Up to a third of ITP patients do not respond well to or are intolerant of first or second-line therapies, are difficult to treat and remain predisposed to bleeding. Sirolimus (rapamycin), a immunosuppresive drug used to prevent rejection of transplanted organs, has been found to increase platelet counts in some patients with ITP refractory to steroids. In a new study, 66 patients with ITP were treated with sirolimus (2 mg daily) for three months. The dose was then tapered to a half milligram every two weeks and the patients were followed for a year, A rise in the platelet count to over 100,000/µL was observed in two-thirds of the treated patients. Responses were seen within a median duration of four weeks. Sirolimus represents a potentially important option for patients who do not do respond to first and second line ITP treatments. However, Sirolumus suppressess the immune system and has effects on blood pressure and renal function that require monitoring. Since the target of sirolimus is known (the m-Tor pathway), it is possible that other inhibitors of this pathway will also be safe and effective. Additional, larger scale studies are needed to help situate Sirolimus in the treatment of patients with ITP not responsive to contemporary approaches to treatment.
Gao, L., et. al. (2017). Sirolimus Is Effective in Refractory Immune Thrombocytopenia: Results of an Open-Label Prospective Multicenter Trial in China. Blood, 130(Suppl 1), 4728. http://bit.ly/2IFQeP7.
Expanded Access (Compassionate Use) Program Available in the US for ITP Patients Unresponsive to Past Therapies
Rigel Pharmaceuticals’ Immune Thrombocytopenia (ITP) investigational drug fostamatinib is now available through an Expanded Access (Compassionate Use) Program for certain patients. Fostamatinib is proposed to work by blocking platelet destruction.
Expanded Access, sometimes also referred to as “Compassionate Use,” is allowed by the FDA for therapies whose NDA applications are still under review to patients for which there are no comparable alternatives for treatment. Through such programs, patients may be able to access investigational new drugs outside of the clinical trial context. Unlike the clinical trial setting, the primary purpose of compassionate use is to use the investigational drug for patient treatment purposes, rather than to gather controlled data on safety and effectiveness. Physicians can request compassionate use of fostamatinib for chronic ITP if a patient is not eligible to enroll in a Rigel clinical trial and no alternative treatment exists, via completion of an application at http://eap.rigel.com. The program is available only to US physicians at this time. NIH Clinical Trials: https://clinicaltrials.gov/ct2/show/NCT03363334.
Rigel Pharmaceuticals, Inc. “Expanded Public Expanded Access Policy.” Rigel Pharmaceuticals, Inc. December 2017. http://bit.ly/2DiF5Vm.