High Response Rate, Durability Maintained With Larotrectinib in TRK Fusion Cancer

An updated analysis confirmed the potential of the targeted therapy larotrectinib (Vitrakvi, Bayer) for use in children and adults with tropomyosin receptor kinase (TRK) fusion cancer, according to findings presented in a poster discussion at the ESMO Congress 2019.

The data presented at this year’s ESMO Congress and the prior meeting are based on 3 different trials: a phase 1 trial in adults, a phase 1/2 trial in pediatric patients, and a phase 2 trial for adolescent patients.

Larotrectinib is already approved by the FDA and European Medicines Agency for patients with solid tumors that display a neurotrophic TRK (NTRK) gene fusion, making it the first tumor-agnostic approval.

According to the authors, the findings now include 153 evaluable adult and pediatric patients at time of new data cut off, representing the largest dataset with longest follow-up of any TRK inhibitor.

The TRK inhibitor demonstrated a high overall response rate (ORR) of 79% (95% CI: 72-85) with 16% complete responses and 63% partial responses. Among the patients with confirmed responses, those responses continued to be durable with a median duration of response of nearly 3 years (35.2 months; 95% CI; 22.8­—NE). For the integrated dataset, median progression-free survival was 28.3 months (95% CI: 22.1­–NE) and median overall survival was 44.4 months (95% CI; 36.5–NE), with 88% (95% CI: 83-94) of patients still alive at 1 year after the start of therapy.

Additionally, a subanalysis from the integrated dataset showed a high ORR of 75% in solid tumors with brain metastases, demonstrating larotrectinib’s activity in primary central nervous system tumors, according to the study authors.

In terms of safety, the data presented at the ESMO Congress 2019 continued to show a favorable safety profile even with an increasing patient population. No treatment-related grade 3 or 4 adverse events occurred in more than 3% of patients and no treatment-related deaths occurred.

In a video interview with Pharmacy Times® and Specialty Pharmacy Times® Ulrik Lassen, MD, PhD, oncology professor at the University of Copenhagen, discussed the clinical implications of the new larotrectinb data presented at the ESMO Congress 2019.

Reference

Hyman DM, van Tilburg CM, Albert CM, et al. Durability of response with larotectinib in adult and paediatric patients with TRK fusion cancer. Presented at ESMO Congress 2019; September 27-October 1, 2019; Barcelona, Spain. Poster 445PD.