Evaluation of the Effects of Repeat-Dose Dabrafenib on the Single-Dose Pharmacokinetics of Rosuvastatin (OATP1B1/1B3 Substrate) and Midazolam (CYP3A4 Substrate)

Dabrafenib; Drug interaction; PharmacokineticsDabrafenib; Interacción de fármacos; FarmacocinéticaDabrafenib; Interacció de fàrmacs; FarmacocinèticaDabrafenib is an oral BRAF kinase inhibitor approved for the treatment of various BRAF V600 mutation–positive solid tumors. In vitro observations suggesting cytochrome P450 (CYP) 3A induction and organic anion transporting polypeptide (OATP) inhibition prompted us to evaluate the effect of dabrafenib 150 mg twice daily on the pharmacokinetics of midazolam 3 mg (CYP3A substrate) and rosuvastatin 10 mg (OATP1B1/1B3 substrate) in a clinical phase 1, open-label, fixed-sequence study in patients with BRAF V600 mutation–positive tumors. Repeat dabrafenib dosing resulted in a 2.56-fold increase in rosuvastatin maximum observed concentration (Cmax), an earlier time to Cmax, but only a 7% increase in area under the concentration-time curve from time 0 (predose) extrapolated to infinite time. Midazolam Cmax and AUC extrapolated to infinite time decreased by 47% and 65%, respectively, with little effect on time to Cmax. No new safety findings were reported. Exposure of drugs that are CYP3A4 substrates is likely to decrease when coadministered with dabrafenib. Concentrations of medicinal products that are sensitive OATP1B1/1B3 substrates may increase during the absorption phase.This study was sponsored by GlaxoSmithKline; dabrafenib and trametinib are assets of Novartis AG as of March 2, 2015

Characteristics of Patients with a Complete Response Treated with Dabrafenib plus Trametinib Combination Therapy: Findings from Pooled COMBI-d and COMBI-v 5-Year Analysis

Abstract not available

P863 KEYNOTE-022 parts 4 and 5: pembrolizumab plus trametinib for patients with solid tumors or BRAF wild-type melanoma

Background Pembrolizumab+dabrafenib+trametinib demonstrated promising antitumor activity and acceptable tolerability in BRAF-mutant melanoma in phase 1/2 KEYNOTE-022 parts 1 and 2 (NCT02130466). Pembrolizumab+dabrafenib+trametinib numerically prolonged PFS and DOR versus placebo+dabrafenib+trametinib but had a higher grade 3-5 TRAE rate in part 3. KEYNOTE-022 parts 4 and 5 evaluated pembrolizumab+trametinib. Methods In part 4 (open-label, 3+3 dose-finding) patients with advanced solid tumors (irrespective of BRAF status) or unresectable/metastatic BRAF wild-type melanoma received pembrolizumab 200 mg Q3W with trametinib as concurrent (2 or 4 weeks of trametinib run-in [1.5 or 2 mg QD], then pembrolizumab+trametinib [1.5 or 2 mg QD]) or intermittent dosing (2 weeks of trametinib run-in [1.5 or 2 mg QD], then pembrolizumab+trametinib [1.5 or 2 mg QD; 1 week off/2 weeks on]). Interim MTDs identified in part 4 were confirmed in part 5 using a modified toxicity probability interval design. The primary objectives were safety, tolerability, and ORR by investigator assessment per RECIST v1.1 of the maximum administered or tolerated dose (MAD/MTD) of pembrolizumab+trametinib. Safety was analyzed for all patients who received ≥1 dose of study drug; patients treated during the trametinib run-in who discontinued study before receiving pembrolizumab were included; patients who did not complete trametinib run-in or receive ≥66% of planned doses during the 6-week dose-limiting toxicity (DLT) evaluable period were not included for DLT evaluation. AEs were graded per NCI CTCAE v4. Results Of 42 enrolled patients, most were female (61.9%); median age was 55.0 years; 57.1% had received ≥2 prior lines of therapy. At database cutoff (June 26, 2019), median follow-up was 9.0 months (range, 1.4-25.6 months). Of 38 DLT-evaluable patients, 10 had DLTs (table 1). Dosing regimens were selected for confirmation in part 5 based on safety data. Any-grade TRAEs occurred in 39 (92.9%) patients; grade 3-4 TRAEs occurred in 19 (45.2%), none were grade 5. TRAEs led to discontinuation in 8 (19.0%) patients. Immune-mediated AEs occurred in 12 (28.6%) patients, most commonly severe skin reactions (n=6; 14.3%), pneumonitis (n=3; 7.1%), hypothyroidism (n=2; 4.8%). The MTD of concurrent pembrolizumab+trametinib was pembrolizumab 200 mg Q3W plus trametinib 1.5 mg with 2 weeks of trametinib run-in (ORR, 0/16; 0%) and the MTD of intermittent pembrolizumab+trametinib was pembrolizumab 200 mg Q3W plus trametinib 2 mg with 2 weeks of run-in (ORR, 4/15; 26.7%). Conclusions Both concurrent or intermittent pembrolizumab+trametinib dosing were feasible and the combination showed antitumor activity in patients with advanced solid tumors or advanced BRAF wild-type melanoma

Spartalizumab or placebo in combination with dabrafenib and trametinib in patients with BRAF V600-mutant melanoma: exploratory biomarker analyses from a randomized phase 3 trial (COMBI-i).

