MiR126-targeted-nanoparticles combined with PI3K/AKT inhibitor as a new strategy to overcome melanoma resistance.

Metastatic melanoma poses significant challenges as a highly lethal disease. Despite the success of molecular targeting using BRAFV600E inhibitors (BRAFis) and immunotherapy, the emergence of early recurrence remains an issue and there is the need for novel therapeutic approaches. This study aimed at creating a targeted delivery system for the oncosuppressor microRNA 126 (miR126) and testing its effectiveness in combination with a phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT) inhibitor for treating metastatic melanoma resistant to BRAFis. To achieve this, we synthesized chitosan nanoparticles containing a chemically modified miR126 sequence. These nanoparticles were further functionalized with an antibody specific to the chondroitin sulfate proteoglycan 4 (CSPG4) melanoma marker. After evaluation in vitro, the efficacy of this treatment was evaluated through an in vivo experiment using mice bearing resistant human melanoma. The co-administration of miR126 and the PI3K/AKT inhibitor in these experiments significantly reduced tumor growth and inhibited the formation of liver and lung metastases. These results provide evidence for a strategy to target an oncosuppressive nucleic acid sequence to tumor cells while simultaneously protecting it from plasma degradation. The system described in this study exhibits encouraging potential for the effective treatment of therapy-resistant metastatic melanoma while also presenting a prospective approach for other forms of cancer.

Adjuvant Systemic Therapies for Resected Stages III and IV Melanoma: A Multi-Center Retrospective Clinical Study.

BACKGROUND: Adjuvant therapies have been approved for resected melanoma based on improved recurrence-free survival. We present early findings from a real-world study on adjuvant treatments for melanoma. METHODS: A comprehensive chart review was conducted for patients receiving adjuvant systemic therapy for resected high-risk stages III and IV melanoma. Statistical analysis was performed to assess recurrence-free survival and subgroup differences. RESULTS: A total of 149 patients (median age = 58.0 years, 61.1% men, 49.7% with BRAF V600E/K genotypes) were included, with 94.6% having resected stage III melanoma. Anti-PD-1 immunotherapy was received by 86.5% of patients, while 13.4% received BRAF-targeted therapy. At a median follow-up of 22.4 months, the recurrence rate was 31.5%, with 1-year and 2-year recurrence-free survival rates of 79% and 62%, respectively. Similar recurrence rates were observed between anti-PD-1 immunotherapy and BRAF-targeted therapy. Long-term toxicity affected 27.4% of patients, with endocrinopathies and late-emergent immune-related adverse events being common. CONCLUSIONS: Real-world adjuvant systemic therapy aligns with clinical trial practice. Recurrence rates remain high despite treatment, and long-term toxicities, including endocrinopathies and chronic inflammatory conditions, are not uncommon.

Five-year analysis of neoadjuvant dabrafenib and trametinib for stage III melanoma.

BACKGROUND: Neoadjuvant dabrafenib plus trametinib has a high pathological response rate and impressive short-term survival in patients with resectable stage III melanoma. We report 5-year outcomes from the phase II NeoCombi trial. PATIENTS AND METHODS: NeoCombi (NCT01972347) was a single-arm, open-label, single-centre, phase II trial. Eligible patients were adults (aged ≥18 years) with histologically confirmed, resectable, RECIST-measurable, American Joint Committee on Cancer seventh edition clinical stage IIIB-C BRAF V600E/K-mutant melanoma and Eastern Cooperative Oncology Group performance status ≤1. Patients received 52 weeks of treatment with dabrafenib 150 mg (orally twice per day) plus trametinib 2 mg (orally once per day), with complete resection of the pre-therapy tumour bed at week 12. RESULTS: Between 20 August 2014 and 19 April 2017, 35 patients were enrolled. At data cut-off (17 August 2021), the median follow-up was 60 months [95% confidence interval (CI) 56-72 months]. Overall, 21 of 35 (60%) patients recurred, including 12 (57%) with first recurrence in locoregional sites (followed by later distant recurrence in 6) and 9 (43%) with first recurrence in distant sites, including 3 in the brain. Most recurrences occurred within 2 years, with no recurrences beyond 3 years. At 5 years, recurrence-free survival (RFS) was 40% (95% CI 27% to 60%), distant metastasis-free survival (DMFS) was 57% (95% CI 42% to 76%), and overall survival was 80% (95% CI 67% to 94%). Five-year survival outcomes were stratified by pathological response: RFS was 53% with pathological complete response (pCR) versus 28% with non-pCR (P = 0.087), DMFS was 59% versus 55% (P = 0.647), and overall survival was 88% versus 71% (P = 0.205), respectively. CONCLUSIONS: Neoadjuvant dabrafenib plus trametinib has high pathological response rates in clinical stage III melanoma, but low rates of RFS, similar to those achieved with adjuvant targeted therapy alone. Patients with a pCR to dabrafenib plus trametinib still had a high risk of recurrence, unlike that seen with immunotherapy where recurrences are rare.

