Vemurafenib plus cobimetinib in unresectable stage IIIc or stage IV melanoma: response monitoring and resistance prediction with positron emission tomography and tumor characteristics (REPOSIT): study protocol of a phase II, open-label, multicenter study

Baseline and on Treatment Biodistribution Variability of 18 F-FLT Uptake in Patients With Advanced Melanoma: Brief Communication

PURPOSE

This prospective study evaluates the biodistribution of 18 F-FLT PET in patients with advanced melanoma before and after treatment with BRAF/MEK inhibitors.

PATIENTS AND METHODS

Eighteen BRAF-positive unresectable stage IIIc or IV melanoma patients referred for 18 F-FLT PET/CT before (BL) and during (D14) BRAF/MEK inhibition were included. 18 F-FLT accumulation in the liver, bone marrow, blood, and muscle was quantified.

RESULTS

Baseline interpatient 18 F-FLT uptake had a coefficient-of-variation between 17.5% and 21.5%. During treatment, liver uptake increased (SUV meanBL = 4.86 ± 0.98, SUV meanD14 = 6.31 ± 1.36, P < 0.001) and bone marrow uptake decreased (SUV meanBL = 7.67 ± 1.65, SUV meanD14 = 6.78 ± 1.19, P < 0.025). Both changes were unrelated to baseline metabolic tumor volume or tumor response.

CONCLUSIONS

To assess 18 F-FLT PET, both liver and bone marrow uptake may be used as normal tissue references at baseline, but 18 F-FLT biodistribution significantly changes in longitudinal response studies when treated with BRAF/MEK inhibitors.

The Predictive Value of FDG PET/CT for Determining Progression-Free Survival in Advanced Stage III-IV BRAF -Mutated Melanoma Patients Treated With Targeted Therapy-What Can Be Learned From Progression?

PURPOSE

The aims of this study were to investigate whether (early) PERCIST response monitoring with 18 F-FDG PET/CT is predictive for progression-free survival (PFS) in unresectable stage III or IV melanoma patients treated with BRAF/MEK inhibitor (MEKi) and to define dissemination patterns at progression with a lesion-based evaluation in direct comparison to baseline to improve our understanding of 18 F-FDG PET/CT during BRAF/MEKi.

PATIENTS AND METHODS

This prospective multicenter single-arm study included 70 patients with unresectable stage III/IV BRAF -mutated melanoma who underwent contrast-enhanced CT and 18 F-FDG PET/CT at baseline and 2 and 7 weeks during treatment with vemurafenib plus cobimetinib and at progression if possible. Tumor response assessment was done with RECIST1.1 and PERCIST. Follow-up PET/CT scans were visually compared with baseline to assess dissemination patterns.

RESULTS

Using RECIST1.1, PFS was not significantly different between the response groups ( P = 0.26). At 2 weeks, PERCIST median PFS was 15.7 months for patients with complete metabolic response (CMR) versus 8.3 months for non-CMR ( P = 0.035). The hazards ratio (HR) for progression/death in non-CMR versus CMR was 1.99 (95% confidence interval [CI], 1.03-3.84; P = 0.040) and 1.77 (95% CI, 0.91-3.43; P = 0.0935) when adjusting for lactate dehydrogenase (LDH). At 7 weeks, median PFS for PERCIST CMR was 16.7 months versus 8.5 months for non-CMR ( P = 0.0003). The HR for progression/death in the non-CMR group was significantly increased (HR, 2.94; 95% CI, 1.60-5.40; P = 0.0005), even when adjusting for LDH (HR, 2.65; 95% CI, 1.43-4.91; P = 0.0020). At week 7, 18 F-FDG PET/CT was false-positive in all 4 (6%) patients with new FDG-avid lesions but CMR of known metastases. When 18 F-FDG PET/CT was performed at progressive disease, 18/22 (82%) patients had progression of known metastases with or without new 18 F-FDG-avid lesions.

CONCLUSIONS

This study shows that PERCIST response assessment at week 7 is predictive for PFS, regardless of LDH. At 2 weeks, patients with CMR have longer PFS than patients with non-CMR, but different PET parameters should be investigated to further evaluate the added value of early 18 F-FDG PET/CT. Disease progression on PET/CT is predominated by progression of known metastases, and new 18 F-FDG-avid lesions during BRAF/MEKi are not automatically a sign of recurrent disease.

