Faeth Therapeutics (FTH) investor relations material

Study design and population

• Open-label, single-arm Phase 2 PIK-201 evaluated oral serabelisib plus sapanisertib (PIKTOR) and paclitaxel in advanced endometrioid endometrial cancer with PAM pathway alterations after platinum chemotherapy and immunotherapy.

• 42 patients were treated and 36 were efficacy-evaluable; median age was 65 and median prior therapy lines were 2. All had prior taxane exposure and 98% had prior immunotherapy.

• The Oct. 30, 2026 data cut included 42 safety-evaluable patients; 16 remained on treatment. Results are preliminary, and the single-arm design cannot establish comparative efficacy or individual drug contribution.

Efficacy

• Confirmed ORR was 33% (12/36) and DCR was 83% (30/36); one additional partial response was unconfirmed.

• Confirmed ORR was 44% (7/16) in PIK3CA-mutated tumors and 25% (5/20) without the mutation; responses occurred in both groups.

• Preliminary median PFS was 7.4 months (95% CI 5.3–NR) among 42 patients; 6-month PFS was 62% (95% CI 43%–75%).

• Median duration of response was not reached; 9 of 12 confirmed responders remained on treatment, and one response deepened from stable disease to partial response after 20 months.

• In exploratory paired ctDNA analyses, tumor fraction fell in 13 of 17 patients and by at least 50% in 12.

Safety and tolerability

• Treatment-related grade 3 or higher adverse events occurred in 64%; neutropenia was the most frequent, at 26% grade 3 or higher. No febrile neutropenia was reported.

• Treatment-related hyperglycemia occurred in 12% (2% grade 3) and stomatitis in 21% (2% grade 3); steroid mouthwash prophylaxis was not used. Nearly half had diabetes or prediabetes at baseline.

• Two patients (5%) discontinued due to treatment-related adverse events; no treatment-related deaths or Hy's Law cases were reported.