Karyopharm Therapeutics has just announced that Eltanexor, their investigative therapy for myelodysplastic syndromes (MDS), has been given Orphan Drug Designation by the FDA. This designation means that the FDA believes this therapy has extreme promise for a patient population with a high unmet need. It also provides various incentives for the development of this treatment, such as 7 years market exclusivity, clinical trial tax credits, exemptions of some fees, and more.

MDS

MDS stands for a group of conditions which are all characterized by an ineffective production of various blood components. This leads to decreased function of the bone marrow. Ultimately, patients are at risk of developing acute myeloid leukemia. There are no FDA-approved treatments for the HMA-refractory form of the condition.

The current standard of care for MDS patients who are at high risk are HMAs (hypomethylating agents). Unfortunately, just 40% to 60% of those treated with HMAs respond. Additionally, those who do respond typically don’t have a sustained response for more than 2 years.

Karyopharm has previously shared data from a Phase 1 clinical trial examining Eltanexor in individuals diagnosed with HMA-refractory MDS. In this trial, Etlanexor was shown to have a 53% overall response rate. There was a 9.9 month median overall survival in this investigation. This data shows improvements from a typical survival rate of 4-6 months post HMA-refractory MDS diagnosis.

Eltanexor

Eltanexor (KPT-8602) is an oral selective inhibitor of nuclear export (SINE) compound. It binds to XPO1, a nuclear export protein, inhibiting it. Tumor suppressor proteins build up in the nucleus of the cell, amplifying the suppressive qualities. Miraculously, it spares the normal cells, selectively harming the cancerous cells.

Preclinical investigations have shown this drug’s potential to treat many different cancers. It has a broad therapeutic ability and only minimally penetrates the blood/brain barrier.

Animal models showed that the treatment led to minimal weight loss and an improved appetite. Since it doesn’t have negative effects on weight, frequent dosing is possible, allowing for greater efficacy.

Currently, Eltanexor is in a Phase 1/2 clinical trial. It is being investigated in various different cancers (solid tumor and hematologic). It is also being examined as a combination therapy.

You can read more about this novel investigative therapy here.