Promising and Minimally Invasive Biomarkers: Targeting Melanoma

The therapeutic landscape of malignant melanoma has been radically reformed in recent years, with novel treatments emerging in both the field of cancer immunotherapy and signalling pathway inhibition. Large-scale tumour genomic characterization has accurately classified malignant melanoma into four different genomic subtypes so far. Despite this, only somatic mutations in BRAF oncogene, as assessed in tumour biopsies, has so far become a validated predictive biomarker of treatment with small molecule inhibitors. The biology of tumour evolution and heterogeneity has uncovered the current limitations associated with decoding genomic drivers based only on a single-site tumour biopsy. There is an urgent need to develop minimally invasive biomarkers that accurately reflect the real-time evolution of melanoma and that allow for streamlined collection, analysis, and interpretation. These will enable us to face challenges with tumour tissue attainment and process and will fulfil the vision of utilizing "liquid biopsy" to guide clinical decisions, in a manner akin to how it is used in the management of haematological malignancies. In this review, we will summarize the most recent published evidence on the role of minimally invasive biomarkers in melanoma, commenting on their future potential to lead to practice-changing discoveries.

Cannabinoids in the management of behavioral, psychological, and motor symptoms of neurocognitive disorders: a mixed studies systematic review

Aim

We undertook this systematic review to determine the efficacy and safety of cannabis-based medicine as a treatment for behavioral, psychological, and motor symptoms associated with neurocognitive disorders.

Methods

We conducted a PRISMA-guided systematic review to identify studies using cannabis-based medicine to treat behavioral, psychological, and motor symptoms among individuals with Alzheimer's disease (AD) dementia, Parkinson’s disease (PD), and Huntington’s disease (HD). We considered English-language articles providing original data on three or more participants, regardless of design.

Findings

We identified 25 studies spanning 1991 to 2021 comprised of 14 controlled trials, 5 pilot studies, 5 observational studies, and 1 case series. In most cases, the cannabinoids tested were dronabinol, whole cannabis, and cannabidiol, and the diagnoses included AD (n = 11), PD (n = 11), and HD (n = 3). Primary outcomes were motor symptoms (e.g., dyskinesia), sleep disturbance, cognition, balance, body weight, and the occurrence of treatment-emergent adverse events.

Conclusions

A narrative summary of the findings from the limited number of studies in the area highlights an apparent association between cannabidiol-based products and relief from motor symptoms in HD and PD and an apparent association between synthetic cannabinoids and relief from behavioral and psychological symptoms of dementia across AD, PD, and HD. These preliminary conclusions could guide using plant-based versus synthetic cannabinoids as safe, alternative treatments for managing neuropsychiatric symptoms in neurocognitive vulnerable patient populations.

Rapid recovery of postnivolumab vemurafenib-induced Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome after tocilizumab and infliximab administration

Background

Immune checkpoint inhibitors such as nivolumab and targeted BRAF inhibitors have dramatically altered the treatment outcomes of metastatic melanoma over the past few years. Skin toxicity is the most common adverse event (AE) related to the commonly used BRAF inhibitor vemurafenib, affecting more than 90% of patients. Vemurafenib-related severe AEs with early onset are reported in patients who were previously treated with anti-programmed cell death-1 (anti PD-1) antibodies. A prolonged administration of systemic steroids is the first-line treatment of severe or life-threatening AEs. We report the case of a woman suffering from vemurafenib-related severe, rapidly worsening Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome, resolved in a few hours after single-dose administration of a combination of TNF-α antagonist infliximab with interleukin (IL)-6 receptor antagonist tocilizumab.

Case presentation

A 41-year-old woman treated with single-agent nivolumab presented with a melanoma progression. Biopsy samples were revised, revealing a BRAF V600E mutation. The patient was started on vemurafenib and cobimetinib treatment only 10 days after the last administration of nivolumab. On the third day of anti-BRAF therapy, profound lymphopenia was detected, and maculopapular eruption appeared afterward. Subsequently, the clinical conditions deteriorated further, and the woman was admitted on an emergency basis with high fever, respiratory and cardiocirculatory failure, diffuse rash, generalized edema, and lymphadenopathy. Diagnosis of DRESS syndrome with overexpressed capillary leakage was made. A single dose of tocilizumab was administered with an improvement of cardiocirculatory and renal function in a few hours. Because of worsening of liver function, skin lesions and mucositis, a single dose of infliximab was prescribed, and dramatic improvement was noted over the next 24 hours. Dabrafenib and trametinib were initiated, and coinciding with washout of infliximab from the patient’s blood, the drug toxicity recurred.

