Characteristics of pyrexia in BRAFV600E/K metastatic melanoma patients treated with combined dabrafenib and trametinib in a phase I/II clinical trial

Effectiveness, safety and utilization of cobimetinib and vemurafenib in patients with BRAF V600 mutant melanoma with and without cerebral metastasis under real-world conditions in Germany: the non-interventional study coveNIS

Cobimetinib/vemurafenib combination therapy is approved for treatment of adults with unresectable or metastatic BRAF V600 mutated malignant melanoma (mM). The non-interventional post-authorisation safety study coveNIS collected real-world data on cobimetinib/vemurafenib treatment focussing on overall survival (OS), safety and utilization. MM patients with brain metastases are usually excluded from clinical studies. coveNIS observed 2 cohorts: mM patients without (Cohort A) and with cerebral metastases (Cohort B), aiming to close the data gap for the latter population. A direct comparison of the 2 cohorts was not intended. The primary effectiveness objective was OS; the safety objective was the incidence of all and of serious adverse events (AEs). Secondary objectives included progression-free survival (PFS), time to development of cerebral metastasis (Cohort A) and time to central nervous system relapse (Cohort B). All statistical analyses were descriptive. Between 2017 and 2021, 95 patients were included (Cohort A: 54, Cohort B: 41 patients) at 32 sites in Germany. Median OS was 21.6 months in Cohort A, 7.4 months in Cohort B. Median PFS was 6.9 months in Cohort A, 5.2 months in Cohort B. The proportion of patients experiencing any AEs was 83.3% (Cohort A) and 87.8% (Cohort B). The two most common AEs in Cohort A were 'diarrhoea' (37%), 'vomiting' (20.4%) and 'pyrexia' (20.4%); in Cohort B 'diarrhoea' (36.6%) and 'fatigue' (22%). In conclusion, the OS rates in Cohort A and Cohort B of coveNIS are in line with the OS data from other trials with BRAF/MEK inhibitors for mM. No new safety signals were observed.

Exposure-response analyses of BRAF- and MEK-inhibitors dabrafenib plus trametinib in melanoma patients

INTRODUCTION

Dabrafenib and trametinib are currently administered at fixed doses, at which interpatient variability in exposure is high. The aim of this study was to investigate whether drug exposure is related to efficacy and toxicity in a real-life cohort of melanoma patients treated with dabrafenib plus trametinib.

PATIENTS AND METHODS

An observational study was performed in which pharmacokinetic samples were collected as routine care. Using estimated dabrafenib Area Under the concentration-time Curve and trametinib trough concentrations (C_min), univariable and multivariable exposure-response analyses were performed.

RESULTS

In total, 140 patients were included. Dabrafenib exposure was not related to either progression-free survival (PFS) or overall survival (OS). Trametinib exposure was related to survival, with C_min ≥ 15.6 ng/mL being identified as the optimal threshold. Median OS was significantly longer in patients with trametinib C_min ≥ 15.6 ng/mL (22.8 vs. 12.6 months, P = 0.003), with a multivariable hazard ratio of 0.55 (95% CI 0.36-0.85, P = 0.007). Median PFS in patients with trametinib C_min levels ≥ 15.6 ng/mL (37%) was 10.9 months, compared with 6.0 months for those with C_min below this threshold (P = 0.06). Multivariable analysis resulted in a hazard ratio of 0.70 (95% CI 0.47-1.05, P = 0.082). Exposure to dabrafenib and trametinib was not related to clinically relevant toxicities.

CONCLUSIONS

Overall survival of metastasized melanoma patients with trametinib C_min levels ≥ 15.6 ng/mL is ten months longer compared to patients with C_min below this threshold. This would theoretically provide a rationale for therapeutic drug monitoring of trametinib. Although a high proportion of patients are underexposed, there is very little scope for dose increments due to the risk of serious toxicity.

Final analysis of a post-marketing surveillance study of dabrafenib and trametinib combination therapy in Japanese patients with unresectable malignant melanoma with BRAF V600 mutation

Targeted therapy with a combination of dabrafenib and trametinib has been developed and widely used for treatment of melanoma. However, data regarding its safety and efficacy in Japanese patients with malignant melanoma are limited. A post-marketing surveillance (PMS) study was conducted to investigate the safety and efficacy of combination therapy in a Japanese clinical setting with a surveillance period of June 2016 to March 2022; 326 patients with unresectable malignant melanoma with BRAF mutation were enrolled. The interim results were published in July 2020. Herein, we report the results of the final analysis based on the data collected until the completion of the PMS study. The safety analysis population included 326 patients, the majority of whom had stage IV disease (79.14%) and Eastern Cooperative Oncology Group performance status 0 or 1 (85.28%). All patients were treated with the approved dose of dabrafenib, while 99.08% were treated with the approved dose of trametinib. Adverse events (AEs) occurred in 282 patients (86.50%) and the major AEs (incidence ≥5%) were pyrexia (47.85%), malignant melanoma (33.44%), hepatic function abnormal (9.82%), rash and blood creatine phosphokinase increased (8.59% each), malaise (6.44%), nausea (5.52%), and diarrhea and rhabdomyolysis (5.21% each). The incidences rates of adverse drug reactions of safety specifications were 45.71% for pyrexia, 15.95% for hepatic impairment, 12.58% for rhabdomyolysis, 4.60% for cardiac disorders, and 3.07% for eye disorders. In the efficacy analysis population of 318 patients, the objective response rate was 58.18% (95% confidence interval [CI] 52.54%-63.66%). The progression-free survival rates at 90, 180, and 360 days were 88.14% (95% CI 84.00%-91.26%), 69.53% (63.85%-74.50%), and 52.07% (45.71%-58.03%), respectively. Consistent with previous interim results, no new safety or efficacy concerns were observed in this final analysis of a PMS study conducted in a Japanese real-world clinical setting.

Monitoring of Dabrafenib and Trametinib in Serum and Self-Sampled Capillary Blood in Patients with BRAFV600-Mutant Melanoma

Patients treated with dabrafenib and trametinib for BRAFV600-mutant melanoma often experience dose reductions and treatment discontinuations. Current knowledge about the associations between patient characteristics, adverse events (AE), and exposure is inconclusive. Our study included 27 patients (including 18 patients for micro-sampling). Dabrafenib and trametinib exposure was prospectively analyzed, and the relevant patient characteristics and AE were reported. Their association with the observed concentrations and Bayesian estimates of the pharmacokinetic (PK) parameters of (hydroxy-)dabrafenib and trametinib were investigated. Further, the feasibility of at-home sampling of capillary blood was assessed. A population pharmacokinetic (popPK) model-informed conversion model was developed to derive serum PK parameters from self-sampled capillary blood. Results showed that (hydroxy-)dabrafenib or trametinib exposure was not associated with age, sex, body mass index, or toxicity. Co-medication with P-glycoprotein inducers was associated with significantly lower trough concentrations of trametinib (p = 0.027) but not (hydroxy-)dabrafenib. Self-sampling of capillary blood was feasible for use in routine care. Our conversion model was adequate for estimating serum PK parameters from micro-samples. Findings do not support a general recommendation for monitoring dabrafenib and trametinib but suggest that monitoring can facilitate making decisions about dosage adjustments. To this end, micro-sampling and the newly developed conversion model may be useful for estimating precise PK parameters.

