July 2022: Dabrafenib (Tafinlar, Novartis) and trametinib (Mekinist, Novartis) received accelerated approval from the Food and Drug Administration for the treatment of adult and paediatric patients older than 6 years old with unresectable or metastatic solid tumours with the BRAF V600E mutation who have progressed after receiving prior therapy and have no other suitable treatment options. For individuals with colorectal cancer, dabrafenib and trametinib are not recommended due to known intrinsic resistance to BRAF inhibition. Patients with solid tumours that are BRAF wild-type are not recommended to take dabrafenib.
36 paediatric patients from CTMT212X2101 (NCT02124772), 131 adult patients from open-label, multiple cohort trials BRF117019 (NCT02034110) and NCI-MATCH (NCT02465060), and results from COMBI-d, COMBI-v, and BRF113928 were used to evaluate the safety and efficacy (studies in melanoma and lung cancer already described in product labeling). Patients with certain solid tumours, such as high grade glioma (HGG), biliary tract cancer, low grade glioma (LGG), small intestinal adenocarcinoma, gastrointestinal stromal tumour, and anaplastic thyroid cancer, that are positive for the BRAF V600E mutation were enrolled in the study BRF117019 (ATC). Except for patients with melanoma, thyroid cancer, or colorectal cancer, NCI-MATCH Subprotocol H recruited adult patients with BRAF V600E mutation positive solid tumours. A total of 36 paediatric patients with BRAF V600 refractory or recurrent LGG or HGG were included in Parts C and D of Study CTMT212X2101. The overall response rate (ORR) utilising conventional response criteria served as the trials’ primary efficacy outcome measure. A total of 54 (41 percent, 95 percent CI: 33, 50) of the 131 adult patients showed an objective response. Patients with 24 distinct tumour types, including several subtypes of LGG and HGG, were enrolled in the study. Among the most prevalent tumour forms, the ORR for biliary tract cancer was 46% (95% CI: 31, 61), for combined high grade gliomas it was 33% (95% CI: 20, 48), and for low grade gliomas it was 50% (95% CI: 23, 77). (combined). The ORR for the 36 paediatric patients was 25% (95% CI: 12, 42); the DOR was 6 months or less for 78 percent of patients and 24 months or less for 44 percent.
Adult patients had pyrexia, tiredness, nausea, rash, chills, headache, bleeding, cough, vomiting, constipation, diarrhoea, myalgia, arthralgia, and edoema the most frequently (20%).
Among paediatric patients, pyrexia, rash, vomiting, exhaustion, dry skin, cough, diarrhoea, dermatitis acneiform, headache, stomach pain, nausea, haemorrhage, constipation, and paronychia were the most frequent side effects (20%).
Adult patients should take trametinib 2 mg orally once day along with 150 mg (two 75 mg capsules) of dabrafenib twice daily. Based on body weight, paediatric patients should take trametinib and dabrafenib at the appropriate doses. For patients who weigh less than 26 kg, there is no set dose.