Advances in the management of anaplastic thyroid carcinoma: transforming a life-threatening condition into a potentially treatable disease.

Anaplastic thyroid cancer (ATC) is an infrequent thyroid tumor that usually occurs in elderly patients. There is often a history of previous differentiated thyroid cancer suggesting a biological progression. It is clinically characterized by a locally invasive cervical mass of rapid onset. Metastases are found at diagnosis in 50% of patients. Due to its adverse prognosis, a prompt diagnosis is crucial. In patients with unresectable or metastatic disease, multimodal therapy (chemotherapy and external beam radiotherapy) has yielded poor outcomes with 12-month overall survival of less than 20%. Recently, significant progress has been made in understanding the oncogenic pathways of ATC, leading to the identification of BRAF V600E mutations as the driver oncogene in nearly 40% of cases. The combination of the BRAF inhibitor dabrafenib (D) and MEK inhibitor trametinib (T) showed outstanding response rates in BRAF-mutated ATC and is now considered the standard of care in this setting. Recently, it was shown that neoadjuvant use of DT followed by surgery achieved 24-month overall survival rates of 80%. Although these approaches have changed the management of ATC, effective therapies are still needed for patients with BRAF wild-type ATC, and high-quality evidence is lacking for most aspects of this neoplasia. Additionally, in real-world settings, timely access to multidisciplinary care, molecular testing, and targeted therapies continues to be a challenge. Health policies are warranted to ensure specialized treatment for ATC.The expanding knowledge of ATC´s molecular biology, in addition to the ongoing clinical trials provides hope for the development of further therapeutic options.

Extracellular vesicles promote migration despite BRAF inhibitor treatment in malignant melanoma cells.

Extracellular vesicles (EVs) constitute a vital component of intercellular communication, exerting significant influence on metastasis formation and drug resistance mechanisms. Malignant melanoma (MM) is one of the deadliest forms of skin cancers, because of its high metastatic potential and often acquired resistance to oncotherapies. The prevalence of BRAF mutations in MM underscores the importance of BRAF-targeted therapies, such as vemurafenib and dabrafenib, alone or in combination with the MEK inhibitor, trametinib. This study aimed to elucidate the involvement of EVs in MM progression and ascertain whether EV-mediated metastasis promotion persists during single agent BRAF (vemurafenib, dabrafenib), or MEK (trametinib) and combined BRAF/MEK (dabrafenib/trametinib) inhibition.Using five pairs of syngeneic melanoma cell lines, we assessed the impact of EVs - isolated from their respective supernatants - on melanoma cell proliferation and migration. Cell viability and spheroid growth assays were employed to evaluate proliferation, while migration was analyzed through mean squared displacement (MSD) and total traveled distance (TTD) measurements derived from video microscopy and single-cell tracking.Our results indicate that while EV treatments had remarkable promoting effect on cell migration, they exerted only a modest effect on cell proliferation and spheroid growth. Notably, EVs demonstrated the ability to mitigate the inhibitory effects of BRAF inhibitors, albeit they were ineffective against a MEK inhibitor and the combination of BRAF/MEK inhibitors. In summary, our findings contribute to the understanding of the intricate role played by EVs in tumor progression, metastasis, and drug resistance in MM.

