FDA Approves Oral Selinexor Tablets for Adults with RRMM

The US Food and Drug Administration (FDA) has approved oral selinexor (Xpovio) tablets in combination with corticosteroid dexamethasone for the treatment of adult patients with relapsed refractory multiple myeloma (RRMM) who have revived at least 4 prior therapies and whose disease is resistant to several other forms of treatment.

According to a press release from Karyopharm Therapeutics, the company the FDA granted the approval to, the nuclear export inhibitor received approval under accelerated approval based on response rate and the ongoing phase 3 BOSTON study will serve as the confirmatory trial.

“With today’s accelerated approval of XPOVIO by the FDA, patients with heavily pretreated multiple myeloma will now have a new therapeutic option to treat their disease,” said Sharon Shacham, PhD, MBA, founder, president and chief scientific officer of Karyopharm.

Karyopharm noted they expect selinexor to become commercially available within the US on or before July 10, 2019. Additionally, a Marketing Authorization Application is also currently under review by the European Medicines Agency.

Efficacy of selinexor was demonstrated in the phase 2b STORM study that included 83 patients with RRMM who were treated with the drug in combination with dexamethasone. The overall response rate at the end of the study was 25.3%. Investigators also noted a median time to first response of 4 weeks, with a range of 1 to 10 weeks, and the median duration of response was 3.8 months.

The ongoing, randomized phase 3 BOSTON study involves 402 participants and is evaluating selinexor in combination with bortezomib (Velcade) and low-dose dexamethasone in adults patients with RRMM. It has an expected completion date of June 2020.

“The accelerated approval of oral Xpovio (selinexor) marks an important advance in the treatment paradigm for patients with relapsed refractory multiple myeloma, and in my view, is an important addition to our therapeutic armamentarium,” said Dr. Paul Richardson, MD, director of clinical research, Jerome Lipper Multiple Myeloma Center at the Dana-Farber Cancer Institute.

The side effects of patients taking selinexor in combination with dexamethasone include leukopenia, low count of neutrophils, neutropenia, thrombocytopenia, and anemia. Patients also reported vomiting, nausea, fatigue diarrhea, fever, decreased weight and appetite, constipation, upper respiratory tract infection and hyponatremia.

The FDA advises health care professional to monitor patients for low blood counts, platelets, and sodium levels. The FDA also advises health care professionals to tell females of reproductive age and males with a female partner of reproductive potential to use effective contraception during treatment with selinexor.