Richard Kefford

Dabrafenib has activity in patients with brain metastases, but little is known of the relative efficacy of treatment within and outside the brain. This study sought to examine the intracranial (IC) and extracranial (EC) patterns of response and progression in patients with active melanoma brain metastases treated with dabrafenib. Clinicopathologic parameters were collected on patients with active brain metastases enrolled in the phase 1 and 2 studies of dabrafenib at a single institution. RECIST (Response Evaluation Criteria In Solid Tumors) response and progression-free survival (PFS) were prospectively assessed by disease site (IC versus EC). Treatments received after disease progression were also assessed. A total of 23 patients were studied. Response rates were similar in IC (78%) and EC (90%) sites (P = .416). IC and EC response was concordant in 71% of patients. Median site-specific PFS was identical in both IC and EC sites (23.6 weeks, P = .465), and exceeded whole-body PFS determined by RECIST (16.3 weeks). Of 20 patients with progressive disease (PD), 6 had IC PD only, 6 had EC PD only, and 8 had PD in both sites. In those with isolated intracranial PD, 5 of 6 underwent local therapy to the brain and continued on dabrafenib longer than 30 days. IC and EC melanoma metastases respond similarly to dabrafenib. There is no dominant site or pattern of disease progression in patients with brain metastases treated with dabrafenib. Salvage local therapy is possible in most patients after IC disease progression, with ongoing dabrafenib treatment possible in a subset of patients.

We report the acute onset of polyarticular inflammatory arthritis in 2 patients receiving the immune check-point inhibitor, pembrolizumab (MK-3475), anti-PD1 drug for metastatic melanoma after 14 and 11 months therapy, respectively. The first patient had severe tenosynovitis, synovitis, bone marrow edema, and myositis, whereas the second patient had predominantly synovitis and tenosynovitis. Good symptomatic control was obtained with bisphosphonates and salazopyrin, avoiding the use of T-cell immunosuppressants. These cases raise important questions on whether anti-PD1 therapy allows preexisting autoimmune T-cell clones to escape tolerance by suppressing regulatory T cells or whether they allow autoimmunity to develop de novo. These conditions heighten our awareness of complications associated with the clinical use of these agents, and provide a prototypical model for future research into the understanding of autoimmunity.

ABSTRACT Background: Anti-PD-1 therapy has demonstrated activity in MM but current data may not fully reflect patterns of response and relapse as discerned by comprehensive lesion-specific analysis. Methods: Bidimensional measurements of every metastasis (met) ≥5mm (≥15mm short axis for lymph nodes [LN]) in MM pts enrolled in the MK3475-001 phase 1 trial at a single center were obtained on CT scan at baseline, 12 wks and thereafter. Response of each individual met was determined by change in product of longest perpendicular diameters (POD) and classified as complete (CR, disappearance or <10mm short axis for LN), partial (PR, ≥50% reduction in POD), stable (SD, neither CR/PR/PD) or progressive (PD, ≥25% increase in POD and ≥5mm in 1 axis). Overall pt response was investigator determined using standard immune related response criteria (irRC). Results: 27 evaluable pts with med. follow up of 54 wks had a total of 442 discrete mets at baseline (med. 10/pt; range 2-68/pt; med. POD 129mm2). 13/27 (48%) pts had an irRC objective response (OR), 11 (85%) by first scan. Med. time to best response in pts with OR was 24 wks. Although only 1/27 pts had CR (3.7%), 228/442 (52%) individual mets underwent CR and 81% of pts (22/27) had ≥1 CR met at first scan. CR mets were smaller than non-CR [med. POD 80 vs 246mm2(p<0.05)] but 92/244 mets (38%) ≥100mm2 reached CR. CR rate was highest in lung vs other sites combined (p<0.05) (Table). Only 1 CR met subsequently progressed. Of 12 (44%) pts who progressed only 1 had prior OR. 10 (83%) of these pts PD in new and existing mets simultaneously. No site of PD predominated; only 1 pt (8%) PD in brain. 98/442 baseline mets (22%) progressed and most (74%) had PD as best response. Of 80 new or growing mets at first scan, only 4 (5%) subsequently had OR. Conclusions: Response to anti-PD1 therapy is rare in mets that are new or growing at first scan. CR in individual mets is common, sustained, and influenced by site and size. These results have implications for the biology of PD-1 inhibition, resistance, biomarker development and patient selection.

