FDA Grants Fast Track Designation for Xpovio for Myelofibrosis

The Food and Drug Administration (FDA) granted fast track designation for the development program behind Xpovio (selinexor) for the treatment of patients with myelofibrosis.

This designation was granted for Xpovio for the treatment of myelofibrosis including primary myelofibrosis, post-essential thrombocytopenia and post-polycythemia vera myelofibrosis, according to a press release from Karyopharm, the drug’s manufacturer.

A fast track designation from the FDA may help expedite the agency’s review of a particular drug to treat a serious condition and fill an unmet medical need, according to the agency’s website. “The purpose is to get important new drugs to the patient earlier,” the Agency noted.

A phase 3 clinical trial — XPORT-MF-034 — was initiated in June 2023 to assess treatment with Xpovio plus Jakafi (ruxolitinib) in patients with JAK inhibitor-naïve patients with myelofibrosis.

“Fast track designation for (Xpovio) highlights its potential to address the unmet medical need in myelofibrosis, an important acknowledgement as we continue our pivotal phase 3 study,” Dr. Reshma Rangwala, chief medical officer of Karyopharm, said in the release. “(Xpovio’s) unique mechanism of action, XPO1 inhibition, is a novel and potentially fundamental mechanism in myelofibrosis.”

In the phase 3 trial, researchers anticipate enrolling 330 patients with treatment-naïve myelofibrosis, all of whom will be treated with Xpovio plus Jakafi, according to the trial’s listing on ClinicalTrials.gov. There are several outcomes of interest that researchers will be focusing on including the spleen volume reduction of at least 35% and symptom reduction. Other areas of focus will include anemia responses at 24 weeks, overall survival (time from treatment assignment to all-cause death), overall response rate and the occurrence of side effects.

Findings from the phase 1 trial were recently presented and demonstrated a rapid, deep and sustain responses in the spleen and symptom improvement in patients treated with this combination.

“We have been highly encouraged by the efficacy and safety data observed to date (in our phase 1 study) with (Xpovio) in combination with (Jakafi) in patients with treatment-naïve myelofibrosis and believe (Xpovio) has the potential to shift the treatment paradigm,” Rangwala said. “We look forward to continued interaction with the FDA as we advance the development of this promising treatment for patients in need.”

Findings from the phase 3 trial are expected in 2025, according to the release.

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