Rigel makes comeback with Phase 3 data
- Rigel Pharmaceuticals announced Tuesday the first of two Phase 3 trials of fostamatinib met its primary endpoint in patients with adult chronic/persistent immune thrombocytopenia (ITP).
- In the 76-patient trial, the oral spleen tyrosine kinase (SYK) inhibitor helped 18% of patients achieve a stable platelet response compared to none of the patients on placebo—a statistically significant response.
- The biotech is also conducting another late-stage trial of the drug which is expected to report later this year. If those results are positive, Rigel intends to file for approval with the U.S. Food and Drug Administration in the first quarter of 2017.
While Rigel is chalking up the results to a win—and investors agreed, pushing the stock up almost 40%—Wall Street analysts were a little disappointed by the results.
J.P. Morgan analysts said in a note to clients they had been expecting a response rate in the mid-20% range, a notch higher than the 18% result seen. Previously reported Phase 2 results in a much smaller trial showed almost half of patients responding to therapy. J.P. Morgan's Anupam Rama called the results a "grind it out win" instead of "home run," but noted the lack of a placebo response de-risked the drug a bit.
"We believe that fostamatinib has significant commercial potential given that it has a unique mechanism of action that may work where other products have failed," said Rigel President and CEO Raul Rodriguez in a statement.
The goal of the study was to raise patient platelet counts above 50,000/uL. Among those who met the primary endpoint, patient platelet counts rose by a median increase of 16,0000/uL to more than 100,000/uL at 24 weeks. All of the patients who met the primary endpoint have continued on the therapy and maintained the positive results.
ITP is an autoimmune disease in which the patient's immune system attacks and destroys platelets in the blood, which are needed for clotting and healing.
While Rodriguez is touting the therapy's potential, it might take more data for others to agree. The company was previously partnered with British pharma AstraZeneca, but the deal fell through in 2013 when fostamatinib failed in a trial for rheumatoid arthritis.
Another failure in asthma prompted Rigel to shift gears and focus on smaller patient populations instead of large disease categories.
- Rigel Statement
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