Sotio Biotech has dealt another blow to attempts to establish cytokines as a cornerstone of cancer care, scrapping ongoing studies of its IL-15 superagonist after seeing insufficient efficacy in the clinic.
The Czech biotech raised 280 million euros ($295 million) to advance the IL-15 candidate, nanrilkefusp alfa, late in 2021. Months later, Bristol Myers Squibb and Nektar Therapeutics’ closely watched IL-2 program imploded, prompting soul searching in the cytokine space, but Sotio forged ahead with its work on the structurally similar IL-15.
Now, Sotio faces its own dark day. A look at interim data on nanrilkefusp alfa, also known as SOT101, has revealed “insufficient efficacy to warrant further development in larger randomized trials” in the settings targeted to date, prompting Sotio to immediately stop enrollment in three studies.
The clinical trials were evaluating nanrilkefusp alfa in combination with Eli Lilly’s Erbitux and Merck & Co.’s Keytruda in solid tumor patients. While Sotio has abandoned hopes of bringing those combinations to market, it continues to see potential to pair its IL-15 drug candidate with other modalities such as cell therapies. The biotech has seen “promising” preclinical data on a cell therapy combination.
Multiple other companies are working on IL-15 candidates. ImmunityBio got as far as filing for approval of its antibody cytokine fusion protein, only for the FDA to reject the request on manufacturing grounds. Nektar Therapeutics is running a phase 2/3 clinical trial of an IL-15 receptor agonist, NKTR-255. Novartis is closing in on the end of a phase 1 trial of its IL-15 prospect, NIZ985, but stopped enrollment well short of its goal.
Sotio retains an interest in cytokines, noting that its next-generation PD-1-inhibiting candidate is set to enter the clinic in the second quarter of next year. But its R&D pipeline now skews toward antibody-drug conjugates, a modality with a star that has risen as enthusiasm for cytokines has fallen away.