A distinct four-value blood signature of pyrexia under combination therapy of malignant melanoma with dabrafenib and trametinib evidenced by an algorithm-defined pyrexia score

Pyrexia is a frequent adverse event of BRAF/MEK-inhibitor combination therapy in patients with metastasized malignant melanoma (MM). The study’s objective was to identify laboratory changes which might correlate with the appearance of pyrexia. Initially, data of 38 MM patients treated with dabrafenib plus trametinib, of which 14 patients developed pyrexia, were analysed retrospectively. Graphical visualization of time series of laboratory values suggested that a rise in C-reactive-protein, in parallel with a fall of leukocytes and thrombocytes, were indicative of pyrexia. Additionally, statistical analysis showed a significant correlation between lactate dehydrogenase (LDH) and pyrexia. An algorithm based on these observations was designed using a deductive and heuristic approach in order to calculate a pyrexia score (PS) for each laboratory assessment in treated patients. A second independent data set of 28 MM patients, 8 with pyrexia, was used for the validation of the algorithm. PS based on the four parameters CRP, LDH, leukocyte and thrombocyte numbers, were statistically significantly higher in pyrexia patients, differentiated between groups (F = 20.8; p = <0.0001) and showed a significant predictive value for the diagnosis of pyrexia (F = 6.24; p = 0.013). We provide first evidence that pyrexia in patients treated with BRAF/MEK-blockade can be identified by an algorithm that calculates a score.

Discovery of SHR2415, a Novel Pyrrole-Fused Urea Scaffold ERK1/2 Inhibitor

ERK1/2 kinase is a key downstream node of the RAS-RAF-MEK-ERK signaling pathway. A highly potent and selective ERK1/2 inhibitor is a promising option for cancer treatment that will provide a potential solution for overcoming drug resistance. Herein we designed and synthesized a novel scaffold featuring a pyrrole-fused urea template. The lead compound, SHR2415, was shown to be a highly potent ERK1/2 inhibitor that exhibited high cell potency based on the Colo205 assay. In addition, SHR2415 displayed favorable PK profiles across species as well as robust in vivo efficacy in a mouse Colo205 xenograft model.

Improved pyrexia-related outcomes associated with an adapted pyrexia adverse event management algorithm in patients treated with adjuvant dabrafenib plus trametinib: Primary results of COMBI-APlus

BACKGROUND

COMBI-AD demonstrated long-term benefit of adjuvant dabrafenib plus trametinib in patients with resected stage III BRAF V600E/K-mutant melanoma; however, 9% of patients permanently discontinued therapy due to pyrexia. COMBI-APlus evaluated whether an adapted pyrexia management algorithm reduces high-grade pyrexia and pyrexia-related adverse outcomes.

METHODS

COMBI-APlus is an open-label, phase IIIb trial evaluating an adapted pyrexia management algorithm in patients with high-risk resected stage III BRAF V600E/K-mutant melanoma treated with up to 12 months of adjuvant dabrafenib plus trametinib. Both drugs were interrupted for pyrexia (temperature ≥38°C) or the occurrence of pyrexia syndrome for suspected recurrent pyrexia. Treatment was restarted at the same dose once patients were symptom free for ≥24 h. The primary endpoint was the composite rate of grade 3/4 pyrexia, hospitalisation due to pyrexia, or permanent discontinuation due to pyrexia versus historical COMBI-AD control (20.0%; 95% confidence interval [CI], 16.3%-24.1%).

RESULTS

At data cutoff (5 October 2020), COMBI-APlus met its primary endpoint of significant improvement in the composite rate of pyrexia (8.0% [95% CI, 5.9%-10.6%]), with rates of 3.8% for grade 3/4 pyrexia, 4.3% for hospitalisation due to pyrexia, and 2.4% for discontinuation due to pyrexia. Estimated 12-month relapse-free survival was 91.8% (95% CI, 89.0%-93.9%). The most common adverse events were consistent with those in COMBI-AD, and 14.7% of patients permanently discontinued treatment due to adverse events.

CONCLUSIONS

The adapted pyrexia management algorithm appears to reduce the incidence of severe pyrexia outcomes, enables patients to manage pyrexia at home, and helps patients remain on treatment.

CLINICAL TRIAL REGISTRATION

NCT03551626.

Interleukin-6 blockade for prophylaxis and management of immune-related adverse events in cancer immunotherapy

BACKGROUND

Immune checkpoint inhibitors (ICIs) have activity across many tumor types, but activation of the immune system may also lead to significant, often steroid-refractory immune-related adverse events (irAEs). We sought to determine the activity of tocilizumab, an anti-interleukin-6 receptor monoclonal antibody, in treatment or prevention of auto-immune irAE in ICI-treated patients.

METHODS

Institutional databases from 2 melanoma centers were reviewed for patients treated with ICIs and tocilizumab. Longitudinal assessment of C-reactive protein (CRP) and assessment of clinical improvement or prevention of flare of pre-existing auto-immune conditions were utilised to evaluate the benefit of tocilizumab.

RESULTS

Twenty-two patients were identified. Two were treated prophylactically. Twenty were treated for management of irAEs. Median time to irAE onset from ICI start was 48 days (range 8-786) and from irAE onset to tocilizumab 32 days (range 1-192). Median time to irAE resolution from tocilizumab was 6.5 days (range 1-93). Clinical improvement/benefit was demonstrated in 21/22 patients. Median CRP prior to ICI administration was 32 mg/l (range 0.3-99), at the onset of irAE 49.5 mg/L (range 0.3-251, P = 0.047) and after tocilizumab 18 mg/L (range 0.3-18, P = 0.0011). Tocilizumab was well tolerated with self-limiting and transient toxicities in 11 (50%) patients. From start of ICI, median progression-free survival was 6 months (range 3.9-18.8) and median overall survival was not reached.

CONCLUSIONS

Tocilizumab was a well-tolerated and effective steroid-sparing treatment for both management of irAEs, as well as prevention of flare of pre-existing auto-immune disorders. Prospective trials to evaluate its efficacy and impact on cancer outcomes compared with standard strategies are required.

Management of Pyrexia Associated with the Combination of Dabrafenib and Trametinib: Canadian Consensus Statements

The combination of dabrafenib and trametinib is a well-established treatment for BRAF-mutated melanoma. However, the effectiveness of this approach may be hindered by the development of treatment-related pyrexia syndrome, which occurs in at least 50% of treated patients. Without appropriate intervention, pyrexia syndrome has the potential to worsen and can result in hypotension secondary to dehydration and associated organ-related complications. Furthermore, premature treatment discontinuation may result in a reduction in progression-free and overall survival. Despite existing guidance, there is still a wide variety of therapeutic approaches suggested in the literature for both the definition and management of dabrafenib and trametinib-related pyrexia. This is reflected in the practice variation of its prevention and treatment within and between Canadian cancer centres. A Canadian working group was formed and consensus statements were constructed based on evidence and finalised through a two-round modified Delphi approach. The statements led to the development of a pyrexia treatment algorithm that can easily be applied in routine practice. The Canadian working group consensus statements serve to provide practical guidance for the management of dabrafenib and trametinib-related pyrexia, hopefully leading to reduced discontinuation rates, and ultimately improve patients' quality of life and cancer-related outcomes.

Evaluating the utility of therapeutic drug monitoring in the clinical use of small molecule kinase inhibitors: a review of the literature

Introduction: Orally administered small molecule kinase inhibitors (KI) are a key class of targeted anti-cancer medicines that have contributed substantially to improved survival outcomes in patients with advanced disease. Since the introduction of KIs in 2001, there has been a building body of evidence that the benefit derived from these drugs may be further enhanced by individualizing dosing on the basis of concentration.Areas covered: This review considers the rationale for individualized KI dosing and the requirements for robust therapeutic drug monitoring (TDM). Current evidence supporting TDM-guided KI dosing is presented and critically evaluated, and finally potential approaches to address translational challenges for TDM-guided KI dosing and alternate approaches to support individualization of KI dosing are discussed.Expert opinion: Intuitively, the individualization of KI dosing through an approach such as TDM-guided dosing has great potential to enhance the effectiveness and tolerability of these drugs. However, based on current literature evidence it is unrealistic to propose that TDM-guided KI dosing should be routinely implemented into clinical practice.

