Aptose signs $125M-plus BET inhibitor deal with Ohm Oncology

Aptose hopes to resolve the FDA clinical hold on its c-Myc drug soon. (Pixabay)

San Diego biotech Aptose Biosciences looks set to have two of its drugs at the clinical trial stage this year and has just found a partner for a third candidate in a deal that could earn it more than $125 million in milestones.

Ohm Oncology is also paying an undisclosed upfront fee for global rights to APL-581—a dual BET/kinase inhibitor in preclinical development for hematologic cancers—as well as related compounds, according to an Aptose statement.

BET has emerged as an intriguing class of epigenetic cancer drugs, with several pharma companies including Johnson & Johnson, Roche, Eli Lilly and GlaxoSmithKline looking at candidates in trials. Scientists believe BET inhibitors work by preventing cancer cells from repairing their DNA, and studies have suggested they may also be able to resensitize tumors to other drugs.

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Aptose and Ohm have effectively been working together on BET/kinase, alongside scientists at Florida’s Moffitt Cancer Center, since 2015. The San Diego biotech signed a deal with Moffitt and India’s Laxai Life Sciences in that year for assistance in developing lead candidates from the program, while Ohm Oncology was set up by Laxai in late 2015 on the strength of that early work.

Aptose CEO William Rice, Ph.D., said the company was “pleased to formalize a new phase of our partnership with Ohm,” adding that he has “every faith that Ohm can advance it to the next stage.” If all goes well, Aptose has kept an option to reacquire rights to some molecules covered by the agreement.

Meanwhile, Aptose’s most advanced project is small-molecule c-Myc inhibitor APTO-253, which is in a phase 1b trial—currently under an FDA clinical hold because of solubility issues with the formulation—involving patients with relapsed/refractory blood cancers, including acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome.

The company said in January that it has a new batch of clinical trial material ready for testing and hopes to file for release of the clinical hold in the coming months and restart dosing.

Following on is CG’806, which it bills as a first-in-class oral pan-FLT3/pan-BTK inhibitor that it reckons could be a big rival to J&J’s Imbruvica (ibrutinib). CG’806 is currently in preclinical development for AML as well as B-cell cancers and is due to start clinical trials later this year.