The treatment of metastatic melanoma has changed greatly with the development of inhibitors targeted at the mutated BRAF kinase present in up to 50% of metastatic melanoma cases. These agents, vemurafenib and dabrafenib, have been shown to increase median survival. Unfortunately, they have also been associated with the development of verrucal keratosis (VK) and cutaneous squamous cell carcinoma (cuSCC). These lesions require surgical excision, and when a large number of these lesions need to be treated, it can significantly affect the patient's quality of life. To determine if acitretin is suitable as a chemopreventative agent against the development of verrucal keratosis and cuSCC, in patients on BRAF inhibitors. Patients treated with a BRAF inhibitor, vemurafenib or dabrafenib, for stage IV metastatic melanoma, who had undergone more than five surgical excisions to remove lesions suggestive of cuSCC, were offered the opportunity to commence acitretin as a chemopreventative agent. Patients were evaluated every 4 weeks. Clinical and histological data were collected. Eight patients, who had a total of 24 cuSCC removed, were included in the study. After commencement of acitretin, only five cuSCC were excised from two patients. The most significant reduction was in a patient who had developed 13 cuSCC over 10 months and only two cuSCC 3 months after commencing acitretin. No modifications in the dose of the BRAF inhibitor were made as a result of cuSCC in any of these patients. Acitretin should be considered as a chemopreventative agent for VK and cuSCC in patients taking BRAF inhibitors, before considering dosage reductions.

Activating mutations in the BRAF gene occur in approximately 50% of melanomas. More than 70% of BRAF mutations are V600E and 10-30% are V600K. Potent and selective BRAF inhibitors have demonstrated significant clinical benefits in patients with V600E and V600K BRAF-mutated melanoma. V600R mutations constitute approximately 3-7% of all BRAF mutations and the activity of BRAF inhibitors in patients with this mutation is unknown. We have treated 45 patients with V600 mutated melanoma including patients with V600R mutation between July 2011 and October 2012 with the selective BRAF inhibitor dabrafenib (n=43) or vemurafenib (n=2) via a compassionate access programme. The overall response rate was 50% for the whole population with a progression-free survival of 5.5 months. Five objective responses were seen in six assessable patients with V600R BRAF mutation (n=9). Our experience suggests that patients with V600R BRAF mutations can be treated successfully with oral BRAF inhibitors, and molecular diagnostic assays should include detection of this type of mutation.

The purpose of this study is to profile the changes in the serum levels of a range of chemokines, cytokines, and growth and angiogenic factors in MAPK inhibitor-treated metastatic melanoma patients and to correlate these changes with clinical outcome and changes in melanoma tissue biopsies taken from the same patients. Forty-two chemokine, cytokine, angiogenic, and growth factors were measured in the sera of 20 BRAF inhibitor-treated and four combination BRAF and MEK inhibitor-treated metastatic melanoma patients using a multiplex chemokine assay. The changes were correlated with Ki-67 and CD8(+) tumor-infiltrating lymphocytes in the tumor biopsies taken at the same time points, as well as clinical outcome, including response rate, progression-free survival, and overall survival. Serum levels of IFN-γ, CCL4, and TNF-α were significantly increased, whereas CXCL8 significantly decreased from pretreatment (PRE) to early during treatment (EDT) serum samples. The decrease in serum CXCL8 levels from PRE to EDT significantly correlated with decreases in markers of melanoma proliferation (Ki-67) and increases in cytotoxic tumor-infiltrating T cells in corresponding tumor biopsies. In addition, a greater fold reduction in CXCL8 serum levels from PRE to EDT serum samples was associated with decreased overall survival. These results suggest that BRAF inhibition causes decreased CXCL8 secretion from melanoma cells and induce an immune response against the tumor associated with increased IFN-γ, CCL4, and TNF-α. Further studies are needed to determine if CXCL8 is predictive of response and to confirm the functions of these chemokine and cytokine in BRAF-mutant melanoma under BRAF inhibition.

