Intradermal Naked DNA Vaccination by DNA Tattooing for Mounting Tumor-Specific Immunity in Stage IV Melanoma Patients: A Phase I Clinical Trial.

INTRODUCTION: Naked DNA vaccination could be a powerful and safe strategy to mount antigen-specific cellular immunity. We designed a phase I clinical trial to investigate the toxicity of naked DNA vaccines encoding CD8+ T-cell epitope from tumor-associated antigen MART-1 in patients with advanced melanoma. METHODS: This dose escalating phase Ia clinical trial investigates the toxicity and immunological response upon naked DNA vaccines encoding a CD8+ T-cell epitope from the tumor-associated antigen MART-1, genetically linked to the gene encoding domain 1 of subunit-tetanus toxin fragment C in patients with advanced melanoma (inoperable stage IIIC-IV, AJCC 7th edition). The vaccine was administrated via intradermal application using a permanent make-up or tattoo device. Safety was monitored according to CTCAE v.3.0 and skin biopsies and blood samples were obtained for immunologic monitoring. RESULTS: Nine pretreated, HLA-A*0201-positive patients with advanced melanoma expressing MART-1 and MHC class I, with a good performance status, and adequate organ function, were included. With a median follow-up of 5.9 months, DNA vaccination was safe, without treatment-related deaths. Common treatment-emergent adverse events of any grade were dermatologic reactions at the vaccination site (100%) and pain (56%). One patient experienced grade 4 toxicity, most likely related to tumor progression. One patient (11%) achieved stable disease, lasting 353 days. Immune analysis showed no increase in vaccine-induced T cell response in peripheral blood of 5 patients, but did show a MART-1 specific CD8+ T cell response at the tattoo administration site. The maximum dose administered was 2 mg due to lack of clinical activity. CONCLUSION: We showed that the developed DNA vaccine, applied using a novel intradermal application strategy, can be administered safely. Further research with improved vaccine formats is required to show possible clinical benefit of DNA vaccination.

Tumor-Infiltrating Lymphocyte Therapy or Ipilimumab in Advanced Melanoma.

BACKGROUND: Immune checkpoint inhibitors and targeted therapies have dramatically improved outcomes in patients with advanced melanoma, but approximately half these patients will not have a durable benefit. Phase 1-2 trials of adoptive cell therapy with tumor-infiltrating lymphocytes (TILs) have shown promising responses, but data from phase 3 trials are lacking to determine the role of TILs in treating advanced melanoma. METHODS: In this phase 3, multicenter, open-label trial, we randomly assigned patients with unresectable stage IIIC or IV melanoma in a 1:1 ratio to receive TIL or anti-cytotoxic T-lymphocyte antigen 4 therapy (ipilimumab at 3 mg per kilogram of body weight). Infusion of at least 5×109 TILs was preceded by nonmyeloablative, lymphodepleting chemotherapy (cyclophosphamide plus fludarabine) and followed by high-dose interleukin-2. The primary end point was progression-free survival. RESULTS: A total of 168 patients (86% with disease refractory to anti-programmed death 1 treatment) were assigned to receive TILs (84 patients) or ipilimumab (84 patients). In the intention-to-treat population, median progression-free survival was 7.2 months (95% confidence interval [CI], 4.2 to 13.1) in the TIL group and 3.1 months (95% CI, 3.0 to 4.3) in the ipilimumab group (hazard ratio for progression or death, 0.50; 95% CI, 0.35 to 0.72; P<0.001); 49% (95% CI, 38 to 60) and 21% (95% CI, 13 to 32) of the patients, respectively, had an objective response. Median overall survival was 25.8 months (95% CI, 18.2 to not reached) in the TIL group and 18.9 months (95% CI, 13.8 to 32.6) in the ipilimumab group. Treatment-related adverse events of grade 3 or higher occurred in all patients who received TILs and in 57% of those who received ipilimumab; in the TIL group, these events were mainly chemotherapy-related myelosuppression. CONCLUSIONS: In patients with advanced melanoma, progression-free survival was significantly longer among those who received TIL therapy than among those who received ipilimumab. (Funded by the Dutch Cancer Society and others; ClinicalTrials.gov number, NCT02278887.).

