FDA Grants Fast Track Status to ALK-Degrading Molecular Glue TRI-611

The FDA has granted fast track designation to TRI-611, an investigational, oral molecular glue degrader (MGD) developed by TRIANA Biomedicines for the treatment of anaplastic lymphoma kinase–positive (ALK+) non–small cell lung cancer (NSCLC). The designation is specifically directed toward patients whose disease has progressed following treatment with 2 or more ALK tyrosine kinase inhibitors (TKIs).¹

Addressing Resistance in the ALK+ NSCLC Landscape

While the advent of third-generation TKIs such as lorlatinib (Lorbrena) and recently approved agents like ensartinib (Ensacove) has significantly improved progression-free survival (PFS) in the frontline and second-line settings, acquired resistance remains a major clinical obstacle. Most patients eventually develop compound mutations within the ALK kinase domain—such as G1202R or L1196M—or experience off-target resistance through bypass signaling pathways.²

Furthermore, central nervous system (CNS) metastasis occurs in up to 50% of patients with ALK+ NSCLC during the course of their disease. Despite the improved blood-brain barrier penetration of newer TKIs, there remains an urgent need for therapies that can effectively clear both systemic and intracranial disease after existing inhibitors fail.

Mechanism of Action: Target-First Molecular Glue Degradation

TRI-611 represents a shift from traditional enzymatic inhibition to targeted protein degradation.¹ Unlike TKIs, which bind to the ATP-binding pocket of the ALK protein to inhibit signaling, TRI-611 functions as an MGD. It facilitates a novel proximity-based interaction between the ALK fusion protein and the E3 ubiquitin ligase cereblon.

By "gluing" the target protein to the E3 ligase, TRI-611 induces the polyubiquitination of ALK, marking it for proteasomal degradation. This mechanism is independent of the ALK kinase active site, potentially allowing TRI-611 to maintain efficacy against the various kinase domain mutations that render current TKIs ineffective.

Clinical Evaluation: The Phase 1/2 Study

The FDA’s fast track decision follows the recent initiation of a global, first-in-human phase 1/2 clinical trial (NCT07491497) designed to evaluate the safety, tolerability, and preliminary efficacy of TRI-611.

The study is divided into 2 primary phases:

1. Phase 1 (Dose Escalation): This portion utilizes a traditional dose-escalation design to determine the maximum tolerated dose and the recommended phase 2 dose. Enrolled patients must have received 2 to 3 prior ALK TKIs, including mandatory prior exposure to lorlatinib.
2. Phase 2 (Dose Expansion): This phase will evaluate TRI-611 across 3 distinct patient cohorts:

• Cohort M1: Patients previously treated with 2 to 3 ALK TKIs (including lorlatinib).
• Cohort M2: Heavily pretreated patients who have failed more than 3 TKIs, including both lorlatinib and neladalkib.
• Cohort M3: TKI-naive patients, intended to explore the potential of degradation as an earlier-line intervention.

The primary end points for the expansion cohorts include the objective response rate (ORR) per RECIST v1.1 and the duration of response. Secondary end points include CNS-specific ORR and various pharmacokinetic parameters.

Implications for the Clinical Oncology Community

The fast track designation allows for more frequent communication between the FDA and TRIANA Biomedicines, as well as eligibility for priority review and rolling review if relevant criteria are met. This accelerated pathway is critical for a patient population that currently has limited options beyond conventional chemotherapy once third-generation TKIs fail.

“This fast track designation underscores the potential of TRI-611 to address the significant unmet need for patients with ALK+ NSCLC who have been previously treated with 2 or more ALK [TKIs],” said Patrick Trojer, PhD, president and CEO of TRIANA Biomedicines, in a news release. “TRI-611 was designed as an innovative therapeutic approach to target ALK fusion proteins. We look forward to working closely with the FDA to potentially bring TRI-611 forward to the lung cancer patient community.”

REFERENCES

1. TRIANA Biomedicines’ TRI-611 Granted U.S. FDA Fast Track Designation for Treatment of ALK Positive Non-small Cell Lung Cancer. News release. TRIANA Biomedicines. March 25, 2026. Accessed March 26, 2026. https://tinyurl.com/2jnnrdhm

2. Lin JJ, Riely GJ, Shaw AT. Targeting ALK: Precision medicine takes on drug resistance. Cancer Discov. 2017;7(2):137-155. doi:10.1158/2159-8290.CD-16-1123