Pliant Therapeutics has reported promising results from its Phase 1 trial of PLN-101095 in combination with pembrolizumab for patients with immune checkpoint inhibitor (ICI)-refractory advanced or metastatic solid tumors. Presented at the AACR 2026 Annual Meeting, the findings indicate significant antitumor activity, with an average maximum tumor reduction of 89% from baseline and a median time on treatment of 19 months for confirmed responders. The trial included patients with various cancers, such as cholangiocarcinoma and non-small cell lung cancer (NSCLC), who demonstrated notable increases in plasma interferon gamma (IFN-γ) levels, a potential biomarker for TGF-β inhibition and PLN-101095 efficacy.

The significance of these findings lies in the ability of PLN-101095, an oral small molecule inhibitor targeting integrins αvβ8 and αvβ1, to mitigate the immunosuppressive effects of TGF-β in the tumor microenvironment. By preventing TGF-β activation, PLN-101095 enhances immune cell infiltration and response to ICI therapy, addressing a critical unmet need in treating refractory tumors. The study reported a 4- to 13-fold increase in plasma IFN-γ levels following a 14-day run-in period with PLN-101095 monotherapy, suggesting a robust immunomodulatory effect that correlates with treatment response.

The implications for the field are substantial, as these results may shift the paradigm for developing combination therapies targeting ICI resistance. The initiation of a Phase 1b trial to expand the indication for PLN-101095 in specific tumor types, including NSCLC and tumors with high mutational burden, signals a strategic move toward refining treatment protocols for challenging cases. As Pliant continues to explore the role of IFN-γ as a biomarker in this context, the findings could accelerate timelines for clinical applications and enhance therapeutic strategies in oncology.

Source: globenewswire.com