Tumor infiltrating lymphocytes (TIL) therapy in metastatic melanoma: boosting of neoantigen-specific T cell reactivity and long-term follow-up.

Treatment of metastatic melanoma with autologous tumor infiltrating lymphocytes (TILs) is currently applied in several centers. Robust and remarkably consistent overall response rates, of around 50% of treated patients, have been observed across hospitals, including a substantial fraction of durable, complete responses. PURPOSE: Execute a phase I/II feasibility study with TIL therapy in metastatic melanoma at the Netherlands Cancer Institute, with the goal to assess feasibility and potential value of a randomized phase III trial. EXPERIMENTAL: Ten patients were treated with TIL therapy. Infusion products and peripheral blood samples were phenotypically characterized and neoantigen reactivity was assessed. Here, we present long-term clinical outcome and translational data on neoantigen reactivity of the T cell products. RESULTS: Five out of 10 patients, who were all anti-PD-1 naïve at time of treatment, showed an objective clinical response, including two patients with a complete response that are both ongoing for more than 7 years. Immune monitoring demonstrated that neoantigen-specific T cells were detectable in TIL infusion products from three out of three patients analyzed. For six out of the nine neoantigen-specific T cell responses detected in these TIL products, T cell response magnitude increased significantly in the peripheral blood compartment after therapy, and neoantigen-specific T cells were detectable for up to 3 years after TIL infusion. CONCLUSION: The clinical results from this study confirm the robustness of TIL therapy in metastatic melanoma and the potential role of neoantigen-specific T cell reactivity. In addition, the data from this study supported the rationale to initiate an ongoing multicenter phase III TIL trial.

Human papillomavirus-negative epithelial proliferations resembling condylomata acuminata in a patient receiving vemurafenib for Stage IV melanoma.

With the discovery of v-Raf murine sarcoma viral oncogene homolog B (BRAF) inhibitors, new treatment possibilities arose against metastatic melanoma. A frequent adverse effect of BRAF inhibitor therapy is the induction of epithelial proliferations such as cutaneous squamous cell carcinoma and verrucous papilloma. Here, we describe a case in which a patient developed extensive anal epithelial proliferations resembling condylomata acuminata, after starting vemurafenib treatment. This adverse effect has rarely been reported in the literature. Interestingly, the lesions in our patient were negative for human papillomavirus, and mutations in BRAF, Neuroblastoma rat sarcoma viral oncogene homolog (NRAS), Kirsten rat sarcoma viral oncogene homolog (KRAS), and Harvey rat sarcoma viral oncogene homolog (HRAS) were not detected. Different pathways can contribute to these epithelial proliferations resembling condylomata acuminata. We show the relevance of a detailed history at the beginning and during treatment, instructions, education, and dermatological follow-up (including the genital area) for patients treated with BRAF inhibitors. Condylomata acuminata can influence the quality of life and are treated, in an early stage, with cryotherapy, coagulation, imiquimod, and/or CO2 laser therapy.

First-line therapy-stratified survival in BRAF-mutant melanoma: a retrospective multicenter analysis.

BACKGROUND: Inhibition of the mitogen-activated protein kinase (MAPK) pathway as well as programmed death 1 receptor (PD-1) blockade was shown to prolong overall survival (OS) in patients with advanced B-Raf proto-oncogene (BRAF)-mutant melanoma. However, due to the lack of head-to-head trials, it remains unclear if one of these therapeutic approaches should be preferred in first-line therapy. Here, we present a retrospective analysis comparing anti-PD-1 monotherapy with BRAF/MAPK/ERK kinase (MEK) combined inhibition used as first-line agents in a real-world clinical setting. PATIENTS AND METHODS: Clinical data, routine blood counts and lactate dehydrogenase (LDH) levels of 301 patients with unresectable or metastatic melanoma harboring an activating mutation in BRAF (V600E/K) were included. Of these, 106 received anti-PD-1 antibodies, while 195 patients were treated with a selective BRAF inhibitor combined with an MEK inhibitor as palliative first-line therapy. Patients were sub-grouped according to previously described predictive and prognostic markers. RESULTS: OS was significantly longer in patients receiving anti-PD-1 monotherapy compared to patients receiving combined MAPK inhibitors. Subsequent therapies were comparable among these groups. The difference in OS was less pronounced in patients with high LDH levels and visceral metastatic spread. CONCLUSION: First-line treatment with a PD-1 blocking antibody might be associated with longer OS than first-line inhibition of the MAPK pathway in patients with advanced melanoma harboring mutant BRAF. These hypothesis-generating data need to be confirmed or rejected in prospective, randomized trials.

