Phase 1 basket study of telisotuzumab adizutecan (Temab-A, ABBV-400), a c-Met protein–targeting antibody-drug conjugate: Results from patients with platinum-resistant ovarian/primary peritoneal/fallopian tube cancer (PROC).

5514 Background: c-Met protein is expressed in several tumor types, including PROC, and is linked with poor clinical outcomes. Temab-A comprises a c-Met protein-targeting antibody conjugated to a topoisomerase 1 inhibitor. Phase 1 studies evaluating Temab-A monotherapy in solid tumors showed antitumor activity and a manageable safety profile (NCT05029882, NCT06084481). Here, we report on the efficacy and safety of Temab-A in PROC. Methods: This phase 1, open-label basket study (NCT06084481) enrolled patients (pts) ≥18 years with histologically/cytologically confirmed recurrent PROC, with Eastern Cooperative Oncology Group performance score ≤1. Pts must have had measurable disease per investigator-assessed RECIST v1.1 criteria, have had platinum-resistant disease, and have received ≥1 but ≤5 prior lines of systemic therapy, with ≤2 prior therapies since the development of platinum resistance. Pts received Temab-A at 2.4 mg/kg every 3 weeks. Primary endpoints were safety and efficacy. Results: As of Sept. 11, 2025, 41 pts with PROC received Temab-A. Tumor histology included serous carcinoma (n=26), clear cell carcinoma (n=7), and other rare histologies (n=8). The median age was 64 years (range 43–89), and the median number of prior lines of systemic therapy was 3 (range 1–6). Median follow-up was 5.1 months. Objective response rate (ORR) was 37%. Duration of response, progression-free survival, and overall survival were immature at data cutoff. Efficacy data are shown in the Table. The most common treatment-related adverse events (TRAEs) of any Grade (G) included anemia (59%), nausea (59%), and fatigue (39%); G ≥3 TRAEs occurring in ≥10% of pts were anemia (34%), neutrophil count decreased (17%), and white blood cell count decreased (15%). The adjudicated interstitial lung disease/pneumonitis rate was 5% (G1, n=2). TRAEs led to treatment discontinuation in 5%, dose interruption in 39%, and dose reduction in 37% of pts. There were no TRAEs that led to death. Temab-A pharmacokinetics in pts with PROC were consistent with those in other tumor types. Exploratory biomarker analyses are ongoing. Conclusions: Temab-A had a manageable safety profile and showed antitumor activity in pts with PROC. Clinical trial information: NCT06084481 . Efficacy of Temab-A. a . Outcome Pts with PROC (N=41) Best overall response, n (%)Complete responsePartial responseStable diseaseProgressive diseaseNot assessed b 019 (46)16 (39)5 (12)1 (2) Objective response rate c , n (%)95% CI 15 (37)22, 53 Clinical benefit rate c , n (%)95% CI 35 (85)71, 94 a Responses were assessed by investigators per RECIST v 1.1 criteria. b Pts without postbaseline scan. c Confirmed. CI, confidence interval.