Pralsetinib in Patients with Advanced/Metastatic Rearranged During Transfection (RET)-Altered Thyroid Cancer: Updated Efficacy and Safety Data from the ARROW Study.

Background: Rearranged during transfection (RET) alterations are targetable oncogenic drivers in thyroid cancer. Primary data from the open-label, phase 1/2 ARROW study demonstrated clinical activity and manageable safety with pralsetinib, a selective RET inhibitor, in patients with advanced/metastatic RET-altered thyroid cancer. We present an updated analysis with more patients and longer follow-up. Methods: Adult patients with advanced/metastatic RET-mutant medullary thyroid cancer (MTC) or RET fusion-positive thyroid cancer who initiated oral pralsetinib at 400 mg once daily were included. Primary endpoints were overall response rate (ORR) by blinded independent central review (per RECIST v1.1) and safety. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), and overall survival. Responses were assessed in three cohorts of patients with baseline measurable disease: patients with RET-mutant MTC who had received prior cabozantinib and/or vandetanib (C/V), treatment-naïve patients with RET-mutant MTC, and patients with previously treated RET fusion-positive thyroid cancer. Patient-reported outcomes (PROs) were an exploratory endpoint. Results: As of October 18, 2021, the measurable disease population comprised of 61 patients with RET-mutant MTC and prior C/V, 62 treatment-naïve patients with RET-mutant MTC, and 22 patients with RET fusion-positive thyroid cancer who had received prior systemic therapy, including radioactive iodine. The ORR was 55.7% [confidence interval; 95% CI: 42.4-68.5] in patients with RET-mutant MTC and prior C/V, 77.4% [95% CI: 65.0-87.1] in treatment-naïve patients with RET-mutant MTC, and 90.9% [95% CI: 70.8-98.9] in patients with previously treated RET fusion-positive thyroid cancer. Median DoR and median PFS were both 25.8 months in patients with RET-mutant MTC and prior C/V, not reached in treatment-naïve patients with RET-mutant MTC, and 23.6 and 25.4 months, respectively, in patients with previously treated RET fusion-positive thyroid cancer. In the RET-altered thyroid cancer safety population (N = 175), 97.1% of patients reported a treatment-related adverse event (TRAE); these led to discontinuation in 5.7% and dose reduction in 52.6% of patients. There was one death (0.6%) due to a TRAE. PROs improved or remained stable after pralsetinib treatment. Conclusions: In this updated analysis of the ARROW study, pralsetinib continued to show deep and durable clinical activity and a manageable safety profile in patients with advanced/metastatic RET-altered thyroid cancer. Clinical Trial Registration: NCT03037385.

Long-Term Efficacy and Safety of Entrectinib in ROS1 Fusion-Positive NSCLC.

Introduction: Entrectinib is an approved tyrosine kinase inhibitor (TKI) for ROS1 fusion-positive NSCLC. An updated integrated analysis of entrectinib from the ALKA-372-001, STARTRK-1, and STARTRK-2 trials is presented, with substantially longer follow-up, more patients, and the first description of the median overall survival (OS). An exploratory analysis of entrectinib in ROS1 fusion-positive NSCLC with the central nervous system (CNS)-only progression post-crizotinib is reported. Methods: Adults with ROS1 fusion-positive, locally advanced or metastatic NSCLC who received at least one dose of entrectinib and had 12 months or longer of follow-up were included in the analysis. Co-primary end points were confirmed objective response rate (ORR) and duration of response (DoR) by blinded independent central review. The data cutoff was on August 31, 2020. Results: The efficacy-assessable population comprised 168 ROS1 TKI-naïve patients. The median survival follow-up was 29.1 months (interquartile range, 21.8-35.9). The ORR was 68% (95% confidence interval [CI]: 60.2-74.8); the median DoR was 20.5 months. The median progression-free survival (PFS) was 15.7 months and the median OS was 47.8 months. In the 25 patients with measurable baseline CNS metastases, the intracranial ORR was 80% (95% CI: 59.3-93.2), median intracranial DoR was 12.9 months, and median intracranial PFS was 8.8 months. Among 18 patients with CNS-only progression on previous crizotinib treatment, two achieved a partial response (11%) and four had stable disease (22%). In seven patients with measurable CNS disease from this cohort, the intracranial ORR was 14% (1 partial response). Conclusions: Entrectinib is active and achieves prolonged survival in ROS1 TKI-naïve patients with ROS1 fusion-positive NSCLC. Modest activity is seen in patients with CNS-only progression post-crizotinib.

Updated Integrated Analysis of the Efficacy and Safety of Entrectinib in Patients With NTRK Fusion-Positive Solid Tumors.

