SY-5609

Exscientia is aiming to publish monotherapy dose escalation date this year. Exscientia has taken full ownership of its oral CDK7 inhibitor candidate, buying out partner GT Apeiron for $20 million. The AI-enabled biotech plans to advance the molecule into a breast cancer combination trial. GT Healthcare, an investor in Exscientia, launched GT Apeiron in 2019 and immediately signed a deal to fund the discovery of cancer drugs with the AI specialist. Exscientia and GT Apeiron terminated the first deal in 2021 and entered into a joint operation and cost sharing arrangement for the development and commercialization of multiple programs. The partners began a phase 1/2 clinical trial of the lead candidate, the oral CDK7 inhibitor GTAEXS617, in July 2023. Now, Exscientia has bought out its partner. GT Apeiron last disclosed funding when it raised a $17.5 million series A round in March 2022.  Exscientia is paying $10 million in upfront cash and a further $10 million in upfront equity to take control of the program and ownership of all intellectual property. GT Apeiron will receive single-digit royalties if GTAEXS617 comes to market. Exscientia will take on all existing development costs but still expects its runway to extend well into 2027. The arrangement gives Exscientia full ownership of an asset it believes can address the limitations that have held CDK7 inhibitors back to date. Eli Lilly took a CDK7 inhibitor into human testing in 2019 but stopped the trial over a lack of efficacy. Syros Pharmaceuticals dropped one asset, SY-1365, and another, SY-5609, is on the backburner. Carrick Therapeutics has pushed its prospect, samuraciclib, into phase 2.  Exscientia discussed the positioning of GTAEXS617 on an earnings call in May, telling investors that, while it expects to see some level of monotherapy activity, combinations will be the focus for clinical use. Toxicity is the barrier to combinations, including with immunotherapies. Ben Taylor, Exscientia’s chief financial and strategy officer, discussed why GTAEXS617 may be free from problems that affect some rival molecules.  “It was specially designed to get around an issue that a number of the other competitive molecules have, which is being a transporter substrate. We think we've got a really nice advantage there and hopefully you'll be able to see that in the data,” Taylor said. “Because if we can get a nice safe profile, this is a mechanism that clearly should work, and there's a number of different combination opportunities for it.” Exscientia is aiming to publish monotherapy dose escalation data this year. If all goes to plan, the biotech will start a dose escalation study combining GTAEXS617 with a selective estrogen receptor degrader in breast cancer around the end of the year.