Gilead Sciences Inc. / Tubulis GmbH

Platinum-resistant ovarian cancer

6K US cases/yr · $3.8B US ovarian cancer drugs market (2026) · 12,450 US ovarian cancer deaths (2026 SEER estimate)

Disease Overview

Ovarian cancer is the fourteenth leading cause of cancer death in the United States, with SEER projecting 21,010 new cases and 12,450 deaths in 2026. The majority of patients present with advanced stage III/IV disease and initially respond to platinum-based chemotherapy, but most relapse; platinum-resistant ovarian cancer (PROC) — defined as disease recurrence within six months of completing platinum-based therapy — represents the most refractory segment. A 2024 ISPOR mixed-source estimation found approximately 14,768 stage III/IV ovarian cancer patients in the US in 2023, with the proportion of platinum-resistant patients rising from 14.7% in second-line to 59.1% in fourth-line therapy. PROC carries dismal prognosis with median overall survival typically under 12 months on standard chemotherapy. Folate receptor alpha (FRα)-directed ADC mirvetuximab soravtansine (Elahere) became the first ADC approved in this setting (2022 accelerated; 2024 full) and has rapidly grown to >$470M US sales in 2024, validating ADC biology in gynecologic oncology and opening the door for next-generation targets including NaPi2b, HER2, B7-H4, and TROP2. Primary source: SEER Cancer Stat Facts: Ovarian Cancer (2026).

Competitive Landscape

The PROC ADC competitive landscape is rapidly densifying. Elahere (mirvetuximab soravtansine, AbbVie/ImmunoGen) remains the only approved ADC in PROC and is the class benchmark with FRα targeting and DM4 payload. Next-generation challengers cluster around three MOA families: (1) NaPi2b-directed ADCs — Tubulis's TUB-040 (now Gilead's lead asset) uses proprietary P5 conjugation with exatecan (TOPO1i) and posted a 50% confirmed ORR at ESMO 2025, plus FDA Fast Track; prior NaPi2b candidate upifitamab rilsodotin (Mersana) failed pivotal trials. (2) HER2-targeted ADCs — Innovent's IBI354 (HER2 TOP1i ADC) is enrolling Phase 3, and trastuzumab deruxtecan (Enhertu, AZ/Daiichi) has shown activity in HER2-expressing OC. (3) Emerging ADCs — Merck/Daiichi's raludotatug deruxtecan (CDH6 TOP1i) posted clinically meaningful ORR in REJOICE-Ovarian01 Phase 2; B7-H4 and TROP2 ADCs (Trodelvy, Datroway) are being explored in gynecologic cancers. Gilead's bet positions TUB-040 as best-in-class NaPi2b and provides a differentiated conjugation platform against Daiichi's DXd dominance.