Undetectable circulating tumor DNA (ctDNA) levels correlate with favorable outcome in metastatic melanoma patients treated with anti-PD1 therapy.

BACKGROUND: Treatment with anti-PD1 monoclonal antibodies improves the survival of metastatic melanoma patients but only a subgroup of patients benefits from durable disease control. Predictive biomarkers for durable benefit could improve the clinical management of patients. METHODS: Plasma samples were collected from patients receiving anti-PD1 therapy for ctDNA quantitative assessment of BRAFV600 and NRASQ61/G12/G13 mutations. RESULTS: After a median follow-up of 84 weeks 457 samples from 85 patients were analyzed. Patients with undetectable ctDNA at baseline had a better PFS (Hazard ratio (HR) = 0.47, median 26 weeks versus 9 weeks, p = 0.01) and OS (HR = 0.37, median not reached versus 21.3 weeks, p = 0.005) than patients with detectable ctDNA. Additionally, the HR for death was lower after the ctDNA level became undetectable during follow-up (adjusted HR: 0.16 (95% CI 0.07-0.36), p-value < 0.001). ctDNA levels > 500 copies/ml at baseline or week 3 were associated with poor clinical outcome. Patients progressive exclusively in the central nervous system (CNS) had undetectable ctDNA at baseline and at subsequent assessments. In multivariate analysis adjusted for LDH, CRP, ECOG and number of metastatic sites, the ctDNA remained significant for PFS and OS. A positive correlation was observed between ctDNA levels and total metabolic tumor volume (TMTV), number of metastatic sites and total tumor burden. CONCLUSIONS: Assessment of ctDNA baseline and during therapy was predictive for tumor response and clinical outcome in metastatic melanoma patients and reflected the tumor burden. ctDNA evaluation provided reliable complementary information during anti-PD1 antibody therapy.

Successful treatment with intralesional talimogene laherparepvec in two patients with immune checkpoint inhibitor-refractory, advanced-stage melanoma.

Monoclonal antibodies that block the programmed death-1 (anti-PD-1) or cytotoxic T-lymphocyte antigen-4 (CTLA-4) immune checkpoint receptors (pembrolizumab, nivolumab, ipilimumab, or the combination of nivolumab with ipilimumab) are approved treatment option for patients with advanced melanoma. Over half of all patients are refractory to these immunotherapies and are in need of alternative or complementary treatment options. Talimogene laherparepvec (T-VEC) is a first-in-class intralesionally delivered oncolytic immunotherapy, which has proven efficacy in the treatment of advanced melanoma. A proportion of patients treated with T-VEC will benefit from an abscopal response of noninjected metastases indicative of a systemic antitumor immune response elicited by the intratumoral injections. At present it remains unknown whether the systemic antitumor responses elicited by T-VEC are nonredundant with immune-checkpoint blockade. Recent data on potential synergy between T-VEC and both PD-1 and CTLA-4 blockade suggest that the mechanism of action may be complementary. We report on the successful treatment with intralesional T-VEC of two female patients with locoregionally advanced BRAF V600 wild-type melanoma who previously progressed on anti-PD-1 and anti-CTLA-4 inhibitors.

Anaphylaxis-like reaction to anti-BRAF inhibitor dabrafenib confirmed by drug provocation test.

The combination of BRAF and MEK inhibitors is a standard therapeutic option for patients with metastatic melanoma with BRAF-mutated tumors. This type of targeted therapy improved patient survival, having a manageable toxicity profile. Nevertheless, potentially life-threatening severe toxicity as anaphylaxis-like reactions was observed in two reported cases. No confirmatory testing was performed for these two patients. We report a case of anaphylactic reaction to the BRAF inhibitor dabrafenib administered as a first-line treatment. The clinical picture is different compared with the reported cases, with the main life-threatening symptom being severe hypotension. An important feature of our case report is the diagnostic assessment by drug provocation test, which is considered the 'gold standard' investigation for the diagnosis of drug hypersensitivity. Additionally, serum tryptase levels were assessed, and the basophil activation test has been performed as an in-vitro diagnostic test. Elements in favor of both IgE-mediated and non-IgE-mediated reaction were observed, which is suggestive of a complex pathomechanism. This can be evocative for the heterogenous clinical manifestation of the immediate hypersensitivity reactions to BRAF inhibitors. The mechanisms responsible for the reactions should be investigated in future molecular and cellular studies.

