ROS1 Fusion NSCLC Clinical Trial Landscape

Key trials in ROS1-fusion NSCLC

The table below reflects recruiting and active trials registered on ClinicalTrials.gov targeting ROS1-fusion non-small cell lung cancer as of early 2026. DataLookout monitors for new registrations and status changes daily.

Sources: ClinicalTrials.gov. DataLookout monitors for new registrations and status updates daily. Table reflects recruiting and active trials as of early 2026.

ROS1 fusions in NSCLC: rare, highly druggable, and increasingly competitive

ROS1 fusions occur in approximately 1–2% of non-small cell lung cancer cases — roughly 4,000–8,000 new patients per year in the United States. Despite their rarity, ROS1-fusion tumors have become a major focus of targeted oncology drug development because they respond dramatically to ROS1 tyrosine kinase inhibitors (TKIs). Objective response rates exceeding 60–70% are routinely observed in treatment-naive ROS1+ NSCLC with approved agents — among the highest response rates seen in any molecularly targeted solid tumor.

The ROS1 fusion landscape includes over 20 described fusion partners. CD74-ROS1 is the most common (~30–40% of cases), followed by EZR-ROS1, SLC34A2-ROS1, and SDC4-ROS1. Unlike EGFR or KRAS, there is no single dominant "hotspot" fusion variant — but the shared feature of all ROS1 fusions is constitutive activation of the ROS1 kinase domain, driving oncogenic signaling through the RAS/MAPK, PI3K/AKT, and JAK/STAT pathways.

The approved ROS1 inhibitor landscape: three drugs, two resistance problems

Crizotinib (Xalkori, Pfizer) — first approved, now largely superseded

Crizotinib was the first FDA-approved treatment for ROS1-fusion NSCLC, receiving accelerated approval in 2016 based on Phase 1 expansion cohort data from PROFILE 1001. In TKI-naive patients, crizotinib achieved an objective response rate (ORR) of ~72% with a median PFS of approximately 19 months — comparable results to its activity in ALK+ NSCLC. However, crizotinib has limited CNS penetration, and the dominant resistance mechanism — the G2032R solvent-front mutation — is not covered by crizotinib. In markets where entrectinib and repotrectinib are available, crizotinib has largely been displaced as front-line therapy, though it remains widely used in countries where newer agents lack approval.

Entrectinib (Rozlytrek, Genentech/Roche) — pan-NTRK/ROS1/ALK with CNS activity

Entrectinib received FDA approval in 2019 for ROS1-fusion NSCLC based on pooled Phase 1/2 data (STARTRK-1, STARTRK-2, ALKA trials) demonstrating an ORR of ~77% in TKI-naive patients and 55% intracranial response rate in patients with CNS metastases. Entrectinib's CNS penetration is superior to crizotinib, making it a preferred option in patients with brain involvement. However, entrectinib does not cover the G2032R mutation, and G2032R-driven resistance remains a significant clinical problem after entrectinib treatment. The ongoing Phase 3 trial (NCT04603807) comparing entrectinib versus crizotinib head-to-head will provide the first prospective randomized data directly comparing these two front-line options.

Repotrectinib (Augtyro, BMS) — the G2032R breakthrough

Repotrectinib (formerly TPX-0005, acquired by Bristol-Myers Squibb via Turning Point Therapeutics) received FDA approval in November 2023 based on the TRIDENT-1 Phase 1/2 trial. Repotrectinib is distinguished by two key features: its compact macrocyclic structure that overcomes the G2032R steric clash, and its broad approval spanning both treatment-naive and previously treated (including crizotinib- and entrectinib-treated) patients. In treatment-naive patients, repotrectinib achieved an ORR of 79% with a median PFS of 35.7 months — the longest PFS data reported for any ROS1 TKI in the front-line setting. In TKI-pretreated patients, repotrectinib achieved ORR of 38%, including responses in patients with the G2032R mutation.

TRUST-IV (NCT07154706): first Phase 3 adjuvant trial in ROS1+ NSCLC

TRUST-IV is a landmark Phase 3 trial run by Nuvation Bio comparing taletrectinib versus placebo as adjuvant therapy following complete resection of ROS1-positive NSCLC. It mirrors the adjuvant development path established in ALK+ NSCLC (lorlatinib's ALINA trial, HR 0.27) and EGFR-mutant NSCLC (osimertinib's ADAURA trial, HR 0.17) — both of which demonstrated that TKI-based adjuvant therapy dramatically reduces recurrence risk after surgery.