Charge Transfer Copper Chelating Complex and Biogenically Synthesized Copper Oxide Nanoparticles Using Salvia officinalis Laves Extract in Comparative Spectrofluorimetric Estimation of Anticancer Dabrafenib.

Cancer is a broad category of disease that can affect virtually any organ or tissue in the body when abnormal cells grow uncontrollably, invade surrounding tissue, and/or spread to other organs. Dabrafenib is indicated for the treatment of adult patients with advanced non-small cell lung cancer. In the present study, two newly developed spectrofluorimetric probes for the detection of the anticancer drug Dabrafenib (DRF) in its authentic and pharmaceutical products using an ecologically synthesized copper oxide nanoparticle (CuONPs) from Salvia officinalis leaf extract and a copper chelate complex are presented. The first system is based on the influence of the particular optical properties of CuONPs on the enhancement of fluorescence detection. The second system, on the other hand, acts through the formation of a copper charge transfer complex. Various spectroscopic and microscopic studies were performed to confirm the environmentally synthesized CuONPs. The fluorescence detections in the two systems were measured at λex 350 and λem of 432 nm. The results showed the linear concentration ranges for the DRF-CuONPs-SDS and DRF-Cu-SDS complexes were determined to be 1.0-500 ng mL- 1 and 1.0-200 ng mL- 1, respectively. FI = 1.8088x + 21.418 (r = 0.9997) and FI = 2.7536x + 163.37 (r = 0.9989) were the regression equations. The lower detection and quantification limits for the aforementioned fluorescent systems were determined to be 0.4 and 0.8 ng mL- 1 and 1.0 ng mL- 1, respectively. The results also showed that intra-day DRF assays using DRF-CuONPs-SDS and DRF-Cu(NO3)2-SDS systems yielded 0.17% and 0.54%, respectively. However, the inter-day assay results for the above systems were 0.27% and 0.65%, respectively. The aforementioned two systems were effectively used in the study of DRF with excellent percent recoveries of 99.66 ± 0.42% and 99.42 ± 0.56%, respectively. Excipients such as magnesium stearate, titanium dioxide, red iron oxide, and silicon dioxide used in pharmaceutical formulations, as well as various common cations, amino acids, and sugars, had no effect on the detection of compound.

Combined therapy of dabrafenib and an anti-HER2 antibody-drug conjugate for advanced BRAF-mutant melanoma.

BACKGROUND: Melanoma is the most lethal skin cancer characterized by its high metastatic potential. In the past decade, targeted and immunotherapy have brought revolutionary survival benefits to patients with advanced and metastatic melanoma, but these treatment responses are also heterogeneous and/or do not achieve durable responses. Therefore, novel therapeutic strategies for improving outcomes remain an unmet clinical need. The aim of this study was to evaluate the therapeutic potential and underlying molecular mechanisms of RC48, a novel HER2-target antibody drug conjugate, either alone or in combination with dabrafenib, a V600-mutant BRAF inhibitor, for the treatment of advanced BRAF-mutant cutaneous melanoma. METHODS: We evaluated the therapeutic efficacy of RC48, alone or in combination with dabrafenib, in BRAF-mutant cutaneous melanoma cell lines and cell-derived xenograft (CDX) models. We also conducted signaling pathways analysis and global mRNA sequencing to explore mechanisms underlying the synergistic effect of the combination therapy. RESULTS: Our results revealed the expression of membrane-localized HER2 in melanoma cells. RC48 effectively targeted and inhibited the growth of HER2-positive human melanoma cell lines and corresponding CDX models. When used RC48 and dabrafenib synergically induced tumor regression together in human BRAF-mutant melanoma cell lines and CDX models. Mechanically, our results demonstrated that the combination therapy induced apoptosis and cell cycle arrest while suppressing cell motility in vitro. Furthermore, global RNA sequencing analysis demonstrated that the combination treatment led to the downregulation of several key signaling pathways, including the PI3K-AKT pathway, MAPK pathway, AMPK pathway, and FOXO pathway. CONCLUSION: These findings establish a preclinical foundation for the combined use of an anti-HER2 drug conjugate and a BRAF inhibitor in the treatment of BRAF-mutant cutaneous melanoma.