Ipilimumab (Yervoy; Bristol-Myers Squibb) is a novel fully humanised monoclonal antibody that blocks cytotoxic T-lymphocyte antigen 4 (CTLA-4), an immune checkpoint molecule, to augment anti-tumour T-cell responses. It is associated with significant immune-related side effects including hypophysitis. We reviewed the clinical and biochemical characteristics of ten patients with ipilimumab-induced hypophysitis (IH), and developed guidelines for the early detection and management of IH based on our experiences at three major teaching hospitals in Sydney. All patients were evaluated at the Crown Princess Mary Cancer Centre and Department of Endocrinology, Westmead Hospital, Department of Endocrinology, Royal Prince Alfred Hospital, the Melanoma Institute Australia, and Macarthur Cancer Therapy Centre, Campbelltown Hospital from 2010 to 2014. Relevant data were extracted by review of medical records. Main outcome measures included clinical features, hormone profile and radiological findings associated with IH, and presence of pituitary recovery. Ten patients were identified with IH. In four patients who underwent monitoring of plasma cortisol, there was a fall in levels in the weeks prior to presentation. The pituitary-adrenal and pituitary-thyroid axes were affected in the majority of patients, with the need for physiological hormone replacement. Imaging abnormalities were identified in five of ten patients, and resolved without high dose glucocorticoid therapy. To date, all patients remain on levothyroxine and hydrocortisone replacement, where appropriate. There is significant morbidity associated with development of IH. We suggest guidelines to assist with early recognition and therapeutic intervention.

MEK1 mutations in melanoma can confer resistance to BRAF inhibitors, although preexisting MEK1(P124) mutations do not preclude clinical responses. We sought to determine whether recurrent, preexisting MEK1(P124) mutations affected clinical outcome in BRAF inhibitor-treated patients with melanoma. Data from four published datasets were analyzed to determine whether preexisting MEK1(P124) mutations affect radiologic response or progression-free survival (PFS) in patients with BRAF(V600)-mutant metastatic melanoma treated with vemurafenib or dabrafenib. The effects of MEK1(P124) mutations on MAPK pathway activity and response to BRAF inhibition were also investigated in a series of cell models. In a pooled analysis of 123 patients, the presence of a pretreatment MEK1(P124) mutation (N = 12, 10%) was associated with a poorer RECIST response (33% vs. 72% in MEK1(P124Q/S) vs. MEK1(P124) wild-type, P = 0.018), and a shorter PFS (median 3.1 vs. 4.8 months, P = 0.004). Furthermore, MEK1(P124...

BRAF inhibitors (BRAFi) cause paradoxical activation of the MAPK pathway in keratinocytes resulting in cutaneous squamous cell carcinoma (cuSCC). We sought to examine the clinical factors involved in BRAFi-induced cuSCC development. We studied 134 patients with BRAF-mutant metastatic melanoma treated with a BRAFi at Westmead Hospital, Sydney, Australia. Details of cuSCC development and associations with melanoma clinicopathologic features and treatment outcome were examined. In all, 32 (24%) patients developed 110 cuSCC after commencing treatment. In all, 61 (55%) cuSCC developed within the first 3 months. Age was the only independent risk factor for cuSCC development. After 3 months of therapy 4% of patients younger than 40 years developed cuSCC compared with 33% who were older than 60 years, and the hazard ratio of developing a cuSCC increased by 1.7 (95% confidence interval 1.3-2.3) per decade (P < .001). BRAFi cuSCC occurred more often in sun-protected areas (42%) compared with sporadic cuSCC (21%) (P < .001). cuSCC was not associated with progression-free survival. The study was from a single center and patients were also at risk of sporadic cuSCC. Most BRAFi-induced cuSCC develop within 3 months of BRAFi therapy. The only independent risk factor is increasing age. cuSCC may present in anatomical locations with low ultraviolet exposure such that thorough dermatologic assessment is required.

One-third of BRAF-mutant metastatic melanoma patients treated with combined BRAF and MEK inhibition progress within 6 months. Treatment options for these patients remain limited. Here we analyse 20 BRAF(V600)-mutant melanoma metastases derived from 10 patients treated with the combination of dabrafenib and trametinib for resistance mechanisms and genetic correlates of response. Resistance mechanisms are identified in 9/11 progressing tumours and MAPK reactivation occurred in 9/10 tumours, commonly via BRAF amplification and mutations activating NRAS and MEK2. Our data confirming that MEK2(C125S), but not the synonymous MEK1(C121S) protein, confers resistance to combination therapy highlight the functional differences between these kinases and the preponderance of MEK2 mutations in combination therapy-resistant melanomas. Exome sequencing did not identify additional progression-specific resistance candidates. Nevertheless, most melanomas carried additional oncogenic mutations at base...

