pyrimidinones and Intracranial-Hemorrhages

About 50% of patients with meta- static or inoperable melanoma carry a tumour with BRAF V600 mutation.The drug of first choice for these patients is vemurafenib, a BRAF inhibitor, which appears to prolong survival by a few months. Dabrafenib is a vemurafenib me-too with a slightly different known profile of adverse effects. Trametinib, a MEK inhibitor, is now authorised in the European Union for use in this setting, either as monotherapy or in combination with dabrafenib (marketed by the same company). Trametinib monotherapy has not been compared to BRAF inhibitor monotherapy. In a randomised, unblinded trial versus cytotoxic drugs in 322 patients, the median survival time did not differ statistically between the groups (15.6 versus 11.3 months; p = 0.09), but 65% of patients in the chemotherapy group received trametinib after disease pro- gression, making it more difficult to detect a difference between the groups. In an unblinded randomised controlled trial in 704 patients who had never received treatment for metastatic or inoperable disease, the trametinib + dabrafenib combination prolonged median survival by about 8 months more than vemurafenib. In another double-blind randomised controlled trial in 423 patients, median survival was about 6 months longer with trametinib + dabrafenib than with placebo + dabrafenib. The trametinib+ dabrafenibcombination was poorly effective after BRAF inhibitor failure in non-comparative trials including a few dozen patients in which the only endpoint was tumour response. Trametinib has many adverse effects, some of which can be life-threatening, such as heart failure, deep vein thrombosis, bleeding (including intracranial haemorrhage), neutropenia, and gastrointestinal perforation. Trametinib also causes retinal disorders and pneumonitis. Combining trametinib with dabrafenib reduces the risk of hyperkeratosis and skin cancer associated with dabrafenib, but increases the frequency of fever (including very high fever). Trametinib interactions mainly involve additive effects or antagonism. In practice, when a patient with metastatic or inoperable BRAF V600-positive melanoma is willing to accept the significant toxicity of trametinib in the hope of gaining several extra months of life, the trametinib + dabrafenib combination is a first-line option.

Topics: Heart Failure; Hemorrhage; Humans; Imidazoles; Intestinal Perforation; Intracranial Hemorrhages; MAP Kinase Kinase 1; Melanoma; Neutropenia; Oximes; Pneumonia; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; Pyridones; Pyrimidinones; Retinal Diseases; Skin Neoplasms; Survival Rate; Venous Thrombosis

Combination therapy with BRAF V600E inhibitor dabrafenib and MEK inhibitor trametinib significantly improves progression-free survival of patients with BRAF V600-positive metastatic melanoma, but their use can be associated with life-threatening toxicities. We report the case of a patient receiving dabrafenib and trametinib for metastatic melanoma who developed intracranial hemorrhage while on therapy. Combination therapy with dabrafenib and trametinib improves progression-free survival of patients with BRAF V600-positive metastatic melanoma. Nevertheless, it is associated with an increased incidence and severity of any hemorrhagic event. To the best of our knowledge, this is the first report of intracranial hemorrhage with pathological confirmation.. We present the case of a 48-year-old man with metastatic melanoma of unknown primary site. He had metastases to the right clavicle, brain, liver, adrenal gland, and the right lower quadrant of the abdomen. He progressed on treatment with alpha-interferon. He was found to have a 4.5-cm mass in the left frontotemporal lobe and underwent gross total resection followed by adjuvant CyberKnife stereotactic irradiation. He was subsequently started on ipilimumab. Treatment was stopped due to kidney injury. He was then placed on dabrafenib and trametinib. He returned for follow-up complaining of severe headache and developed an episode of seizure. MRI showed a large area of edema at the left frontal lobe with midline shift. Emergency craniotomy was performed. Intracranial hemorrhage was found intra-operatively. Pathology from surgery did not find tumor cells, reported as organizing hemorrhage and necrosis with surrounding gliosis; immunohistochemistry for S100 and HMB45 were negative.. This case demonstrates the life-threatening adverse effects that can be seen with the newer targeted biological therapies. It is therefore crucial to maintain a high index of suspicion when patients on this combination therapy present with new neurologic symptoms.

Topics: Antineoplastic Agents; Craniotomy; Diagnosis, Differential; Drug Therapy, Combination; Humans; Imidazoles; Intracranial Hemorrhages; Male; MAP Kinase Kinase 1; Melanoma; Middle Aged; Oximes; Positron-Emission Tomography; Proto-Oncogene Proteins B-raf; Pyridones; Pyrimidinones; Tomography, X-Ray Computed