Douglas J Demarini

Bio: Douglas J Demarini is an academic researcher from Novartis. The author has contributed to research in topics: Pharmacodynamics & Trametinib. The author has an hindex of 6, co-authored 6 publications receiving 1174 citations. Previous affiliations of Douglas J Demarini include Research Triangle Park.

Safety and efficacy results from the first-in-human study of the oral MEK 1/2 inhibitor GSK1120212.

Abstract: 2503 Background: GSK1120212 is a potent and selective allosteric inhibitor of MEK1/2. The objectives of this study are to define the maximum tolerated dose (MTD), and to evaluate the pharmacokinetics (PK), pharmacodynamics (PD), and response rate of GSK1120212 in advanced solid tumors and lymphoma. Methods: GSK1120212 is given orally, once daily (QD). This is a three-part study:Part 1, dose-escalation; Part 2, expansion in selected tumor types to evaluate recommended phase II doses (RP2D); Part 3, PK-PD assessment using tumor biopsies or FDG-PET. Results: 84 patients (pts) have received ≥ 1 dose of GSK1120212, including 29 melanoma and 15 pancreatic cancer pts. The MTD is 3 mg QD and the current RP2D is 2 mg QD. Dose-limiting toxicities are rash (N=2), diarrhea (N=1), central serous retinopathy (N=2) and are reversible. At doses ≥ RP2D (N=77), the most common adverse events are rash (77%; 42% G1, 30% G2, 5% G3) and diarrhea (45%; 34% G1, 9% G2, 3% G3). GSK1120212 has a small peak: trough ratio of ∼ 2 and ...

COMBI-d: A randomized, double-blinded, Phase III study comparing the combination of dabrafenib and trametinib to dabrafenib and trametinib placebo as first-line therapy in patients (pts) with unresectable or metastatic BRAFV600E/K mutation-positive cutaneous melanoma

Abstract: 9011^ Background: As monotherapies, the BRAF inhibitor dabrafenib (D) and the MEK inhibitor trametinib (T) demonstrated superior progression-free survival (PFS) v chemotherapy in pts with BRAFV600 ...

Phase I dose-escalation of the oral MEK1/2 inhibitor GSK1120212 (GSK212) dosed in combination with the oral AKT inhibitor GSK2141795 (GSK795).

Abstract: 3085 Background: The RAS/RAF/MEK and PI3K/AKT pathways are activated in many human cancers. GSK212 is a potent and selective allosteric inhibitor of MEK1/2 and GSK795 is a potent ATP-competitive in...

A three-part, phase I, dose-escalation study of GSK1120212, a potent MEK inhibitor, administered orally to subjects with solid tumors or lymphoma

Abstract: e14584 Background: GSK1120212 is a potent and highly selective inhibitor of MEK1, a component of the MAP kinase pathway. GSK1120212 demonstrates efficient inhibition of p-ERK which correlates with inhibition of cell proliferation and induction of apoptosis. PO administration of GSK1120212 achieved tumor regression in multiple mouse xenograft models. The objectives of this study are to define the maximum tolerated dose (MTD) and to evaluate the pharmacokinetics (PK) and pharmacodynamic (PD) effects of GSK1120212. Methods: In Part 1, patients (pts) with solid tumors or lymphoma are enrolled in successive cohorts and receive a single PO dose of GSK1120212 followed by QD doses on days 1 - 21 of each 28-day cycle. Tumor response is assessed Q 8 weeks. PK blood samples are collected from all pts. Ophthalmic exams are administered at baseline and as clinically warranted. Dose escalation occurs via an accelerated titration followed by a standard 3+3 escalation. In Part 2, pts with pancreatic or K-Ras mutant CRC w...

