Biotechs put assets up for sale and on the shelf in quarterly pipeline clear-outs

Biotech earnings season has delivered a deck of dead and deprioritized assets, with Xilio Therapeutics, Protagonist Therapeutics, Arbutus Biopharma and Aptinyx all deciding they have better uses for their cash. 

Xilio posted preliminary pharmacokinetic data from a phase 1 trial of its tumor-activated anti-CTLA-4 candidate XTX101 over the summer, leading it to outline plans to explore a phase 2 study in colorectal cancer. Months later, and with initial results from the trial still on the horizon, the biotech has decided to wind down its investment in the candidate. 

Management is looking for strategic collaborations to advance XTX101. Until a partner is found, neither the phase 1 anti-PD-1 combination cohort nor a phase 2 study will get underway. Xilio now expects its $139.1 million pile of cash and equivalents to last into the second quarter of 2024, having previously given a vaguer forecast that covered the first half of that year. The money will fund work on two cytokine programs.  

The other discontinuations also followed shortly after data drops. Protagonist has chosen to deprioritize its PN-943 program months after CEO Dinesh Patel, Ph.D., claimed to be “delighted” with midphase ulcerative colitis data and set out plans to move into a phase 3 registrational program. 

Patel’s upbeat reading of the data contrasted with the reaction of investors, who zeroed in on the failure of the 45-mg dose to beat the rate of clinical remission achieved by placebo—the primary endpoint—to send the stock spiraling down. Months later, Protagonist has quietly backed away from PN-943, while also “streamlining … certain discovery programs,” to free up cash for rusfertide in polycythemia vera. The biotech will wrap up a 40-week extended treatment period but otherwise stop spending on PN-943.

The other two discontinuations were signposted previously. Arbutus Biopharma decided to dose a new cohort of healthy volunteers with its oral capsid inhibitor AB-836 for a longer period over the summer to probe a safety signal. After seeing elevated levels of a liver enzyme in two people, Arbutus discontinued development of AB-836 and confirmed the decision in its third-quarter results.

Aptinyx outlined plans to focus its resources on projects other than NYX-2925 in August, when the failure of a phase 2b fibromyalgia trial arrived hot on the heels of a painful diabetic peripheral neuropathy flop. The biotech used its third-quarter results to confirm it is ending investment in NYX-2925 in chronic pain.