0001503802 2026-05-21 2026-05-21 0001503802 false 8-K 2026-05-21 Karyopharm Therapeutics Inc. DE 001-36167 26-3931704 85 Wells Avenue 2nd Floor Newton MA 02459 (617) 658-0600 false false false false Common Stock, $0.0001 par value KPTI NASDAQ false