Reprogrammed mRNA translation drives resistance to therapeutic targeting of ribosome biogenesis.

Elevated ribosome biogenesis in oncogene-driven cancers is commonly targeted by DNA-damaging cytotoxic drugs. Our previous first-in-human trial of CX-5461, a novel, less genotoxic agent that specifically inhibits ribosome biogenesis via suppression of RNA polymerase I (Pol I) transcription, revealed single-agent efficacy in refractory blood cancers. Despite this clinical response, patients were not cured. In parallel, we demonstrated a marked improvement in the in vivo efficacy of CX-5461 in combination with PI3K/AKT/mTORC1 pathway inhibitors. Here, we reveal the molecular basis for this improved efficacy observed in vivo, which is associated with specific suppression of translation of mRNAs encoding regulators of cellular metabolism. Importantly, acquired resistance to this cotreatment is driven by translational rewiring that results in dysregulated cellular metabolism and induction of a cAMP-dependent pathway critical for the survival of blood cancers including lymphoma and acute myeloid leukemia. Our studies thus identify key molecular mechanisms underpinning the response of blood cancers to selective inhibition of ribosome biogenesis and define metabolic vulnerabilities that will facilitate the rational design of more effective regimens for Pol I-directed therapies.

Uncovering molecular mechanisms for amelanotic/hypopigmented primary cutaneous melanoma.

BACKGROUND: A portion of approximately 2-20% of cutaneous melanoma (CM) are diagnosed as amelanotic/hypopigmented melanoma (AHM) and represent a challenge for early diagnosis. OBJECTIVES: Since the degree to which somatic mutations and copy number aberrations (CNA) in genes associated with skin-lightening or albinism may contribute to the loss of tumour pigmentation in AHM samples has not yet been addressed, we have investigated loss of function mutations of key pigmentation genes in matched germline and AHM as well as pigmented melanoma (PM) tumour DNA samples. METHODS: An analysis of clinical and histopathological characteristics together with whole exome sequencing data of 34 fresh frozen primary CM, graded according to the amount of pigmentation present was performed. Together with germline and somatic variant analysis, 30 samples were previously analysed for CNA changes. This study focussed on germline and somatic variants in the coding region of 16 genes known to be associated with albinism/hypopigmentation or variation in human pigmentation in all samples. Chromosomal regions encompassing these 16 genes were examined for DNA copy loss or gain. RESULTS: The finding that red hair related MC1R and TYR R402Q loss of activity gene variant alleles and genotypes are associated with AHM was validated in this study. Germline AHM-related gene variants were enriched in 70% (n=7 of 10) of AHM patients vs 8.3% (n=2 of 24) of PM patients. This surprisingly high frequency of rare germline variants in AHM patients constitutes the "first hit" and confirms that AHM patients are more likely to be albinism allele carriers than patients with PM. Next, in CNA analysis of each tumour sample, 50% (n=4 of 8) AHM samples with a pigmentation gene variant had LOH in the region containing the corresponding gene, and 25% (=2 of 8) had loss-of-heterozygosity (LOH) in chromosomal regions of two AHM-related genes. CONCLUSIONS: This study proposes that the likely molecular mechanism for development of amelanogenesis in AHM is carriage of an albinism/hypopigmentation allele followed by LOH of the corresponding gene in the tumour.

Validation of epidermal AMBRA1 and loricrin (AMBLor) as a prognostic biomarker for nonulcerated American Joint Committee on Cancer stage I/II cutaneous melanoma.

BACKGROUND: Combined expression of the autophagy-regulatory protein AMBRA1 (activating molecule in Beclin1-regulated autophagy) and the terminal differentiation marker loricrin in the peritumoral epidermis of stage I melanomas can identify tumour subsets at low risk of -metastasis. OBJECTIVES: To validate the combined expression of peritumoral AMBRA1 and loricrin (AMBLor) as a prognostic biomarker able to identify both stage I and II melanomas at low risk of tumour recurrence. METHODS: Automated immunohistochemistry was used to analyse peritumoral AMBRA1 and loricrin expression in geographically distinct discovery (n = 540) and validation (n = 300) cohorts of nonulcerated American Joint Committee on Cancer (AJCC) stage I and II melanomas. AMBLor status was correlated with clinical outcomes in the discovery and validation cohorts separately and combined. RESULTS: Analysis of AMBLor in the discovery cohort revealed a recurrence-free survival (RFS) rate of 95.5% in the AMBLor low-risk group vs. 81.7% in the AMBLor at-risk group (multivariate log-rank, P < 0.001) and a negative predictive value (NPV) of 96.0%. In the validation cohort, AMBLor analysis revealed a RFS rate of 97.6% in the AMBLor low-risk group vs. 78.3% in the at-risk group (multivariate log-rank, P < 0.001) and a NPV of 97.6%. In a multivariate model considering AMBLor, Breslow thickness, age and sex, analysis of the combined discovery and validation cohorts showed that the estimated effect of AMBLor was statistically significant, with a hazard ratio of 3.469 (95% confidence interval 1.403-8.580, P = 0.007) and an overall NPV of 96.5%. CONCLUSIONS: These data provide further evidence validating AMBLor as a prognostic biomarker to identify nonulcerated AJCC stage I and II melanoma tumours at low risk of disease recurrence.