Illustrative cases for monitoring by quantitative analysis of BRAF/NRAS ctDNA mutations in liquid biopsies of metastatic melanoma patients who gained clinical benefits from anti-PD1 antibody therapy.

Anti-programmed death 1 (PD-1) monoclonal antibodies improve the survival of metastatic melanoma patients. Predictive or monitoring biomarkers for response to this therapy could improve the clinical management of these patients. To date, no established biomarkers are available for monitoring the response to immunotherapy. Tumor- specific mutations in circulating tumor DNA (ctDNA) such as BRAF and NRAS mutations for melanoma patients have been proposed for monitoring of immunotherapy response. We present seven illustrative cases for the use of ctDNA BRAF and NRAS mutations' monitoring in plasma. The cases described exemplify four distinct clinical benefit patterns: rapid and durable complete response (CR), early progression, followed by CR, CR followed by early progression after interrupting treatment and long-term disease stabilization. These representative cases suggest that comprehensive BRAF/NRAS ctDNA monitoring during anti-PD1 therapy is informative and can be of added value for the monitoring of melanoma patients gaining clinical benefit on anti-PD1 treatment. An important advantage of our approach is that using the cartridge system on the Idylla platform for mutation analysis, the results become available the same day 2 h after plasma collection. Therefore, in the future, the ctDNA level can be an element in the clinical management of the patients.

Molecular and epigenetic features of melanomas and tumor immune microenvironment linked to durable remission to ipilimumab-based immunotherapy in metastatic patients.

BACKGROUND: Ipilimumab (Ipi) improves the survival of advanced melanoma patients with an incremental long-term benefit in 10-15 % of patients. A tumor signature that correlates with this survival benefit could help optimizing individualized treatment strategies. METHODS: Freshly frozen melanoma metastases were collected from patients treated with either Ipi alone (n: 7) or Ipi combined with a dendritic cell vaccine (TriMixDC-MEL) (n: 11). Samples were profiled by immunohistochemistry (IHC), whole transcriptome (RNA-seq) and methyl-DNA sequencing (MBD-seq). RESULTS: Patients were divided in two groups according to clinical evolution: durable benefit (DB; 5 patients) and no clinical benefit (NB; 13 patients). 20 metastases were profiled by IHC and 12 were profiled by RNA- and MBD-seq. 325 genes were identified as differentially expressed between DB and NB. Many of these genes reflected a humoral and cellular immune response. MBD-seq revealed differences between DB and NB patients in the methylation of genes linked to nervous system development and neuron differentiation. DB tumors were more infiltrated by CD8(+) and PD-L1(+) cells than NB tumors. B cells (CD20(+)) and macrophages (CD163(+)) co-localized with T cells. Focal loss of HLA class I and TAP-1 expression was observed in several NB samples. CONCLUSION: Combined analyses of melanoma metastases with IHC, gene expression and methylation profiling can potentially identify durable responders to Ipi-based immunotherapy.

Successful (neo)adjuvant BRAF-targeted therapy in a patient with locally advanced BRAF V600E mutant melanoma.

The treatment of locally advanced metastasized melanoma is challenging because there is no level 1 evidence to guide clinical decision-making. Moreover, the treatment options available fail to improve overall survival and are associated with considerable morbidity. Here, we show that systemic treatment with BRAF inhibitor vemurafenib substituted by dual BRAF/MEK inhibition (dabrafenib and trametinib) before surgery can offer the potential to cure the initially difficult or inoperable melanoma. A 62-year-old woman was diagnosed with an AJCC stage IIIB melanoma harboring the BRAF V600E mutation after a complete initial evaluation. Clinically, the patient presented a large primary lesion that was surrounded by ∼25 secondary epidermotropic lesions both satellite and 'in transit' with a diameter between 1 and 6 mm. Following multidisciplinary consultation, the patient was started on 960 mg twice-daily vemurafenib, which was stopped and resumed at 720 mg twice daily, and finally substituted with the combination dabrafenib and trametinib to reduce the persistent side effects. Successive clinical examinations had shown a progressive reduction in the thickness of the melanoma lesions. After about 5 months of therapy, surgery was performed and the histopathological analysis showed an almost complete regression of tumor cells. The treatment with dabrafenib/trametinib was continued only 3 months after surgery and stopped at the patient's request. The patient currently remains in complete remission at 8 months after surgery. The case presented here supports the use of neoadjuvant treatment with BRAF inhibitors in advanced 'in transit' melanoma.

Objective responses can be obtained by CTLA-4 inhibition in metastatic melanoma after BRAF inhibitor failure.

