In 2008, the company had reported encouraging data from a Phase 2 trial in ITP, but had set the project aside while awaiting results in rheumatoid arthritis. The Phase 3 trial in ITP that Rigel is now preparing for would cost about $25 million, and could yield results by mid-2015, Rodriguez estimates.
Rodriguez sees a market opportunity in ITP of $300 to $400 million for Rigel—about the current revenue range for two ITP treatments already approved, GlaxoSmithKline’s Promacta and Amgen’s Nplate. These drugs boost the production of platelets, while Rigel’s fostamatinib interferes with immune cells that destroy existing platelets, Rodriguez says. About half of the estimated 100,000 US patients with ITP don’t benefit from currently available treatments, he says.
Investors will soon see data on one of the two other lead programs Rigel has identified. The company’s compound R333, an SYK/JAK inhibitor, is being tested against discoid lupus erythematosus, a disfiguring skin disorder that afflicts about 300,000 people in the United States. Rodriguez doesn’t see any currently available treatment setting a high bar for R333 in this indication.
“Even if it works OK, it would be a big advance,” he says. Results of a Phase 2 trial could come out as soon as next month.
The third compound in Rigel’s newly prioritized program is R348, a topical preparation for dry eye, a chronic eye inflammation that affects about 5 million US patients. Allergan’s preparation of cyclosporine for the eye, Restasis, already serves this population, but Rodriguez sees it as vulnerable to a superior competitor. Rigel expects Phase 2 results for R348, another SYK/JAK inhibitor, in the second half of 2014.
If both the dry eye and the lupus trial results look good, Rigel expects to have the resources to advance only one into Phase 3 studies, unless it can partner up on a second drug, Rodriguez says. Each of those late-stage trials would cost about $20 million. Meanwhile, the company is eliminating 30 positions, leaving a staff of about 130.
For the time being, Rigel has let go its visions of a blockbuster first drug. Success in any of its three main programs would yield revenues of under a billion dollars.
But “For a Rigel-size company, that’s actually quite attractive,” Rodriguez says.