Treatment With Tumor-infiltrating Lymphocytes in Advanced Melanoma: Evaluation of Early Clinical Implementation of an Advanced Therapy Medicinal Product.

Tumor-infiltrating lymphocytes (TIL)-therapy in advanced melanoma is an advanced therapy medicinal product (ATMP) which, despite promising results, has not been implemented widely. In a European setting, TIL-therapy has been in use since 2011 and is currently being evaluated in a randomized controlled trial. As clinical implementation of ATMPs is challenging, this study aims to evaluate early application of TIL-therapy, through the application of a constructive technology assessment (CTA). First the literature on ATMP barriers and facilitators in clinical translation was summarized. Subsequently, application of TIL-therapy was evaluated through semistructured interviews with 26 stakeholders according to 6 CTA domains: clinical, economic, patient-related, organizational, technical, and future. In addition, treatment costs were estimated. A number of barriers to clinical translation were identified in the literature, including: inadequate financial support, lack of regulatory knowledge, risks in using live tissues, and the complex path to market approval. Innovative reimbursement procedures could particularly facilitate translation. The CTA survey of TIL-therapy acknowledged these barriers, and revealed the following facilitators: the expected effectiveness resulting in institutional support for an internal pilot, the results of which led to the inclusion of TIL-therapy in a national coverage with evidence development program, the availability of an in-house pharmacist, quality assurance expertise and a TIL-skilled technician. Institutional and national implementation of TIL-therapy remains complex. The promising clinical effectiveness is expected to facilitate the adoption of TIL-therapy, especially when validated through a randomized controlled trial. Innovative and conditional reimbursement procedures, together with the organization of knowledge transfer, could support and improve clinical translation of TIL and ATMPs.

Early cost-effectiveness of tumor infiltrating lymphocytes (TIL) for second line treatment in advanced melanoma: a model-based economic evaluation.

BACKGROUND: An emerging immunotherapy is infusion of tumor infiltrating Lymphocytes (TIL), with objective response rates of around 50% versus 19% for ipilimumab. As an Advanced Therapeutic Medicinal Products (ATMP), TIL is highly personalized and complex therapy. It requests substantial upfront investments from the hospital in: expensive lab-equipment, staff expertise and training, as well as extremely tight hospital logistics. Therefore, an early health economic modelling study, as part of a Coverage with Evidence Development (CED) program, was performed. METHODS: We used a Markov decision model to estimate the expected costs and outcomes (quality-adjusted life years; QALYs) for TIL versus ipilimumab for second line treatment in metastatic melanoma patients from a Dutch health care perspective over a life long time horizon. Three mutually exclusive health states (stable disease (responders)), progressive disease and death) were modelled. To inform further research prioritization, Value of Information (VOI) analysis was performed. RESULTS: TIL is expected to generate more QALYs compared to ipilimumab (0.45 versus 0.38 respectively) at lower incremental cost (presently €81,140 versus €94,705 respectively) resulting in a dominant ICER (less costly and more effective). Based on current information TIL is dominating ipilimumab and has a probability of 86% for being cost effective at a cost/QALY threshold of €80,000. The Expected Value of Perfect Information (EVPI) amounted to €3 M. CONCLUSIONS: TIL is expected to have the highest probability of being cost-effective in second line treatment for advanced melanoma compared to ipilimumab. To reduce decision uncertainty, a clinical trial investigating e.g. costs and survival seems most valuable. This is currently being undertaken as part of a CED program in the Netherlands Cancer Institute, Amsterdam, the Netherlands, in collaboration with Denmark.

