The South Korean Ministry of Food and Drug Safety has granted approval for selinexor (Xpovio), in combination with bortezomib (Velcade) and dexamethasone (SVd), for treating adult patients with multiple myeloma who have undergone at least one prior line of therapy. This decision expands the treatment options for patients facing relapsed or refractory disease in South Korea.
This approval marks the third indication for selinexor in South Korea. The drug was previously approved for use in combination with dexamethasone for adult patients with relapsed or refractory multiple myeloma, and as a monotherapy for adult patients with relapsed or refractory diffuse large B-cell lymphoma.
The approval is based on data from the phase 3 BOSTON trial (NCT03110562), which compared SVd to bortezomib and dexamethasone (Vd) alone in patients who had received one to three prior lines of therapy. The study demonstrated a statistically significant improvement in progression-free survival (PFS) with the selinexor-containing regimen.
Efficacy Data from BOSTON Trial
The BOSTON trial's primary endpoint was progression-free survival (PFS). Results showed an estimated PFS of 13.9 months (95% CI, 11.7-not estimable) with SVd compared to 9.5 months (95% CI, 7.6-10.8) with Vd alone (HR, 0.70; 95% CI, 0.53-0.93; one-sided P = .0075). The overall response rates with SVd and Vd were 76.4% (95% CI, 69.8%-82.2%) and 62.3% (95% CI, 55.3%-68.9%), respectively (one-sided P =.0012).
With a median follow-up of 17.4 months, the median overall survival (OS) was not reached (NR) with SVd versus 25.0 months with Vd alone (HR, 0.84; 95% CI, 0.57-1.23; P =.19).
Extended Follow-Up Analysis
An extended, post-hoc follow-up analysis published in the European Journal of Hematology showed that, at a median follow-up of over 28 months, SVd maintained clinically meaningful improvements in PFS compared to Vd alone across all subgroups. In patients with lenalidomide (Revlimid)-refractory disease, the median PFS was 10.2 months with SVd versus 7.1 months with Vd (HR, 0.52; 95% CI, 0.31-0.88; P =.006). Patients who had not received a prior proteasome inhibitor had a median PFS of 29.5 months with SVd versus 9.7 months with Vd (HR, 0.29; 95% CI, 0.14-0.63; P <.001).
Patients with lenalidomide-refractory disease also experienced longer median OS with SVd, at 26.7 months versus 18.6 months with Vd alone (HR, 0.53; 95% CI, 0.30-0.95; P =.015).
Reimbursement and Further Expansion
Selinexor was added to the reimbursement drug list in South Korea on July 24, 2024, making it the first XPO1 inhibitor to receive approval for public insurance coverage in the country. The agent is also included in national health insurance or reimbursement schemes in Australia and Singapore. Antengene, the codeveloper of selinexor, has also submitted a new drug application for the agent in Indonesia, with approval expected in the second half of 2024.