Pyrexia in patients treated with dabrafenib plus trametinib across clinical trials in BRAF-mutant cancers

BACKGROUND

Dabrafenib plus trametinib has demonstrated clinical benefit across multiple BRAF-mutant tumours, leading to approval for resected stage III and metastatic melanoma, non-small-cell lung cancer (NSCLC) and anaplastic thyroid cancer. Pyrexia is a common adverse event in patients treated with dabrafenib plus trametinib. Here, we characterise the incidence, patterns and management of pyrexia in patients receiving dabrafenib plus trametinib in clinical trials.

METHODS

Patients (N = 1076) included in the analysis received dabrafenib plus trametinib in the following clinical trials: phase II registration trial in advanced NSCLC (N = 82), phase III COMBI-AD study in resectable stage III melanoma (N = 435) and phase III COMBI-d and COMBI-v studies in unresectable or metastatic melanoma (N = 209 and N = 350, respectively).

RESULTS

Among the 1076 patients enrolled in the clinical trials, 61.3% developed pyrexia, 5.7% developed grade 3/4 pyrexia and 15.6% developed a protocol-defined serious pyrexia event. Among the 660 patients with pyrexia, 33.0% had 1 occurrence, 19.8% had 2 occurrences and 47.1% had ≥3 occurrences. The incidence of pyrexia was highest early in treatment and decreased with time on treatment. Temporary dose interruption of dabrafenib or trametinib was the most common and effective management strategy.

CONCLUSIONS

Pyrexia is the most common adverse event associated with dabrafenib plus trametinib but is manageable with dose interruption.

TRIAL REGISTRATION

ClinicalTrials.gov (Phase II NSCLC, NCT01336634; COMBI-AD, NCT01682083; COMBI-d, NCT01584648; COMBI-v, NCT01597908).

Sarcoid-like reaction in a BRAF V600E-mutated metastatic melanoma patient during treatment with BRAF/MEK-targeted therapy

Treatment with combined BRAF and MEK inhibition is widely accepted as a first-line treatment option for patients with advanced BRAF V600E mutant melanoma. It is generally well-tolerated and has limited side-effects. However, we report a case of a sarcoid-like syndrome induced by treatment with dabrafenib/trametinib (D/T) in a patient with stage IV-M1d melanoma. Sarcoid-like syndrome is a known side-effect of immune checkpoint-inhibition therapy but has only rarely been described in BRAF/MEK inhibition. However, recognizing this side-effect is important because of potential misinterpretation as progressive disease and influence on treatment. We describe a 48-year-old female patient who initially presented with solitary brain metastasis and diffuse lung lesions. She was treated with D/T to which she had an initial response in all lesions. One year later, new hilar and mediastinal lymphadenopathies were detected. Imaging was suggestive of the sarcoid-like syndrome. An endoscopic biopsy of the enlarged lymph node showed no melanoma cells. Treatment was continued. Three months later, the patient experienced a drop in hemoglobin, which prompted further investigations into possible occult intestinal metastasis. Video capsule examination revealed a metastatic lesion in the small intestine. A treatment switch to the combination of checkpoint inhibitors nivolumab and ipilimumab successfully treated both lung and small intestine lesions. After the third dose of this combination therapy, she developed an immune-related pneumonitis. Treatment with corticosteroids resolved the pneumonitis and decreased metabolism in the sarcoid-like syndrome. The treatment was not restarted afterward. She remains free of the disease up to today, 2.5 years after diagnosis.

A Retrospective Analysis of Dabrafenib and/or Dabrafenib Plus Trametinib Combination in Patients with Metastatic Melanoma to Characterize Patients with Long-Term Benefit in the Individual Patient Program (DESCRIBE III)

Simple Summary

Compassionate-use programs provide an opportunity to retrospectively evaluate the treatment patterns and clinical outcomes in a real-world setting to validate the results derived from controlled randomized clinical trials. The COMBI-d and COMBI-v studies established the superior efficacy of dabrafenib + trametinib (dab + tram) versus BRAF inhibitor monotherapy in patients with BRAF V600–mutant metastatic melanoma. In light of their five-year results demonstrating long-term benefit with first-line dab + tram, it is important to get a real-world perspective of the long-term treatment duration for dab + tram. DESCRIBE III was designed to retrospectively evaluate the impact of patient characteristics on the long-term outcomes of dab + tram in a real-world setting based on the duration of clinical benefit. Consistent with the findings from the pooled analysis of COMBI-d and COMBI-v, lower LDH level and <3 metastatic sites at baseline were associated with a longer duration of treatment benefit in a real-world setting.

Abstract

The dabrafenib plus trametinib (dab + tram) combination has demonstrated durable long-term efficacy in patients with BRAF V600–mutant metastatic melanoma. However, real-world data characterizing patients with long-term benefit are limited. DESCRIBE III was a global, observational, retrospective, chart review study in patients with unresectable or metastatic melanoma treated with dab monotherapy and/or dab + tram combination therapy as part of the Named Patient Program or Individual Patient Program. Overall, 509 patients were enrolled. Patients were categorized into three groups based on their observed treatment duration: long-term (on therapy ≥12 months), intermediate (on therapy ≥6 months and <12 months), and short-term (on therapy <6 months) duration of benefit. More patients in the short-term duration of benefit group had baseline characteristics associated with poor prognosis compared with the other two groups. Median lactate dehydrogenase (LDH) levels (368 U/L) at baseline were also higher in the short-term duration of benefit group. No new safety signals were identified. DESCRIBE III identified baseline characteristics associated with long-term benefit of dab + tram. Lower LDH level and <3 metastatic sites at baseline were associated with a longer duration of benefit, confirming that the findings from COMBI-d and COMBI-v are relevant to patients treated in a real-world setting.

Edoxaban prevented adverse effects including pyrexia and elevation of D-dimer caused by the combination of BRAF and MEK inhibitors in a patient with BRAF-mutant melanoma

The combination of BRAF inhibitor and MEK inhibitor is one of the first-line treatments for unresectable BRAF-mutant melanoma or as an adjuvant therapy. However, some patients who received the combination of dabrafenib and trametinib (CombiDT) or the combination of encorafenib and binimetinib (CombiEB) had adverse events (AEs) including pyrexia. We herein report a patient with BRAF-mutated melanoma who repeatedly developed elevated levels of D-dimer and pyrexia after CombiDT and CombiEB treatments. Moreover, concomitant edoxaban prevented these AEs, enabling the patient to continue receiving CombiEB.

Combined PD-1, BRAF and MEK inhibition in advanced BRAF-mutant melanoma: safety run-in and biomarker cohorts of COMBI-i

Immune and targeted therapies achieve long-term survival in metastatic melanoma; however, new treatment strategies are needed to improve patients' outcomes^1,2. We report on the efficacy, safety and biomarker analysis from the single-arm safety run-in (part 1; n = 9) and biomarker (part 2; n = 27) cohorts of the randomized, placebo-controlled, phase 3 COMBI-i trial (NCT02967692) of the anti-PD-1 antibody spartalizumab, in combination with the BRAF inhibitor dabrafenib and MEK inhibitor trametinib. Patients (n = 36) had previously untreated BRAF V600-mutant unresectable or metastatic melanoma. In part 1, the recommended phase 3 regimen was identified based on the incidence of dose-limiting toxicities (DLTs; primary endpoint): 400 mg of spartalizumab every 4 weeks plus 150 mg of dabrafenib twice daily plus 2 mg of trametinib once daily. Part 2 characterized changes in PD-L1 levels and CD8⁺ cells following treatment (primary endpoint), and analyzed additional biomarkers. Assessments of efficacy and safety were key secondary endpoints (median follow-up, 24.3 months). Spartalizumab plus dabrafenib and trametinib led to an objective response rate (ORR) of 78%, including 44% complete responses (CRs). Grade ≥3 treatment-related adverse events (TRAEs) were experienced by 72% of patients. All patients had temporary dose modifications, and 17% permanently discontinued all three study drugs due to TRAEs. Early progression-free survival (PFS) events were associated with low tumor mutational burden/T cell-inflamed gene expression signature (GES) or high immunosuppressive tumor microenvironment (TME) GES levels at baseline; an immunosuppressive TME may also preclude CR. Overall, the efficacy, safety and on-treatment biomarker modulations associated with spartalizumab plus dabrafenib and trametinib are promising, and biomarkers that may predict long-term benefit were identified.

