Many patients with advanced cancers achieve dramatic responses to a panoply of therapeutics yet retain minimal residual disease (MRD), which ultimately results in relapse. To gain insights into the ...biology of MRD, we applied single-cell RNA sequencing to malignant cells isolated from BRAF mutant patient-derived xenograft melanoma cohorts exposed to concurrent RAF/MEK-inhibition. We identified distinct drug-tolerant transcriptional states, varying combinations of which co-occurred within MRDs from PDXs and biopsies of patients on treatment. One of these exhibited a neural crest stem cell (NCSC) transcriptional program largely driven by the nuclear receptor RXRG. An RXR antagonist mitigated accumulation of NCSCs in MRD and delayed the development of resistance. These data identify NCSCs as key drivers of resistance and illustrate the therapeutic potential of MRD-directed therapy. They also highlight how gene regulatory network architecture reprogramming may be therapeutically exploited to limit cellular heterogeneity, a key driver of disease progression and therapy resistance.
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•Minimal residual diseases in melanoma exhibit cellular and spatial heterogeneity•Cell-state transition contributes to co-emergence of distinct drug-tolerant states•RXR signaling drives emergence of a cell population conferring treatment resistance•Targeting RXR signaling is promising for delaying or obviating relapse in melanoma
Drug-tolerant cells that persist through treatment of melanoma exhibit multiple transcriptional states, one of which is a key driver that can be targeted therapeutically.
Novel therapies have achieved unprecedented benefit in survival of advanced melanoma patients. While immunotherapy (ICI) can be administered independent of mutational status, BRAF and MEK kinase ...inhibitors represent another effective treatment option for patients with BRAF mutant melanoma. Given the benefits these therapies demonstrate, the natural instinct was to combine. Three studies have investigated the benefit of combination of ICI using anti-PD-1 or anti-PD-L1 antibody and targeted therapy (TT) with BRAF and MEK inhibitors over TT and placebo. Among these studies, statistically significantly superior duration of response was observed, however overall and progression-free survival were only numerically superior, if at all. One triple combination was approved for BRAF mutant metastatic melanoma; however, the expected synergistic effect of triple therapy could not be universally confirmed and the observed benefits with triple seem to depend on statistical considerations rather than a biological reason. As patients with BRAF mutant melanoma have both ICI and TT as their first-line treatment options, the question whether the sequence matters was addressed. Two prospective trials compared first-line ICI, followed by TT at progression, or vice-versa, with additional "sandwich" approach (8 weeks of TT followed by ICI until progression, then TT again) in the Secombit study. The benefit of first-line ICI was demonstrated in both studies with Secombit study showing the "sandwich" approach to have similar effect. Current data advices for immunotherapy based regiments in patients with BRAF mutant melanoma or, possibly, sandwich approach. Whether triple therapy is superior to ICI monotherapy still needs to be addressed considering not only efficacy, but also safety.
Recent developments in immunotherapy have prolonged overall survival in metastatic melanoma with the possibility to reach a long-term benefit. Targeted therapies based on BRAF and MEK inhibition also ...seem to have a long-term beneficial effect, which is more evident in patients with favorable baseline characteristics, namely normal levels of lactate dehydrogenase, without brain metastases, and low tumor burden. This long-term benefit of targeted therapies might be related to an immune-modulation: indeed BRAF and MEK inhibitors affect tumor microenvironment and immune surveillance, and it has been shown that patients with complete response to targeted treatment have a pre-existing favorable immunologic signature.
Talimogene laherparepvec (T-VEC) is a genetically modified herpes simplex 1 virus (HSV-1) approved for cancer therapy. We investigate its effect on the clinical, histological, single-cell ...transcriptomic, and immune repertoire level using repeated fine-needle aspirates (FNAs) of injected and noninjected lesions in primary cutaneous B cell lymphoma (pCBCL). Thirteen patients received intralesional T-VEC, 11 of which demonstrate tumor response in the injected lesions. Using single-cell sequencing of the FNAs, we identify the malignant population and separate three pCBCL subtypes. Twenty-four hours after the injection, we detect HSV-1T-VEC transcripts in malignant and nonmalignant cells of the injected lesion but not of the noninjected lesion. Oncolytic virotherapy results in a rapid eradication of malignant cells. It also leads to interferon pathway activation and early influx of natural killer cells, monocytes, and dendritic cells. These events are followed by enrichment in cytotoxic T cells and a decrease of regulatory T cells in injected and noninjected lesions.