Clinical Pharmacy Initiatives Contribute to the Excellent Efficacy of the Dabrafenib/Trametinib Combination for Iodine-Refractory Thyroid Carcinoma: A Case Report.

A 76-year-old female patient presented with an iodine-refractory papillary thyroid carcinoma (PTC), diagnosed eight years earlier, with several lymph node recurrences requiring successive surgeries. Fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) imaging revealed a new unresectable loco-regional recurrence. The patient was diagnosed with a somatic BRAF V600E mutation. Therefore, dabrafenib and trametinib combination therapy was introduced and closely monitored by a dedicated multidisciplinary team, involving pharmaceutical consultations. As early as six weeks after treatment initiation, the patient reported multiple adverse events (AEs) to the clinical pharmacy team, who provided advice on resolving AEs or improving tolerance. Close interprofessional collaboration among healthcare workers involved in the care pathway allowed for the identification of the most opportune times for temporary suspension of treatment (four suspensions over seven months) or dose reduction (two reductions over 3.5 months). This resulted in a total treatment duration (one year) longer than the average times reported in the literature. The patient showed a rapid and excellent response to treatment immediately after initiation, culminating in a complete metabolic response assessed by [18F]FDG PET/CT imaging at nine months. Twenty-five months after treatment discontinuation, the disease remained controlled. Overall, dabrafenib and trametinib combination could offer excellent outcomes in selected patients with refractory BRAF-mutated PTC, with additional clinical pharmacy initiatives allowing for the optimized management of AEs and prolonged treatment periods.

Targeting of PDGF-C/NRP-1 autocrine loop as a new strategy for counteracting the invasiveness of melanoma resistant to braf inhibitors.

Melanoma resistance to BRAF inhibitors (BRAFi) is often accompanied by a switch from a proliferative to an invasive phenotype. Therefore, the identification of signaling molecules involved in the development of metastatic properties by resistant melanoma cells is of primary importance. We have previously demonstrated that activation of neuropilin-1 (NRP-1) by platelet-derived growth factor (PDGF)-C confers melanoma cells with an invasive behavior similar to that of BRAFi resistant tumors. Aims of the present study were to evaluate the role of PDGF-C/NRP-1 autocrine loop in the acquisition of an invasive and BRAFi-resistant phenotype by melanoma cells and the effect of its inhibition on drug resistance and extracellular matrix (ECM) invasion. Furthermore, we investigated whether PDGF-C serum levels were differentially modulated by drug treatment in metastatic melanoma patients responsive or refractory to BRAFi as single agents or in combination with MEK inhibitors (MEKi). The results indicated that human melanoma cells resistant to BRAFi express higher levels of PDGF-C and NRP-1 as compared to their susceptible counterparts. Overexpression occurs early during development of drug resistance and contributes to the invasive properties of resistant cells. Accordingly, silencing of NRP-1 or PDGF-C reduces tumor cell invasiveness. Analysis of PDGF-C in the serum collected from patients treated with BRAFi or BRAFi+MEKi, showed that in responders PDGF-C levels decrease after treatment and raise again at tumor progression. Conversely, in non-responders treatment does not affect PDGF-C serum levels. Thus, blockade of NRP-1 activation by PDGF-C might represent a new therapeutic approach to counteract the invasiveness of BRAFi-resistant melanoma.

Unusual Adverse Events in a Patient With BRAF-Mutated Non-Small Cell Lung Cancer Treated With BRAF/MEK Inhibition.

BRAF/MEK inhibition remains standard of care for treatment of BRAF-mutated non-small cell lung cancer (NSCLC). Although common adverse events (AEs) have been reported through clinical trials and ongoing clinical practice, only a handful of reports have detailed unusual adverse events associated with these medications. This report presents a patient with BRAF-mutated NSCLC treated with dabrafenib and trametinib who experienced 2 unusual AEs-Sweet syndrome and MEK-associated retinopathy-that responded to steroid treatment. The patient was able to continue BRAF/MEK inhibition through a coordinated multidisciplinary approach. This case highlights the importance for all clinicians to recognize unusual AEs associated with BRAF/MEK inhibition, particularly in the setting of expanded use for all BRAF V600E-mutated solid tumors.

