Arena Pharamceuticals’ plan to reshape itself is advancing with new data for an ulcerative colitis drug that could pose a threat to biotech giant Celgene.
San Diego, CA-based Arena (NASDAQ: ARNA) said late Monday that its experimental compound etrasimod has succeeded in a Phase 2 trial in patients with moderate-to-severe ulcerative colitis, a form of inflammatory bowel disease. A high dose of the drug met its main and secondary goals in a 156-patient, 12-week study called OASIS, besting a placebo in measures evaluating the treatment’s impact on disease symptoms and severity.
The main goal of the study was an improvement, relative to placebo, on a three-component “Mayo Clinic Score” that evaluated rectal bleeding, stool frequency, and findings on an endoscopy at different time points. The higher the score, the more severe patients’ disease is. Patients who took a high dose of etrasimod started the study with an average 8.8 point Mayo Clinic Score; placebo patients started off with a mean 8.7 point score.
Mayo Clinic Scores fell for patients on a high (2 mg) dose of etrasimod by 2.49 points after 12 weeks of treatment, compared to a 1.94-point drop for low dose patients (1 mg) and a 1.50-point dip for placebo patients. The difference between the high dose group and placebo was statistically significant; the low dose group’s results weren’t.
More patients had improvements on their endoscopies on etrasimod than placebo (41.8 percent for Arena’s drug, 17.8 percent for placebo), a secondary goal. More patients on the high dose achieved clinical remissions compared to placebo as well, an exploratory goal of the study.
Arena said more patients on placebo had severe side effects (11.1 percent) than those on etrasimod (5.8 percent in the low dose group, none in the high dose group). The company disclosed that two patients had an “asymptomatic” atrioventricular block that naturally resolved, but side effects were mostly mild to moderate, Arena said.
Leerink analyst Joseph Schwartz said while the few instances of possible heart problems may give “some investors pause,” the results are “better than expected” and distinguish etrasimod favorably versus other, similar drugs. “The magnitude of etrasimod’s efficacy is impressive,” Schwartz wrote.
Arena shares climbed 34 percent in pre-market trading on Tuesday morning.
The news positions Arena’s drug as a potential threat to ozanimod, a drug being developed by Celgene (NASDAQ: CELG) for ulcerative colitis, Crohn’s disease, and multiple sclerosis. Celgene bought Receptos for $7.2 billion in 2015 to get its hands on the drug, which like etrasimod is a pill that targets a signaling molecule called sphingosine 1-phosphate (S1P) thought to play a role in inflammation. The FDA recently delayed Celgene’s efforts to bring ozanimod to market for MS, calling its approval application “insufficient,” but studies remain on track in ulcerative colitis. Phase 3 data are expected in 2019.
The data also bolsters Arena’s plans to reshape itself. The company made its mark initially by winning FDA approval of an obesity pill, lorcaserin (Belviq). But obesity drugs have struggled mightily commercially—Orexigen Therapeutics, the developer of a rival obesity drug, just filed for bankruptcy last week—and Arena cut its losses by selling lorcaserin to partner Eisai in January 2017. Since then, the company has put its resources behind etrasimod and other drugs for pulmonary hypertension and pain.