The US Food and Drug Administration (FDA) granted selinexor fast-track designation for the treatment of myelofibrosis (MF), according to a press release from Karyopharm, the developers of the treatment. 

This means that the development of selinexor could be facilitated, and the product could reach the market expeditiously.

Read more about MF prognosis

“Fast Track Designation for selinexor highlights its potential to address the unmet medical need in myelofibrosis, an important acknowledgment as we continue our pivotal Phase 3 study,” said Reshma Rangwala, MD, PhD, the chief medical officer of Karyopharm. “We look forward to continued interaction with the FDA as we advance the development of this promising treatment for patients in need.”

The phase 3 trial in question that started last month is evaluating the safety and efficacy of selinexor in combination with ruxolitinib in JAK inhibitor treatment-naïve patients with MF. It is currently recruiting participants in the United States and is expected to be completed in March 2028.

Results from a phase 1 clinical trial showed that treatment with selinexor plus ruxolitinib led to spleen responses and symptom improvements in patients with MF.

“We have been highly encouraged by the efficacy and safety data observed to date [in our Phase 1 study] with selinexor in combination with ruxolitinib in patients with treatment-naïve myelofibrosis and believe selinexor has the potential to shift the treatment paradigm,” Dr. Rangwala said.

Karyopharm is planning to investigate selinexor in novel combinations to benefit a greater number of patients with myelofibrosis.

Myelofibrosis is a rare disease characterized by marrow scarring due to the production of excess fibrous tissue, which interferes with the normal production of blood cells.

Selinexor is an exportin-1 (XPO1) inhibitor, which itself inhibits tumor suppressor genes. So XPO1 inhibition leads to an increased expression of tumor suppressor genes. The treatment is already approved for the treatment of multiple myeloma in combination with bortezomib and dexamethasone.


Karyopharm receives FDA fast track designation for selinexor for the treatment of myelofibrosis. News release. Karyopharm Therapeutics; July 17, 2023.

Study of selinexor in combination with ruxolitinib in myelofibrosis. US National Library of Medicine. Last updated July 3, 2023. Accessed July 20, 2023.