Antibe builds case for GI safety of naproxen alternative

Toronto Skyline
The skyline of Toronto, where Antibe is based. (LukeAbrahams/iStock/Getty Images Plus/Getty Images)

Antibe Therapeutics has posted secondary endpoint data from a phase 2b trial of its alternative to nonsteroidal anti-inflammatory drug (NSAID) naproxen. The data add to evidence that Antibe’s drug, ATB-346, is safer than naproxen, potentially making it a better choice for patients with osteoarthritis, rheumatoid arthritis and other diseases addressable by the NSAID.

Naproxen works by reducing inflammation and pain, making it a go-to drug in the early treatment of a range of joint diseases. However, use of the drug is linked to gastrointestinal problems including ulcers, bleeding and holes in the stomach. To free patients from these risks, Antibe is developing a hydrogen sulfide-releasing derivative of naproxen. The hope is that hydrogen sulfide will mediate the mucosal defense of the gastrointestinal tract and thereby create a cleaner safety profile.

Antibe tested the idea in a 224-subject, two-week safety study that compared ATB-346 to naproxen. The trial posted top-line data in March, revealing it had met its primary endpoint by linking ATB-346 to a lower incidence of 3mm or larger gastric or duodenal ulcers than naproxen.

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Now, Antibe has shared a look at the secondary endpoints. The data drop suggests ATB-346 is less prone to causing 5mm ulcers than naproxen. An endpoint that looked at the total number of ulcers also handed the advantage to ATB-346. Other endpoints that looked at cases of indigestion that led to study discontinuation and change in hematocrit levels found no differences between the groups. 

Antibe sees the data as a positive for the prospects of ATB-346.

“The secondary GI safety endpoint data for ATB-346 are consistent with the primary endpoint data, showing unequivocal superiority over naproxen,” Antibe CSO John Wallace said in a statement. “We look to fully validate the effectiveness of ATB-346 in our upcoming phase 2 dose-ranging, efficacy study.”