Immune checkpoint inhibition-related colitis: symptoms, endoscopic features, histology and response to management.

BACKGROUND: Immune checkpoint inhibitors are successfully introduced as anticancer treatment. However, they may induce severe immune-related adverse events (irAEs). One of the most frequent irAEs is diarrhoea. The main objective of this study was to analyse symptoms (ie, grade of diarrhoea), endoscopic and histological features and response to management in immune checkpoint inhibition-related colitis (IRC). PATIENTS AND METHODS: We retrospectively analysed patients who developed diarrhoea on checkpoint inhibition and therefore underwent an endoscopy and/or were treated with corticosteroids. Patients were treated between August 2010 and March 2016 for metastatic melanoma or non-small cell lung cancer. Severity of IRC was scored using the endoscopic Mayo score and the van der Heide score. RESULTS: Out of a cohort of 781 patients, 92 patients were identified who developed diarrhoea and therefore underwent an endoscopy and/or were treated with corticosteroids. Patients were treated with monotherapy anticytotoxic T-lymphocyte antigen-4, antiprogrammed death receptor-1 or a combination of both. All patients had symptoms of diarrhoea (grade 1: 16%; grade 2: 39% and grade 3: 44%). A complete colonoscopy was performed in 62 (67%) patients, of whom 42 (68%) had a pancolitis (≥3 affected segments). Ulcers were seen in 32% of endoscopies. There was no significant correlation between the grade of diarrhoea at presentation and endoscopic severity scores, the presence of ulcers or histological features. In 54 episodes of diarrhoea (56%), patients received one or more cycles infliximab for steroid-refractory colitis. Patients with higher endoscopic severity scores, ulcers and/or a pancolitis needed infliximab more often. CONCLUSIONS: The correlation between grade of diarrhoea and endoscopic or histological features for severity of colitis is poor. Patients with higher endoscopic severity scores, ulcers or a pancolitis needed the addition of infliximab more often. Therefore, endoscopy may have value in the evaluation of the severity of IRC and may help in decision making for optimal management.

Clinical and radiological response of BRAF inhibition and MEK inhibition in patients with brain metastases from BRAF-mutated melanoma.

Patients with brain metastases (BM) from melanoma have an overall survival (OS) of 2-6 months after whole-brain radiotherapy. Targeted therapy (TT) is an effective treatment for BRAF-mutated metastatic melanoma. Moreover, recent studies indicate intracranial responses of TT in patients with BM. We analyzed 146 patients with BM from BRAF-mutated melanoma treated with vemurafenib, dabrafenib, or dabrafenib+trametinib between 2010 and 2016. We determined clinical and radiological response, progression-free survival (PFS), and OS. Median OS of patients treated with dabrafenib+trametinib was 11.2 months [n=30; 95% confidence interval (CI): 6.8-15.7], 8.8 months for dabrafenib alone (n=31; 95% CI: 3.9-13.7), and 5.7 months for vemurafenib (n=85; 95% CI: 4.6-6.8). A significantly longer OS was observed in the dabrafenib+trametinib group than in the vemurafenib group (hazard ratio for death, 0.52; 95% CI: 0.30-0.89; P=0.02). Median intracranial PFS of all patients was 4.1 months. Median intracranial PFS for patients treated with dabrafenib+trametinib was 5.8 months (95% CI: 3.2-8.5), 5.7 months (95% CI: 3.0-8.4) for dabrafenib, and 3.6 months (95% CI: 3.5-3.8) for vemurafenib (P=0.54). A total of 63 (43%) patients had symptomatic BM. Intracranial disease control rate at 8 weeks in these patients was 65 versus 70% extracranially. Neurological symptoms improved in 46% of patients with symptomatic BM, whereas in 21%, they remained stable. Median OS in patients with BM from BRAF-mutated melanoma treated with dabrafenib+trametinib was significantly longer than for vemurafenib. Improvement of neurological symptoms was seen in almost half of the patients with symptomatic BM treated with TT.