Hairy Cell Leukemia: Where Are We in 2023?

PURPOSE OF REVIEW: This article summarizes the current state of knowledge of hairy cell leukemia (HCL) regarding presentation, diagnosis, therapy, and monitoring, including perspectives on emergent therapies. RECENT FINDINGS: Over the past decade, there has been enormous progress in the understanding of the biology of HCL which has led to the development of novel therapeutic strategies. The maturation of data regarding existing management strategies has also lent considerable insight into therapeutic outcomes and prognosis of patients treated with chemo- or chemoimmunotherapy. Purine nucleoside analogs remain the cornerstone of treatment, and the addition of rituximab has deepened and prolonged responses in the upfront and relapsed setting. Targeted therapies now have a more defined role in the management of HCL, with BRAF inhibitors now having a potential in the first-line setting in selected cases as well as in relapse. Next-generation sequencing for the identification of targetable mutations, evaluation of measurable residual disease, and risk stratification continue to be areas of active investigation. Recent advances in HCL have led to more effective therapeutics in the upfront and relapsed setting. Future efforts will focus on identifying patients with high-risk disease who require intensified regimens. Multicenter collaborations are the key to improving overall survival and quality of life in this rare disease.

Case report: Drug-induced vitiligo during treatment with BRAF/MEK inhibitors in a patient with metastatic conjunctival melanoma.

INTRODUCTION: Autoimmune side effects can be detected during the use of BRAF/MEK inhibitor. Although its frequency, mechanism and importance are not known exactly, there are cases reported in the literature. CASE REPORT: We report a case of drug-induced vitiligo in a patient with metastatic conjunctival malignant melanoma who was treated with BRAF/MEK inhibition therapy. MANAGEMENT AND OUTCOME: In the case, vitiligo was controlled with topical treatments. Follow-up process of the patient has been continuing with no progression on month 12 of the current treatment. DISCUSSION: Although ICI-related autoimmune side effects and vitiligo have been described more frequently, vitiligo may also occur secondary to BRAK/MEK inhibition. This case also points out that cutaneous toxicity is manageable with no delay in treatment thanks to collaboration of dermatologists and oncologists.

Extemporaneous compounding of dabrafenib and trametinib for cancer patients with feeding tubes.

INTRODUCTION: Dabrafenib and trametinib are oral targeted agents indicated for BRAF mutated non-small cell lung cancer and melanoma. There is little data to support the administration of these two agents via enteral feeding tube. This case series describes three patients who received compounded dabrafenib and trametinib suspensions through enteral feeding tubes. CASE REPORT: We present three patients who required dabrafenib and trametinib to be prepared as a non-standard compound for the medications to be administered via feeding tube. The patients were diagnosed with with BRAF mutated cancers including melanoma, non-small-cell lung carcinoma, and anaplastic thyroid cancer. In all three cases, there was evidence of initial disease response on imaging, and there were no unexpected toxicities secondary to dabrafenib and trametinib. DISCUSSION: There are patients that are unable to tolerate medications by mouth due to dysphagia, anatomical malfunctions, or other digestive disorders. There is limited literature that describes preparation of trametinib and dabrafenib into an enteral suspension. Identifying a safe and efficacious method of administering these two medications via feeding tube ensures that these patients continue to be able to receive them as part of their anti-cancer therapy. CONCLUSION: Despite the lack of available data, compounding of dabrafenib and trametinib may be clinically appropriate when benefits outweigh the risk of unconventional administration. Further studies are warranted to assess for the pharmacokinetics, pharmacodynamics, stability, and storage for these liquid medications.

The Cytoprotective Role of Autophagy in Response to BRAF-Targeted Therapies.

