Abstract CT020: Long-term outcomes of patients with TRK fusion cancer treated with larotrectinib

Efficacy of immune checkpoint inhibitors in non-small cell lung cancer with NTRK family mutations

BACKGROUND

The efficacy of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC) patients harboring neurotrophin receptor kinase (NTRK) family mutations remains obscure.

METHODS

The Zehir cohort from cBioPortal was used to analyze the mutations (MT) frequency of NTRK family in patients with NSCLC, and their correlation with clinical characteristics and patient survival. The influence of NTRK MT on ICIs efficacy was evaluated in ICIs-treated patients from Samstein cohort and further validated by use of data from OAK/POPLAR cohort.

RESULTS

In the Zehir cohort, a significant difference was observed in median overall survival (mOS) between patients with NTRK MT and wild-type (WT) (mOS: 18.97 vs. 21.27 months, HR = 1.34, 95%CI 1.00-1.78; log-rank P = 0.047). In Samstein cohort, the mOS of NTRK mutant patients receiving ICIs has improved compared to WT patients (mOS: 21.00 vs. 11.00 months, log-rank P = 0.103). Notably, in subgroup analysis, ICIs significantly prolonged mOS in patients with NTRK3 MT than in WT patients (mOS: not available vs. 11.00 months, HR = 0.36, 95%CI 0.16-0.81; log-rank P = 0.009). Identical mOS between NTRK MT and WT patients receiving ICIs treatment (mOS: 13.24 vs. 13.50 months, log-rank P = 0.775) was observed in OAK/POPLAR cohort. Moreover, a similar programmed death ligand 1 (PD-L1) expression, but higher tumor mutational burden (TMB), blood TMB (bTMB) and enriched anti-tumor immunity were observed in NTRK MT compared to WT (P < 0.05).

CONCLUSION

Taking high TMB or bTMB into consideration, patients with NTRK mutant NSCLC could benefit from ICIs treatment.

NTRK fusions in lung cancer: From biology to therapy

Fusions involving TRK protein tyrosine kinases are oncogenic drivers in a variety of tumors in children and adults, with a prevalence of ∼0.2% in non-small cell lung cancer. Diagnosis can be challenging due to structural features such as NTRK intron length, but next-generation sequencing (NGS), including RNA-based NGS, increases detection. The first-generation TRK inhibitors, larotrectinib and entrectinib, have demonstrated clinically meaningful antitumor activity in TRK fusion-positive cancers in a tumor-agnostic fashion and should be considered first-line therapeutic options for TRK fusion-positive lung cancers. Furthermore, the first-generation TRK inhibitors are well tolerated. Care should be taken, however, to monitor on-target adverse events, such as dizziness, weight gain, paresthesias, and withdrawal pain. On-target and off-target mechanisms mediating TRK inhibitor resistance may occur. Next-generation TRK inhibitors, such as selitrectinib, repotrectinib, and taletrectinib, are available on ongoing clinical trials and address on-target resistance. This review will focus on NTRK fusions and TRK-directed targeted therapy specifically in the context of lung cancer.