Cancer drug addiction is relayed by an ERK2-dependent phenotype switch.

Observations from cultured cells, animal models and patients raise the possibility that the dependency of tumours on the therapeutic drugs to which they have acquired resistance represents a vulnerability with potential applications in cancer treatment. However, for this drug addiction trait to become of clinical interest, we must first define the mechanism that underlies it. We performed an unbiased CRISPR-Cas9 knockout screen on melanoma cells that were both resistant and addicted to inhibition of the serine/threonine-protein kinase BRAF, in order to functionally mine their genome for 'addiction genes'. Here we describe a signalling pathway comprising ERK2 kinase and JUNB and FRA1 transcription factors, disruption of which allowed addicted tumour cells to survive on treatment discontinuation. This occurred in both cultured cells and mice and was irrespective of the acquired drug resistance mechanism. In melanoma and lung cancer cells, death induced by drug withdrawal was preceded by a specific ERK2-dependent phenotype switch, alongside transcriptional reprogramming reminiscent of the epithelial-mesenchymal transition. In melanoma cells, this reprogramming caused the shutdown of microphthalmia-associated transcription factor (MITF), a lineage survival oncoprotein; restoring this protein reversed phenotype switching and prevented the lethality associated with drug addiction. In patients with melanoma that had progressed during treatment with a BRAF inhibitor, treatment cessation was followed by increased expression of the receptor tyrosine kinase AXL, which is associated with the phenotype switch. Drug discontinuation synergized with the melanoma chemotherapeutic agent dacarbazine by further suppressing MITF and its prosurvival target, B-cell lymphoma 2 (BCL-2), and by inducing DNA damage in cancer cells. Our results uncover a pathway that underpins drug addiction in cancer cells, which may help to guide the use of alternating therapeutic strategies for enhanced clinical responses in drug-resistant cancers.

Peripheral CD8 effector-memory type 1 T-cells correlate with outcome in ipilimumab-treated stage IV melanoma patients.

The role of the assessment of peripheral T-cell phenotypes in predicting overall survival (OS) after ipilimumab treatment is unclear. Here, we analysed mononuclear cells in the blood before and at different time points during treatment with ipilimumab in 137 late-stage melanoma patients. The proportions of baseline naïve and memory T-cells were measured by flow cytometry and correlated with OS, with an emphasis on PD-1 expression. High frequencies (>13%) of CD8 effector-memory type 1 (EM1) T-cells at baseline correlated with longer OS (p = 0.029) and higher clinical response rates (p = 0.01). The frequency of these EM1 cells and the M category had independent impacts on OS (hazard ratio = 1.5, p = 0.033; and hazard ratio = 1.9, p = 0.007). In contrast, high baseline frequencies of late stage-differentiated effector memory CD8 cells (>23.8%) were negatively associated with OS (p = 0.034) but did not correlate with clinical response. Following treatment, a decrease of CD8 cells from baseline to the time of the second drug dose and at later time points was strongly and consistently correlated with a high clinical response rate. Our observations thus suggest an important predictive role of baseline CD8 EM1 cells and changes in CD8 cells for clinical response of ipilimumab. Further validation of these biomarker candidates is warranted.

Ipilimumab administered to metastatic melanoma patients who progressed after dendritic cell vaccination.

