Safety
The most common adverse drug reactions (observed in ≥ 20% of patients) of larotrectinib were: increased ALT (31%), increased AST (29%), vomiting (29%), constipation (28%), fatigue (26%), nausea (25%), anaemia (24%), dizziness (23%), and myalgia (20%) [1, 2].
As summarized in the table below, the majority of adverse reactions were Grade 1 or 2, with Grade 4 being the highest reported grade for adverse reactions including: neutrophil count decreased (2%), ALT increased (1%), AST increased, leucocyte count decreased, and blood alkaline phosphatase increased (each in < 1%). Grade 3 was the highest reported grade for adverse reactions anaemia, weight increased, fatigue, dizziness, paraesthesia, muscular weakness, nausea, myalgia, gait disturbance, and vomiting [2]. All the reported Grade 3-4 adverse reactions occurred in less than 5% of patients, except for anaemia (7%).
In 2% of the patients larotrectinib treatment was permanently discontinued due to emergent adverse reactions (one case each of ALT increased, AST increased, gait disturbance, neutrophil count decreased) and most adverse reactions leading to dose reduction occurred in the first three months of treatment.
In the three trials, the safety profile of larotrectinib in paediatric was comparable to that of adult patients, as summarized in the table below.
References
- VITRAKVI® (larotrectinib), USA Prescribing Information. 2021.
- VITRAKVI® (larotrectinib), EMA Summary of medicinal Product Characteristics. 2022.