Potential utilization of neopterin measurements in the assessment of pyrexia in metastatic melanoma treated with combined targeted therapy: a case report

In patients with metastatic melanoma the advent of targeted therapy and immune checkpoint inhibitors has transformed the management of advanced and metastatic disease, resulting in improved outcomes. Neopterin is a biomarker of immune activation increased in cancer as well as in other conditions associated with immune activation. We present a case of a patient with advanced metastatic melanoma responding to the combination targeted therapy with dabrafenib and trametinib. The treatment was complicated by a fever that was accompanied by a marked rise in serum and urinary neopterin concentrations. Present case report illustrates not only the efficacy of combined targeted therapy, but also the utilization of neopterin measurements in the diagnosis and monitoring of pyrexia in patients with metastatic malignant melanoma.

Clinical Pharmacokinetics and Pharmacodynamics of Dabrafenib

Dabrafenib is a potent and selective inhibitor of BRAF-mutant kinase that is approved, as monotherapy or in combination with trametinib (mitogen-activated protein kinase (MAPK) kinase (MEK) inhibitor), for unresectable or metastatic BRAF-mutated melanoma, advanced non-small cell lung cancer and anaplastic thyroid cancer harbouring the BRAF^V600E mutation. The recommended dose of dabrafenib is 150 mg twice daily (bid) under fasted conditions. After single oral administration of the recommended dose, the absolute oral bioavailability (F) of dabrafenib is 95%. Dabrafenib shows a time-dependent increase in apparent clearance (CL/F) following multiple doses, which is likely due to induction of its own metabolism through cytochrome P450 (CYP) 3A4. Therefore, steady state is reached only after 14 days of daily dose administration. Moreover, the extent of this auto-induction process is dependent on the dose, which explains why dabrafenib systemic exposure at steady state increases less than dose proportionally over the dose range of 75-300 mg bid. The main elimination route of dabrafenib is the oxidative metabolism via CYP3A4/2C8 and biliary excretion. Among the three major metabolites identified, hydroxy-dabrafenib appears to contribute to the pharmacological activity. Age, sex and body weight did not have any clinically significant influence on plasma exposure to dabrafenib. No dose adjustment is needed for patients with mild renal or hepatic impairment, whereas the impacts of severe impairment on dabrafenib pharmacokinetics remain unknown. Considering that dabrafenib is a substrate of CYP3A4/2C8 and is a CYP3A4/2B6/2C inducer, drug-drug interactions are expected with dabrafenib. The relationship between clinical outcomes and plasma exposure to dabrafenib and hydroxy-dabrafenib should be investigated more deeply.

Clinical Development of BRAF plus MEK Inhibitor Combinations

Genomic profiling shows that many solid tumors are characterized by specific driver aberrations, and this has expanded the therapeutic options for many patients. The mitogen-activated protein kinase (MAPK) pathway is a key cell signaling pathway involved in regulating cellular growth, proliferation, and survival. Driver mutations in the BRAF gene, a key player in the MAPK pathway, are described in multiple tumor types, including subsets of melanoma, non-small cell lung cancer (NSCLC), and anaplastic thyroid cancer (ATC), making BRAF a desirable target for inhibition. BRAF inhibitors have shown efficacy in several cancers; however, most patients eventually develop resistance. To delay or prevent resistance, combination therapy targeting BRAF and MEK, a downstream signaling target of BRAF in the MAPK pathway, was evaluated and demonstrated synergistic benefit. BRAF and MEK inhibitor combinations have been approved for use in various cancers by the US FDA. We review the clinical data for various BRAF plus MEK combination regimens in three cancer types with underlying BRAF driver mutations: melanoma, NSCLC, and ATC. We also discuss practical treatment considerations and management of selected combination therapy toxicities.

Population Pharmacokinetics/Pharmacodynamics of Dabrafenib Plus Trametinib in Patients with BRAF-Mutated Metastatic Melanoma

Patients treated with dabrafenib/trametinib (DAB/TRA) exhibit a large interindividual variability in clinical outcomes. The aims of this study were to characterize the pharmacokinetics of DAB, hydroxy-dabrafenib (OHD), and TRA in BRAF-mutated patients and to investigate the exposure–response relationship for toxicity and efficacy in metastatic melanoma (MM) patients. Univariate Fisher and Wilcoxon models including drug systemic exposure (area under the plasma concentration curve, AUC) were used to identify prognostic factors for the onset of dose-limiting toxicities (DLT), and Cox models for overall (OS) and progression-free survival (PFS). Seventy-three BRAF-mutated patients were included in pharmacokinetic (n = 424, NONMEM) and 52 in pharmacokinetic/pharmacodynamic analyses. Age and sex were identified as determinants of DAB and OHD clearances (p < 0.01). MM patients experiencing DLT were overexposed to DAB compared to patients without DLT (AUC: 9624 vs. 7485 ng∙h/mL, respectively, p < 0.01). Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥ 2 and plasma ratio AUC_OHD/AUC_DAB ≥ 1 were independently associated with shorter OS (HR: 6.58 (1.29–33.56); p = 0.023 and 10.61 (2.34–48.15), p = 0.022, respectively). A number of metastatic sites ≥3 and cerebral metastases were associated with shorter PFS (HR = 3.25 (1.11–9.50); p = 0.032 and HR = 1.23 (1.35–10.39), p = 0.011; respectively). TRA plasma exposure was neither associated with toxicity nor efficacy. Our results suggest that early drug monitoring could be helpful to prevent the onset of DLT in MM patients, especially in fragile patients such as the elderly. Regarding efficacy, the clinical benefit to monitor plasma ratio AUC_OHD/AUC_DAB deserves more investigation in a larger cohort of MM patients.

A novel chalcone derivative has antitumor activity in melanoma by inducing DNA damage through the upregulation of ROS products

Background

Melanoma is one of the most aggressive tumors with the remarkable characteristic of resistance to traditional chemotherapy and radiotherapy. Although targeted therapy and immunotherapy benefit advanced melanoma patient treatment, BRAFi (BRAF inhibitor) resistance and the lower response rates or severe side effects of immunotherapy have been observed, therefore, it is necessary to develop novel inhibitors for melanoma treatment.

Methods

We detected the cell proliferation of lj-1-59 in different melanoma cells by CCK 8 and colony formation assay. To further explore the mechanisms of lj-1-59 in melanoma, we performed RNA sequencing to discover the pathway of differential gene enrichment. Western blot and Q-RT-PCR were confirmed to study the function of lj-1-59 in melanoma.

Results

We found that lj-1-59 inhibits melanoma cell proliferation in vitro and in vivo, induces cell cycle arrest at the G2/M phase and promotes apoptosis in melanoma cell lines. Furthermore, RNA-Seq was performed to study alterations in gene expression profiles after treatment with lj-1-59 in melanoma cells, revealing that this compound regulates various pathways, such as DNA replication, P53, apoptosis and the cell cycle. Additionally, we validated the effect of lj-1-59 on key gene expression alterations by Q-RT-PCR. Our findings showed that lj-1-59 significantly increases ROS (reactive oxygen species) products, leading to DNA toxicity in melanoma cell lines. Moreover, lj-1-59 increases ROS levels in BRAFi -resistant melanoma cells, leading to DNA damage, which caused G2/M phase arrest and apoptosis.