The aim of this study was to determine the activity of ipilimumab (ipi)-based therapy after treatment failure with a BRAF inhibitor (BRAFi). Sixty-four patients with unresectable stage III or stage IV BRAF V600-mutant melanoma who were treated sequentially with a BRAFi and ipi-based therapy [ipi as monotherapy or ipi in combination with an autologous mRNA electroporated dendritic cell vaccine (TriMixDC-MEL)] were identified. Thirty-three patients had been treated with a BRAFi before ipi-based therapy (BRAFi-first), and 31 patients had been treated with ipi-based therapy first (ipi-first). In patients treated with a BRAFi first (n=33), the best response on sequential ipi-based therapy was three complete responses and six partial responses (best objective response rate of 27%). In patients treated with ipi-based therapy first (n=31), the best response on ipi-based therapy was 0 complete response and four partial responses (best objective response rate of 13%). The response rate did not differ significantly between the two groups (P=0.14). The median overall survival from the start of ipi-based therapy was 10 months (95% confidence interval: 5.7-14.3) in the BRAFi-first group and 12.3 months (95% confidence interval: 7.4-17.2) in the ipi-first group (P=0.34). We report that objective tumor responses to ipi-based immunotherapy can still be obtained after progression has occurred upon treatment with a BRAFi. A part of this observation might be related to the results obtained with a combination of ipi and TriMixDC-MEL.

Single-center experience with ipilimumab in an expanded access program for patients with pretreated advanced melanoma.

Ipilimumab, a CTLA-4-blocking monoclonal antibody, improved the overall survival (OS) of advanced melanoma patients treated in prospective clinical trials. We here report a study on the outcome of patients with pretreated advanced melanoma offered ipilimumab (at its licensed dose of 3 mg/kg, every 3 wk for a total of 4 doses) in an expanded access program at a single-center university hospital. Of the 50 patients initiating ipilimumab, 31 patients completed induction therapy and 9 patients were offered reinduction therapy. Most immune-related adverse events were mild and reversible. The best objective response rate by mWHO-criteria included 1 complete response and 4 partial responses (best objective response rate of 10%). Two additional patients obtained a partial response by immune-related response criteria. Median OS was 7 months, with a 1- and 2-year survival rate of 45.2% and 28.8%, respectively. Long-term disease control with ipilimumab was observed in 7 patients of which 4 received reinduction. Baseline serum C-reactive protein (CRP) and the absolute lymphocyte count (ALC) measured on week 6 significantly correlated with OS. In conclusion, in this single-center experience with ipilimumab for advanced pretreated melanoma patients, clinical outcome was comparable with the results of published prospective studies. Reinduction therapy was of importance for maintaining long-term disease control in the majority of responding patients. Baseline CRP and ALC at week 6 deserve further prospective evaluation as prognostic and/or predictive (surrogate) markers.

Pattern and clinical significance of cancer-testis gene expression in head and neck squamous cell carcinoma.

Cancer-testis (CT) antigens comprise families of tumor-associated antigens that are immunogenic in patients with various cancers. Their restricted expression makes them attractive targets for immunotherapy. The aim of this study was to determine the expression of several CT genes and evaluate their prognostic value in head and neck squamous cell carcinoma (HNSCC). The pattern and level of expression of 12 CT genes (MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, MAGE-C2, NY-ESO-1, LAGE-1, SSX-2, SSX-4, BAGE, GAGE-1/2, GAGE-3/4) and the tumor-associated antigen encoding genes PRAME, HERV-K-MEL, and NA-17A were evaluated by RT-PCR in a panel of 57 primary HNSCC. Over 80% of the tumors expressed at least 1 CT gene. Coexpression of three or more genes was detected in 59% of the patients. MAGE-A4 (60%), MAGE-A3 (51%), PRAME (49%) and HERV-K-MEL (42%) were the most frequently expressed genes. Overall, the pattern of expression of CT genes indicated a coordinate regulation; however there was no correlation between expression of MAGE-A3/A4 and BORIS, a gene whose product has been implicated in CT gene activation. The presence of MAGE-A and NY-ESO-1 proteins was verified by immunohistochemistry. Analysis of the correlation between mRNA expression of CT genes with clinico-pathological characteristics and clinical outcome revealed that patients with tumors positive for MAGE-A4 or multiple CT gene expression had a poorer overall survival. Furthermore, MAGE-A4 mRNA positivity was prognostic of poor outcome independent of clinical parameters. These findings indicate that expression of CT genes is associated with a more malignant phenotype and suggest their usefulness as prognostic markers in HNSCC.