BRAF-targeted therapies are widely used for the treatment of melanoma patients with BRAF V600 mutations. Vemurafenib, dabrafenib as well as encorafenib have demonstrated substantial therapeutic activity; however, as is the case with other chemotherapeutic agents, the frequent development of resistance limits their efficacy. Autophagy is one tumor survival mechanism that could contribute to BRAF inhibitor resistance, and multiple studies support an association between vemurafenib-induced and dabrafenib-induced autophagy and tumor cell survival. Clinical trials have also demonstrated a potential benefit from the inclusion of autophagy inhibition as an adjuvant therapy. This review of the scientific literature relating to the role of autophagy that is induced in response to BRAF-inhibitors supports the premise that autophagy targeting or modulation could be an effective adjuvant therapy.

Efficacy of Dabrafenib and Trametinib in a Patient with Squamous-Cell Carcinoma, with Mutation p.D594G in BRAF and p.R461* in NF1 Genes-A Case Report with Literature Review.

The 3rd class of BRAF (B-Raf Proto-Oncogene, Serine/Threonine Kinase) variants including G466, D594, and A581 mutations cause kinase death or impaired kinase activity. It is unlikely that RAF (Raf Proto-Oncogene, Serine/Threonine Kinase) inhibitors suppress ERK (Extracellular Signal-Regulated Kinase) signaling in class 3 mutant-driven tumors due to the fact that they preferentially inhibit activated BRAF V600 mutants. However, there are suggestions that class 3 mutations are still associated with enhanced RAS/MAPK (RAS Proto-Oncogene, GTPase/Mitogen-Activated Protein Kinase) activation, potentially due to other mechanisms such as the activation of growth factor signaling or concurrent MAPK pathway mutations, e.g., RAS or NF1 (Neurofibromin 1). A 75-year-old male patient with squamous-cell cancer (SqCC) of the lung and with metastases to the kidney and mediastinal lymph nodes received chemoimmunotherapy (expression of Programmed Cell Death 1 Ligand 1 (PD-L1) on 2% of tumor cells). The chemotherapy was limited due to the accompanying myelodysplastic syndrome (MDS), and pembrolizumab monotherapy was continued for up to seven cycles. At the time of progression, next-generation sequencing was performed and a c.1781A>G (p.Asp594Gly) mutation in the BRAF gene, a c.1381C>T (p.Arg461Ter) mutation in the NF1 gene, and a c.37C>T (p.Gln13Ter) mutation in the FANCC gene were identified. Combined therapy with BRAF (dabrafenib) and MEK (trametinib) inhibitors was used, which resulted in the achievement of partial remission of the primary lesion and lung nodules and the stabilization of metastatic lesions in the kidney and bones. The therapy was discontinued after five months due to myelosuppression associated with MDS. The molecular background was decisive for the patient's fate. NSCLC patients with non-V600 mutations in the BRAF gene rarely respond to anti-BRAF and anti-MEK therapy. The achieved effectiveness of the treatment could be related to a mutation in the NF1 tumor suppressor gene. The loss of NF1 function causes the excessive activation of KRAS and overactivity of the signaling pathway containing BRAF and MEK, which were the targets of the therapy. Moreover, the mutation in the FANCC gene was probably related to MDS development. The NGS technique was crucial for the qualification to treatment and the prediction of the NSCLC course in our patient. The mutations in two genes­the BRAF oncogene and the NF1 tumor suppressor gene­were the reason for the use of dabrafenib and trametinib treatment. The patients achieved short-term disease stabilization. This proved that coexisting mutations in these genes affect the disease course and treatment efficacy.

Dabrafenib plus trametinib in patients with BRAF V600E-mutant anaplastic thyroid cancer: updated analysis from the phase II ROAR basket study.