Improved Overall Survival in Melanoma with Combined Dabrafenib and Trametinib

Abstract: Background The BRAF inhibitors vemurafenib and dabrafenib have shown efficacy as monotherapies in patients with previously untreated metastatic melanoma with BRAF V600E or V600K mutations. Combining dabrafenib and the MEK inhibitor trametinib, as compared with dabrafenib alone, enhanced antitumor activity in this population of patients. Methods In this open-label, phase 3 trial, we randomly assigned 704 patients with metastatic melanoma with a BRAF V600 mutation to receive either a combination of dabrafenib (150 mg twice daily) and trametinib (2 mg once daily) or vemurafenib (960 mg twice daily) orally as first-line therapy. The primary end point was overall survival. Results At the preplanned interim overall survival analysis, which was performed after 77% of the total number of expected events occurred, the overall survival rate at 12 months was 72% (95% confidence interval [CI], 67 to 77) in the combination-therapy group and 65% (95% CI, 59 to 70) in the vemurafenib group (hazard ratio for death in the combination-therapy group, 0.69; 95% CI, 0.53 to 0.89; P = 0.005). The prespecified interim stopping boundary was crossed, and the study was stopped for efficacy in July 2014. Median progression-free survival was 11.4 months in the combinationtherapy group and 7.3 months in the vemurafenib group (hazard ratio, 0.56; 95% CI, 0.46 to 0.69; P<0.001). The objective response rate was 64% in the combinationtherapy group and 51% in the vemurafenib group (P<0.001). Rates of severe adverse events and study-drug discontinuations were similar in the two groups. Cutaneous squamous-cell carcinoma and keratoacanthoma occurred in 1% of patients in the combination-therapy group and 18% of those in the vemurafenib group. Conclusions Dabrafenib plus trametinib, as compared with vemurafenib monotherapy, significantly improved overall survival in previously untreated patients with metastatic melanoma with BRAF V600E or V600K mutations, without increased overall toxicity. (Funded by GlaxoSmithKline; ClinicalTrials.gov number, NCT01597908.)

Improved Survival with MEK Inhibition in BRAF-Mutated Melanoma

Abstract: Background Activating mutations in serine–threonine protein kinase B-RAF (BRAF) are found in 50% of patients with advanced melanoma Selective BRAF-inhibitor therapy improves survival, as compared with chemotherapy, but responses are often short-lived In previous trials, MEK inhibition appeared to be promising in this population Methods In this phase 3 open-label trial, we randomly assigned 322 patients who had metastatic melanoma with a V600E or V600K BRAF mutation to receive either trametinib, an oral selective MEK inhibitor, or chemotherapy in a 2:1 ratio Patients received trametinib (2 mg orally) once daily or intravenous dacarbazine (1000 mg per square meter of body-surface area) or paclitaxel (175 mg per square meter) every 3 weeks Patients in the chemotherapy group who had disease progression were permitted to cross over to receive trametinib Progression-free survival was the primary end point, and overall survival was a secondary end point Results Median progression-free survival was 48 months in the trametinib group and 15 months in the chemotherapy group (hazard ratio for disease progression or death in the trametinib group, 045; 95% confidence interval [CI], 033 to 063; P<0001) At 6 months, the rate of overall survival was 81% in the trametinib group and 67% in the chemotherapy group despite crossover (hazard ratio for death, 054; 95% CI, 032 to 092; P = 001) Rash, diarrhea, and peripheral edema were the most common toxic effects in the trametinib group and were managed with dose interruption and dose reduction; asymptomatic and reversible reduction in the cardiac ejection fraction and ocular toxic effects occurred infrequently Secondary skin neoplasms were not observed Conclusions Trametinib, as compared with chemotherapy, improved rates of progression-free and overall survival among patients who had metastatic melanoma with a BRAF V600E or V600K mutation (Funded by GlaxoSmithKline; METRIC ClinicalTrials gov number, NCT01245062)

Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual.

