The purpose of this research study is to see if the oral medication selinexor (KPT-330, Xpovio) given in combination with other oral medications Clarithromycin, Pomalidomide, and Dexamethasone has any effects against relapsed/refractory multiple myeloma. Selinexor works by trapping “tumor suppressing proteins” within the cell, causing the cancer cells to die or stop growing.

Selinexor has been approved by the U.S. Food and Drug Administration (FDA) in combination with dexamethasone for the treatment of adult patients with relapsed/refractory multiple myeloma. Selinexor in combination with Clarithromycin, Pomalidomide, and Dexamethasone is considered investigational, which means it has not been approved by the FDA. This study will examine this treatment plan for multiple myeloma patients.

All participants enrolled on the study will receive the same treatment plan, which will be given in repeated 28-day cycles and will continue until either unacceptable toxicity or disease progression, judgement of the treating physician, or participants choose to withdraw consent at any point in the study. Participants may be followed up for survival and checked for current disease status for up to 24 months.

The treatment plan includes:

• 60 mg of Selinexor orally on Day 1, 8, and 15
• 40 mg of Dexamethasone orally once a week
• 500 mg of Clarithromycin orally every day twice a day
• 4 mg of Pomalidomide orally daily from Day 1 to Day 21

Participants can receive a $50 stipend for each completed study visit.