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•34 longitudinal samples from oncolytic virotherapy-treated patients analyzed•Malignant population and subtypes of primary cutaneous B cell lymphoma identified•Cell-type-unselective replication and cytopathic effect of oncolytic virotherapy•Rapid reduction of malignant population and tumor microenvironment remodeling
Using single-cell sequencing of longitudinally collected samples from primary cutaneous B cell lymphoma patients treated with oncolytic virotherapy, Ramelyte et al. show that malignant cells can be rapidly eliminated but viral replication is not restricted in malignant cells. In addition, remodeling of tumor microenvironment can happen in both injected and noninjected lesions.
Purpose of Review
As cancer remains an increasing problem in industrial countries, the incidence of melanoma has risen rapidly in many populations during the last decades and still continues to rise. ...Current strategies aiming to control the disease have largely focused on improving the understanding of the interplay of causal factors for this cancer.
Recent Findings
Cutaneous melanoma shows clear differences in incidence, mortality, genomic profile, and anatomic presentation, depending on the country of residence, ethnicity, and socioeconomic status. Known risk factors are multiple atypical nevi, positive family and/or personal history, immune suppressive diseases or treatments, and fair skin phenotype. Besides new adjuvant therapeutic options, changed attitude toward leisure and sun exposure, primary prevention, and early detection are major contributors to disease control.
Summary
Melanoma is a disease of multifactorial causality and heterogeneous presentation. Its subtypes differ in origin, anatomical site, role of UV radiation, and mutational profile. Better understanding of these differences may improve prevention strategies and therapeutic developments.
Summary Background Patients with melanoma that progresses on ipilimumab and, if BRAFV600 mutant-positive, a BRAF or MEK inhibitor or both, have few treatment options. We assessed the efficacy and ...safety of two pembrolizumab doses versus investigator-choice chemotherapy in patients with ipilimumab-refractory melanoma. Methods We carried out a randomised phase 2 trial of patients aged 18 years or older from 73 hospitals, clinics, and academic medical centres in 12 countries who had confirmed progressive disease within 24 weeks after two or more ipilimumab doses and, if BRAFV600 mutant-positive, previous treatment with a BRAF or MEK inhibitor or both. Patients had to have resolution of all ipilimumab-related adverse events to grade 0–1 and prednisone 10 mg/day or less for at least 2 weeks, an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and at least one measurable lesion to be eligible. Using a centralised interactive voice response system, we randomly assigned (1:1:1) patients in a block size of six to receive intravenous pembrolizumab 2 mg/kg or 10 mg/kg every 3 weeks or investigator-choice chemotherapy (paclitaxel plus carboplatin, paclitaxel, carboplatin, dacarbazine, or oral temozolomide). Randomisation was stratified by ECOG performance status, lactate dehydrogenase concentration, and BRAFV600 mutation status. Individual treatment assignment between pembrolizumab and chemotherapy was open label, but investigators and patients were masked to assignment of the dose of pembrolizumab. We present the primary endpoint at the prespecified second interim analysis of progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov , number NCT01704287 . The study is closed to enrolment but continues to follow up and treat patients. Findings Between Nov 30, 2012, and Nov 13, 2013, we enrolled 540 patients: 180 patients were randomly assigned to receive pembrolizumab 2 mg/kg, 181 to receive pembrolizumab 10 mg/kg, and 179 to receive chemotherapy. Based on 410 progression-free survival events, progression-free survival was improved in patients assigned to pembrolizumab 2 mg/kg (HR 0·57, 95% CI 0·45–0·73; p<0·0001) and those assigned to pembrolizumab 10 mg/kg (0·50, 0·39–0·64; p<0·0001) compared with those assigned to chemotherapy. 6-month progression-free survival was 34% (95% CI 27–41) in the pembrolizumab 2 mg/kg group, 38% (31–45) in the 10 mg/kg group, and 16% (10–22) in the chemotherapy group. Treatment-related grade 3–4 adverse events occurred in 20 (11%) patients in the pembrolizumab 2 mg/kg group, 25 (14%) in the pembrolizumab 10 mg/kg group, and 45 (26%) in the chemotherapy group. The most common treatment-related grade 3–4 adverse event in the pembrolizumab groups was fatigue (two 1% of 178 patients in the 2 mg/kg group and one <1% of 179 patients in the 10 mg/kg group, compared with eight 5% of 171 in the chemotherapy group). Other treatment-related grade 3–4 adverse events include generalised oedema and myalgia (each in two 1% patients) in those given pembrolizumab 2 mg/kg; hypopituitarism, colitis, diarrhoea, decreased appetite, hyponatremia, and pneumonitis (each in two 1%) in those given pembrolizumab 10 mg/kg; and anaemia (nine 5%), fatigue (eight 5%), neutropenia (six 4%), and leucopenia (six 4%) in those assigned to chemotherapy. Interpretation These findings establish pembrolizumab as a new standard of care for the treatment of ipilimumab-refractory melanoma. Funding Merck Sharp & Dohme.