Conclusions

Taken together, we found that lj-1-59 treatment inhibits melanoma cell growth by inducing apoptosis and DNA damage through increased ROS levels, suggesting that this compound is a potential therapeutic drug for melanoma treatment.

Promising Strategies for Overcoming BRAF Inhibitor Resistance Based on Known Resistance Mechanisms

BACKGROUND

Almost 50% of metastatic melanomas harbor BRAF mutations. Since 2011, BRAF inhibitors have exhibited striking clinical benefits in BRAF-mutant melanoma patients. Unfortunately, their therapeutic effects are often temporary. The resistance mechanisms vary and can be broadly classified as MAPK reactivation-dependent and -independent. Elucidation of these resistance mechanisms provides new insights into strategies for overcoming resistance. Indeed, several alternative treatment strategies, including changes in the mode of administration, combinations of BRAF and MEK inhibitors, and immunotherapy have been verified as beneficial to BRAF inhibitor-resistant melanoma patients.

Prospect

In this review, we discuss promising strategies for overcoming drug resistance and highlighting the prospects for discovering strategies to counteract BRAF inhibitor resistance.

A Phase I and Pharmacokinetic Study of Oral Dabrafenib in Children and Adolescent Patients with Recurrent or Refractory BRAF V600 Mutation-Positive Solid Tumors

PURPOSE

The 2-part, phase I/IIa, open-label study (NCT01677741) sought to determine the safety, tolerability, pharmacokinetics, and preliminary activity of dabrafenib in pediatric patients with advanced BRAF V600-mutated cancers.

PATIENTS AND METHODS

This phase I dose-finding part treated patients ages 1 to <18 years with BRAF V600 mutation-positive tumors with oral dabrafenib 3 to 5.25 mg/kg/day to determine the RP2D based on safety and drug exposure target.

RESULTS

Between May 2013 and November 2014, 27 patients [12 male; median age, 9 years (range, 1-17 years)] with BRAF V600-mutant solid tumors recurrent/refractory to treatment (low- or high-grade glioma, Langerhans cell histiocytosis, neuroblastoma, or thyroid cancer) were enrolled. The median treatment duration was 75.6 weeks (range, 5.6-148.7 weeks), with 63% treated for >52 weeks and 52% undergoing treatment at data cutoff date. The most common grade 3/4 adverse events suspected to be related to study drug were maculopapular rash and arthralgia (2 patients each). No dose-limiting toxicities were observed. Pharmacokinetic analyses showed a dose-dependent increase in AUC0-12 and achievement of adult exposure levels at the recommended phase II doses of 5.25 mg/kg/day (age <12 years) and 4.5 mg/kg/day (age ≥12 years) divided into 2 equal doses daily, not exceeding 300 mg daily.

CONCLUSIONS

In this first clinical trial in pediatric patients with pretreated BRAF V600-mutant tumors, dabrafenib was well tolerated while achieving target exposure levels; the average treatment duration was >1 year with many patients still on treatment. The phase II component is also closed and will be reported separately.

Adverse events associated with encorafenib plus binimetinib in the COLUMBUS study: incidence, course and management

BACKGROUND

Dual inhibition of the mitogen-activated protein kinase pathway with BRAF/MEK inhibitor (BRAFi/MEKi) therapy is a standard treatment for BRAFV600-mutant metastatic melanoma and has historically been associated with grade III pyrexia or photosensitivity depending on the combination used. The objective of this study was to fully describe adverse events from the COLUMBUS study evaluating the most recent BRAF/MEK inhibitor combination encorafenib+binimetinib.

PATIENTS AND METHODS

Patients with locally advanced, unresectable or metastatic BRAFV600-mutant melanoma were randomised to receive encorafenib 450 mg once daily plus binimetinib 45 mg twice daily, encorafenib 300 mg once daily or vemurafenib 960 mg twice daily. Adverse events that represent known effects of available BRAFi and/or MEKi were evaluated.

RESULTS

The safety population included a total of 570 patients (encorafenib+binimetinib = 192; encorafenib = 192; vemurafenib = 186). Median duration of exposure was longer with encorafenib+binimetinib (51 weeks) than with encorafenib (31 weeks) or vemurafenib (27 weeks). Common BRAFi/MEKi toxicities with encorafenib+binimetinib were generally manageable, reversible and infrequently associated with discontinuation. Pyrexia was less frequent with encorafenib+binimetinib (18%) and encorafenib (16%) than with vemurafenib (30%) and occurred later in the course of therapy with encorafenib+binimetinib (median time to first onset: 85 days versus 2.5 days and 19 days, respectively). The incidence of photosensitivity was lower with encorafenib+binimetinib (5%) and encorafenib (4%) than with vemurafenib (30%). The incidence of serous retinopathy was higher with encorafenib+binimetinib (20%) than with encorafenib (2%) or vemurafenib (2%), but no patients discontinued encorafenib+binimetinib because of this event.

CONCLUSION

Encorafenib+binimetinib is generally well tolerated and has a low discontinuation rate in patients with BRAFV600-mutant melanoma, with a distinct safety profile as compared with other anti-BRAF/MEK targeted therapies.

TRIAL REGISTRATION

ClinicalTrials.gov (Identifier: NCT01909453) and with EudraCT (number 2013-001176-38).

Clinical outcomes of BRAF plus MEK inhibition in melanoma: A meta-analysis and systematic review

Background

Melanoma is a potentially fatal malignancy with poor prognosis. Several recent studies have demonstrated that combination therapy of BRAF and MEK inhibition achieved better curative effect and appeared less toxic effects. We conducted a meta‐analysis to evaluate the efficacy and safety between BRAF inhibition plus MEK inhibition combination therapy and BRAF inhibition monotherapy in melanoma patients.

Methods

We performed the search in PubMed, EMBASE, and the Cochrane Library from January 2010 to January 2019. Inclusion and exclusion of studies, assessment of quality, outcome measures, data extraction, and synthesis were independently accomplished by two reviewers. Revman 5.3 software was used for the meta‐analysis.

Results

Totally, seven randomized controlled trials involving 3146 patients met our inclusion criteria. Comparing the results of combination therapy and monotherapy, combination therapy significantly improved OS (RR = 1.13; 95% CI, 1.08, 1.19; P < 0.00001), ORR (RR = 1.36; 95% CI, 1.28, 1.45; P < 0.00001), PFS (RR = 0.57; 95% CI, 0.52, 0.63; P < 0.00001) and reduced deaths (RR = 0.78; 95% CI, 0.69, 0.88; P < 0.0001). Skin‐related adverse events such as hyperkeratosis, cutaneous squamous‐cell carcinoma were less compared with monotherapy. However, gastrointestinal events like nausea, diarrhea, and vomiting were at a higher frequency.

Conclusion

Doublet BRAF and MEK inhibition achieved better survival outcomes over single‐agent BRAF inhibition and occurred less skin‐related events, but gastrointestinal events were more in combination therapy.