Conclusion

Anti-IL-6 and anti-TNF-α target treatment of very severe AEs may afford an immediate resolution of potentially life-threatening symptoms and reduce the duration and the costs of hospitalization. Maintenance of therapeutic infliximab blood concentrations permits an early switch to dabrafenib after vemurafenib-related AEs.

FLT-PET At 6 Weeks Predicts Response Assessed by CT at 12 Weeks in Melanoma Patients Treated With Pembrolizumab

PURPOSE

Investigate the ability of F-fluorothymidine (FLT) PET combined with CT at 6 weeks to predict treatment response at 12 weeks after treatment with pembrolizumab.

METHODS

Five patients with unresectable stage IV melanoma were included in this single-institution pilot study. Patients underwent FLT-PET/CT (baseline and 6 weeks) and CT (baseline and 12 weeks). FLT-PET/CT response and CT response were assessed using PET Response Criteria in Solid Tumors and immune Response Evaluation Criteria in Solid Tumors, respectively. Patients were categorized as responders (complete response, partial response) and nonresponders (stable disease, progressive disease). Agreement between 6-week FLT-PET/CT and 12-week CT was calculated using Cohen kappa's agreement. Eight baseline FLT-PET/CT parameters were extracted: SUVmax, SUVpeak, SUVSD, SUVmean, proliferative tumor volume, total lesion proliferation, bone marrow-to-liver SUVmax ratio, and spleen-to-liver SUVmax ratio. Eight delta-parameters were extracted at 6 weeks by calculating variation in FLT uptake as percentage change from baseline.

RESULTS

Agreement between 6-week FLT-PET/CT and 12-week CT was kappa = 0.615, P = 0.025. Three of 5 patients were categorized as responders on CT by immune Response Evaluation Criteria in Solid Tumors. At baseline, responders had a lower mean proliferative tumor volume and a higher bone marrow-to-liver SUVmax ratio. At 6 weeks, responders demonstrated a decrease in tumor volume and tumor proliferation.

CONCLUSIONS

Our study illustrates the potential for FLT-PET/CT as an early predictor of response for patients with metastatic melanoma on anti-PD1 immunotherapy. Larger studies are indicated to confirm these findings.

Is single versus combination therapy problematic in the treatment of cutaneous melanoma?

Introduction: The development of immunotherapies and targeted therapies has changed the treatment approach in resectable, nonresectable, and metastatic melanoma. Because of their different pharmacological profiles, immunotherapies and/or targeted therapies have been studied in various combinations. Areas covered: We reviewed PubMed for most important clinical trials investigating efficacy and tolerability of combinatorial and single-agent approaches for the treatment of melanoma that were published up to June 2019. We discuss the most promising therapy approaches and highlight challenges of melanoma treatment. Expert opinion: Combinatorial approaches seem to be very promising in the treatment of resectable and advanced melanoma. Currently, dual immune checkpoint inhibition (ICI) with nivolumab and ipilimumab offers the best first-line treatment option for patients with BRAF-wt and -mutated, advanced melanoma. It is therapy of choice in younger patients with good ECOG performance status and poor prognostic features, whereas ICI monotherapy should be preferred in elderly patients with advanced melanoma. Benefit-risk ratio, patient's QoL and expectations, as well as treatment costs have to be considered in the choice of treatment. However, to elucidate mechanisms of resistance, biomarkers of response and to better define personalized strategies in the treatment of cutaneous melanoma, larger clinical trials comparing combined versus sequential therapies are necessary.

Utility of PET/CT in patients with stage I-III melanoma

PURPOSE

To study the utility of positron emission tomography with computerized tomography (PET/CT) in patients with a stage I-III melanoma.

PATIENTS AND METHODS

PET/CT findings from all patients with a stage I-III melanoma attended at our hospital from September 2011 to November 2015 were reviewed.

RESULTS

Data from 83 patients with a stage I-III melanoma, 39 patients with a positive sentinel lymph node biopsy (SLNB) and 35 patients with locoregional recurrences were analyzed. Sensitivity of PET/CT in clinical stage I-III patients was 5%, with a 14% of false positives. In patients with a positive SLNB, PET/CT previous to complete lymph node dissection had a 23% of false negatives. In patients with clinical locoregional recurrences, PET/CT findings revealed asymptomatic visceral distant metastasis in 25.7%.

CONCLUSIONS

PET/CT has a significant rate of false positive and negative results in patients with a stage I-III melanoma. Utility in patients with nodal locoregional recurrences seems higher than in patients with skin metastases.