BACKGROUND: Ipilimumab has proven to be effective in metastatic melanoma patients. The purpose of this study was to determine the efficacy of ipilimumab in advanced melanoma patients who showed progressive disease upon experimental dendritic cell (DC) vaccination. METHODS: Retrospective analysis of 48 stage IV melanoma patients treated with ipilimumab after progression upon DC vaccination earlier in their treatment. DC vaccination was given either as adjuvant treatment for stage III disease (n = 18) or for stage IV disease (n = 30). Ipilimumab (3 mg/kg) was administered every 3 weeks for up to 4 cycles. RESULTS: Median time between progression upon DC vaccination and first gift of ipilimumab was 5.4 mo. Progression-free survival (PFS) rates for patients that received ipilimumab after adjuvant DC vaccination, and patients that received DC vaccination for stage IV melanoma, were 35% and 7% at 1 y and 35% and 3% at 2 y, while the median PFS was 2.9 mo and 3.1 mo, respectively. Median overall survival of patients pre-treated with adjuvant DC vaccination for stage III melanoma was not reached versus 8.0 mo (95% CI, 5.2-10.9) in the group pre-treated with DC vaccination for stage IV disease (HR of death, 0.36; p = 0.017). Grade 3 immune-related adverse events occurred in 19% of patients and one death (2%) was related to ipilimumab. CONCLUSIONS: Clinical responses to ipilimumab were found in a considerable number of advanced melanoma patients with progression after adjuvant DC vaccination for stage III disease, while the effect was very limited in patients who showed progression after DC vaccination for stage IV disease.

Proportions of blood-borne Vδ1+ and Vδ2+ T-cells are associated with overall survival of melanoma patients treated with ipilimumab.

Human γδ T-cells possess regulatory and cytotoxic capabilities, and could potentially influence the efficacy of immunotherapies. We analysed the frequencies of peripheral γδ T-cells, including their most prominent subsets (Vδ1+ and Vδ2+ cells) and differentiation states in 109 melanoma patients and 109 healthy controls. We additionally analysed the impact of γδ T-cells on overall survival (OS) calculated from the first dose of ipilimumab in melanoma patients. Higher median frequencies of Vδ1+ cells and lower median frequencies of Vδ2+ cells were identified in patients compared to healthy subjects (Vδ1+: 30% versus 15%, Vδ2+: 39% versus 64%, both p < 0.001). Patients with higher frequencies of Vδ1+ cells (≥30%) had poorer OS (p = 0.043) and a Vδ1+ differentiation signature dominated by late-differentiated phenotypes. In contrast, higher frequencies of Vδ2+ cells (≥39%) were associated with longer survival (p = 0.031) independent of the M category or lactate dehydrogenase level. Patients with decreasing frequencies of Vδ2+ cells under ipilimumab treatment had worse OS and a lower rate of clinical benefit than patients without such decreases. Therefore, we suggest frequencies of both Vδ1+ and Vδ2+ cells as candidate biomarkers for outcome in melanoma patients following ipilimumab. Further studies are needed to validate these results and to clarify whether they represent prognostic associations or whether γδ T-cells are specifically and/or functionally linked to the mode of action of ipilimumab.

Baseline Peripheral Blood Biomarkers Associated with Clinical Outcome of Advanced Melanoma Patients Treated with Ipilimumab.

PURPOSE: To identify baseline peripheral blood biomarkers associated with clinical outcome following ipilimumab treatment in advanced melanoma patients. EXPERIMENTAL DESIGN: Frequencies of myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg), serum lactate dehydrogenase (LDH), routine blood counts, and clinical characteristics were assessed in 209 patients. Endpoints were overall survival (OS) and best overall response. Statistical calculations were done by Kaplan-Meier and Cox regression analysis, including calibration and discrimination by C-statistics. RESULTS: Low baseline LDH, absolute monocyte counts (AMC), Lin(-)CD14(+)HLA-DR(-/low)-MDSC frequencies, and high absolute eosinophil counts (AEC), relative lymphocyte counts (RLC), and CD4(+)CD25(+)FoxP3(+)-Treg frequencies were significantly associated with better survival, and were considered in a combination model. Patients (43.5%) presenting with the best biomarker signature had a 30% response rate and median survival of 16 months. In contrast, patients with the worst biomarkers (27.5%) had only a 3% response rate and median survival of 4 months. The occurrence of adverse events correlated with neither baseline biomarker signatures nor the clinical benefit of ipilimumab. In another model, limited to the routine parameters LDH, AMC, AEC, and RLC, the number of favorable factors (4 vs. 3 vs. 2-0) was also associated with OS (P < 0.001 for all pairwise comparisons) in the main study and additionally in an independent validation cohort. CONCLUSIONS: A baseline signature of low LDH, AMC, and MDSCs as well as high AEC, Tregs, and RLC is associated with favorable outcome following ipilimumab. Prospective investigation of the predictive impact of these markers following ipilimumab and other treatments, e.g., PD-1 antibodies, is warranted. Clin Cancer Res; 22(12); 2908-18. ©2016 AACR.