Dynamics of neutrophil and C-reactive protein reflect the clinical course of pyrexia during combination therapy with dabrafenib and trametinib

Pyrexia is the most common adverse event in patients with melanoma or other solid organ malignancies that are treated with the combination of dabrafenib and trametinib (combi-DT). Given the expanded indication for combi-DT, management of pyrexia is a high priority. No previous case series has revealed which blood markers reflect the course of pyrexia and there is no consensus on the management strategy for pyrexia. The current case series study describes the utility of neutrophil count (NC), neutrophil ratio (NR) and C-reactive protein (CRP) in 11 patients with metastatic melanoma and BRAF V600 mutations who experienced pyrexia during combi-DT in our department. We also described the clinical course of pyrexia episodes that were managed with the concomitant use of oral prednisolone and immediate withdrawal of combi-DT. Consequently, the analysis of 37 pyrexia episodes in 11 patients showed that the differences in NC, NR and CRP at the onset of pyrexia were significantly different from those at pyretolysis (P = 0.01, 0.006 and 0.03, respectively). Additionally, in the 24 pyrexia episodes treated with the concomitant use of oral prednisolone and the immediate withdrawal of combi-DT, the mean duration of pyrexia and the mean time to restart combi-DT were 3 and 6 days, respectively. Therefore, the blood markers that reflect the course of pyrexia during combi-DT may be helpful for the appropriate management of pyrexia; also, our management strategy for pyrexia successfully reduced the duration of pyrexia and did not require a long-term drug holiday. Further large-scale studies are required to verify our results.

Tolerability of BRAF/MEK inhibitor combinations: adverse event evaluation and management

The inhibition of the mitogen-activated protein kinases signalling pathway through combined use of BRAF and MEK inhibitors (BRAFi+MEKi) represents an established therapeutic option in patients with BRAF-mutated, advanced melanoma. These efficient therapies are well tolerated with mostly moderate and reversible side effects and a discontinuation rate due to adverse events of 11.5%-15.7%. Median duration of therapy ranges between 8.8 and 11.7 months. Based on data from confirmatory trials, safety profiles of three BRAFi+MEKi combinations were reviewed, that is, dabrafenib plus trametinib, vemurafenib plus cobimetinib and encorafenib plus binimetinib. Many adverse events are class effects, such as cutaneous, gastrointestinal, ocular, cardiac and musculoskeletal events; some adverse events are substance associated. Fever (dabrafenib) and photosensitivity (vemurafenib) are the most common and clinically prominent examples. Other adverse events are less frequent and the association to one substance is less strong such as anaemia, facial paresis (encorafenib), neutropenia (dabrafenib), skin rash, QTc prolongation and increased liver function tests (vemurafenib). This narrative review provides recommendations for monitoring, adverse event evaluation and management focusing on the clinically relevant side effects of the three regimens.

Female genitourinary tract melanoma: mutation analysis with clinicopathologic correlation: a single-institution experience

Female genitourinary tract melanoma (FGTM) is a rare and often-fatal form of mucosal melanoma. We describe our institutional experience with 55 cases of FGTM, 16 of which were evaluated with next-generation sequencing targeting 151 cancer-associated genes. Tumors tended to be thicker than conventional melanoma at presentation (median: 3.2 mm), were frequently ulcerated (50%), and characterized by incomplete initial resections. Regional lymph nodes showed tumor involvement at presentation in 28% of cases. With a median follow-up of 23.6 months, the median recurrence free survival was 14.5 months and the median overall survival was 29.6 months. Genomic analysis revealed mutually exclusive mutations in TP53 and KIT in 25%, while 19% of cases showed BRAF mutation. NRAS mutation was found in 13% of cases. Mutation in ATRX, previously undescribed in mucosal melanoma, was seen in three (10%) of 16 patients. Only invasive melanoma cases were included in statistical analyses. Patients with three or more mutations had marginally worse overall survival rates than those with two or less (P=0.07). Further studies are required for potential adjuvant treatment modalities to improve survival outcomes of FGTM.

Patient-reported outcomes in patients with resected, high-risk melanoma with BRAFV600E or BRAFV600K mutations treated with adjuvant dabrafenib plus trametinib (COMBI-AD): a randomised, placebo-controlled, phase 3 trial

BACKGROUND

In the phase 3 COMBI-AD study, patients with resected, stage III melanoma with BRAF^V600E or BRAF^V600K mutations received adjuvant dabrafenib plus trametinib or placebo. The primary analysis showed that dabrafenib plus trametinib significantly improved relapse-free survival at 3 years. These results led to US Food and Drug Administration approval of dabrafenib plus trametinib as adjuvant treatment for patients with resected stage III melanoma with BRAF^V600E or BRAF^V600K mutations. Here, we report the patient-reported outcomes from COMBI-AD.

METHODS

COMBI-AD was a randomised, double-blind, placebo-controlled, phase 3 study done at 169 sites in 25 countries. Study participants were aged 18 years or older and had complete resection of stage IIIA (lymph node metastases >1 mm), IIIB, or IIIC cutaneous melanoma as per American Joint Committee on Cancer 7th edition criteria, with BRAF^V600E or BRAF^V600K mutations, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned (1:1) via an interactive voice response system, stratified by mutation type and disease stage, to receive oral dabrafenib (150 mg twice daily) plus oral trametinib (2 mg once daily) or matching placebos for 12 months. Patients, physicians, and the investigators who analysed the data were masked to treatment allocation. The primary endpoint was relapse-free survival, reported elsewhere. Health-related quality of life, reported here, was a prespecified exploratory endpoint, and was assessed with the European Quality of Life 5-Dimensions 3-Levels (EQ-5D-3L) questionnaire in the intention-to-treat population. We used a mixed-model repeated-measures analysis to assess differences in health-related quality of life between groups. This study is registered with ClinicalTrials.gov, number NCT01682083. The trial is ongoing, but is no longer recruiting participants.

FINDINGS

Between Jan 31, 2013, and Dec 11, 2014, 870 patients were enrolled and randomly assigned to receive dabrafenib plus trametinib (n=438) or matching placebos (n=432). Data were collected until the data cutoff for analyses of the primary endpoint (June 30, 2017). The median follow-up was 34 months (IQR 28-39) in the dabrafenib plus trametinib group and 33 months (20·5-39) in the placebo group. During the 12-month treatment phase, there were no significant or clinically meaningful changes from baseline between groups in EQ-5D-3L visual analogue scale (EQ-VAS) or utility scores. During treatment, there were no clinically meaningful differences in VAS scores or utility scores in the dabrafenib plus trametinib group between patients who did and did not experience the most common adverse events. During long-term follow-up (range 15-48 months), VAS and utility scores were similar between groups and did not differ from baseline scores. At recurrence, there were significant decreases in VAS scores in both the dabrafenib plus trametinib group (mean change -6·02, SD 20·57; p=0·0032) and the placebo group (-6·84, 20·86; p<0·0001); the mean change in utility score also differed significantly at recurrence for both groups (dabrafenib plus trametinib -0·0626, 0·1911, p<0·0001; placebo -0·0748, 0·2182, p<0·0001).

INTERPRETATION

These findings show that dabrafenib plus trametinib did not affect patient-reported outcome scores during or after adjuvant treatment, and suggest that preventing or delaying relapse with adjuvant therapy could be beneficial in this setting.

FUNDING

Novartis.