BACKGROUND: Combined therapy with dabrafenib plus trametinib was approved in several countries for treatment of BRAF V600E-mutant anaplastic thyroid cancer (ATC) based on an earlier interim analysis of 23 response-assessable patients in the ATC cohort of the phase II Rare Oncology Agnostic Research (ROAR) basket study. We report an updated analysis describing the efficacy and safety of dabrafenib plus trametinib in the full ROAR ATC cohort of 36 patients with ∼4 years of additional study follow-up. PATIENTS AND METHODS: ROAR (NCT02034110) is an open-label, nonrandomized, phase II basket study evaluating dabrafenib plus trametinib in BRAF V600E-mutant rare cancers. The ATC cohort comprised 36 patients with unresectable or metastatic ATC who received dabrafenib 150 mg twice daily plus trametinib 2 mg once daily orally until disease progression, unacceptable toxicity, or death. The primary endpoint was investigator-assessed overall response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1. Secondary endpoints were duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. RESULTS: At data cutoff (14 September 2020), median follow-up was 11.1 months (range, 0.9-76.6 months). The investigator-assessed ORR was 56% (95% confidence interval, 38.1% to 72.1%), including three complete responses; the 12-month DOR rate was 50%. Median PFS and OS were 6.7 and 14.5 months, respectively. The respective 12-month PFS and OS rates were 43.2% and 51.7%, and the 24-month OS rate was 31.5%. No new safety signals were identified with additional follow-up, and adverse events were consistent with the established tolerability of dabrafenib plus trametinib. CONCLUSIONS: These updated results confirm the substantial clinical benefit and manageable toxicity of dabrafenib plus trametinib in BRAF V600E-mutant ATC. Dabrafenib plus trametinib notably improved long-term survival and represents a meaningful treatment option for this rare, aggressive cancer.

Characteristics and Treatment Outcomes of Pediatric Langerhans Cell Histiocytosis with Thymic Involvement.

OBJECTIVE: To evaluate the characteristics and treatment outcomes of patients with pediatric Langerhans cell histiocytosis (LCH) with thymic involvement. STUDY DESIGN: We retrospectively described the clinical, biological, and imaging characteristics of a series of 19 patients with pediatric LCH with thymic involvement in our center between September 2016 and December 2019. We further analyzed the treatment response and outcomes of patients treated with chemotherapy or targeted therapy. RESULTS: Thymic involvement was found in 4.4% of a 433-consecutive pediatric LCH cohort; all LCH-thymic involvement presented with multisystem disease. Patients with thymic involvement were typically younger, harboring more lung and thyroid involvement and less bone involvement than those without thymic involvement. Most patients with thymic involvement had alteration of immunocompetence with decreased numbers of T-lymphocyte subsets and immunoglobulin G levels. Overall, 47.1% of patients demonstrated a response after 6 weeks of induction therapy, and 92.3% of the patients who did not respond to the first-line treatment had resolution of thymus after the second-line and/or targeted therapy. The progression/relapse rate showed no difference between patients who shifted to second-line therapy and those to dabrafenib (33.3% vs 25%, P = 1.000). The survival for patients with thymic involvement did not differ from those without thymic involvement. More patients treated with second-line chemotherapy had severe adverse events than those given dabrafenib (88.9% vs 0, P < .001). CONCLUSIONS: Thymic involvement was observed rarely in LCH and had specific clinical characteristics. Chemotherapy could resolve most thymic lesions, and BRAF inhibitors might provide a promising treatment option with less toxicity for infants with BRAF-V600E mutation. TRIAL REGISTRATION: http://www.chictr.org.cn, identifier: ChiCTR2000030457 (BCH-LCH 2014 study); ChiCTR2000032844 (dabrafenib study).

Targeting wild-type TP53 using AMG 232 in combination with MAPK inhibition in Metastatic Melanoma; a phase 1 study.