Abstract: Answer questions and earn CME/CNE To update the melanoma staging system of the American Joint Committee on Cancer (AJCC) a large database was assembled comprising >46,000 patients from 10 centers worldwide with stages I, II, and III melanoma diagnosed since 1998. Based on analyses of this new database, the existing seventh edition AJCC stage IV database, and contemporary clinical trial data, the AJCC Melanoma Expert Panel introduced several important changes to the Tumor, Nodes, Metastasis (TNM) classification and stage grouping criteria. Key changes in the eighth edition AJCC Cancer Staging Manual include: 1) tumor thickness measurements to be recorded to the nearest 0.1 mm, not 0.01 mm; 2) definitions of T1a and T1b are revised (T1a, <0.8 mm without ulceration; T1b, 0.8-1.0 mm with or without ulceration or <0.8 mm with ulceration), with mitotic rate no longer a T category criterion; 3) pathological (but not clinical) stage IA is revised to include T1b N0 M0 (formerly pathologic stage IB); 4) the N category descriptors "microscopic" and "macroscopic" for regional node metastasis are redefined as "clinically occult" and "clinically apparent"; 5) prognostic stage III groupings are based on N category criteria and T category criteria (ie, primary tumor thickness and ulceration) and increased from 3 to 4 subgroups (stages IIIA-IIID); 6) definitions of N subcategories are revised, with the presence of microsatellites, satellites, or in-transit metastases now categorized as N1c, N2c, or N3c based on the number of tumor-involved regional lymph nodes, if any; 7) descriptors are added to each M1 subcategory designation for lactate dehydrogenase (LDH) level (LDH elevation no longer upstages to M1c); and 8) a new M1d designation is added for central nervous system metastases. This evidence-based revision of the AJCC melanoma staging system will guide patient treatment, provide better prognostic estimates, and refine stratification of patients entering clinical trials. CA Cancer J Clin 2017;67:472-492. © 2017 American Cancer Society.

COT drives resistance to RAF inhibition through MAP kinase pathway reactivation

Abstract: Oncogenic mutations in the serine/threonine kinase B-RAF (also known as BRAF) are found in 50-70% of malignant melanomas. Pre-clinical studies have demonstrated that the B-RAF(V600E) mutation predicts a dependency on the mitogen-activated protein kinase (MAPK) signalling cascade in melanoma-an observation that has been validated by the success of RAF and MEK inhibitors in clinical trials. However, clinical responses to targeted anticancer therapeutics are frequently confounded by de novo or acquired resistance. Identification of resistance mechanisms in a manner that elucidates alternative 'druggable' targets may inform effective long-term treatment strategies. Here we expressed ∼600 kinase and kinase-related open reading frames (ORFs) in parallel to interrogate resistance to a selective RAF kinase inhibitor. We identified MAP3K8 (the gene encoding COT/Tpl2) as a MAPK pathway agonist that drives resistance to RAF inhibition in B-RAF(V600E) cell lines. COT activates ERK primarily through MEK-dependent mechanisms that do not require RAF signalling. Moreover, COT expression is associated with de novo resistance in B-RAF(V600E) cultured cell lines and acquired resistance in melanoma cells and tissue obtained from relapsing patients following treatment with MEK or RAF inhibitors. We further identify combinatorial MAPK pathway inhibition or targeting of COT kinase activity as possible therapeutic strategies for reducing MAPK pathway activation in this setting. Together, these results provide new insights into resistance mechanisms involving the MAPK pathway and articulate an integrative approach through which high-throughput functional screens may inform the development of novel therapeutic strategies.

Adjuvant Dabrafenib plus Trametinib in Stage III BRAF-Mutated Melanoma

Abstract: BackgroundCombination therapy with the BRAF inhibitor dabrafenib plus the MEK inhibitor trametinib improved survival in patients with advanced melanoma with BRAF V600 mutations. We sought to determine whether adjuvant dabrafenib plus trametinib would improve outcomes in patients with resected, stage III melanoma with BRAF V600 mutations. MethodsIn this double-blind, placebo-controlled, phase 3 trial, we randomly assigned 870 patients with completely resected, stage III melanoma with BRAF V600E or V600K mutations to receive oral dabrafenib at a dose of 150 mg twice daily plus trametinib at a dose of 2 mg once daily (combination therapy, 438 patients) or two matched placebo tablets (432 patients) for 12 months. The primary end point was relapse-free survival. Secondary end points included overall survival, distant metastasis–free survival, freedom from relapse, and safety. ResultsAt a median follow-up of 2.8 years, the estimated 3-year rate of relapse-free survival was 58% in the combination-therapy group a...