Shares of Corbus Pharmaceuticals skyrocketed this morning after the company said an experimental drug it’s been developing for a variety of autoimmune diseases succeeded in the first of several Phase 2 trials.
Norwood, MA-based Corbus (NASDAQ: CRBP) said the drug, resunab, helped improve the condition of patients with diffuse systemic sclerosis—a severe form of scleroderma, a disease in which the immune system erroneously attacks the skin—better than a placebo. The results of the small, short, randomized, controlled trial were statistically significant, meaning they were unlikely to be due to chance. Shares of Corbus climbed almost 80 percent, from $5.85 to $10.50 apiece in early trading on Monday.
According to the Scleroderma Foundation, about 300,000 people in the U.S. have scleroderma, and roughly a third of them have diffuse systemic sclerosis, the most severe form. While patients with mild scleroderma might not need any treatment, for instance, the hardening of the skin that characterizes the disease is more dangerous in those with diffuse systemic sclerosis, as it might lead to fibrosis (internal scarring) in their lungs, esophagus, kidneys, or heart. There are no effective treatments for the disease.
Corbus’s drug, resunab, binds to the CB2 receptor on immune cells, which Corbus says should help drive an anti-inflammatory response and possibly halt patients’ fibrosis. The drug was originally discovered by University of Massachusetts Medical School professor Sumner Burstein some 20 years ago and then changed hands a few times, from Atlantic Pharmaceutical to Indevus Pharmaceuticals to JB Therapeutics—the predecessor to Corbus.
Over that time, resunab was largely tested as a pain medication, but never made it very far. Corbus—which went public by registering shares with the SEC, not by holding an IPO—believes the drug is viable as a chronically administered anti-inflammatory for several diseases, among them diffuse systemic sclerosis, cystic fibrosis, and lupus. Today’s study marks the first placebo-controlled, randomized trial in humans to support that theory. Corbus has two other mid-stage trials underway in CF and another skin disease, dermatomyositis. The CF study could produce data next year.
Corbus enrolled patients who have had diffuse systemic sclerosis for up to six years and gave them either a low, medium, or high dose of resunab daily, or a placebo, for four weeks. After that four-week period, all patients on Corbus’ drug were switched to the highest dose and evaluated for another eight weeks. Between weeks 13 to 16, all patients were taken off drug or placebo and followed. Corbus’s goal was to improve patients’ scores on the American College of Rheumatology Combined Response Index in diffuse cutaneous Systemic Sclerosis (CRISS), a quantitative measure of patients’ disease.
Corbus says a “medically meaningful” improvement on the CRISS is 20 percent or greater, and that patients on resunab improved by an average of 33 percent after 16 weeks, compared to a zero percent improvement for placebo patients. Corbus said the drug was safe. One patient on resunab dropped out of testing due to dizziness. Corbus didn’t disclose any other specific side effects, but the company will now test how its safety stacks up as a chronic therapy—patients in the Phase 2 trial have the chance to take the drug for an additional 12 months
In a statement, Corbus chief medical officer Barbara White said the company would now reach out to regulators about the drug’s path forward. The results “exceeded our expectations,” CEO Yuval Cohen said in the statement.
Corbus will hold a conference call this morning to discuss the data.