Adverse Event Management in Patients with BRAF V600E-Mutant Non-Small Cell Lung Cancer Treated with Dabrafenib plus Trametinib

Therapies for advanced non-small cell lung cancer (NSCLC) continue to become more sophisticated. Chemotherapeutics are giving way to newer approaches such as immune checkpoint inhibitors and targeted therapies for greater efficacy and improved outcomes. Dabrafenib plus trametinib combination therapy was first approved for the treatment of metastatic melanoma harboring the BRAF V600-mutation in 2014. In 2017, the U.S. Food and Drug Administration approved the combination for patients with NSCLC with the same mutation based on an ≈ 65% response rate and median progression-free survival of 10-11 months. BRAF mutations are a high-frequency event in melanoma (≈ 50%), whereas the overall incidence in lung cancer is ≈ 2%, but similar in number, because of the high incidence of the disease. As a new approach in NSCLC treatment, dabrafenib plus trametinib has a unique toxicity profile that is likely unfamiliar to care providers in thoracic and general oncology who have not used the combination to treat patients with melanoma. Common adverse events such as pyrexia, fatigue, and nausea, as well as a range of less frequent cutaneous, ocular, and hemorrhagic events, can be observed during treatment with dabrafenib plus trametinib. Previous experience in metastatic melanoma revealed that these events can be effectively managed to improve patient quality of life and reduce unnecessary drug discontinuation. The aim of this review is to summarize treatment guidelines, along with key insights obtained from previous clinical-trial and real-world experience in patients with metastatic melanoma, to properly manage toxicities associated with dabrafenib plus trametinib for NSCLC. IMPLICATIONS FOR PRACTICE: The combination of dabrafenib plus trametinib has demonstrated substantial clinical activity in patients with BRAF V600E-mutant non-small cell lung cancer, leading to U.S. Food and Drug Administration approval. Although the combination has a manageable safety profile, many toxicities associated with the regimen may not be familiar to thoracic specialists or general oncologists. Extensive clinical experience with the combination in patients with metastatic melanoma has provided a wealth of strategies to identify and manage adverse events associated with dabrafenib plus trametinib. These can be used by medical oncologists to enhance early recognition of toxicities and facilitate effective management, thereby improving quality of treatment for patients.

MAPK Pathway-Targeted Therapies: Care and Management of Unique Toxicities in Patients With Advanced Melanoma

BACKGROUND

Agents targeting the MAPK pathway, including inhibitors of BRAF and MEK, have dramatically transformed the treatment landscape for patients with BRAF-mutant metastatic melanoma. Although generally well tolerated, targeted agents were associated with unique toxicities.
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OBJECTIVES

This article aims to provide nurses with an overview of the key toxicities and associated management strategies of the characteristic adverse event (AE) profile associated with agents targeting the MAPK pathway.
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METHODS

Data from clinical trials evaluating vemurafenib, dabrafenib, trametinib, and cobimetinib were reviewed and summarized along with research on management of AEs identified in clinical trials.
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FINDINGS

The key AEs associated with these agents included pyrexia and cutaneous toxicities. Other notable AEs included arthralgias, ocular toxicities, and cardiac events. Because these agents are administered until progressive disease or unacceptable toxicity, nurses should be aware of management strategies to optimize treatment outcomes.

Incidence, course, and management of toxicities associated with cobimetinib in combination with vemurafenib in the coBRIM study

Background

In the coBRIM phase III trial, the addition of cobimetinib, an MEK inhibitor, to vemurafenib, a BRAF inhibitor, significantly improved progression-free survival [hazard ratio (HR), 0.58; P < 0.0001] and overall survival (HR, 0.70; P = 0.005) in advanced BRAF-mutated melanoma. Here, we report on the incidence, course, and management of key adverse events (AEs) in the coBRIM study.

Patients and methods

Patients were randomly assigned 1:1 to receive vemurafenib (960 mg twice a day) and either cobimetinib (60 mg once a day, 21 days on/7 days off) or placebo. In addition to standard safety evaluations, patients underwent regular ophthalmic, cardiac, and dermatologic surveillance examinations.

Results

Of 495 patients recruited to the study, 493 patients received treatment and constituted the safety population (cobimetinib combined with vemurafenib, 247; vemurafenib, 246). At data cut-off (30 September 2015), median follow-up was 18.5 months. Nearly every patient experienced an AE. In patients who received cobimetinib combined with vemurafenib, the frequency of grade ≥3 AEs was higher than in patients who received vemurafenib alone (75% versus 61%). Most AEs, including grade ≥3 AEs, occurred within the first treatment cycle. After the first cycle (28 days), the incidence of common AEs (rash, diarrhoea, photosensitivity, elevated creatine phosphokinase, serous retinopathy, pyrexia, and liver laboratory abnormalities) decreased substantially over time. Most AEs were managed conservatively by supportive care measures, dose modifications of study treatment, and, occasionally, permanent treatment discontinuation.

Conclusions

These data indicate that most AEs arising from treatment with cobimetinib combined with vemurafenib generally occur early in the treatment course, are mild or moderate and are manageable by patient monitoring, dose modification and supportive care.

ClinicalTrials.gov

NCT01689519.

Dabrafenib plus trametinib versus dabrafenib monotherapy in patients with metastatic BRAF V600E/K-mutant melanoma: long-term survival and safety analysis of a phase 3 study

Background

Previous analysis of COMBI-d (NCT01584648) demonstrated improved progression-free survival (PFS) and overall survival (OS) with combination dabrafenib and trametinib versus dabrafenib monotherapy in BRAF V600E/K-mutant metastatic melanoma. This study was continued to assess 3-year landmark efficacy and safety after ≥36-month follow-up for all living patients.

Patients and methods

This double-blind, phase 3 study enrolled previously untreated patients with BRAF V600E/K-mutant unresectable stage IIIC or stage IV melanoma. Patients were randomized to receive dabrafenib (150 mg twice daily) plus trametinib (2 mg once daily) or dabrafenib plus placebo. The primary endpoint was PFS; secondary endpoints were OS, overall response, duration of response, safety, and pharmacokinetics.

Results

Between 4 May and 30 November 2012, a total of 423 of 947 screened patients were randomly assigned to receive dabrafenib plus trametinib (n = 211) or dabrafenib monotherapy (n = 212). At data cut-off (15 February 2016), outcomes remained superior with the combination: 3-year PFS was 22% with dabrafenib plus trametinib versus 12% with monotherapy, and 3-year OS was 44% versus 32%, respectively. Twenty-five patients receiving monotherapy crossed over to combination therapy, with continued follow-up under the monotherapy arm (per intent-to-treat principle). Of combination-arm patients alive at 3 years, 58% remained on dabrafenib plus trametinib. Three-year OS with the combination reached 62% in the most favourable subgroup (normal lactate dehydrogenase and <3 organ sites with metastasis) versus only 25% in the unfavourable subgroup (elevated lactate dehydrogenase). The dabrafenib plus trametinib safety profile was consistent with previous clinical trial observations, and no new safety signals were detected with long-term use.

Conclusions

These data demonstrate that durable (≥3 years) survival is achievable with dabrafenib plus trametinib in patients with BRAF V600-mutant metastatic melanoma and support long-term first-line use of the combination in this setting.

Aberrations and clinical significance of BRAF in malignant melanoma: A series of 60 cases in Chinese Uyghur

Malignant melanoma (MM) is a highly malignant melanocytic tumor, it occurs mostly in the skin, the mucous membrane close to the skin, but also in the tunicae rhagoides and the pia mater. The Uyghur is the largest ethnic group living in the Xinjiang Uyghur Autonomous Region of China, accounting for 46% of the total population of 20 million. Large-scale studies on MMs in Asian countries are limited. This study aimed to investigate BRAF mRNA expression and mutations in Chinese Uyghur patients with MMs and to identify the clinical features associated with these parameters.Formalin-fixed, paraffin wax-embedded tumor sections from 60 MMs were analyzed for BRAF expression using reverse transcription polymerase chain reaction (RT-PCR). Exons 11 and 15 of BRAF were analyzed for the presence of mutations using PCR and DNA sequencing. Sixty MMs were followed by mobile phone for survival analysis.BRAF mRNA expression was higher in MMs than in pigmented moles and normal skin tissues. Fourteen of 60 MMs had BRAF mutations. The frequency of BRAF mutations was significantly higher in patients younger than 60 years (10/28, 4/32, P = .02). A significant difference was observed in the frequency of BRAF mutations among specimens of mucosal, acral, chronic sun-induced damage (CSD), and non-CSD MMs (2/10, 3/19, 8/25, 1/6, P = .002). No significant association was found among BRAF mutations, sex, ulceration, or lymph node metastasis. MMs lymph node metastasis (hazard ratio 2.54 [95% confidence interval 1.062 - 6.066], P = .01) affected survival.This study indicated that BRAF mutations and expression might serve as independent adverse prognostic factors in melanoma.

