zidesamtinib (NVL-520)

Crizotinib first demonstrated substantial clinical benefit, but its limitations, including poor central nervous system (CNS) penetration and acquired resistance, highlighted the need for next-generation inhibitors. Several agents have since been developed, including entrectinib, lorlatinib, repotrectinib, taletrectinib, and zidesamtinib, each offering improved intracranial (IC) activity and efficacy against resistance mutations, notably ROS1^G2032R. Despite these advances, optimal sequencing strategies remain undefined, and resistance ultimately emerges in most patients. This review provides an updated overview of ROS1 biology, diagnostic approaches, clinical outcomes with currently available TKIs, mechanisms of resistance, and ongoing challenges, emphasizing the rapidly evolving therapeutic landscape.

P1/2, N=359, Recruiting, Nuvalent Inc. | Trial completion date: Oct 2026 --> Dec 2028 | Trial primary completion date: Oct 2025 --> Dec 2027

At clinically relevant concentrations, zidesamtinib robustly inhibited >1,500 pooled ROS1 mutants with virtually no resistance emerging (≤1%), outperforming comparators crizotinib, entrectinib, and repotrectinib. Zidesamtinib also induced more durable responses than repotrectinib and taletrectinib in an aggressive intracranial ROS1 G2032R xenograft model. A 2.2 Å co-crystal structure with ROS1 G2032R, the most frequently identified ROS1 resistance mutation, reveals that zidesamtinib uniquely accommodates the mutated residue while potentially clashing with TRK, consistent with its selective ROS1-targeting design and supported by computational modeling. Taken together, these data support zidesamtinib's potential as a novel best-in-class ROS1 inhibitor.

First-generation inhibitors, such as crizotinib and entrectinib, have demonstrated impressive efficacy, with objective response rates exceeding 60%-70%...Next-generation TKIs, including lorlatinib, taletrectinib, and repotrectinib, have been developed to overcome these challenges...Zidesamtinib, a highly selective next-generation ROS1 inhibitor, further addresses TRK-mediated off-target neurological toxicities seen with prior agents, and is poised to offer improved tolerability...In addition, the development of novel diagnostic tools, including RNA-based next-generation sequencing, has enhanced the detection of functional ROS1 fusions by ensuring that patients with actionable mutations receive appropriate targeted therapies. These advances highlight the evolving landscape of treatment for ROS1-positive NSCLC, with the aim of maximizing long-term survival and quality of life.

For EGFR exon 20 insertion mutation positive NSCLC, results from REZILIENT-1, a single arm phase II study with zipalertinib, were presented, showing an objective response rate (ORR) of 50% in patients that were pretreated with amivantamab, and 25% in patients pretreated with amivantamab and an EGFR exon 20 insertion-directed TKI...For ALK, results from ALKOVE-1, a single arm phase I/II study with NVL-655, a next generation ALK TKI, were presented. The ORR was 35 % in patients pretreated with ≥ 2 ALK TKIs including lorlatinib and 57 % in patients pretreated with ≥ 1 ALK TKI, excluding lorlatinib...In addition, results of the first-line randomized phase III INSPIRE study were presented, in which iruplinalkib, an ALK and ROS1 selective TKI, is being evaluated versus crizotinib...Finally, results from ARROS-1, a single arm phase I/II study with zidesamtinib, a ROS1 selective and TRK-sparing TKI, were presented. An ORR of 73% was obtained in patients that were pretreated with crizotinib and an ORR of 38% in patients pretreated with repotrectinib. In this review, we will discuss the relevant study results presented at ESMO 2024 for these three genomic drivers and hypothesize on their respective place in the sequence of treatment options.

P=N/A, N=0, Available, Nuvalent Inc.

Despite ROS1 fusion positive (ROS1+) NSCLC accounting approximately 1-2% of NSCLC, there is a dizzying list of ROS1 tyrosine kinase inhibitor (TKIs) being developed in addition to two approved ROS1 TKIs, crizotinib and entrectinib...Additionally, the less known central β-sheet 6 (Cβ6) mutation ROS1 L2086F confer resistances to next-generation ROS1 TKIs (taletrectinib, lorlatinib, potentially NVL-520) that can be overcome by cabozantinib as documented in published patient reports and may potentially by certain L-shaped Type I ROS1 TKIs including gilteritinib which is approved as a FLT3 inhibitor for AML. Future clinical trials should investigate cabozantinib and gilteritinib to repurpose them as ROS1 TKIs that can target Cβ6 mutation.

P1/2, N=359, Recruiting, Nuvalent Inc. | N=247 --> 359

Crizotinib and entrectinib are FDA-approved ROS1 tyrosine kinase inhibitors (TKIs), but clinical emergence of ROS1 resistance mutations S1986F/Y, F2004C/I/V, L2026M, G2032R, and D2033N restricts their therapeutic utility...TRKB inhibition in the central nervous system has been implicated in adverse events observed with FDA-approved dual TRK/ROS1 inhibitor entrectinib and FDA-approved ALK inhibitor lorlatinib...In conclusion, the preclinical profile of NVL-520 supports its potential to address a medical need for patients with a diverse array of ROS1 fusion partners and kinase-domain mutations, both in NSCLC and in other cancers such as glioblastoma. NVL-520 is being evaluated in a Phase 1/2 clinical trial for patients with advanced ROS1-positive NSCLC or other solid tumors (NCT05118789).

P1/2, N=246, Recruiting, Nuvalent Inc.

P1/2, N=246, Nuvalent, Inc.