What is Karyopharm Therapeutics Inc. (KPTI) worth?

Karyopharm is a going-concern-flagged, negative-equity commercial-stage oncology company whose stock is best understood as an out-of-the-money option on survival plus a myelofibrosis approval — not as a cash-flow business. The lead asset, XPOVIO (selinexor), generates ~$146M of flat-to-declining revenue at ~96% gross margin, but the company burns ~$75-90M of operating cash a year and carries roughly $235M of face debt plus ~$116M of revenue-interest/royalty obligations that all rank ahead of common equity, which sits at roughly -$266M of book value.

Two binary events define the story. On July 30, 2026 the Phase 3 XPORT-EC-042 endometrial cancer trial FAILED its primary PFS endpoint (mITT trend HR 0.76, p=0.079, not significant) — a real blow that erased a growth pillar and drove a ~69% single-day drop. Offsetting it, the Phase 3 SENTRY myelofibrosis trial hit its spleen-volume (SVR35) co-primary with a 'promising' overall-survival signal, and management plans an accelerated-approval sNDA for selinexor+ruxolitinib in August 2026 — but it missed the symptom-score co-primary and the FDA has said it 'requires further discussion' before the filing.

Against that, the balance sheet is the binding constraint: substantial-doubt going-concern language, a runway warned only 'into Q2 2026,' and an active 'strategic alternatives' review with Centerview point to a high probability of a dilutive recapitalization, asset sale, or restructuring that would subordinate or wipe common holders. A deterministic sum-of-parts puts the equity at roughly -$3/share; the positive market price is pure option premium. Weighing bear (restructuring), base (survive + MF approval, heavily diluted) and bull (MF success + strategic deal) outcomes yields a probability-weighted equity value near $1.75, with a very wide distribution. The stock is roughly a coin-flip trading around that option value — fairly priced to slightly rich versus the odds, not a value discount.

Probability-weighted scenarios on a distressed equity stub (deterministic SOTP as cross-check only)

Every figure is computed from SEC filings by the analyst’s calculator tools and fact-checked by a second, independent model.