NTRK positive

Many repotrectinib AEs, including neurological AEs secondary to TRK inhibition, were mitigated with appropriate management, including dose modification and/or pharmacologic intervention.

Particularly, the detection sensitivity for NTRK3 fusions was significantly enhanced and reached 95.89 %. This study contributes to clarifying NTRK fusion distribution in patients and validates a standardized, sensitive pan-TRK IHC strategy for clinical screening.

Targeted therapies with TRK inhibitors (TRKi), including larotrectinib and entrectinib, have shown promising efficacy with rapid and durable responses for patients with LGGs and HGGs. Overall, TRKi represent a significant advance for treating NTRK fusion-positive CNS tumors, especially in pediatric populations, offering new hope for patients with limited treatment options. Further studies are required to optimize their use and address unresolved challenges.

NTRK gene fusions are a critical marker for pediatric soft tissue tumors and are used for precision medicine in these tumors. NTRK gene fusions are used as diagnostic markers for infantile fibrosarcoma, congenital mesoblastic nephroma, and secretory carcinomas, and they play a critical role in the management of these tumors.

Many repotrectinib AEs, including neurological AEs secondary to TRK inhibition, were mitigated with appropriate management, including dose modification and/or pharmacologic intervention.

Functional NTRK fusion-positive tumors comprise biologically and clinically distinct subsets defined by tumor type and MSI/TMB context. Concurrent reporting of MSI/TMB (and HRD/EBV when available) together with NTRK fusion status may facilitate integrated clinical interpretation, support precision treatment selection, and refine trial stratification in clinical practice.

Owing to the presence of neural tissue, NTRKs are highly positive in IHC, making these genes unsuitable as biomarkers for assessing NTRK inhibitor sensitivity and resistance, which are tissue-agnostic drugs. The observed low fusion rate is consistent with the literature, and the significance of the numerous point mutations identified as agnostic markers warrants further investigation. NTRK expression, fusion, and point mutations were not associated with clinical parameters or survival.

Inhibitors such as larotrectinib, entrectinib and repotrectinib are used when cancer cells harbor NTRK1, NTRK2 or NTRK3 fusion...Short courses of prednisone for the former and dexamethasone for the latter were initiated after failure of standard analgesia... For patients experiencing TRK inhibitor withdrawal pain, especially when tapering down the inhibitor is not an available strategy, a short course of corticosteroids can provide lasting relief. These cases emphasize the importance of better understanding the mechanism underlying the relationship between NRTK, NGF and nociception.

NCI-MATCH subprotocol Z1E demonstrates that larotrectinib offers clinically significant benefit with marked ORR across NTRK fusion-positive tumors with no clinically significant toxicities. These findings support the rationale for the US Food and Drug Administration's tissue-agnostic approval of larotrectinib for NTRK fusion-positive tumors. Our findings demonstrate the necessity of including NTRK1, NTRK2, and NTRK3 within comprehensive molecular assays of cancer to navigate patients to an easily administered and highly effective therapy.

These results support the use of repotrectinib to treat patients with NTRK+ solid tumors. ClinicalTrials.gov identifier: NCT03093116 .

Concurrent comprehensive genome profiling (FoundationOne® CDx) confirmed the LMNA-NTRK1 fusion, and treatment with the TRK inhibitor larotrectinib was started. With larotrectinib treatment, the tumor shrank in size at an early stage, and the response has been maintained for > 2 years.