Oncternal Therapeutics’s stock has slumped after the company announced it is dropping its clinical trials and will lay off staff to save cash.
The US-based biotech is discontinuing its clinical trials evaluating ONCT-534, a dual action androgen receptor inhibitor for metastatic castration-resistant prostate cancer, and ONCT-808, a ROR1-targeting autologous CAR-T candidate for patients with aggressive B-cell lymphoma.
The biotech’s stock plummeted by 60%, dropping from $4.17 per share before market close on 11 September to $1.70 at market close on 12 September, the day of the announcement.
This update comes after ONCT-534 failed to perform in the interim Phase I trial (NCT05917470) results. In the 20 enrolled patients, ONCT-534 did not show clinically meaningful improvements in disease, including prostate-specific antigen (PSA) levels. The patients were treated in eight dosing cohorts with varying schedules of administration and doses.
In December 2023, Oncternal reported the death of a patient in a Phase I/II dose escalation study (NCT05588440) of B-cell lymphoma therapy ONCT-808. The patient, who was the first to receive a higher dose level in the study, died after showing signs consistent with cytokine release syndrome, as well as immune effector cell-associated neurotoxicity syndrome, said Oncternal.
Oncternal’s CEO James Breitmeyer said: “The early results during dose escalation in the Phase I/II studies of ONCT-534 in heavily pretreated patients are disappointing, as the study was supported by extensive preclinical data and was designed to address important unmet medical needs for patients with advanced prostate cancer.”
While Oncternal plans to explore alternative options for the programmes, it will discontinue all product development activities and take other steps to reduce costs, including reducing its workforce.
In a 12 September SEC filing, Oncternal shared that it will slash its workforce by 37%. The layoffs – which it expects to complete by Q3 2024 – are estimated to incur workforce reduction-related charges of about $1m.
The latest news adds to a string of failures from the company that terminated two trials investigating its tyrosine kinase inhibitor (TKI) zilovertamab in April 2023 to free up cash. One of these was a Phase III study that investigated the TKI in combination with Johnson & Johnson and AbbVie’s blockbuster TKI Imbruvica (ibrutinib) in mantle cell lymphoma.