Although genetic studies have reported a number of loci associated with melanoma risk, the complex genetic architecture of the disease is not yet fully understood. We sought to identify common genetic variants associated with melanoma risk in a genome-wide association study (GWAS) of 2298 cases and 6654 controls. Thirteen of 15 known loci were replicated with nominal significance. A total of 69 single-nucleotide polymorphisms (SNPs) were selected for in silico replication in two independent melanoma GWAS datasets (a total of 5149 cases and 12 795 controls). Seven novel loci were nominally significantly associated with melanoma risk. These seven SNPs were further genotyped in 234 melanoma cases and 238 controls. The SNP rs4698934 was nominally significantly associated with melanoma risk. The combined odds ratio per T allele = 1.18; 95% confidence interval (1.10-1.25); combined P = 7.70 × 10(-) (7). This SNP is located in the intron of the TET2 gene on chromosome 4q24. In addition, a ...

Dabrafenib is a selective, potent ATP-competitive inhibitor of the BRAFV600-mutant kinase that has demonstrated efficacy in clinical trials. We report the rationale for dose selection in the first-in-human study of dabrafenib, including pharmacokinetics, tissue pharmacodynamics, 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) pharmacodynamics, and dose-response relationship. Dabrafenib was administered orally once, twice (BID), or three times daily (TID). Selected dose cohorts were expanded to collect adequate data on safety, pharmacokinetics, or pharmacodynamics. A recommended phase II dose (RP2D) was chosen based on safety, pharmacokinetic, pharmacodynamic, and response data. One hundred and eighty-four patients were enrolled and treated with doses ranging from 12 mg once daily to 300 mg BID in 10 cohorts. Pharmacokinetic assessment of dabrafenib demonstrated a less-than-dose-proportional increase in exposure after repeat dosing above 150 mg BID. Similar to p...

Purpose: To evaluate the expression of tumor PD-L1 and changes in tumor-infiltrating lymphocyte (TIL) populations in metastatic melanoma patients treated with targeted MAPK inhibitors. Experimental Design: Ninety-three tumors were analyzed from 40 patients treated with a BRAF inhibitor alone (BRAFi) (n=28) or combination of BRAF and MEK inhibitors (Combi) (n=12). Tumors were excised prior to treatment (PRE), early during treatment (EDT), and at progression (PROG). Immunohistochemical staining was performed for CD4, CD8, CD68, FOXP3, LAG3, PD-1, and PD-L1 and correlated with clinical outcome. Results: Patients' tumors that were PD-L1 positive at baseline showed a significant decrease in PD-L1 expression at PROG (p=0.028), whereas patients' tumors that were PD-L1 negative at baseline showed a significant increase in PD-L1 expression at PROG (p=0.008) irrespective of treatment with BRAFi or Combi. Overall PD-L1 expression highly correlated with TIL immune markers. BRAFi-treated patients showed significant increases in CD4+, CD8+ and PD-1+ lymphocytes from PRE to EDT (p=0.001, p=0.001, p=0.017, respectively) and Combi-treated patients showed similar increases in CD4+ and CD8+ lymphocytes from PRE to EDT (p=0.017, p=0.021). Conclusions: The addition of MEKi to BRAFi did not result in significant reduction in immune-infiltration in EDT biopsies. This provides support for conducting trials that combine MAPKi with immune-checkpoint inhibitors in the hope of improving complete and durable response rates. PD-L1 expression at PROG on MAPK inhibitors varied according to baseline expression suggesting that combining MAPKi with immunotherapies concurrently may be more effective in patients with PD-L1 expression…

Of more than 150 000 published studies evaluating new biomarkers, fewer than 100 biomarkers have been implemented for patient care. One reason for this is lack of rigorous testing by the medical community to validate claims for biomarker clinical relevance, and potential reluctance to publish negative results when confirmation is not obtained. Here we sought to determine the utility and reproducibility of immunohistochemical detection of hepatocyte growth factor (HGF) in melanoma tissue, an approach of potential assistance in defining patients with innate resistance to BRAF inhibitor therapy. To this end, a published and a revised method that retained sensitivity but with greater specificity for HGF detection, were evaluated in cells known to endogenously express HGF, and in models where HGF is upregulated via cytokine induction and via overexpression by gene transfection. Consequent patient evaluation in collaboration with the Melanoma Institute Australia of a cohort of 41 melanoma specimens with extensive clinical annotation failed to validate HGF immunohistochemistry as a predictor of response to BRAF inhibitors. Targeted therapies for advanced melanoma and other cancers show great promise, and rigorous validation studies are thus indicated for approaches that seek to personalize such therapies to maximize therapeutic efficacy.