Selinexor

Selinexor sold under the brand name Xpovio among others, is a selective inhibitor of nuclear export used as an anti-cancer medication. It works by blocking the action of exportin 1 and thus blocking the transport of several proteins involved in cancer-cell growth from the cell nucleus to the cytoplasm, which ultimately arrests the cell cycle and leads to apoptosis. It is the first drug with this mechanism of action.

The most common side effects include nausea (feeling sick), vomiting, decreased appetite, weight loss, diarrhea, tiredness, thrombocytopenia (low blood-platelet counts), anaemia (low red-blood cell counts), low levels of white blood cells and hyponatraemia (low blood sodium levels).

Selinexor was granted accelerated approval by the U.S. Food and Drug Administration (FDA) in July 2019, for use in combination with the corticosteroid dexamethasone for the treatment of adults with relapsed refractory multiple myeloma (RRMM) who have received at least four prior therapies and whose disease is resistant to several other forms of treatment, including at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody. In December 2020, selinexor was approved by the FDA in combination with bortezomib and dexamethasone for the treatment of adults with multiple myeloma who have received at least one prior therapy. In clinical trials, it was associated with a high incidence of severe side effects, including low platelet counts and low blood sodium levels.

The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication. Selinexor was approved for medical use in the European Union in March 2021.

Selinexor is approved in combination with bortezomib and dexamethasone for the treatment of adults with multiple myeloma who have received at least one prior therapy. Selinexor is also approved for use in combination with the steroid dexamethasone in people with relapsed or refractory multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteosome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody (so-called "quad-refractory" or "penta-refractory" myeloma), for whom no other treatment options are available. It is the first drug to be approved for this indication.

In June 2020, the U.S. Food and Drug Administration (FDA) approved an additional indication for selinexor to treat adults with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), not otherwise specified, including DLBCL arising from follicular lymphoma, after at least two lines of systemic therapy.

In the European Union, selinexor is indicated in combination with dexamethasone for the treatment of multiple myeloma in adults who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, two immunomodulatory agents and an anti-CD38 monoclonal antibody, and who have demonstrated disease progression on the last therapy. Selinexor is also ivestigated as a potential therapeutic option in liposarcoma.

In the clinical study (the BOSTON study) used to support FDA approval in patients with multiple myeloma after at least one prior therapy (once-weekly selinexor in combination with once-weekly bortezomib and dexamethasone), the most common adverse reactions were cytopenias, along with gastrointestinal and constitutional symptoms and were consistent with those previously reported from other selinexor studies. Most adverse reactions were manageable with dose modifications and/or standard supportive care. The most common non-hematologic adverse reactions were fatigue (59%), nausea (50%), decreased appetite (35%), and diarrhea (32%) and were mostly Grade 1 and 2 events. The most common Grade 3 and 4 adverse reactions were thrombocytopenia (43%), lymphopenia (38%), fatigue (28%) and anemia (17%).