Taletrectinib (formerly AB-106, developed by Nuvation Bio via license from Abbisko Therapeutics) is a next-generation, highly selective ROS1/NTRK inhibitor with excellent CNS penetration and activity against the G2032R solvent-front mutation. Phase 2 TRUST data showed an ORR of 91% in TKI-naive patients and 51% in patients previously treated with a ROS1 TKI, including responses in G2032R-positive patients. These results motivated the Phase 3 investment.

If TRUST-IV is positive, taletrectinib would become the first approved adjuvant therapy for resected ROS1+ NSCLC — a commercially meaningful indication given the early-stage patient population and the demonstrated durability of adjuvant TKI benefit in adjacent molecular subgroups.

SOLAR-1: Nuvalent's NVL-520 targeting post-repotrectinib resistance

NVL-520, Nuvalent's highly selective ROS1 inhibitor, is being evaluated in the SOLAR-1 Phase 1/2 trial. Unlike the dual ALK/ROS1 inhibitors (neladalkib, lorlatinib), NVL-520 is designed specifically for ROS1+ tumors with a selectivity profile intended to minimize off-target activity, including CNS-relevant selectivity against TRK kinases (which share homology with ROS1). More importantly, NVL-520 was designed with compound ROS1 mutation coverage as a primary goal — specifically targeting the post-repotrectinib resistance landscape where compound mutations (particularly combinations involving G2032R) are emerging.

The relationship between Nuvalent's two drug programs is strategically coherent: neladalkib (NVL-655) is the ALK/ROS1 program, designed to succeed lorlatinib in both ALK+ and potentially ROS1+ NSCLC; NVL-520 is the dedicated ROS1 program, designed to succeed repotrectinib specifically in ROS1+ NSCLC. The two programs provide Nuvalent with a comprehensive strategy across the ALK/ROS1 TKI landscape, covering both treatment-naive and post-resistance settings.

ROS1 and ALK: shared kinase homology, shared TKI landscape

ROS1 and ALK share approximately 49% amino acid identity in their kinase domains — a structural similarity that explains why many ALK inhibitors also have ROS1 activity. Crizotinib, lorlatinib, and entrectinib are all approved for or have demonstrated activity in both ALK+ and ROS1+ NSCLC. This kinase overlap has both clinical and competitive intelligence implications.

On the clinical side, it means that patients with ROS1 fusions can sometimes benefit from agents developed primarily for ALK — lorlatinib, for example, has demonstrated activity in ROS1+ NSCLC in Phase 1/2 data. On the competitive side, drugs entering the ROS1 space are often entering the ALK space simultaneously (and vice versa), requiring pharma BD teams to monitor both programs. Nuvalent's ALKALI-1 (neladalkib in ALK+ NSCLC) and SOLAR-1 (NVL-520 in ROS1+ NSCLC) represent a deliberate strategy to dominate both adjacent markets.

Brain metastases and CNS activity: critical endpoints in ROS1+ NSCLC

Like ALK+ NSCLC, ROS1-fusion NSCLC has a high rate of CNS metastases — approximately 35% of patients have brain metastases at initial diagnosis, and the cumulative incidence over the treatment course is higher. CNS penetration is therefore a primary pharmacological requirement for any ROS1 TKI, and intracranial response rate and CNS PFS are standard secondary or co-primary endpoints in ROS1 clinical trials.

The CNS activity hierarchy among approved agents roughly mirrors their systemic activity: entrectinib and repotrectinib have superior CNS penetration versus crizotinib. The Phase 2 trial of repotrectinib in patients with active (untreated or progressive) brain metastases (NCT06315010) is specifically designed to characterize CNS activity in patients typically excluded from registration trials, which required stable or treated brain disease. These results will be particularly relevant for the significant subset of ROS1+ NSCLC patients with CNS involvement at diagnosis.

Related clinical trials and monitoring resources

ROS1-fusion NSCLC is part of the broader targeted therapy revolution in lung cancer. DataLookout monitors related areas including:

• NSCLC clinical trials — full non-small cell lung cancer pipeline, all mutation subgroups
• ALK-positive lung cancer clinical trials — the closest analog to ROS1; shared TKI landscape and kinase homology
• EGFR mutant lung cancer clinical trials — largest NSCLC molecular subgroup by volume
• RET-fusion NSCLC clinical trials — another rare fusion-driven NSCLC subtype (~2%) with dedicated approved inhibitors
• HER2-mutant NSCLC clinical trials — exon 20 insertion subgroup with T-DXd approval and active Phase 3 pipeline

Frequently asked questions