On November 9, 2026 Faeth Therapeutics (Nasdaq: FTH), a clinical-stage oncology company developing multi-node therapies for cancer patients, including its lead program PIKTOR, reported topline clinical data from its Phase 2 trial (FTH-PIK-201; NCT06463028; GOG-3111) of PIKTOR, an investigational all-oral combination of serabelisib and sapanisertib, given with paclitaxel to patients with advanced endometrioid endometrial cancer and a PI3K/AKT/mTOR (PAM) pathway mutation who had received at least one prior line of therapy. The trial is being conducted in collaboration with The GOG Foundation, Inc. (GOG-F).

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The Phase 2 trial is ongoing, and the topline data include 42 patients with endometrioid endometrial cancer who had a median of 2 prior lines of therapy (range 1-4 lines). As of the October 30, 2026 efficacy data cut, confirmed objective responses were observed in 12 of the 36 efficacy-evaluable patients, for a confirmed objective response rate (ORR) of 33%. One additional patient had a partial response that could not be confirmed because the patient discontinued the study before a confirmatory scan, for an unconfirmed ORR of 36% (13 of 36). Among patients with a PIK3CA mutation, the confirmed ORR was 44% (7 of 16). In the 42 treated patients, the preliminary Kaplan-Meier estimated median progression-free survival (PFS) was 7.4 months (95% CI 5.3-NR), and the 6-month PFS rate was 62% (95% CI 43%-75%); 16 patients remained on treatment at the data cut.

"We believe these data support the multi-nodal PAM targeting hypothesis, whereby more complete inhibition of the pathway may drive durable responses and extend progression-free survival without the safety limitations of single-node inhibitors," said Anand Parikh, Co-Founder and Chief Executive Officer of Faeth. "Endometrial cancer has among the highest rates of PI3K pathway alterations of any cancer, yet no drug that targets the pathway is approved to treat it.

"In PIK-201, PIKTOR delivered a preliminary estimated median PFS of 7.4 months, which we believe compares favorably to the 3-4 months typical for salvage chemotherapy alone, or the 6-7 months observed with newer treatments including TOPO1-based ADCs." Mr. Parikh continued, "In our view, these preliminary data set PIKTOR apart. On the safety side, hyperglycemia and stomatitis were mostly low grade in a population in which nearly half of patients had diabetes or prediabetes and prophylactic steroid mouthwash was not required. We now plan to advance toward a Phase 3 trial, subject to regulatory alignment, with the goal of getting PIKTOR into the hands of patients as expeditiously as possible."

"We need more treatment options for patients whose advanced endometrial cancer has progressed after platinum chemotherapy and immunotherapy," said David Starks, MD, MPH, a PIK-201 and GOG Foundation principal investigator and Gynecologic Oncologist at Avera Cancer Institute, Sioux Falls, South Dakota. "I believe the response and progression-free survival data reported for PIKTOR with paclitaxel give physicians a reason to follow it closely. I am excited by the potential that this treatment could have for my patients."

Phase 2 FTH-PIK-201 Topline Clinical Data Highlights

Baseline characteristics

The open-label, single-arm Phase 2 trial (NCT06463028, GOG-3111) is evaluating patients with PIKTOR plus paclitaxel.
48% of patients had diabetes or pre-diabetes at baseline.
76% of patients had distant metastases, including liver and lung lesions.
Patients had a median of 2 prior lines of therapy (range 1 to 4), with 3 or more prior lines in 15 patients (36%).
All patients had been previously treated with taxane-based chemotherapy (100%), and prior immunotherapy was reported in 41 patients (98%).
Of the 42 treated patients, 6 were not evaluable for efficacy, having discontinued prior to the first post-baseline scan due to early disease progression (n=3) or non-treatment-related reasons (n=3).
Efficacy

As of the October 30, 2026 efficacy data cut:

The confirmed ORR was 33% (12 of 36 efficacy-evaluable patients). One additional patient had a partial response that could not be confirmed because the patient discontinued the study before a confirmatory scan, for an unconfirmed ORR of 36% (13 of 36).
Among patients with a PIK3CA mutation, the confirmed ORR was 44% (7 of 16).
At the data cut, 9 of the 12 confirmed responders and 7 patients with a best response of stable disease remained on treatment. Several responses deepened over the course of therapy, including one patient who converted from stable disease to partial response after 20 months of treatment.
The disease control rate (DCR) was 83% (30 of 36), defined as the percentage of patients with a best overall response of complete response, partial response or stable disease.
In all 42 treated patients, the preliminary Kaplan-Meier estimated median PFS was 7.4 months (95% CI: 5.3 to NR), and the preliminary 6-month PFS rate was 62% (95% CI: 43% to 75%).
Safety

As of the October 23, 2026 safety data cut:

Two patients (5%) discontinued treatment due to a treatment-related adverse event (TRAE; headache, dizziness). There were no treatment-related deaths.
64% of patients had a grade 3 or higher TRAE. Neutropenia, a grouped term including neutropenia and decreased neutrophil count, occurred in 36% of patients overall and was the most frequent grade 3 or higher TRAE (26%).
Hyperglycemia TRAEs occurred in 5 of 42 patients (12%), and 1 patient (2%) had a grade 3 event. 48% of patients had diabetes or pre-diabetes at baseline.
Stomatitis TRAEs occurred in 21% of patients, and 1 patient (2%) had a grade 3 event. Patients did not receive steroid mouthwash prophylaxis.
Webcast details

Faeth will host a webcast today, November 9, 2026, at 8:00 a.m. ET to discuss the data. David Starks, MD, MPH, Gynecologic Oncologist at Avera Cancer Institute, Sioux Falls, South Dakota, will join management. To access the live webcast, click here. A replay will be available in the Events and Presentations (Events and Presentations — Faeth Therapeutics, Inc) section of Faeth’s corporate website.

(Press release, Faeth Therapeutics, NOV 9, 2026, View Source [SID1234674503])