title: Dabrafenib in patients with melanoma, untreated brain metastases, and other solid tumours: a phase 1 dose-escalation trial.
abstract: BACKGROUND
  Dabrafenib is an inhibitor of BRAF kinase that is selective for mutant BRAF. We aimed to assess its safety and tolerability and to establish a recommended phase 2 dose in patients with incurable solid tumours, especially those with melanoma and untreated, asymptomatic brain metastases.
  
  
  METHODS
  We undertook a phase 1 trial between May 27, 2009, and March 20, 2012, at eight study centres in Australia and the USA. Eligible patients had incurable solid tumours, were 18 years or older, and had adequate organ function. BRAF mutations were mandatory for inclusion later in the study because of an absence of activity in patients with wild-type BRAF. We used an accelerated dose titration method, with the first dose cohort receiving 12 mg dabrafenib daily in a 21-day cycle. Once doses had been established, we expanded the cohorts to include up to 20 patients. On the basis of initial data, we chose a recommended phase 2 dose. Efficacy at the recommended phase 2 dose was studied in patients with BRAF-mutant tumours, including those with non-Val600Glu mutations, in three cohorts: metastatic melanoma, melanoma with untreated brain metastases, and non-melanoma solid tumours. This study is registered with ClinicalTrials.gov, number NCT00880321.
  
  
  RESULTS
  We enrolled 184 patients, of whom 156 had metastatic melanoma. The most common treatment-related adverse events of grade 2 or worse were cutaneous squamous-cell carcinoma (20 patients, 11%), fatigue (14, 8%), and pyrexia (11, 6%). Dose reductions were necessary in 13 (7%) patients. No deaths or discontinuations resulted from adverse events, and 140 (76%) patients had no treatment-related adverse events worse than grade 2. Doses were increased to 300 mg twice daily, with no maximum tolerated dose recorded. On the basis of safety, pharmacokinetic, and response data, we selected a recommended phase 2 dose of 150 mg twice daily. At the recommended phase 2 dose in 36 patients with Val600 BRAF-mutant melanoma, responses were reported in 25 (69%, 95% CI 51·9-83·7) and confirmed responses in 18 (50%, 32·9-67·1). 21 (78%, 57·7-91·4) of 27 patients with Val600Glu BRAF-mutant melanoma responded and 15 (56%, 35·3-74·5) had a confirmed response. In Val600 BRAF-mutant melanoma, responses were durable, with 17 patients (47%) on treatment for more than 6 months. Responses were recorded in patients with non-Val600Glu BRAF mutations. In patients with melanoma and untreated brain metastases, nine of ten patients had reductions in size of brain lesions. In 28 patients with BRAF-mutant non-melanoma solid tumours, apparent antitumour activity was noted in a gastrointestinal stromal tumour, papillary thyroid cancers, non-small-cell lung cancer, ovarian cancer, and colorectal cancer.
  
  
  CONCLUSIONS
  Dabrafenib is safe in patients with solid tumours, and an active inhibitor of Val600-mutant BRAF with responses noted in patients with melanoma, brain metastases, and other solid tumours.
  
  
  BACKGROUND
  GlaxoSmithKline.
authors.affiliation: Department of Investigational Cancer Therapeutics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. gfalchoo@mdanderson.org
authors.forename: Gerald S
authors.initials: GS
authors.lastname: Falchook
authors.forename: Georgina V
authors.initials: GV
authors.lastname: Long
authors.forename: Razelle
authors.initials: R
authors.lastname: Kurzrock
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Kim
authors.forename: Tobias H
authors.initials: TH
authors.lastname: Arkenau
authors.forename: Michael P
authors.initials: MP
authors.lastname: Brown
authors.forename: Omid
authors.initials: O
authors.lastname: Hamid
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Infante
authors.forename: Michael
authors.initials: M
authors.lastname: Millward
authors.forename: Anna C
authors.initials: AC
authors.lastname: Pavlick
authors.forename: Steven J
authors.initials: SJ
authors.lastname: O'Day
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Blackman
authors.forename: C Martin
authors.initials: CM
authors.lastname: Curtis
authors.forename: Peter
authors.initials: P
authors.lastname: Lebowitz
authors.forename: Bo
authors.initials: B
authors.lastname: Ma
authors.forename: Daniele
authors.initials: D
authors.lastname: Ouellet
authors.forename: Richard F
authors.initials: RF
authors.lastname: Kefford
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001932:Brain Neoplasms / Q000188:drug therapy / Q000556:secondary; D002294:Carcinoma, Squamous Cell / Q000139:chemically induced; D004334:Drug Administration Schedule; D005221:Fatigue / Q000139:chemically induced; D005260:Female; D005334:Fever / Q000139:chemically induced; D005838:Genotype; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage* / Q000009:adverse effects; D007211:Indoles / Q000008:administration & dosage / Q000009:adverse effects; D008297:Male; D020714:Maximum Tolerated Dose; D008545:Melanoma / Q000188:drug therapy / Q000235:genetics / Q000556:secondary; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D009369:Neoplasms / Q000188:drug therapy* / Q000235:genetics; D010091:Oximes / Q000008:administration & dosage* / Q000009:adverse effects; D048493:Proto-Oncogene Proteins B-raf / Q000037:antagonists & inhibitors* / Q000235:genetics; D012878:Skin Neoplasms / Q000139:chemically induced; D013449:Sulfonamides / Q000008:administration & dosage / Q000009:adverse effects; D016896:Treatment Outcome; D000077484:Vemurafenib
chemical_list: D000970:Antineoplastic Agents; D007093:Imidazoles; D007211:Indoles; D010091:Oximes; D013449:Sulfonamides; D000077484:Vemurafenib; D048493:Proto-Oncogene Proteins B-raf; C561627:dabrafenib