BACKGROUND: Targeting the MDM2-p53 interaction using AMG 232 is synergistic with MAPK inhibitors (MAPKi) in preclinical melanoma models. We postulated that AMG 232 plus MAPKi is safe and more effective than MAPKi alone in TP53-wild type, MAPKi-naïve metastatic melanoma. METHODS: Patients were treated with increasing (120 mg, 180 mg, 240 mg) oral doses of AMG 232 (seven-days-on, 15-days-off, 21-day cycle) plus dabrafenib (D) and trametinib (T) (Arm 1, BRAFV600-mutant) or T alone (Arm 2, BRAFV600-wild type). Patients were treated for seven days with AMG 232 alone before adding T±D. Safety and efficacy were assessed using CTCAE v4.0 and RECIST v1.1 criteria, respectively. Pharmacokinetic (PK) analysis was performed at baseline and steady-state levels for AMG 232. RESULTS: 31 patients were enrolled. Ten and 21 patients were enrolled in Arm 1 and Arm 2, respectively. The most common AMG 232-related adverse events (AEs) were nausea (87%), diarrhea (77%), and fatigue (74%). Seven patients (23%) were withdrawn from the study due to AMG 232-related AEs. Three dose-limiting AEs occurred (Arm 1, 180 mg, nausea; Arm 2, 240 mg, grade 3 pulmonary embolism; Arm 2, 180 mg, grade 4 thrombocytopenia). AMG 232 PK exposures were not altered when AMG 232 was combined with T±D. Objective responses were seen in 8/10 (Arm 1) and 3/20 (Arm 2) evaluable patients. The median progression-free survival for Arm 1 and Arm 2 was 19.0 months-not reached and 2.8 months, respectively. CONCLUSION: The maximum tolerated dose of AMG 232 for both arms was 120 mg. AMG 232 plus T±D exhibited a favorable PK profile. Although objective responses occurred in both arms, adding AMG 232 to T±D did not confer additional clinical benefit.

Dabrafenib inhibits ABCG2 and cytochrome P450 isoenzymes; potential implications for combination anticancer therapy.

Dabrafenib is a BRAF inhibitor used in combination treatment of malignant melanoma and non-small cell lung carcinoma. In this study, we aimed to characterize its interactions with cytochrome P450 (CYP) isoenzymes and ATP-binding cassette (ABC) efflux transporters that have critical impact on the pharmacokinetics of drugs and play a role in drug resistance development. Using accumulation assays, we showed that dabrafenib inhibited ABCG2 and, less potently, ABCB1 transporter. We also confirmed dabrafenib as a CYP2C8, CYP2C9, CYP3A4, and CYP3A5 inhibitor. Importantly, inhibition of ABCG2 and CYP3A4 by dabrafenib led to the potentiation of cytotoxic effects of mitoxantrone and docetaxel toward respective resistant cell lines in drug combination studies. On the contrary, the synergistic effect was not consistently observed in ABCB1-expressing models. We further demonstrated that mRNA levels of ABCB1, ABCG2, ABCC1, and CYP3A4 were increased after 24 h and 48 h exposure to dabrafenib. Overall, our data confirm dabrafenib as a drug frequently and potently interacting with ABC transporters and CYP isoenzymes. This feature should be addressed with caution when administering dabrafenib to patients with polypharmacy but also could be utilized advantageously when designing new dabrafenib-containing drug combinations to improve the therapeutic outcome in drug-resistant cancer.

First-line pembrolizumab versus dabrafenib/trametinib treatment for BRAF V600-mutant advanced melanoma.

BACKGROUND: Limited data are available to assist the selection between immune checkpoint inhibitors and BRAF/mitogen-activated protein kinase kinase inhibitors as first-line treatment for patients with BRAF-mutant advanced malignant melanoma. OBJECTIVE: To investigate the outcomes associated with first-line pembrolizumab or dabrafenib/trametinib treatment for advanced melanoma with activating BRAF V600 mutation. METHODS: Data of patients with BRAF V600-mutant melanoma who were treated with first-line pembrolizumab (n = 40) or dabrafenib/trametinib (n = 32) were analyzed. Tumor response, progression-free survival, and overall survival were evaluated. Immune evasion accompanied with emerging resistance to BRAF/mitogen-activated protein kinase kinase inhibitors was assessed. RESULTS: A longer overall survival was observed after first-line pembrolizumab treatment than after first-line dabrafenib/trametinib treatment (hazard ratio = 2.910, 95% CI: 1.552-5.459), although there were no significant differences in progression-free survival (P = .375) and response rate (P = .123). Emergence of resistance to dabrafenib/trametinib co-occurred with immune evasion, enabling melanoma cells to escape recognition and killing by Melan-A-specific CD8+ T cells. LIMITATIONS: Analysis was conducted in a retrospective manner. CONCLUSION: Pembrolizumab may be recommended over BRAF/mitogen-activated protein kinase kinase inhibitors as the first-line treatment in patients with advanced BRAF V600-mutant melanoma.