AbCellera has become the latest drug developer to abandon its attempts to crack the OX40 code.
The biotech had been developing ABCL575, an antibody drug targeting OX40 ligand for the treatment of atopic dermatitis and other autoimmune conditions. In its third-quarter earnings results on Monday, AbCellera confirmed that a phase 1 study of ABCL575 had hit all its endpoints by “demonstrating a favorable tolerability profile and a pharmacokinetic profile that supports an extended dosing interval.”
But that positive start wasn’t enough to persuade the company to persevere with the candidate. Instead, AbCellera confirmed in the earnings release that it “currently does not plan to develop ABCL575 past phase 1.” Explaining the decision, the biotech cited “external developments in the OX40/OX40L class.”
It’s true that this drug class has struggled in 2026. In March, Kyowa Kirin shuttered all clinical studies of its Amgen-partnered anti-OX40 monoclonal rocatinlimab for inflammatory diseases over “emerging concerns of malignancies with possible viral or immune-related links.”
Four months later, Sanofi revealed it had cancelled plans to submit the anti-OX40 ligand antibody amlitelimab to regulators for atopic dermatitis after admitting the drug “would not represent a meaningful improvement” to existing treatments. That decision was especially tough for Sanofi as it had acquired amlitelimab as part of its $1.1 billion acquisition of Kymab, and gone on to tout the therapy as a potential blockbuster.
Still, not everyone is pessimistic about the prospects of this drug class. In September, Inhibrx Biosciences revealed fresh phase 2 data for its hexavalent OX40 agonist INBRX-106 in combination with Keytruda that demonstrated a 48.3% confirmed objective response rate in patients with treatment-naïve, PD-L1 positive metastatic or unresectable recurrent head and neck squamous cell carcinoma.
At the time, Inhibrix CEO Mark Lappe said the results “strengthen our conviction in OX40-mediated T-cell co-stimulation and give us a strong rationale to expand the program.”
While AbCellera may have lost interest in the OX40 mechanism, it has plenty of other drugs in its pipeline to keep it busy. They are led by ABCL635, a neurokinin 3 receptor (NK3R)-targeting antibody drug that scored a recent phase 2 win in patients with hot flashes caused by menopause.
Executives have been touting ABCL635 as a “potential best-in-class non-hormonal therapy” with “strong differentiation” against approved NK3R competitors like Astellas’ Veozah and Bayer’s Lynkuet.
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