What are the precautions for dabrafenib?

During the clinical studies of Dabrafenib, warnings and precautions such as new primary malignant tumors, tumor-promoting effects of BRAF wild-type tumors, bleeding, cardiomyopathy, uveitis, severe febrile reactions, severe skin toxicity, hyperglycemia, glucose-6-phosphate dehydrogenase deficiency, phagocytic lymphohistiocytosis, and embryo-fetal toxicity have emerged. Discontinue and resume at reduced dose upon recovery, or permanently discontinue based on severity.

1. New primary malignant tumors: According to its mechanism of action, dabrafenib may activate RAS through mutation or other mechanisms, thereby promoting the growth and development of malignant tumors. In clinical trials of monotherapy, cutaneous squamous cell carcinoma (cuSCC) and keratoacanthomas, basal cell carcinomas, and new primary melanomas have occurred, and dermatological evaluations were performed before initiation of dabrafenib, every 2 months during treatment, and up to 6 months after discontinuation.

2. Tumor-promoting effects of BRAF wild-type tumors: In vitro experiments have demonstrated abnormal activation of MAP kinase signaling and increased cell proliferation in BRAF wild-type cells exposed to BRAF inhibitors. Confirm evidence of BRAF V600E or V600K mutation status before using dabrafenib as a single agent or in combination with trametinib.

3. Bleeding: When dabrafenib is combined with trametinib, bleeding may occur, including major bleeding defined as symptomatic bleeding in critical areas or organs, and death cases have been reported. Bleeding events in adults include gastrointestinal bleeding, intracranial hemorrhage, cerebral hemorrhage, and brainstem hemorrhage; bleeding events in combination therapy include epistaxis, gastrointestinal bleeding, cerebral hemorrhage, uterine bleeding, and postoperative bleeding.

4. Cardiomyopathy: that is, the left ventricular ejection fraction (LVEF) decreases by ≥10% from baseline and is lower than the institutional lower limit of normal (LLN). The development of cardiomyopathy may lead patients to interrupt or discontinue dabrafenib. LVEF was assessed by echocardiography or multiplex acquisition (MUGA) scan before starting dabrafenib plus trametinib treatment, one month after starting treatment, and then every 2 to 3 months during treatment. Dabrafenib should be discontinued in patients with symptomatic cardiomyopathy or asymptomatic LV dysfunction exceeding 20% u200bu200bof baseline and below the institutional LLN.

5. Uveitis: Treatments used in clinical trials include steroids and mydriatic eye drops. Monitor patients for visual signs and symptoms of uveitis (e.g., vision changes, photophobia, eye pain). If iritis is diagnosed, initiate ocular treatment and continue dabrafenib without a change in dose. If severe uveitis (i.e., iridocyclitis) or mild or moderate uveitis does not respond to ocular therapy, discontinue dabrafenib and treat as clinically indicated. If the condition improves to grade 0 or 1, resume dabrafenib at the same or lower dose. Permanently discontinue dabrafenib therapy in patients with persistent Grade 2 or higher uveitis for >6 weeks.

6. Severe febrile reaction: Dabrafenib can cause severe febrile reaction and fever of any severity, accompanied by hypotension, chills or chills, dehydration or renal failure. The incidence and severity of pyrexia are increased when administered with trametinib compared to dabrafenib as a single agent. If the patient's temperature is ≥100.4°F (38°C), discontinue dabrafenib alone or both in combination. In case of recurrence, treatment can also be interrupted at the first symptom of fever.

If the patient has had a previous severe febrile reaction or febrile episode associated with complications, administer antipyretics as secondary prevention when resuming dabrafenib. Give corticosteroids (eg, prednisone, 10 mg daily) for at least 5 days for a second or subsequent fever if body temperature does not return to baseline within 3 days of a febrile episode, or if fever is associated with complications such as dehydration, hypotension, renal failure, or severe chills/chills and there is no evidence of active infection.

7. Serious skin toxicity: Serious skin adverse reactions (SCARs) have occurred, including Stevens-Johnson syndrome (SJS) and drug reactions with eosinophilia and systemic symptoms (DRESS), which may be life-threatening or fatal. Monitor for new or worsening serious skin reactions. Permanently discontinue use of dabrafenib to treat SCARs. For other skin toxicities, discontinue dabrafenib for intolerable or severe skin toxicity.

8. Hyperglycemia: When patients with diabetes or hyperglycemia start taking dabrafenib, monitor blood glucose levels based on clinical conditions. Initiate or optimize antihyperglycemic medications as clinically indicated.

9. Glucose-6-phosphate dehydrogenase deficiency:Dabrafenib contains a sulfonamide moiety, which has a potential risk of hemolytic anemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Monitor patients with G6PD deficiency for signs of hemolytic anemia while taking dabrafenib.

10. Hemolymphohistiocytosis: Hemolymphohistiocytosis (HLH) has been observed in the post-marketing setting when dabrafenib was administered with trametinib. If HLH is suspected, interrupt treatment. If HLH is confirmed, discontinue treatment and initiate appropriate management of HLH.

11. Embryo-Fetotoxicity: Based on the results of animal studies and its mechanism of action, dabrafenib can cause harm to the fetus when administered to pregnant women. The teratogenicity and embryotoxicity of dabrafenib in rats was three times greater than human exposure at recommended clinical doses for adults. Inform pregnant women of potential risks to the fetus. Advise female patients of childbearing potential to use effective non-hormonal contraceptives during treatment and for 2 weeks after the last dose because dabrafenib renders hormonal contraceptives ineffective.