First-in-Class ERK1/2 Inhibitor Ulixertinib (BVD-523) in Patients with MAPK Mutant Advanced Solid Tumors: Results of a Phase I Dose-Escalation and Expansion Study

Ulixertinib (BVD-523) is an ERK1/2 kinase inhibitor with potent preclinical activity in BRAF- and RAS-mutant cell lines. In this multicenter phase I trial (NCT01781429), 135 patients were enrolled to an accelerated 3 + 3 dose-escalation cohort and six distinct dose-expansion cohorts. Dose escalation included 27 patients, dosed from 10 to 900 mg twice daily and established the recommended phase II dose (RP2D) of 600 mg twice daily. Ulixertinib exposure was dose proportional to the RP2D, which provided near-complete inhibition of ERK activity in whole blood. In the 108-patient expansion cohort, 32% of patients required dose reduction. The most common treatment-related adverse events were diarrhea (48%), fatigue (42%), nausea (41%), and dermatitis acneiform (31%). Partial responses were seen in 3 of 18 (17%) patients dosed at or above maximum tolerated dose and in 11 of 81 (14%) evaluable patients in dose expansion. Responses occurred in patients with NRAS-, BRAF V600-, and non-V600 BRAF-mutant solid tumors.Significance: Here, we describe the first-in-human dose-escalation study of an ERK1/2 inhibitor for the treatment of patients with advanced solid tumors. Ulixertinib has an acceptable safety profile with favorable pharmacokinetics and has shown early evidence of clinical activity in NRAS- and BRAF V600- and non-V600-mutant solid-tumor malignancies. Cancer Discov; 8(2); 184-95. ©2017 AACR.See related commentary by Smalley and Smalley, p. 140This article is highlighted in the In This Issue feature, p. 127.

The safety and efficacy of dabrafenib and trametinib for the treatment of melanoma

INTRODUCTION

The introduction of BRAF and MEK inhibitors into clinical practice improved the prognosis of metastatic melanoma patients. The combination of BRAF inhibitor dabrafenib with MEK inhibitor trametinib has shown its superiority to single agent therapy and is characterized by a tolerable spectrum of adverse events which shows a decrease in incidence over time on treatment. Areas covered: The current scientific literature on safety and adverse events (AEs) related to BRAF and MEK-inhibition has been investigated with special focus on the large phase 3 studies (COMBI-v, COMBI-d and CoBRIM) as well as recent updates presented at oncology and melanoma meetings. Additionally, published case series/case reports were screened for information on AEs. Expert opinion: Even though almost every patient (98%) under combination therapy with dabrafenib and trametinib experiences at least one adverse event, these are generally mild to moderate, reversible and can be managed with dose reductions or interruptions. However, due to an increased life expectancy, there is a substantial need to prevent and treat also mild adverse events, as they play a central role for the quality of life of patients. Ongoing clinical trials will have to demonstrate the efficacy as well as safety of triple combination with anti-PD-1/anti-PD-L1 antibodies.

Practical Recommendations for Therapeutic Drug Monitoring of Kinase Inhibitors in Oncology

Despite the fact that pharmacokinetic exposure of kinase inhibitors (KIs) is highly variable and clear relationships exist between exposure and treatment outcomes, fixed dosing is still standard practice. This review aims to summarize the available clinical pharmacokinetic and pharmacodynamic data into practical guidelines for individualized dosing of KIs through therapeutic drug monitoring (TDM). Additionally, we provide an overview of prospective TDM trials and discuss the future steps needed for further implementation of TDM of KIs.

Meningeal melanomatosis following discontinuation of dabrafenib: implications for the maintenance of long-term complete remission

A subset of 10-20% of patients under continuous BRAF inhibitor monotherapy achieve long-term progression-free and overall survival. Definitive criteria for the safe cessation of BRAF inhibitor monotherapy in treatment-responsive melanoma patients are lacking. We report a patient who remained in complete remission (CR) for 5 years under dabrafenib. The treatment was withdrawn because of concerns about cardiac toxicity. Four months thereafter the patient developed neurological symptoms, including diplopia and bilateral visual loss. Meningeal melanomatosis and parenchymal brain metastases were diagnosed. Extracerebral metastases were excluded. Reinduction of dabrafenib, combined with trametinib, led to the rapid relief of the neurological symptoms, and a partial remission was confirmed radiologically. Unfortunately, the response was not maintained and the patient died 9 months later. This observation demonstrates that discontinuation of BRAF inhibition can result in loss of disease control. On the basis of this observation, we suggest that BRAF-targeted therapy should be withdrawn only when the risks of continued treatment exceed the risk for disease relapse. However, future studies are urgently required to confirm and quantify the risk for rapid disease relapse following withdrawal of BRAF inhibitor monotherapy.

Management of Treatment-Related Adverse Events with Agents Targeting the MAPK Pathway in Patients with Metastatic Melanoma

Tremendous progress has been made in the clinical landscape of advanced-stage BRAF V600-mutant melanoma treatment over the past 5 years. Targeted therapies that inhibit specific steps of the mitogen-activated protein kinase pathway have been shown to provide significant overall treatment benefit in patients with this difficult-to-treat disease. Combination therapy with BRAF and MEK inhibitors (dabrafenib plus trametinib or vemurafenib plus cobimetinib, respectively) has become standard of care. These agents are administered until disease progression or unacceptable toxicity occurs; thus, some patients may remain on maintenance therapy for an extended period of time, while toxicities may result in early discontinuation in other patients. Because the goal of treatment is to prolong survival with minimal impairment of quality of life, drug-related adverse events (AEs) require prompt management to ensure that patients derive the best possible benefit from therapy. Proper management depends on an understanding of which AEs are most likely BRAF or MEK inhibitor associated, thus providing a rationale for dose modification of the appropriate drug. Additionally, the unique safety profile of the chosen regimen may influence patient selection and monitoring. This review discusses the toxicity profiles of these agents, with a focus on the most commonly reported and serious AEs. Here, we offer practical guidance derived from our clinical experience for the optimal management of key drug-related AEs.

IMPLICATIONS FOR PRACTICE

Targeted therapy with BRAF plus MEK inhibitors has become the standard of care for patients with advanced-stage BRAF V600-mutant metastatic melanoma. To provide optimal therapeutic benefit to patients, clinicians need a keen understanding of the toxicity profiles of these drugs. Prompt identification and an understanding of which adverse events are most likely BRAF or MEK inhibitor associated provide a rationale for appropriate therapy adjustments. Practical recommendations derived from clinical experience are provided for management of key drug-related toxicities.

Optimizing combination dabrafenib and trametinib therapy in BRAF mutation-positive advanced melanoma patients: Guidelines from Australian melanoma medical oncologists

BRAF mutations occur commonly in metastatic melanomas and inhibition of mutant BRAF and the downstream kinase MEK results in rapid tumor regression and prolonged survival in patients. Combined therapy with BRAF and MEK inhibition improves response rate, progression free survival and overall survival compared with single agent BRAF inhibition, and reduces the skin toxicity that is seen with BRAF inhibitor monotherapy. However, this combination is associated with an increase in other toxicities, particularly drug-related pyrexia, which affects approximately 50% of patients treated with dabrafenib and trametinib (CombiDT). We provide guidance on managing adverse events likely to arise during treatment with combination BRAF and MEK inhibition with CombiDT: pyrexia, skin conditions, fatigue; and discuss management of CombiDT during surgery and radiotherapy. By improving tolerability and in particular preventing unnecessary treatment cessations or reduction in drug exposure, best outcomes can be achieved for patients undergoing CombiDT therapy.