Activating mutations in serine-threonine protein kinase B-RAF (BRAF) are found in 50% of patients with advanced melanoma. Selective BRAF-inhibitor therapy improves survival, as compared with ...chemotherapy, but responses are often short-lived. In previous trials, MEK inhibition appeared to be promising in this population.
In this phase 3 open-label trial, we randomly assigned 322 patients who had metastatic melanoma with a V600E or V600K BRAF mutation to receive either trametinib, an oral selective MEK inhibitor, or chemotherapy in a 2:1 ratio. Patients received trametinib (2 mg orally) once daily or intravenous dacarbazine (1000 mg per square meter of body-surface area) or paclitaxel (175 mg per square meter) every 3 weeks. Patients in the chemotherapy group who had disease progression were permitted to cross over to receive trametinib. Progression-free survival was the primary end point, and overall survival was a secondary end point.
Median progression-free survival was 4.8 months in the trametinib group and 1.5 months in the chemotherapy group (hazard ratio for disease progression or death in the trametinib group, 0.45; 95% confidence interval CI, 0.33 to 0.63; P<0.001). At 6 months, the rate of overall survival was 81% in the trametinib group and 67% in the chemotherapy group despite crossover (hazard ratio for death, 0.54; 95% CI, 0.32 to 0.92; P=0.01). Rash, diarrhea, and peripheral edema were the most common toxic effects in the trametinib group and were managed with dose interruption and dose reduction; asymptomatic and reversible reduction in the cardiac ejection fraction and ocular toxic effects occurred infrequently. Secondary skin neoplasms were not observed.
Trametinib, as compared with chemotherapy, improved rates of progression-free and overall survival among patients who had metastatic melanoma with a BRAF V600E or V600K mutation. (Funded by GlaxoSmithKline; METRIC ClinicalTrials.gov number, NCT01245062.).
Summary Background Ipilimumab is an approved treatment for patients with advanced melanoma. We aimed to assess ipilimumab as adjuvant therapy for patients with completely resected stage III melanoma ...at high risk of recurrence. Methods We did a double-blind, phase 3 trial in patients with stage III cutaneous melanoma (excluding lymph node metastasis ≤1 mm or in-transit metastasis) with adequate resection of lymph nodes (ie, the primary cutaneous melanoma must have been completely excised with adequate surgical margins) who had not received previous systemic therapy for melanoma from 91 hospitals located in 19 countries. Patients were randomly assigned (1:1), centrally by an interactive voice response system, to receive intravenous infusions of 10 mg/kg ipilimumab or placebo every 3 weeks for four doses, then every 3 months for up to 3 years. Using a minimisation technique, randomisation was stratified by disease stage and geographical region. The primary endpoint was recurrence-free survival, assessed by an independent review committee, and analysed by intention to treat. Enrollment is complete but the study is ongoing for follow-up for analysis of secondary endpoints. This trial is registered with EudraCT, number 2007-001974-10, and ClinicalTrials.gov , number NCT00636168. Findings Between July 10, 2008, and Aug 1, 2011, 951 patients were randomly assigned to ipilimumab (n=475) or placebo (n=476), all of whom were included in the intention-to-treat analyses. At a median follow-up of 2·74 years (IQR 2·28–3·22), there were 528 recurrence-free survival events (234 in the ipilimumab group vs 294 in the placebo group). Median recurrence-free survival was 26·1 months (95% CI 19·3–39·3) in the ipilimumab group versus 17·1 months (95% CI 13·4–21·6) in the placebo group (hazard ratio 0·75; 95% CI 0·64–0·90; p=0·0013); 3-year recurrence-free survival was 46·5% (95% CI 41·5–51·3) in the ipilimumab group versus 34·8% (30·1–39·5) in the placebo group. The most common grade 3–4 immune-related adverse events in the ipilimumab group were gastrointestinal (75 16% vs four <1% in the placebo group), hepatic (50 11% vs one <1%), and endocrine (40 8% vs none). Adverse