Melanoma staging: Evidence-based changes in the American Joint Committee on Cancer eighth edition cancer staging manual.

Answer questions and earn CME/CNE To update the melanoma staging system of the American Joint Committee on Cancer (AJCC) a large database was assembled comprising >46,000 patients from 10 centers worldwide with stages I, II, and III melanoma diagnosed since 1998. Based on analyses of this new database, the existing seventh edition AJCC stage IV database, and contemporary clinical trial data, the AJCC Melanoma Expert Panel introduced several important changes to the Tumor, Nodes, Metastasis (TNM) classification and stage grouping criteria. Key changes in the eighth edition AJCC Cancer Staging Manual include: 1) tumor thickness measurements to be recorded to the nearest 0.1 mm, not 0.01 mm; 2) definitions of T1a and T1b are revised (T1a, <0.8 mm without ulceration; T1b, 0.8-1.0 mm with or without ulceration or <0.8 mm with ulceration), with mitotic rate no longer a T category criterion; 3) pathological (but not clinical) stage IA is revised to include T1b N0 M0 (formerly pathologic stage IB); 4) the N category descriptors "microscopic" and "macroscopic" for regional node metastasis are redefined as "clinically occult" and "clinically apparent"; 5) prognostic stage III groupings are based on N category criteria and T category criteria (ie, primary tumor thickness and ulceration) and increased from 3 to 4 subgroups (stages IIIA-IIID); 6) definitions of N subcategories are revised, with the presence of microsatellites, satellites, or in-transit metastases now categorized as N1c, N2c, or N3c based on the number of tumor-involved regional lymph nodes, if any; 7) descriptors are added to each M1 subcategory designation for lactate dehydrogenase (LDH) level (LDH elevation no longer upstages to M1c); and 8) a new M1d designation is added for central nervous system metastases. This evidence-based revision of the AJCC melanoma staging system will guide patient treatment, provide better prognostic estimates, and refine stratification of patients entering clinical trials. CA Cancer J Clin 2017;67:472-492. © 2017 American Cancer Society.

Overall survival with first-line atezolizumab in combination with vemurafenib and cobimetinib in BRAFV600 mutation-positive advanced melanoma (IMspire150): second interim analysis of a multicentre, randomised, phase 3 study.

BACKGROUND: Primary analysis of the phase 3 IMspire150 study showed improved investigator-assessed progression-free survival with first-line atezolizumab, vemurafenib, and cobimetinib (atezolizumab group) versus placebo, vemurafenib, and cobimetinib (control group) in patients with BRAFV600 mutation-positive melanoma. With a median follow-up of 18·9 months (IQR 10·4-23·8) at the primary analysis, overall survival data were immature. Here, we report the results from the second, prespecified, interim overall survival analysis. METHODS: The multicentre, double-blind, placebo-controlled, randomised, phase 3 IMspire150 study was done at 108 academic and community hospitals in 20 countries. Patients aged 18 years or older with previously untreated unresectable stage IIIc or stage IV melanoma and an Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible for inclusion. Patients were randomly assigned (1:1) to receive either atezolizumab (840 mg intravenously on day 1 and 15) or placebo plus vemurafenib (960 mg or 720 mg twice daily orally) and cobimetinib (60 mg once daily orally; 21 days on and 7 days off) in 28-day cycles. Atezolizumab and placebo were added to treatment regimens from cycle two onwards. Randomisation was done centrally (Durham, NC, USA) based on a permuted block randomisation scheme (block size of 4) using an interactive web-based response system and was stratified by geographical region and baseline lactate dehydrogenase concentration. Overall survival was analysed in the intention-to-treat population and safety was analysed in all patients who received at least one dose of study drug according to actual treatment received. The primary endpoint was investigator-assessed progression-free survival, which was previously reported. Here, we report the second, prespecified, interim overall survival analysis, which was planned after about 270 overall survival events had occurred. The trial is ongoing, but is no longer enrolling patients, and it is registered with ClinicalTrials.gov, NCT02908672. FINDINGS: Between Jan 13, 2017, and April 26, 2018, 514 patients (median age 54 years [IQR 43-63]; 299 [58%] men and 215 [42%] women) were enrolled in the trial and randomly assigned to the atezolizumab group (256 [50%] patients) or the control group (258 [50%] patients). At the data cutoff (Sept 8, 2021), 273 patients had died (126 in the atezolizumab group and 147 in the control group). Median follow-up was 29·1 months (IQR 10·1-45·4) for the atezolizumab group versus 22·8 months (10·6-44·1) for the control group. Median overall survival was 39·0 months (95% CI 29·9-not estimable) in the atezolizumab group versus 25·8 months (22·0-34·6) in the control group (HR 0·84 [95% CI 0·66-1·06]; p=0·14). The most common adverse events of any grade in the atezolizumab group were blood creatine phosphokinase increased (123 [53%] of 231 patients), diarrhoea (116 [50%]), and pyrexia (115 [50%]). The most common adverse events of any grade in the control group were diarrhoea (157 [56%] of 280 patients), blood creatine phosphokinase increased (135 [48%]), and rash (119 [43%]). The most common grade 3-4 adverse events were increased lipase (54 [23%] of 231 patients in the atezolizumab group vs 62 [22%] of 280 patients in the control group), increased blood creatine phosphokinase (51 [22%] vs 50 [18%]), and increased alanine aminotransferase (32 [14%] vs 26 [9%]). Serious adverse events were reported in 112 (48%) patients in the atezolizumab group and 117 (42%) patients in the control group. Grade 5 adverse events were reported in eight (3%) patients in the atezolizumab group versus six (2%) patients in the control group. Two grade 5 adverse events (hepatitis fulminant and hepatic failure) in the atezolizumab group were considered to be associated with the triplet combination, and one event in the control group (pulmonary haemorrhage) was considered to be associated with cobimetinib. INTERPRETATION: Additional follow-up of the IMspire150 trial showed that overall survival was not significantly improved with atezolizumab, vemurafenib, and cobimetinib compared with placebo, vemurafenib, and cobimetinib in patients with BRAFV600 mutation-positive advanced melanoma. Results of the final analysis are awaited to establish whether a significant improvement in overall survival can be achieved with long-term treatment with this triplet combination versus vemurafenib plus cobimetinib. FUNDING: F Hoffmann-La Roche.

Triplet Therapy in Melanoma - Combined BRAF/MEK Inhibitors and Anti-PD-(L)1 Antibodies.

PURPOSE OF REVIEW: We provide an updated review of clinical trials evaluating the combination of BRAF/MEK inhibitors with anti-PD-(L)1 therapy (triplet therapy) for patients with advanced BRAF-mutant melanoma, accompanied by a summary of the biological evidence supporting this combination. RECENT FINDINGS: Resistance to BRAF/MEK inhibition and comparatively low response rates to immune checkpoint inhibitors remain clinical challenges in the treatment of melanoma. Preclinical data demonstrates that targeted therapy is immune-modulatory and synergises with immune checkpoint inhibition. Several randomised controlled trials have evaluated the combination of targeted therapy with immune checkpoint inhibition. Triplet therapy has shown improvements in progression-free survival and durability of response compared to BRAF/MEK inhibition alone; however, questions remain regarding the best clinical scenario for implementation of this regimen in the era of front-line immunotherapy.

Regulation of PRMT5-MDM4 axis is critical in the response to CDK4/6 inhibitors in melanoma.

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are an established treatment in estrogen receptor-positive breast cancer and are currently in clinical development in melanoma, a tumor that exhibits high rates of CDK4 activation. We analyzed melanoma cells with acquired resistance to the CDK4/6 inhibitor palbociclib and demonstrate that the activity of PRMT5, a protein arginine methyltransferase and indirect target of CDK4, is essential for CDK4/6 inhibitor sensitivity. By indirectly suppressing PRMT5 activity, palbociclib alters the pre-mRNA splicing of MDM4, a negative regulator of p53, leading to decreased MDM4 protein expression and subsequent p53 activation. In turn, p53 induces p21, leading to inhibition of CDK2, the main kinase substituting for CDK4/6 and a key driver of resistance to palbociclib. Loss of the ability of palbociclib to regulate the PRMT5-MDM4 axis leads to resistance. Importantly, combining palbociclib with the PRMT5 inhibitor GSK3326595 enhances the efficacy of palbociclib in treating naive and resistant models and also delays the emergence of resistance. Our studies have uncovered a mechanism of action of CDK4/6 inhibitors in regulating the MDM4 oncogene and the tumor suppressor, p53. Furthermore, we have established that palbociclib inhibition of the PRMT5-MDM4 axis is essential for robust melanoma cell sensitivity and provide preclinical evidence that coinhibition of CDK4/6 and PRMT5 is an effective and well-tolerated therapeutic strategy. Overall, our data provide a strong rationale for further investigation of novel combinations of CDK4/6 and PRMT5 inhibitors, not only in melanoma but other tumor types, including breast, pancreatic, and esophageal carcinoma.

Atezolizumab, vemurafenib, and cobimetinib as first-line treatment for unresectable advanced BRAFV600 mutation-positive melanoma (IMspire150): primary analysis of the randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: IMspire150 aimed to evaluate first-line combination treatment with BRAF plus MEK inhibitors and immune checkpoint therapy in BRAFV600 mutation-positive advanced or metastatic melanoma. METHODS: IMspire150 was a randomised, double-blind, placebo-controlled phase 3 study done at 112 institutes in 20 countries. Patients with unresectable stage IIIc-IV, BRAFV600 mutation-positive melanoma were randomly assigned 1:1 to 28-day cycles of atezolizumab, vemurafenib, and cobimetinib (atezolizumab group) or atezolizumab placebo, vemurafenib, and cobimetinib (control group). In cycle 1, all patients received vemurafenib and cobimetinib only; atezolizumab placebo was added from cycle 2 onward. Randomisation was stratified by lactate dehydrogenase concentration and geographical region. Blinding for atezolizumab was achieved by means of an identical intravenous placebo, and blinding for vemurafenib was achieved by means of a placebo tablet. The primary outcome was investigator-assessed progression-free survival. This trial (ClinicalTrials.gov, NCT02908672) is ongoing but no longer recruiting patients. FINDINGS: Between Jan 13, 2017, and April 26, 2018, 777 patients were screened and 514 were enrolled and randomly assigned to the atezolizumab group (n=256) or control group (n=258). At a median follow-up of 18·9 months (IQR 10·4-23·8), progression-free survival as assessed by the study investigator was significantly prolonged with atezolizumab versus control (15·1 vs 10·6 months; hazard ratio [HR] 0·78; 95% CI 0·63-0·97; p=0·025). Common treatment-related adverse events (>30%) in the atezolizumab and control groups were blood creatinine phosphokinase increased (51·3% vs 44·8%), diarrhoea (42·2% vs 46·6%), rash (40·9%, both groups), arthralgia (39·1% vs 28·1%), pyrexia (38·7% vs 26·0%), alanine aminotransferase increased (33·9% vs 22·8%), and lipase increased (32·2% vs 27·4%); 13% of patients in the atezolizumab group and 16% in the control group stopped all treatment because of adverse events. INTERPRETATION: The addition of atezolizumab to targeted therapy with vemurafenib and cobimetinib was safe and tolerable and significantly increased progression-free survival in patients with BRAFV600 mutation-positive advanced melanoma. FUNDING: F Hoffmann-La Roche and Genentech.

Impact of initial treatment and prognostic factors on postprogression survival in BRAF-mutated metastatic melanoma treated with dacarbazine or vemurafenib ± cobimetinib: a pooled analysis of four clinical trials.

BACKGROUND: We sought to identify patient subgroups with distinct postprogression overall survival (ppOS) outcomes and investigate the impact of original treatment assignment and initial postprogression treatment (ppRx) on ppOS. METHODS: Recursive partitioning analysis (RPA) was performed to model relationships between prespecified covariates and ppOS in patients with BRAFV600-mutated metastatic melanoma who had experienced progressive disease (PD) following treatment with cobimetinib plus vemurafenib, vemurafenib monotherapy, or dacarbazine in the BRIM-2, BRIM-3, BRIM-7, and coBRIM studies. Prognostic subgroups identified by RPA were then applied to pooled treatment cohorts. The primary endpoint was ppOS, defined as time from first PD to death from any cause. RESULTS: RPA identified baseline lactate dehydrogenase (LDH), baseline disease stage, Eastern Cooperative Oncology Group performance status at PD, and ppRx as significant prognostic factors for ppOS. Median ppOS was longest in patients with normal baseline LDH, stage M1c disease at baseline, and ppRx with immunotherapy or targeted therapy (12.2 months; 95% CI 10.3-16.1) and shortest in those with elevated baseline LDH > 2 × upper limit of normal (2.3 months; 95% CI 1.8-2.7). Original treatment assignment did not impact ppOS. Across treatment cohorts, patients treated with immunotherapy or targeted therapy after PD had better ppOS than those given other treatments. CONCLUSION: A combination of factors at baseline (LDH, disease stage) and PD (performance status, ppRx) impact ppOS outcomes. ppRx with immunotherapy or targeted therapy is an independent prognostic factor for improved overall survival following progression regardless of original treatment. Trial registration The trials included in this analysis are registered with ClinicalTrials.gov: NCT00949702 (BRIM-2), NCT01006980 (BRIM-3), NCT01271803 (BRIM-7), and NCT01689519 (coBRIM).

Impact of depth of response on survival in patients treated with cobimetinib ± vemurafenib: pooled analysis of BRIM-2, BRIM-3, BRIM-7 and coBRIM.

BACKGROUND: This pooled analysis investigated the prognostic value of depth of response in two cohorts of patients with BRAFV600-mutated metastatic melanoma treated with vemurafenib or cobimetinib plus vemurafenib. METHODS: The data were pooled from BRIM-2, BRIM-3, BRIM-7 and coBRIM. Association of depth of response with survival was estimated by Cox proportional hazards regression, adjusted for clinically relevant covariates. Depth of response was analysed in previously identified prognostic subgroups based on disease characteristics and gene signatures. RESULTS: Greater tumour reduction and longer time to maximal response were significantly associated with longer progression-free survival (PFS) and overall survival (OS) when evaluated as continuous variables. Patients with the deepest responses had long-lasting survival outcomes (median PFS: 14 months; OS: 32 months with vemurafenib; not estimable with cobimetinib plus vemurafenib). Cobimetinib plus vemurafenib improved depth of response versus vemurafenib monotherapy regardless of other prognostic factors, including gene signatures. CONCLUSIONS: Greater depth of response was associated with improved survival, supporting its utility as a measure of treatment efficacy in melanoma and further evaluation of its incorporation into existing prognostic models. Cobimetinib plus vemurafenib improved outcomes across quartiles of response regardless of prognostic factors or gene signatures and provided durable survival benefits in patients with deep responses.

Inhibition of Pol I transcription treats murine and human AML by targeting the leukemia-initiating cell population.

Despite the development of novel drugs, the prospects for many patients with acute myeloid leukemia (AML) remain dismal. This study reveals that the selective inhibitor of RNA polymerase I (Pol I) transcription, CX-5461, effectively treats aggressive AML, including mixed-lineage leukemia-driven AML, and outperforms standard chemotherapies. In addition to the previously characterized mechanism of action of CX-5461 (ie, the induction of p53-dependent apoptotic cell death), the inhibition of Pol I transcription also demonstrates potent efficacy in p53null AML in vivo. This significant survival advantage in both p53WT and p53null leukemic mice treated with CX-5461 is associated with activation of the checkpoint kinases 1/2, an aberrant G2/M cell-cycle progression and induction of myeloid differentiation of the leukemic blasts. The ability to target the leukemic-initiating cell population is thought to be essential for lasting therapeutic benefit. Most strikingly, the acute inhibition of Pol I transcription reduces both the leukemic granulocyte-macrophage progenitor and leukemia-initiating cell (LIC) populations, and suppresses their clonogenic capacity. This suggests that dysregulated Pol I transcription is essential for the maintenance of their leukemia-initiating potential. Together, these findings demonstrate the therapeutic utility of this new class of inhibitors to treat highly aggressive AML by targeting LICs.

Combination nivolumab and ipilimumab or nivolumab alone in melanoma brain metastases: a multicentre randomised phase 2 study.

BACKGROUND: Nivolumab monotherapy and combination nivolumab plus ipilimumab increase proportions of patients achieving a response and survival versus ipilimumab in patients with metastatic melanoma; however, efficacy in active brain metastases is unknown. We aimed to establish the efficacy and safety of nivolumab alone or in combination with ipilimumab in patients with active melanoma brain metastases. METHODS: This multicentre open-label randomised phase 2 trial was done at four sites in Australia, in three cohorts of immunotherapy-naive patients aged 18 years or older with melanoma brain metastases. Patients with asymptomatic brain metastases with no previous local brain therapy were randomly assigned using the biased coin minimisation method, stratified by site, in a 30:24 ratio (after a safety run-in of six patients) to cohort A (nivolumab plus ipilimumab) or cohort B (nivolumab). Patients with brain metastases in whom local therapy had failed, or who had neurological symptoms, or leptomeningeal disease were enrolled in non-randomised cohort C (nivolumab). Patients in cohort A received intravenous nivolumab 1 mg/kg combined with ipilimumab 3 mg/kg every 3 weeks for four doses, then nivolumab 3 mg/kg every 2 weeks; patients in cohort B or cohort C received intravenous nivolumab 3 mg/kg every 2 weeks. The primary endpoint was intracranial response from week 12. Primary and safety analyses were done on an intention-to-treat basis in all patients who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, number NCT02374242, and is ongoing for the final survival analysis. FINDINGS: Between Nov 4, 2014, and April 21, 2017, 79 patients were enrolled; 36 in cohort A, 27 in cohort B, and 16 in cohort C. One patient in cohort A and two in cohort B were found to be ineligible and excluded from the study before receiving the study drug. At the data cutoff (Aug 28, 2017), with a median follow up of 17 months (IQR 8-25), intracranial responses were achieved by 16 (46%; 95% CI 29-63) of 35 patients in cohort A, five (20%; 7-41) of 25 in cohort B, and one (6%; 0-30) of 16 in cohort C. Intracranial complete responses occurred in six (17%) patients in cohort A, three (12%) in cohort B, and none in cohort C. Treatment-related adverse events occurred in 34 (97%) of 35 patients in cohort A, 17 (68%) of 25 in cohort B, and eight (50%) of 16 in cohort C. Grade 3 or 4 treatment-related adverse events occurred in 19 (54%) patients in cohort A, four (16%) in cohort B, and two (13%) in cohort C. No treatment-related deaths occurred. INTERPRETATION: Nivolumab combined with ipilimumab and nivolumab monotherapy are active in melanoma brain metastases. A high proportion of patients achieved an intracranial response with the combination. Thus, nivolumab combined with ipilimumab should be considered as a first-line therapy for patients with asymptomatic untreated brain metastases. FUNDING: Melanoma Institute Australia and Bristol-Myers Squibb.

Palbociclib synergizes with BRAF and MEK inhibitors in treatment naïve melanoma but not after the development of BRAF inhibitor resistance.

Increased CDK4 activity occurs in the majority of melanomas and CDK4/6 inhibitors in combination with BRAF and MEK inhibitors are currently in clinical trials for the treatment of melanoma. We hypothesize that the timing of the addition of CDK4/6 inhibitors to the current BRAF and MEK inhibitor regime will impact on the efficacy of this triplet drug combination. The efficacy of BRAF, MEK and CDK4/6 inhibitors as single agents and in combination was assessed in human BRAF mutant cell lines that were treatment naïve, BRAF inhibitor tolerant or had acquired resistance to BRAF inhibitors. Xenograft studies were then performed to test the in vivo efficacy of the BRAF and CDK4/6 inhibitor combination. Melanoma cells that had developed early reversible tolerance or acquired resistance to BRAF inhibition remained sensitive to palbociclib. In drug-tolerant cells, the efficacy of the combination of palbociclib with BRAF and/or MEK inhibitors was equivalent to single agent palbociclib. Similarly, acquired BRAF inhibitor resistance cells lost efficacy to the palbociclib and BRAF combination. In contrast, upfront treatment of melanoma cells with palbociclib in combination with BRAF and/or MEK inhibitors induced either cell death or senescence and was superior to a BRAF plus MEK inhibitor combination. In vivo palbociclib plus BRAF inhibitor induced rapid and sustained tumor regression without the development of therapy resistance. In summary, upfront dual targeting of CDK4/6 and mutant BRAF signaling enables tumor cells to evade resistance to monotherapy and is required for robust and sustained tumor regression. Melanoma patients whose tumors have acquired resistance to BRAF inhibition are less likely to have favorable responses to subsequent treatment with the triplet combination of BRAF, MEK and CDK4/6 inhibitors.

Tumour mutation status and melanoma recurrence following a negative sentinel lymph node biopsy.

BACKGROUND: A proportion of patients develop recurrence following a tumour-negative sentinel lymph node biopsy (SLNB). This study aimed to explore whether melanoma patients with BRAF or NRAS mutant tumours have an increased risk of developing disease recurrence following a negative SLNB compared to patients with wild-type tumours. METHODS: Prospective cohort study of melanoma patients at three tertiary referral centres in Melbourne, who underwent SLNB. Clinical, pathological and molecular characteristics and recurrence data were prospectively recorded. Multivariate Cox proportional hazards regression models estimated the adjusted hazard ratio (aHR) and corresponding 95% confidence interval (CI) for the association between mutation status and development of recurrence following a negative-SLNB. RESULTS: Overall, 344/477 (72.1%) patients had a negative SLNB. Of these, 54 (15.7%) developed subsequent recurrence. The risk of disease recurrence following a negative SLNB was increased for patients with either a BRAF or NRAS mutant tumour compared to wild-type tumours (aHR 1.92, 95% CI: 1.02-3.60, p = 0.04). CONCLUSION: Melanoma patients with BRAF or NRAS mutant tumours had an increased risk compared to patients with BRAF/NRAS wild-type tumours of developing disease recurrence following a tumour-negative SLNB. The findings also confirm the importance of continued surveillance to monitor for disease recurrence among SLNB-negative patients.

Health-related quality of life impact of cobimetinib in combination with vemurafenib in patients with advanced or metastatic BRAFV600 mutation-positive melanoma.

BACKGROUND: In the coBRIM study, cobimetinib plus vemurafenib (C+V) significantly improved survival outcomes vs placebo and vemurafenib (P+V) in patients with advanced/metastatic BRAFV600-mutated melanoma. An analysis of health-related quality of life (HRQOL) from coBRIM is reported. METHODS: Patients completing the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (QLQ-C30) at baseline and ⩾1 time point thereafter constituted the analysis population. Change from baseline ⩾10 points was considered clinically meaningful. RESULTS: Mean baseline scores for all QLQ-C30 domains were similar between arms. Most on-treatment scores for QLQ-C30 domains were also comparable between arms. A transient deterioration in role function in cycle 1 day 15 (C1D15; -14.7 points) in the P+V arm and improvement in insomnia in the C+V arm at C2D15 (-12.4 points) was observed. Among patients who experienced a ⩾10-point change from baseline (responders), between-group differences were greatest for insomnia (16%), social functioning (10%), fatigue (9%) and pain (7%), all favouring C+V. Diarrhoea, photosensitivity reaction, pyrexia, and rash did not meaningfully affect global health status (GHS). Serous retinopathy was associated with a transient decrease in GHS at C1D15 assessment. CONCLUSIONS: In patients with advanced/metastatic BRAFV600-mutated melanoma, treatment with C+V maintained HRQOL compared with P+V, with superior efficacy.

Combined Nivolumab and Ipilimumab or Monotherapy in Untreated Melanoma.

BACKGROUND: Nivolumab (a programmed death 1 [PD-1] checkpoint inhibitor) and ipilimumab (a cytotoxic T-lymphocyte-associated antigen 4 [CTLA-4] checkpoint inhibitor) have been shown to have complementary activity in metastatic melanoma. In this randomized, double-blind, phase 3 study, nivolumab alone or nivolumab plus ipilimumab was compared with ipilimumab alone in patients with metastatic melanoma. METHODS: We assigned, in a 1:1:1 ratio, 945 previously untreated patients with unresectable stage III or IV melanoma to nivolumab alone, nivolumab plus ipilimumab, or ipilimumab alone. Progression-free survival and overall survival were coprimary end points. Results regarding progression-free survival are presented here. RESULTS: The median progression-free survival was 11.5 months (95% confidence interval [CI], 8.9 to 16.7) with nivolumab plus ipilimumab, as compared with 2.9 months (95% CI, 2.8 to 3.4) with ipilimumab (hazard ratio for death or disease progression, 0.42; 99.5% CI, 0.31 to 0.57; P<0.001), and 6.9 months (95% CI, 4.3 to 9.5) with nivolumab (hazard ratio for the comparison with ipilimumab, 0.57; 99.5% CI, 0.43 to 0.76; P<0.001). In patients with tumors positive for the PD-1 ligand (PD-L1), the median progression-free survival was 14.0 months in the nivolumab-plus-ipilimumab group and in the nivolumab group, but in patients with PD-L1-negative tumors, progression-free survival was longer with the combination therapy than with nivolumab alone (11.2 months [95% CI, 8.0 to not reached] vs. 5.3 months [95% CI, 2.8 to 7.1]). Treatment-related adverse events of grade 3 or 4 occurred in 16.3% of the patients in the nivolumab group, 55.0% of those in the nivolumab-plus-ipilimumab group, and 27.3% of those in the ipilimumab group. CONCLUSIONS: Among previously untreated patients with metastatic melanoma, nivolumab alone or combined with ipilimumab resulted in significantly longer progression-free survival than ipilimumab alone. In patients with PD-L1-negative tumors, the combination of PD-1 and CTLA-4 blockade was more effective than either agent alone. (Funded by Bristol-Myers Squibb; CheckMate 067 ClinicalTrials.gov number, NCT01844505.).

Tumour mutation status and sites of metastasis in patients with cutaneous melanoma.

BACKGROUND: Cutaneous melanoma can metastasise haematogenously and/or lymphogenously to form satellite/in-transit, lymph node or distant metastasis. This study aimed to determine if BRAF and NRAS mutant and wild-type tumours differ in their site of first tumour metastasis and anatomical metastatic pathway. METHODS: Prospective cohort of patients with a histologically confirmed primary cutaneous melanoma at three tertiary referral centres in Melbourne, Australia from 2010 to 2015. Multinomial regression determined clinical, histological and mutational factors associated with the site of first metastasis and metastatic pathway. RESULTS: Of 1048 patients, 306 (29%) developed metastasis over a median 4.7 year follow-up period. 73 (24%), 192 (63%) and 41 (13%) developed distant, regional lymph node and satellite/in-transit metastasis as the first site of metastasis, respectively. BRAF mutation was associated with lymph node metastasis (adjusted RRR 2.46 95% CI 1.07-5.69, P=0.04) and sentinel lymph node positivity (adjusted odds ratio [aOR] OR 1.55, 95% CI 1.14-2.10, P=0.005). BRAF mutation and NRAS mutation were associated with increased odds of developing liver metastasis (aOR 3.09, 95% CI 1.49-6.42, P=0.003; aOR 3.17, 95% CI 1.32-7.58, P=0.01) and central nervous system (CNS) metastasis (aOR 4.65, 95% CI 2.23-9.69, P<0.001; aOR 4.03, 95% CI 1.72-9.44, P=0.001). NRAS mutation was associated with lung metastasis (aOR 2.44, 95% CI 1.21-4.93, P=0.01). CONCLUSIONS: BRAF mutation was found to be associated with lymph node metastasis as first metastasis and sentinel lymph node positivity. BRAF and NRAS mutations were associated with CNS and liver metastasis and NRAS mutation with lung metastasis. If these findings are validated in additional prospective studies, a role for heightened visceral organ surveillance may be warranted in patients with tumours harbouring these somatic mutations.

Health Care Resource Utilization and Associated Costs Among Metastatic Cutaneous Melanoma Patients Treated with Ipilimumab (INTUITION Study).

BACKGROUND: There are limited real-world data on health care resource utilization (HCRU) among advanced melanoma patients. The objective of this study was to describe HCRU and health care costs associated with the management of advanced melanoma patients receiving ipilimumab. METHODS: This retrospective multinational, observational study included advanced melanoma patients from Australia, Germany, Italy, and Spain who had received at least 1 dose of ipilimumab. Data extracted from medical charts included inpatient admissions, outpatient visits, surgical procedures, laboratory investigations, radiation therapy, imaging studies, and concomitant medications. Cost estimates were based on unit costs from country-specific standard reimbursement sources. Subgroup analyses were performed for BRAF mutation status and ipilimumab refractory patients, who had disease progression within 24 weeks of their last dose of ipilimumab. RESULTS: Mean age of 362 enrolled patients was 60.6 years (standard deviation [SD] 14.4). During a median follow-up period of 30.2 weeks, 57% of patients were admitted to hospital and 16% underwent surgery. Health care resource utilization rates varied substantially across countries and were highest in Germany. Concomitant medications to treat adverse events were commonly used. Subgroup analyses showed higher utilization rates among ipilimumab refractory and BRAF mutant patients. Mean weekly total costs associated with HCRU were lower in the pre-progression period (€107; 95% confidence interval (CI): 79-145) than in the post-progression period (€216; 95% CI: 180-259). CONCLUSION: Health care resource utilization pattern and associated costs among patients treated with ipilimumab varied greatly among countries and between pre- and post-progression periods. There is a high economic burden associated with ipilimumab refractory melanoma. IMPLICATIONS FOR PRACTICE: Metastatic melanoma patients treated with the anti-CTLA-4 inhibitor ipilimumab have a high utilization of various types of health care services, such as inpatient hospital stays or doctor visits. There are differences across countries regarding patterns of health care utilization and economic burden of the disease. Health care services are used more frequently after patients experience progression of their disease. The study highlights that better therapies leading to durable response in patients with metastatic melanoma have the potential to decrease health care costs and patient burden in terms of hospitalizations and other health care services.

Combined vemurafenib and cobimetinib in BRAF-mutated melanoma.

BACKGROUND: The combined inhibition of BRAF and MEK is hypothesized to improve clinical outcomes in patients with melanoma by preventing or delaying the onset of resistance observed with BRAF inhibitors alone. This randomized phase 3 study evaluated the combination of the BRAF inhibitor vemurafenib and the MEK inhibitor cobimetinib. METHODS: We randomly assigned 495 patients with previously untreated unresectable locally advanced or metastatic BRAF V600 mutation-positive melanoma to receive vemurafenib and cobimetinib (combination group) or vemurafenib and placebo (control group). The primary end point was investigator-assessed progression-free survival. RESULTS: The median progression-free survival was 9.9 months in the combination group and 6.2 months in the control group (hazard ratio for death or disease progression, 0.51; 95% confidence interval [CI], 0.39 to 0.68; P<0.001). The rate of complete or partial response in the combination group was 68%, as compared with 45% in the control group (P<0.001), including rates of complete response of 10% in the combination group and 4% in the control group. Progression-free survival as assessed by independent review was similar to investigator-assessed progression-free survival. Interim analyses of overall survival showed 9-month survival rates of 81% (95% CI, 75 to 87) in the combination group and 73% (95% CI, 65 to 80) in the control group. Vemurafenib and cobimetinib was associated with a nonsignificantly higher incidence of adverse events of grade 3 or higher, as compared with vemurafenib and placebo (65% vs. 59%), and there was no significant difference in the rate of study-drug discontinuation. The number of secondary cutaneous cancers decreased with the combination therapy. CONCLUSIONS: The addition of cobimetinib to vemurafenib was associated with a significant improvement in progression-free survival among patients with BRAF V600-mutated metastatic melanoma, at the cost of some increase in toxicity. (Funded by F. Hoffmann-La Roche/Genentech; coBRIM ClinicalTrials.gov number, NCT01689519.).

Checkpoint inhibitors in melanoma and early phase development in solid tumors: what's the future?

Anti-programmed death (PD)-1 and PD-ligand (L)-1 checkpoint inhibitors have revolutionized the therapy of several cancers. Immunotherapy of cancer can offer long-term durable benefit to patients, is active regardless of tumour histology, has a unique immune-related safety profile, and can be used in combination with other cancer treatments. In addition, recent research has shown that immune-based therapy can be used as adjuvant therapy, that outcomes may be influenced by dose, and that clinical activity is observed in patients with brain metastases. Despite our increased understanding of these agents, there are still several important questions that need to be answered. These include strategies to overcome primary and acquired resistance, the influence of mutational status on treatment outcomes, the optimal duration of treatment, and the need to identify novel combination regimens that offer increased anti-tumour potency and/or reduced toxicity. Here we review recent developments in these areas, with particular focus on new data reported at the 2017 ASCO Annual Meeting.