On 22 June 2022, the US Food and Drug Administration (FDA) granted accelerated approval to dabrafenib (Tafinlar, Novartis) in combination with trametinib (Mekinist, Novartis) for the treatment of adult and paediatric patients ≥ 6 years of age with unresectable or metastatic solid tumours with BRAF V600E mutation who have progressed following prior treatment and have no satisfactory alternative treatment options. Dabrafenib in combination with trametinib is not indicated for patients with colorectal cancer because of known intrinsic resistance to BRAF inhibition. Dabrafenib is not indicated for patients with wild-type BRAF solid tumours.
The safety and efficacy were evaluated in 131 adult patients from open-label, multiple cohort studies BRF117019 (NCT02034110) and NCI-MATCH (NCT02465060), 36 paediatric patients from CTMT212X2101 (NCT02124772), and supported by results in COMBI-d, COMBI-v, and BRF113928 (studies in melanoma and lung cancer already described in product labelling).
Study BRF117019 enrolled patients with BRAF V600E mutation positive specific solid tumours including high grade glioma, biliary tract cancer, low grade glioma, adenocarcinoma of small intestine, gastrointestinal stromal tumour, and anaplastic thyroid cancer. NCI-MATCH Subprotocol H enrolled adult patients with BRAF V600E mutation positive solid tumours except patients with melanoma, thyroid cancer, or colorectal cancer. Parts C and D of Study CTMT212X2101 enrolled 36 paediatric patients with BRAF V600 refractory or recurrent low grade glioma or high grade glioma.
The major efficacy outcome measure of these studies was overall response rate (ORR) using standard response criteria. For the 131 adult patients, a total of 54 (41%, 95% confidence interval CI 33, 50) experienced an objective response. The studies enrolled patients with 24 tumour types, including different subtypes of low grade glioma and high grade glioma. Among the highest representative tumour types, the ORR was 46% (95% CI 31, 61) for biliary tract cancer, 33% (95% CI 20, 48) for high grade glioma (combined) and 50% (95% CI 23, 77) for low grade glioma (combined). For the 36 paediatric patients, the ORR was 25% (95% CI 12, 42). Duration of response was ≥ 6 months for 78% of patients and ≥ 24 months for 44% of patients.
The most common (≥ 20%) adverse reactions in adult patients were pyrexia, fatigue, nausea, rash, chills, headache, haemorrhage, cough, vomiting, constipation, diarrhoea, myalgia, arthralgia, and oedema. The most common (≥ 20%) adverse reactions in paediatric patients were pyrexia, rash, vomiting, fatigue, dry skin, cough, diarrhoea, dermatitis acneiform, headache, abdominal pain, nausea, haemorrhage, constipation, and paronychia.
The recommended dabrafenib dose in adult patients is 150 mg (two 75 mg capsules) orally twice daily in combination with trametinib 2 mg orally once daily. The recommended doses for dabrafenib and trametinib in paediatric patients are based on body weight. A recommended dose has not been established in patients who weigh less than 26 kg.
This review used the Assessment Aid, a voluntary submission from the applicant to facilitate the FDA’s assessment.
This application was granted priority review.
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