Pliant Therapeutics has initiated a Phase 1b indication expansion trial for PLN-101095, an oral dual inhibitor of αvβ8 and αvβ1 integrins designed to block TGF-β activation in the tumor microenvironment and overcome checkpoint resistance. The move follows early signals from its ongoing Phase 1 trial showing deep and durable responses in heavily pretreated, ICI-refractory patients when PLN-101095 was given with pembrolizumab, including one complete response and three partial responses among ten evaluable secondary-refractory patients across cholangiocarcinoma, melanoma, head and neck, and NSCLC. The program will present new data at AACR 2026 and is now enrolling cohorts in NSCLC, clear cell RCC, and TMB-high tumors with a 14-day monotherapy “priming” period before pembrolizumab is added. First patient enrollment is expected in the second quarter of 2026, with interim readouts guided for 2027. Alongside the clinical update, Pliant reported a streamlined fourth quarter with reduced R&D and G&A expenses, a narrower net loss, and $192.4 million in cash and investments, extending runway into the second half of 2028.

The strategic question is whether integrin-mediated control of TGF-β can finally unlock durable responses in ICI-resistant disease—and do so with a practical, biomarker-led playbook. Pliant’s design is notable for its 14-day monotherapy lead-in that induced marked rises in plasma interferon-gamma only in eventual clinical responders, a pharmacodynamic signal that could evolve into an on-treatment enrichment tool. If reproducible, this approach reframes combination I/O not as empiric layering but as a mechanistically defined “prime-then-blockade” sequence, potentially reducing trial risk and clarifying a path to precision use.

This matters now because the industry’s first wave of next-gen I/O combinations has struggled to rescue refractory patients at scale, while payers increasingly demand clear incremental value for add-on therapies. For oncologists, a tolerable oral agent that resets the microenvironment and flags likely benefit within two weeks could meaningfully inform sequencing decisions, particularly in tumors like NSCLC and RCC where second-line options are crowded yet outcomes remain suboptimal. For patients with cholangiocarcinoma and head and neck cancers—where durable post-ICI responses are rare—the early breadth of signal, albeit from small numbers, is directionally encouraging.

The competitive lens is sharpening around the TGF-β axis. Antibodies, traps, and latent TGF-β activation blockers have generated mixed results; a small-molecule integrin inhibitor with early evidence of immune activation and response adds a differentiated mechanism to the field. Tumor selection that spans PD-1–sensitive settings (TMB-high) and more resistant phenotypes will test whether PLN-101095’s value lies in true salvage of refractory disease, in priming earlier lines, or both. The biomarker story will be pivotal: standardizing IFN-γ assays, defining clinically actionable thresholds, and validating correlation with durable benefit will shape regulatory and payer conversations, especially if future labeling seeks biomarker-informed positioning.

Commercially, Pliant’s tightened cost base and long cash runway give it time to prosecute a focused development plan without near-term financing pressure, an edge in the current capital-constrained market. The company’s parallel work on integrin-targeted delivery of siRNA to skeletal muscle also aligns with a broader industry push to expand ligand-directed payload delivery beyond the liver, opening optionality for partnering and platform monetization even as the oncology asset matures.

The near-term read-through will come from AACR: durability curves, depth of response, and the robustness of the IFN-γ linkage. The medium-term test is whether the Phase 1b cohorts can convert a provocative signal into a reproducible, biomarker-guided effect across defined tumor types. The forward-looking question for competitors and potential partners is whether a short priming window with integrin inhibition becomes a new backbone for PD-1 combinations—or whether the path to impact runs through a narrower, high-fidelity biomarker niche that rewards precision over breadth.

Source link: https://www.globenewswire.com/news-release/2026/03/11/3254126/0/en/Pliant-Therapeutics-Provides-Corporate-Update-and-Reports-Fourth-Quarter-2025-Financial-Results.html

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Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.