BackgroundThe randomized phase 3 COMBI-i trial did not meet its primary endpoint of improved progression-free survival (PFS) with spartalizumab plus dabrafenib and trametinib (sparta-DabTram) vs placebo plus dabrafenib and trametinib (placebo-DabTram) in the overall population of patients with unresectable/metastatic BRAF V600-mutant melanoma. This prespecified exploratory biomarker analysis was performed to identify subgroups that may derive greater treatment benefit from sparta-DabTram.MethodsIn COMBI-i (ClinicalTrials.gov, NCT02967692), 532 patients received spartalizumab 400 mg intravenously every 4 weeks plus dabrafenib 150 mg orally two times daily and trametinib 2 mg orally one time daily or placebo-DabTram. Baseline/on-treatment pharmacodynamic markers were assessed via flow cytometry-based immunophenotyping and plasma cytokine profiling. Baseline programmed death ligand 1 (PD-L1) status and T-cell phenotype were assessed via immunohistochemistry; BRAF V600 mutation type, tumor mutational burden (TMB), and circulating tumor DNA (ctDNA) via DNA sequencing; gene expression signatures via RNA sequencing; and CD4+/CD8+ T-cell ratio via immunophenotyping.ResultsExtensive biomarker analyses were possible in approximately 64% to 90% of the intention-to-treat population, depending on sample availability and assay. Subgroups based on PD-L1 status/TMB or T-cell inflammation did not show significant differences in PFS benefit with sparta-DabTram vs placebo-DabTram, although T-cell inflammation was prognostic across treatment arms. Subgroups defined by BRAF V600K mutation (HR 0.45 (95% CI 0.21 to 0.99)), detectable ctDNA shedding (HR 0.75 (95% CI 0.58 to 0.96)), or CD4+/CD8+ ratio above median (HR 0.58 (95% CI 0.40 to 0.84)) derived greater PFS benefit with sparta-DabTram vs placebo-DabTram. In a multivariate analysis, ctDNA emerged as strongly prognostic (p=0.007), while its predictive trend did not reach significance; in contrast, CD4+/CD8+ ratio was strongly predictive (interaction p=0.0131).ConclusionsThese results support the feasibility of large-scale comprehensive biomarker analyses in the context of a global phase 3 study. T-cell inflammation was prognostic but not predictive of sparta-DabTram benefit, as patients with high T-cell inflammation already benefit from targeted therapy alone. Baseline ctDNA shedding also emerged as a strong independent prognostic variable, with predictive trends consistent with established measures of disease burden such as lactate dehydrogenase levels. CD4+/CD8+ T-cell ratio was significantly predictive of PFS benefit with sparta-DabTram but requires further validation as a biomarker in melanoma. Taken together with previous observations, further study of checkpoint inhibitor plus targeted therapy combination in patients with higher disease burden may be warranted.Trial registration numberNCT02967692

Long-Term Outcomes in Patients With BRAF V600-Mutant Metastatic Melanoma Who Received Dabrafenib Combined With Trametinib.

Purpose To report 5-year landmark analysis efficacy and safety outcomes in patients with BRAF V600-mutant metastatic melanoma (MM) who received BRAF inhibitor dabrafenib (D) and MEK inhibitor trametinib (T) combination therapy versus D monotherapy in the randomized phase II BRF113220 study part C. Patients and Methods BRAF inhibitor-naive patients with BRAF V600-mutant MM were randomly assigned 1:1:1 to receive D 150 mg twice a day, D 150 mg twice a day plus T 1 mg once daily, or D 150 mg twice a day plus T 2 mg once daily (D + T 150/2). Patients who received D monotherapy could cross over to D + T 150/2 postprogression. Efficacy and safety were analyzed 4 and 5 years after initiation in patients with ≥ 5 years of follow-up. Results As of October 13, 2016, 18 patients who received D + T 150/2 remained in the study (13 [24%] of 54 enrolled at this dose plus five [11%] of 45 initially administered D who crossed over to D + T). With D + T 150/2, overall survival (OS; 4 years, 30%; 5 years, 28%) and progression-free survival (4 and 5 years, both 13%) appeared to stabilize with extended follow-up. Increased OS was observed in patients who received D + T with baseline normal lactate dehydrogenase (5 years, 45%) and normal lactate dehydrogenase with fewer than three organ sites with metastasis (5 years, 51%). With extended follow-up, one additional patient who received D + T 150/2 improved from a partial to a complete response. No new safety signals were observed. Conclusion This 5-year analysis represents the longest follow-up to date with BRAF + MEK inhibitor combination therapy in BRAF V600-mutant MM. Consistent with trends observed in landmark analyses with shorter follow-up, this therapy elicits durable plateaus of long-term OS and progression-free survival that last ≥ 5 years in some patients with MM