PURPOSE: Entrectinib potently inhibits tropomyosin receptor kinases (TRKAs)/B/C and ROS1, and previously induced deep [objective response rate (ORR) 57.4%] and durable [median duration of response (DoR) 10.4 months] responses in adults with NTRK fusion-positive solid tumors from three phase I/II trials. This article expands prior reports with additional patients and longer follow-up. PATIENTS AND METHODS: Patients with locally advanced/metastatic NTRK fusion-positive solid tumors and ≥12 months' follow-up were included. Primary endpoints were ORR and DoR by blinded independent central review (BICR); secondary endpoints included progression-free survival (PFS), intracranial efficacy, and safety. The safety-evaluable populations included all patients who had received ≥1 entrectinib dose. RESULTS: At clinical cut-off (August 31, 2020), the efficacy-evaluable population comprised 121 adults with 14 tumor types and ≥30 histologies. Median follow-up was 25.8 months; 61.2% of patients had a complete (n = 19) or partial response (n = 55). Median DoR was 20.0 months [95% confidence interval (CI), 13.0-38.2]; median PFS was 13.8 months (95% CI, 10.1-19.9). In 11 patients with BICR-assessed measurable central nervous system (CNS) disease, intracranial ORR was 63.6% (95% CI, 30.8-89.1) and median intracranial DoR was 22.1 (95% CI, 7.4-not estimable) months. The safety profile of entrectinib in adults and pediatric patients was aligned with previous reports. Most treatment-related adverse events (TRAEs) were grade 1/2 and manageable/reversible with dose modifications. TRAE-related discontinuations occurred in 8.3% of patients. CONCLUSIONS: With additional clinical experience, entrectinib continues to demonstrate durable systemic and intracranial responses and can address the unmet need of a CNS-active treatment in patients with NTRK fusion-positive solid tumors.

New molecules for the treatment of pain.

PURPOSE OF REVIEW: To inform on preclinical and early clinical advances in the effort to identify novel classes of analgesic drugs. RECENT FINDINGS: Human genetic and animal preclinical studies have identified several mechanisms that appear to make important contributions to abnormal pain states. From human genetics, a small number of patients with mutations in the genes encoding nerve growth factor/TrkA signaling and in a particular sodium channel subunit (SCN9a, encoding Nav1.7) show congenital analgesia with limited other effects. There are, therefore, considerable hopes that pharmacological manipulation of these systems in chronic pain patients might be an effective analgesic strategy. A substantial body of preclinical work has focussed on interactions between the immune and the nervous system and this has led to the identification of a number of novel putative inflammatory mediators and receptors, which are being explored as potential analgesic targets. A recent preclinical effort has studied intracellular signaling cascades recruited in the transition from acute to chronic pain states - the analgesic opportunities on offer here are being pursued in early clinical trials. SUMMARY: Existing analgesic drugs are small in number, limited in efficacy and associated with significant side-effects. There is, therefore, a need for new pain medications. In the last decade or so, clinical and preclinical research have progressed rapidly and this work has identified multiple plausible drug targets, which are currently being evaluated. We review here the rationale of some of the most promising mechanisms and report on progress in drug development.

High-threshold mechanosensitive ion channels blocked by a novel conopeptide mediate pressure-evoked pain.

Little is known about the molecular basis of somatosensory mechanotransduction in mammals. We screened a library of peptide toxins for effects on mechanically activated currents in cultured dorsal root ganglion neurons. One conopeptide analogue, termed NMB-1 for noxious mechanosensation blocker 1, selectively inhibits (IC(50) 1 microM) sustained mechanically activated currents in a subset of sensory neurons. Biotinylated NMB-1 retains activity and binds selectively to peripherin-positive nociceptive sensory neurons. The selectivity of NMB-1 was confirmed by the fact that it has no inhibitory effects on voltage-gated sodium and calcium channels, or ligand-gated channels such as acid-sensing ion channels or TRPA1 channels. Conversely, the tarantula toxin, GsMTx-4, which inhibits stretch-activated ion channels, had no effects on mechanically activated currents in sensory neurons. In behavioral assays, NMB-1 inhibits responses only to high intensity, painful mechanical stimulation and has no effects on low intensity mechanical stimulation or thermosensation. Unexpectedly, NMB-1 was found to also be an inhibitor of rapid FM1-43 loading (a measure of mechanotransduction) in cochlear hair cells. These data demonstrate that pharmacologically distinct channels respond to distinct types of mechanical stimuli and suggest that mechanically activated sustained currents underlie noxious mechanosensation. NMB-1 thus provides a novel diagnostic tool for the molecular definition of channels involved in hearing and pressure-evoked pain.