XPO1 (Exportin-1) Inhibitor Pregnancy: Can cause fetal harm when administered to a pregnant woman, based on findings in animal studies and its mechanism of action. There are no available data in pregnant women. Advise pregnant women of the risk to a fetus, and advise females of reproductive potential and males with a female partner of reproductive potential to use effective contraception.

Selinexor

Brand names: Nexpovio

Selinexor is an oral selective inhibitor of nuclear export (SINE) used in combination regimens for relapsed or refractory multiple myeloma.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Multiple myeloma in combination with bortezomib and dexamethasone (XVd): 100 mg orally once weekly on Day 1 of each week. Multiple myeloma in combination with dexamethasone (Xd): 80 mg orally on Days 1 and 3 of each week (160 mg total per week).

Route: Oral

Frequency: XVd regimen: once weekly (Day 1). Xd regimen: Days 1 and 3 of each week. Continue until disease progression or unacceptable toxicity.

SOURCE: US FDA prescribing information (XPOVIO, Karyopharm Therapeutics, label date 2026-05-12) via openFDA/DailyMed — NO UK SPC was present in the fetched bundle, so UK posology has not been verified; clinician to cross-check against the UK SPC. COMBINATION PARTNERS as stated in the US label: with XVd, bortezomib 1.3 mg/m2 subcutaneously once weekly on Day 1 of each week for 4 weeks followed by 1 week off, plus dexamethasone 20 mg orally twice weekly on Days 1 and 2 of each week; with Xd, dexamethasone 20 mg orally with each selinexor dose on Days 1 and 3 of each week. DOSE REDUCTION STEPS: from a 100 mg once-weekly start — first reduction 80 mg once weekly, second 60 mg once weekly, third 40 mg once weekly, fourth permanently discontinue. From an 80 mg Days 1 and 3 start — first reduction 100 mg once weekly, second 80 mg once weekly, third 60 mg once weekly, fourth permanently discontinue. MONITORING: complete blood count with differential, standard blood chemistries, body weight, nutritional status and volume status at baseline and during treatment, more frequently during the first three months. CONCOMITANT CARE: advise adequate fluid and caloric intake; consider intravenous hydration in patients at risk of dehydration; give prophylactic antiemetics — a 5-HT3 receptor antagonist and other anti-nausea agents prior to and during treatment. Dosage modifications are specified for thrombocytopenia (platelets 25,000 to <75,000/mcL, with or without bleeding, and <25,000/mcL), neutropenia (ANC 0.5 to 1 x 10^9/L, and <0.5 x 10^9/L or febrile neutropenia), anaemia (haemoglobin <8 g/dL), nausea/vomiting, diarrhoea and weight loss/anorexia. Dosage in severe hepatic impairment is given in the full prescribing information (§2.5, §8.6) and was not captured in the fetched excerpt.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None (US label §4 states: None)

Side effects

Thrombocytopenia (Grade 3-4 laboratory abnormality in >=10% of patients) — monitor platelet counts throughout treatment
Neutropenia and lymphopenia; serious infection — monitor and treat promptly
Gastrointestinal toxicity: nausea, vomiting, diarrhoea, decreased appetite and weight decreased
Fatigue (most common adverse reaction, >=20% with both regimens) and anaemia
Hyponatremia — monitor serum sodium throughout treatment (correct for concurrent hyperglycaemia and high serum paraprotein)
Neurological toxicity (dizziness, mental status changes — advise against driving until resolved), cataract, and peripheral neuropathy (with the XVd regimen)

Clinical monograph

How it works

It blocks exportin-1 (XPO1), trapping tumour-suppressor proteins in the nucleus and reducing oncoprotein translation, thereby promoting apoptosis of malignant plasma cells.

Prescribing in practice

Causes frequent and sometimes severe gastrointestinal toxicity and hyponatraemia, so prophylactic antiemetics, attention to hydration, and sodium monitoring are essential from the outset.
Marked thrombocytopenia and neutropenia are common and require regular blood counts with dose modification or interruption.
Monitor for fatigue, anorexia, weight loss, and neurological effects, providing supportive care to maintain treatment tolerability.

Monitoring

Monitor full blood count, serum sodium, body weight, and hydration status throughout treatment.

Counselling the patient

Take antiemetics as prescribed and maintain fluid intake to reduce nausea and dehydration.
Report persistent vomiting, confusion, or significant weight loss promptly.
Regular blood tests are needed to monitor platelets and sodium.

Evidence & guidelines

Selinexor combination therapy in relapsed/refractory myeloma is supported by the BOSTON trial and licensed for this indication.

Reference: BOSTON trial (Grosicki et al. NEJM 2020); NICE TA680; MHRA SPC Nexpovio; STORM trial (Chari et al. NEJM 2019 — penta-refractory); Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways