TRK fusion cancer: updated analysis for Larotrectinib has confirmed high response rate and durable responses over three years in children and adults
Updated clinical data for Larotrectinib ( Vitrakvi ) in adult and pediatric patients with TRK fusion cancer showed a high response rate with an overall response rate ( ORR ) of 79% ( 95% CI: 72–85 ) with 16% complete responses ( n=24 ) and 63% partial responses ( n=97 ).
These results, which are based on 153 evaluable patients at a data cut-off of February 19, 2019, makes it the largest dataset and longest follow-up data of any TRK inhibitor.
Among the patients with confirmed responses ( n=108 ), those responses continued to be durable with a median duration of response of nearly three years ( 35.2 months; 95% CI: 22.8–NE ).
For the integrated dataset ( n=159 ), 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 being still alive at one year after the start of therapy.
The data were presented at the 44th European Society for Medical Oncology ( ESMO ) Congress 2019.
In a subanalysis from the integrated dataset ( n=12 ), Larotrectinib showed a high ORR of 75% in solid tumors with brain metastases.
Larotrectinib activity was previously reported in primary CNS tumors ( ASCO 2019 ).
CNS tumors are aggressive and Larotrectinib has achieved disease control in this patient population over an extended period of time.
The safety data presented at the ESMO 2019 Congress encompassed the entire larotrectinib safety database in cancer patients ( n=260 ), continuing to show a favorable safety profile even as the patient population increases.
The majority of adverse events reported were grade 1 or 2.
No treatment-related grade 3 or 4 adverse reactions occurred in more than 3% of patients, and no treatment-related deaths were reported.
Larotrectinib was approved in September 2019 in the European Union under the brand name Vitrakvi for the treatment of adult and pediatric patients with solid tumors that display a Neurotrophic Tyrosine Receptor Kinase ( NTRK ) gene fusion, who have a disease that is locally advanced, metastatic or where surgical resection is likely to result in severe morbidity, and who have no satisfactory treatment options.
TRK fusion cancer occurs when an NTRK gene fuses with another unrelated gene, producing an altered TRK protein. The altered protein, or TRK fusion protein, becomes constitutively active or overexpressed, triggering a signaling cascade.
These TRK fusion proteins act as oncogenic drivers promoting cell growth and survival, leading to TRK fusion cancer, regardless to where it originates in the body.
TRK fusion cancer is not limited to certain types of tissues and can occur in any part of the body.
TRK fusion cancer occurs in various adult and pediatric solid tumors with varying frequency, including lung, thyroid, gastrointestinal cancers ( colon, cholangiocarcinoma, pancreatic and appendiceal ), sarcoma, CNS cancers ( glioma and glioblastoma ), salivary gland cancers ( mammary analogue secretory carcinoma ) and pediatric cancers ( infantile fibrosarcoma and soft tissue sarcoma ). ( Xagena )
Source: Bayer, 2019