MicroRNA-3662 targets ZEB1 and attenuates the invasion of the highly aggressive melanoma cell line A375

Background

Cutaneous melanoma is the most aggressive form of skin cancer. It accounts for approximately 5% of all cutaneous malignancies and is currently responsible for the majority of skin cancer-related deaths. However, the exact mechanisms responsible for the occurrence of melanoma, in particular the invasive growth in normal skin or muscle tissue, remain unknown.

Materials and methods

miR-3662, a microRNA is a potential tumor suppressor targeting zinc finger E-box binding homeobox 1 (ZEB1), which functions as a key regulator of the epithelial-mesenchymal transition (EMT) process. This microRNA was identified using an online database (miRDB) and expression was confirmed by Western blot analysis. Quantitative polymerase chain reaction (qPCR) was used to examine whether miR-3662 inhibits the EMT process in the aggressive melanoma cell line, A375, through the modification of the expression of invasion-related genes in A375 cells. The effects of miR-3662 on the in vivo growth of A375 cells were examined in a nude mouse model.

Results

Using virtual screening of the miRDB database, miR-3662 was shown to target the 3ʹ untranslated region (UTR) of the ZEB1 gene. Expression of miR-3662 via a lentivirus vector significantly decreased protein levels of ZEB1 and inhibited the growth of A375 cells in vitro and in vivo. The reduction in ZEB1 expression induced by miR-3662 resulted in EMT inhibition in A375 cells and decreased the relative expression of metastasis genes.

Conclusion

Down-regulation of ZEB1’s expression via miR-3662 lentivirus vectors significantly decreased the in vitro and in vivo growth of the highly aggressive melanoma cell line A375.

Evaluation of the Performance of 18F-Fluorothymidine Positron Emission Tomography/Computed Tomography (18F-FLT-PET/CT) in Metastatic Brain Lesions

18F-fluorothymidine (18F-FLT) is a radiolabeled thymidine analog that has been reported to help monitor tumor proliferation and has been studied in primary brain tumors; however, knowledge about 18F-FLT positron emission tomography/computed tomography (PET/CT) in metastatic brain lesions is limited. The purpose of this study is to evaluate the performance of 18F-FLT-PET/CT in metastatic brain lesions. A total of 20 PET/CT examinations (33 lesions) were included in the study. Semiquantitative analysis was performed: standard uptake value (SUV) with the utilization of SUVmax, tumor-to-background ratio (T/B), SUVpeak, SUV1cm³, SUV0.5cm³, SUV50%, SUV75%, PV50% (volume × SUV50%), and PV75% (volume × SUV75%) were calculated. Sensitivity, specificity, and accuracy for each parameter were calculated. Optimal cutoff values for each parameter were obtained. Using a receiver operating characteristic (ROC) curve analysis, the optimal cutoff values of SUVmax, T/B, and SUVpeak for discriminating active from non-active lesions were found to be 0.615, 4.21, and 0.425, respectively. In an ROC curve analysis, the area under the curve (AUC) is higher for SUVmax (p-value 0.017) compared to the rest of the parameters, while using optimal cutoff T/B shows the highest sensitivity and accuracy. PVs (proliferation × volumes) did not show any significance in discriminating positive from negative lesions. 18F-FLT-PET/CT can detect active metastatic brain lesions and may be used as a complementary tool. Further investigation should be performed.

BRAF kinase inhibitors for treatment of melanoma: developments from early-stage animal studies to Phase II clinical trials

INTRODUCTION

Approximately, 30.4-66.0% of cutaneous melanomas possess a mutation in the BRAF gene that activates downstream signaling through the mitogen-activated protein (MAP) kinase pathway; this provides an attractive target for the treatment of advanced melanoma. Although BRAF inhibitors rapidly suppress melanoma growth, median progression-free survival remains unsatisfactory. Recent clinical trials have investigated drugs that can optimally enhance and prolong the anti-melanoma effects of BRAF inhibitors.

AREAS COVERED

This review discusses the development of BRAF inhibitor-based combination therapies for BRAF-mutant advanced melanoma.

EXPERT OPINION

Future strategies for the treatment of advanced melanoma include novel combination therapies using BRAF/MEK inhibitors and immune checkpoints inhibitors or histone deacetylase inhibitors. These combination therapies might enhance antitumor responses against melanoma, prolonging survival in advanced melanoma patients. Further clinical studies are needed to optimize these novel combination therapies.