events led to discontinuation of treatment in 245 (52%) of 471 patients who started ipilimumab (182 39% during the initial treatment period of four doses). Five patients (1%) died due to drug-related adverse events. Five (1%) participants died because of drug-related adverse events in the ipilimumab group; three patients died because of colitis (two with gastrointestinal perforation), one patient because of myocarditis, and one patient because of multiorgan failure with Guillain-Barré syndrome. Interpretation Adjuvant ipilimumab significantly improved recurrence-free survival for patients with completely resected high-risk stage III melanoma. The adverse event profile was consistent with that observed in advanced melanoma, but at higher incidences in particular for endocrinopathies. The risk–benefit ratio of adjuvant ipilimumab at this dose and schedule requires additional assessment based on distant metastasis-free survival and overall survival endpoints to define its definitive value. Funding Bristol-Myers Squibb.
The stimulator of IFN genes (STING) is a transmembrane protein that plays a role in the immune response to tumors. Single-agent STING agonist MIW815 (ADU-S100) has demonstrated immune activation but ...limited antitumor activity. This phase Ib, multicenter, dose-escalation study assessed the safety and tolerability of MIW815 plus spartalizumab (PDR001), a humanized IgG4 antibody against PD-1, in 106 patients with advanced solid tumors or lymphomas.
Patients were treated with weekly intratumoral injections of MIW815 (50-3,200 μg) on a 3-weeks-on/1-week-off schedule or once every 4 weeks, plus a fixed dose of spartalizumab (400 mg) intravenously every 4 weeks.
Common adverse events were pyrexia (n = 23; 22%), injection site pain (n = 21; 20%), and diarrhea (n = 12; 11%). Overall response rate was 10.4%. The MTD was not reached. Pharmacodynamic biomarker analysis demonstrated on-target activity.
The combination of MIW815 and spartalizumab was well tolerated in patients with advanced/metastatic cancers, including in patients with anti-PD-1 refractory disease. Minimal antitumor responses were seen.
Phase 1 and 2 clinical trials of the BRAF kinase inhibitor vemurafenib (PLX4032) have shown response rates of more than 50% in patients with metastatic melanoma with the BRAF V600E mutation.
We ...conducted a phase 3 randomized clinical trial comparing vemurafenib with dacarbazine in 675 patients with previously untreated, metastatic melanoma with the BRAF V600E mutation. Patients were randomly assigned to receive either vemurafenib (960 mg orally twice daily) or dacarbazine (1000 mg per square meter of body-surface area intravenously every 3 weeks). Coprimary end points were rates of overall and progression-free survival. Secondary end points included the response rate, response duration, and safety. A final analysis was planned after 196 deaths and an interim analysis after 98 deaths.
At 6 months, overall survival was 84% (95% confidence interval CI, 78 to 89) in the vemurafenib group and 64% (95% CI, 56 to 73) in the dacarbazine group. In the interim analysis for overall survival and final analysis for progression-free survival, vemurafenib was associated with a relative reduction of 63% in the risk of death and of 74% in the risk of either death or disease progression, as compared with dacarbazine (P<0.001 for both comparisons). After review of the interim analysis by an independent data and safety monitoring board, crossover from dacarbazine to vemurafenib was recommended. Response rates were 48% for vemurafenib and 5% for dacarbazine. Common adverse events associated with vemurafenib were arthralgia, rash, fatigue, alopecia, keratoacanthoma or squamous-cell carcinoma, photosensitivity, nausea, and diarrhea; 38% of patients required dose modification because of toxic effects.
Vemurafenib produced improved rates of overall and progression-free survival in patients with previously untreated melanoma with the BRAF V600E mutation. (Funded by Hoffmann-La Roche; BRIM-3 ClinicalTrials.gov number, NCT01006980.).
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