Targeting the MAPK and PI3K pathways in combination with PD1 blockade in melanoma.

Immunotherapy of advanced melanoma with CTLA-4 or PD-1/PD-L1 checkpoint blockade induces in a proportion of patients long durable responses. In contrast, targeting the MAPK-pathway by selective BRAF and MEK inhibitors induces high response rates, but most patients relapse. Combining targeted therapy with immunotherapy is proposed to improve the long-term outcomes of patients. Preclinical data endorsing this hypothesis are accumulating. Inhibition of the PI3K-Akt-mTOR pathway may be a promising treatment option to overcome resistance to MAPK inhibition and for additional combination with immunotherapy. We therefore evaluated to which extent dual targeting of the MAPK and PI3K-Akt-mTOR pathways affects tumor immune infiltrates and whether it synergizes with PD-1 checkpoint blockade in a BRAFV600E/PTEN-/--driven melanoma mouse model. Short-term dual BRAF + MEK inhibition enhanced tumor immune infiltration and improved tumor control when combined with PD-1 blockade in a CD8+ T cell dependent manner. Additional PI3K inhibition did not impair tumor control or immune cell infiltration and functionality. Analysis of on-treatment samples from melanoma patients treated with BRAF or BRAF + MEK inhibitors indicates that inhibitor-mediated T cell infiltration occurred in all patients early after treatment initiation but was less frequent found in on-treatment biopsies beyond day 15. Our findings provide a rationale for clinical testing of short-term BRAF + MEK inhibition in combination with immune checkpoint blockade, currently implemented at our institutes. Additional PI3K inhibition could be an option for BRAF + MEK inhibitor resistant patients that receive targeted therapy in combination with immune checkpoint blockade.

Low MITF/AXL ratio predicts early resistance to multiple targeted drugs in melanoma.

Increased expression of the Microphthalmia-associated transcription factor (MITF) contributes to melanoma progression and resistance to BRAF pathway inhibition. Here we show that the lack of MITF is associated with more severe resistance to a range of inhibitors, while its presence is required for robust drug responses. Both in primary and acquired resistance, MITF levels inversely correlate with the expression of several activated receptor tyrosine kinases, most frequently AXL. The MITF-low/AXL-high/drug-resistance phenotype is common among mutant BRAF and NRAS melanoma cell lines. The dichotomous behaviour of MITF in drug response is corroborated in vemurafenib-resistant biopsies, including MITF-high and -low clones in a relapsed patient. Furthermore, drug cocktails containing AXL inhibitor enhance melanoma cell elimination by BRAF or ERK inhibition. Our results demonstrate that a low MITF/AXL ratio predicts early resistance to multiple targeted drugs, and warrant clinical validation of AXL inhibitors to combat resistance of BRAF and NRAS mutant MITF-low melanomas.

Practical implications of liver and heart iron load assessment by T2*-MRI in children and adults with transfusion-dependent anemias.

This study examined the relationship between hepatic and myocardial iron concentration, assessed by T2*-MRI in 66 patients (3-82 years) with transfusion-dependent anemias and thalassemia intermedia, to determine whether hepatic iron levels alone suffice for chelation adjustments. We found a poor correlation between hepatic and myocardial iron (r = 0.10, P = 0.43) and identified a subgroup (14%) with increased myocardial iron without a matched degree of hepatic hemosiderosis. Left ventricular ejection fraction was insensitive for detecting elevated myocardial iron. These findings were present in both adult and pediatric patients. We recommend therapeutic monitoring of iron burden by evaluation of both liver and myocardial iron with T2*-MRI.