GENFIT's GNS561 Combination Therapy Shows Disease Stabilization in Advanced Cholangiocarcinoma Patients
Key Insights
GENFIT reports encouraging Phase 1b data showing GNS561 combined with MEK inhibitor (search) trametinib achieved disease stabilization in all four evaluable patients with advanced KRAS-mutated cholangiocarcinoma (search).
The combination therapy demonstrated tumor shrinkage in a subset of heavily pretreated patients, with the best response showing a 20% reduction approaching partial response threshold.
No dose-limiting toxicity has been observed to date, enabling recruitment of a third patient cohort and positioning the combination as a potential breakthrough for this difficult-to-treat cancer.
GENFIT has reported encouraging preliminary results from its ongoing Phase 1b clinical trial evaluating the investigational drug GNS561 in combination with a MEK inhibitor (search) for patients with advanced KRAS-mutated cholangiocarcinoma (search) (CCA). The combination therapy achieved disease stabilization in all evaluable patients, with evidence of tumor shrinkage in a subset of heavily pretreated patients.
Trial Design and Patient Population
The GNS561-222-1 Phase 1b study enrolled patients with advanced KRAS (search)-mutated CCA who had previously failed one or two lines of standard care therapies. The trial evaluates the safety and tolerability of GNS561 when combined with trametinib, a MEK inhibitor (search), while identifying recommended doses for Phase 2 development. The study uses RECIST 1.1 criteria to assess tumor response and includes comprehensive biomarker analyses.
Promising Early Efficacy Signals
Among nine patients with measurable disease at baseline, four reached tumor assessment at week 6. The combination therapy demonstrated disease stabilization in all four evaluated patients, who had all shown disease progression during previous treatment. Notably, tumor shrinkage was observed in a subgroup of patients, with the best response showing a 20% reduction approaching the partial response threshold.
Dr. Mark Yarchoan, Associate Professor of Oncology at Johns Hopkins Medicine (search) and principal investigator of the program, commented: "Advanced KRAS-mutated cholangiocarcinoma (search) remains a formidable clinical challenge, and the emerging activity seen in this initial study is encouraging. Because MEK inhibition alone has historically shown limited efficacy in this setting, the early signs of benefit with dual targeting of autophagy and MAPK signaling provide meaningful rationale for continued evaluation of this combination strategy."
Novel Mechanism of Action
GNS561 is a first-in-class investigational lysosomotropic agent that targets PPT1 (search), leading to autophagy inhibition and lysosomal dysfunction. By blocking autophagy, GNS561 aims to promote cancer cell death and may enhance sensitivity to other treatments. The combination with a MEK inhibitor (search) aims to unlock synergistic potential by simultaneously targeting autophagy and MAPK signaling pathways.
Safety Profile and Dose Escalation
No dose-limiting toxicity has been reached to date, enabling recruitment of a third patient cohort. This favorable safety profile allows for continued dose escalation to identify optimal therapeutic doses for the combination therapy.
Addressing Critical Unmet Medical Need
Cholangiocarcinoma (search) represents approximately 15% of all primary liver tumors and 3% of gastrointestinal cancers. The disease presents significant clinical challenges, with most patients diagnosed at advanced stages due to limited early symptoms. Current therapeutic options are severely limited, with 5-year survival rates dropping to 5-15% in advanced and unresectable settings. Only about 25% of patients are eligible for potentially curative surgical resection at diagnosis, and even after surgery, 5-year survival rates range from 7% to 20%.
Pascal Prigent, Chief Executive Officer of GENFIT, added: "These early results suggest a potential breakthrough for patients with limited options, and we are committed to advancing this program rapidly to individuals impacted by cholangiocarcinoma (search). We will also explore GNS561 potential in combination with other agents and in other tumors where autophagy inhibition plays a central role."
Development Timeline
Phase 1b dose escalation will continue as planned to confirm the activity signal, with new data for additional patient cohorts expected in the first quarter of 2026. These results will establish recommended Phase 2 combination doses, with completion expected in the first half of 2026. Phase 2 initiation is targeted for the second half of 2026.
The consistent pattern of disease stabilization observed across all evaluated patients, combined with objective tumor shrinkage in heavily pretreated patients, suggests the combination has potential to provide meaningful clinical benefit in this challenging patient population.