-2, and we look forward to now investigating its potential in our first clinical development program.”

STK-012 is designed as an alpha/beta-biased IL-2 partial agonist to selectively stimulate antigen-activated T cells, which are associated with potent anti-tumor activity, and avoid stimulation of toxicity causing immune cells, such as natural killer cells. Synthekine has presented data at AACR 2021 from preclinical studies demonstrating a mouse surrogate of STK-012 achieved superior tumor regression compared to both wild-type mouse IL-2 and a non-alpha-IL-2 agent, representing a different approach to biasing IL-2. In toxicity models, the mouse surrogate of STK-012, unlike these same comparators, was well tolerated and did not induce capillary leak syndrome (CLS), a dose-limiting IL-2-related toxicity which can result in death. In non-human primate models, STK-012 demonstrated a significantly improved pharmacokinetic and toxicity profile versus both aldesleukin (a recombinant IL-2 therapy) and a non-alpha-IL-2 agent.

About Synthekine

Synthekine is harnessing the potential of cytokine therapeutics to develop selective immunotherapies designed to improve the treatment paradigm of cancer and inflammatory disease. Using insights on cytokine structure and function, the company engineers therapeutics designed to unlock the full efficacy potential of cytokines while avoiding their associated toxicities. Synthekine is applying principles of cytokine partial agonism and immunological specificity across multiple protein engineering platforms to create a broad and deep pipeline of product candidates. These novel immunotherapies include modified cytokines, cytokine-enhanced cell therapies and surrogate cytokine agonists. For more information, visit

SOURCE: Synthekine