selitrectinib (BAY 2731954)

TRK inhibitors like larotrectinib and entrectinib marked a paradigm shift - prioritizing molecular alterations over the tumor's anatomical location...Combination therapies with TRK inhibitors are emerging as a key strategy to enhance efficacy and overcome resistance. The FDA's recent approval of repotrectinib underscores progress in the TRK inhibitor landscape, while highlighting the continued need for innovation.

Among them, compound 10o exhibited superior antiproliferative activity in the Ba/F3-MPRIP-TRKAG667C cell line compared to selitrectinib, one of the most advanced selective next-generation TRK inhibitors, and it potently inhibited TRK kinase activity with high selectivity...In vivo treatment with 10o·HCl led to a marked delay in tumor growth in a Ba/F3-MPRIP-TRKAG667C subcutaneous tumor model. Thus, our work offers valuable insights for the development of next-generation TRK inhibitors.

NTRK1/3 fusions are seen in PTC, PDTC, and ATC, and a follicular growth pattern was observed in a high proportion of cases. In patients treated with larotrectinib, NTRK solvent front mutations are the main resistance mechanism, frequently occurring in PDTC/ATC. Responses to single-agent TRK inhibitor are short-lived in patients with ATC; thus, these drugs should be used with caution in this population.

First-generation TRK inhibitors, i.e., Larotrectinib sulfate and Entrectinib, received clinical approval in 2018 and 2019, respectively...Fortunately, the second-generation Trk inhibitor Repotrectinib (TPX-0005) was approved by the FDA in November 2023, while Selitrectinib (Loxo-195) has provided an effective solution to this issue...This article focuses on a comprehensive review of chronological synthetic developments and the structure-activity relationships (SAR) of pyrazolo[1,5-a]pyrimidine derivatives as Trk inhibitors. This article will also provide comprehensive knowledge and future directions to the researchers working in the field of medicinal chemistry by facilitating the structural modification of pyrazolo [1,5-a]pyrimidine derivatives to synthesize more effective novel chemotherapeutics as TRK inhibitors.

NTRK fusion-positive cancers can be treated with the first-generation TRK inhibitors, larotrectinib and entrectinib...And the inhibitory effect against TRKAG667C (IC50 = 9.9 nM) was better than that of selitrectinib (IC50 = 113.1 nM). Further, compound B31 exhibited moderate kinase selectivity and excellent plasma stability (t1/2 > 480 min). In vivo pharmacokinetic studies in Sprague-Dawley rats showed that B31 had acceptable pharmacokinetic properties.

These results suggest that HMGCS2 overexpression induces resistance to NTRK-TKIs via the mevalonate pathway in colon cancer cells. Statin inhibition of the mevalonate pathway may be useful for overcoming this mechanistic resistance.

Our data identifies zurletrectinib as a novel, highly potent next-generation TRK inhibitor with stronger in vivo brain penetration and intracranial activity than other next-generation agents.

We detected (de novo/somatic) missense mutation variants in cis position of the NTRK1 gene in a subset of DDLPS indicating modifying mutations that may contribute to tumorigenesis in a subset of DDLPS. These variants beget resistance to TRK inhibitors indicating an interesting biomarker for other studies with TRK inhibitors.

The representative second-generation inhibitors selitrectinib and repotrectinib were designed to overcome clinic acquired resistance of the first-generation inhibitors larotrectinib or entrectinib resulted from solvent-front and gatekeeper on-target mutations. In this review, we summarize the acquired resistance mechanism of the first- and second-generation TRK inhibitors, and firstly put forward the emerging selective type II TRK inhibitors to overcome xDFG mutations mediated resistance. Additionally, we concluded our perspectives on new challenges and future directions in this field.

In 2017, first-generation TRK inhibitor (TRKi) larotrectinib was granted accelerated approval from the FDA, having demonstrated histologic-agnostic activity against NTRKs fusions tumors. Since this new era has begun, resistance to first-generation TRKi has been described and has opened the development of second-generation molecules, such as selitrectinib and repotrectinib. In this review, we provide a brief overview of the studies on NTRK alterations found in pediatric central nervous system tumors and first and second-generation TRKi useful in clinical practice.

The solvent front and xDFG mutations induced by larotrectinib and entrectinib result in acquired resistance in advanced-stage patients...In biochemical and cellular assays, 40l showed better inhibitory activity against TRKA than that by the positive control, selitrectinib...In vitro assays indicated that 40l possessed outstanding plasma stability and moderate liver microsomal stability. Based on the above results, compound 40l could be further optimized to overcome the solvent front and xDFG TRK mutations.

Challenges remain in accurately diagnosing NTRK gene alterations and integrating screening into routine clinical practice. Trk inhibitors have surpassed their conventional role of inhibition and are now seeing new applications in radiopharmaceutical development and as molecular targeting agents.