- Some analysts are questioning AnaptysBio Inc.'s decision to exclude certain patients from a interim analysis that showed the biotech's lead candidate is an effective treatment for peanut allergies.
- The early data, coming from a Phase 2a proof-of-concept trial, found 46% of patients who received a single shot of ANB020 were able to tolerate a cumulative 500 mg dose of peanut protein two weeks later. Conversely, none of the patients on placebo reached that level of tolerance.
- The trial enrolled 20 adults, with 15 in the investigational arm and five in the placebo arm. Despite those already small numbers, AnaptysBio disclosed that two patients from each group who had mild allergy symptoms at baseline were left out of the interim analysis — causing concern the company was propping up ANB020's potential.
Between 0.5% to 1.5% of the U.S. population has a peanut allergy, yet there are few available treatments. Attracted by the unmet medical need, several drugmakers, including Aimmune Therapeutics Inc. and DBV Technologies SA, are racing to bring new therapies to market.
AnaptysBio's pipeline focuses largely on medicines that affect the immune system. ANB020, for instance, is an antibody that inhibits the immune system-regulating protein interleukin (IL)-33. As such, the drug has also been investigated in atopic dermatitis.
ANB020's mechanism of action helps it stand apart from rival therapies, and so far it has notched solid efficacy results in the clinic. Yet the move to keep patients with mild baseline symptoms out of the interim analysis put a damper on the otherwise positive data.
"The trial results were somewhat confounded by the company's patient selection and reporting approach, which amplified the trial signal compared to an intent-to-treat (ITT) approach, but overall the study established strong proof-of-concept for the utility of inhibiting IL-33 specifically ... in patients with challenging food allergies, particularly nut allergies," Leerink analyst Geoffrey Porges wrote in a March 27 note on Regeneron Pharmaceuticals Inc.
That may be good news for Regeneron, which has its own IL-33 candidate, REGN3500, in early-stage testing.
ANB020's effect on concomitant allergy symptoms like asthma flares or stuffy nose may be particularly compelling. In the Phase 2a trial, 80% of the placebo patients experienced concomitant allergy symptoms versus 7% of the drug-treated patients.
"Regeneron's REGN3500 appears to have a similar target and profile to ANB020, and the positive signals from this trial, in terms of tolerance to challenge, food allergy symptom improvement and concomitant atopic disease improvement provide additional evidence that IL-33 presents an attractive target for expanding and enhancing the anti-allergy effect already conferred by [Sanofi/Regeneron's] Dupixent," Porges wrote.
AnaptysBio stock was up less than 1% to $114.58 per share at market's open Tuesday, but fell down to around $110 per share by late morning. DBV and Aimmune, meanwhile, were up 4.3% and less than 1%, respectively.
DBV has faced issues with its Viaskin Peanut treatment, which failed a Phase 3 study late last year. The company is forging ahead with a regulatory filing nonetheless, meaning its drug could hit the market in 2020.
Viaskin Peanut's biologics license application (BLA) would be just for children, however, giving it a different market segment than AnaptysBio appears to be targeting.
"With today's result, Anaptys appears focused on adult peanut allergic [patients]. Therefore, whereas we cannot rule out Anaptys' future expansions into the younger demographic, with DBV's 2H plans for a BLA submission, we do not see any immediate/near-term effects on DBV," Leerink analyst Dae Gon Ha wrote in a note.