Shares of Rigel Pharmaceuticals Inc. (NASDAQ: RIGL) skyrocketed early on Tuesday after the company reported incredibly positive results from its late-stage blood platelet clinical trial. The company announced that fostamatinib, its oral spleen tyrosine kinase inhibitor, met the primary endpoint in the first of two double-blind studies in the FIT Phase 3 clinical program for the treatment of adult chronic/persistent immune thrombocytopenia (ITP).
Some 18% of patients receiving fostamatinib achieved a stable platelet response, compared to none receiving a placebo control. A stable platelet response was defined as achieving greater than 50,000 platelets per uL of blood on at least four of the past six scheduled visits between weeks 14 and 24 of treatment.
Looking ahead, the results from the second FIT Phase 3 study are expected in October or November of this year.
In terms of adverse events from the study, the most frequent were gastrointestinal related. The safety profile for the study was consistent with prior clinical experience with no new or unusual safety issues.
In general, the clinical goal of ITP treatment is to raise platelet counts to more than 50,000/uL. Patients who met the primary endpoint in this study had their platelet counts increase from a median of 16,000/uL at baseline to a median of more than 100,000/uL at week 24.
All the patients from this study who met the stable platelet response endpoint enrolled in the long-term, Phase 3 extension study and continued to maintain their platelet levels for months past the initial study.
The company expects to submit a New Drug Application with the U.S. Food and Drug Administration (FDA) in the first quarter of 2017. Further results from the FIT Phase 3 studies and long-term extension will be presented at future medical meetings.
Raul Rodriguez, president and CEO of Rigel, commented on the results:
These data demonstrate the potential benefit of fostamatinib for chronic ITP patients who are in need of new treatment options. 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.
Excluding Tuesday’s move, Rigel has underperformed the broad markets, with the stock down 13% year to date. Over the past 52 weeks, the number is more or less the same.
Shares of Rigel were trading up 45% at $3.81 on Tuesday, with a consensus analyst price target of $6.40 and a 52-week trading range of $1.88 to $3.68.