Shares of iTeos Therapeutics Inc. ITOS, -4.00% soared 58.5% in premarket trading on Monday after the company announced a deal with GlaxoSmithKline GSK, +0.20% to develop and commercialize an experimental cancer therapy. GSK will make a $625 million upfront payment to iTeos, with an additional $1.4 billion in possible milestone payments available in the future.
The immuno-oncology drug candidate is currently being tested in an open-label, Phase 1 clinical trial in patients with advanced solid tumors; as part of this deal, the companies plan to pair the iTeos drug with GSK’s Jemperli in studies next year. (Jemperli was initially approved by the Food and Drug Administration as a treatment for endometrial cancer in April.) Shares of iTeos are down 40.8% so far this year, while the S&P 500 SPX, -0.20% has gained 13.1%.