Fresh from $316M raise, Sotio inks Merck deal for Keytruda combo trial

Keytruda
Sotio will run its Keytruda combination trial alongside a study of SOT101 as a monotherapy. (Merck & Co.)

Sotio Biotech has advanced its effort to become a major player in the solid tumor space. Days after raising $316 million, Sotio has unveiled a deal with Merck to use Keytruda in a clinical trial that is central to its plans for investing in the megaround. 

Last week, the Czech Republic-based biotech disclosed the financing and put a phase 2 trial of SOT101, its IL-15 superagonist, and a checkpoint inhibitor at the center of its R&D plans. Now, Sotio has revealed the identity of the checkpoint inhibitor. Merck, as it has done many times before with other biotechs, has agreed to supply Keytruda for use in the combination clinical trial.  

Entering into the clinical collaboration with Merck positions Sotio to start the phase 2 clinical trial in the first half of next year. The study will enroll up to 300 patients across six solid tumor indications, including second-line non-small cell lung cancer (NSCLC), and give them SOT101 and a standard dose of Keytruda. 

The phase 2 study opens another front in the exploration of the combination of IL-15 superagonists and checkpoint inhibitors. Altor Bioscience, now part of ImmunityBio, helped put the idea on the map with ALT-803. Now known as N-803, the IL-15 superagonist was recently selected for a Keytruda combination by a National Cancer Institute study of NSCLC patients.

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Interest in adding IL-15 superagonists to checkpoint inhibitors is underpinned by evidence that the target increases PD-L1 expression. ImmunityBio sees potential to use its IL-15 superagonist to restore the effect of checkpoint inhibitors in patients who progress after treatment with drugs such as Keytruda. A phase 2b trial in that setting linked the combination to a disease control rate of 59%, with 8% partial responses. 

Sotio will run its Keytruda combination trial alongside a study of SOT101 as a monotherapy. That study will assess the effect of single agent SOT101 in patients with melanoma, squamous skin carcinoma and kidney cancer.