Vaccination of melanoma patients with Melan-A/Mart-1 peptide and Klebsiella outer membrane protein p40 as an adjuvant.

Toll-like receptor ligands are potentially useful adjuvants for the development of clinical T cell vaccination. Here we investigated the novel Toll-like receptor2 ligand P40, the outer membrane protein A derived from Klebsiella pneumoniae. Seventeen human leukocyte antigen-A*0201 positive stage III/IV melanoma patients were vaccinated with P40 and Melan-A/Mart-1 peptide subcutaneously in monthly intervals. Adverse reactions were mild-to-moderate. Fourteen patients received at least 8 vaccinations and were thus evaluable for clinical tumor and immune responses. Seven patients experienced progressive disease, whereas 2 patients had stable disease throughout the trial period, 1 of them with regression of multiple skin metastases. The remaining 5 patients had no measurable disease. Melan-A/Mart-1 specific CD8 T cells were analyzed ex vivo, with positive results in 6 of 14 evaluable patients. Increased percentages of T cells were found in three patients, memory/effector T cell differentiation in 4 patients, and a positive interferon-gamma Elispot assay in 1 patient. Antibody responses to P40 were observed in all patients. We conclude that vaccination with peptide and P40 was feasible and induced ex vivo detectable tumor antigen specific T cell responses in 6 of 14 patients with advanced melanoma.

Evaluation of the prognostic significance of serum galectin-3 in American Joint Committee on Cancer stage III and stage IV melanoma patients.

Galectin-3 (Gal-3) is a member of the beta-galactoside-binding lectins family and has been implicated in angiogenesis, tumor invasion, and metastatic process in vitro and in vivo. As we showed recently that advanced melanoma patients presented high serum level of Gal-3, we investigated the association of this protein with the outcome of melanoma patients. Whether this protein could be a biomarker has not been assessed, and we compared the prognostic value of serum Gal-3 in multivariate analysis with lactate dehydrogenase, C-reactive protein and S100B. We conclude that Gal-3 could be of prognostic value in melanoma patients; more precisely, this protein has a strong independent prognostic signification with a cut-off value of 10 ng/ml. After these data, we believe that serum Gal-3 measurement can have an important role in the follow-up and management of advanced American Joint Commission on Cancer stage III and stage IV melanoma patients. Further studies will uncover whether Gal-3 will be able to open new therapeutic perspectives.

A phase I pharmacokinetic study of hypoxic abdominal stop-flow perfusion with gemcitabine in patients with advanced pancreatic cancer and refractory malignant ascites.

PURPOSE: As no curative treatment for advanced pancreatic and biliary cancer with malignant ascites exists, new modalities possibly improving the response to available chemotherapies must be explored. This phase I study assesses the feasibility, tolerability and pharmacokinetics of a regional treatment of gemcitabine administered in escalating doses by the stop-flow approach to patients with advanced abdominal malignancies (adenocarcinoma of the pancreas, n = 8, and cholangiocarcinoma of the liver, n = 1). EXPERIMENTAL DESIGN: Gemcitabine at 500, 750 and 1,125 mg/m(2) was administered to three patients at each dose level by loco-regional chemotherapy, using hypoxic abdominal stop-flow perfusion. This was achieved by an aorto-caval occlusion by balloon catheters connected to an extracorporeal circuit. Gemcitabine and its main metabolite 2',2'-difluorodeoxyuridine (dFdU) concentrations were measured by high performance liquid chromatography with UV detection in the extracorporeal circuit during the 20 min of stop-flow perfusion, and in peripheral plasma for 420 min. Blood gases were monitored during the stop-flow perfusion and hypoxia was considered stringent if two of the following endpoints were met: pH /=1.35. The tolerability of this procedure was also assessed. RESULTS: Stringent hypoxia was achieved in four patients. Very high levels of gemcitabine were rapidly reached in the extracorporeal circuit during the 20 min of stop-flow perfusion, with C (max) levels in the abdominal circuit of 246 (+/-37%), 2,039 (+/-77%) and 4,780 (+/-7.3%) mug/ml for the three dose levels 500, 750 and 1,125 mg/m(2), respectively. These C (max) were between 13 (+/-51%) and 290 (+/-12%) times higher than those measured in the peripheral plasma. Similarly, the abdominal exposure to gemcitabine, calculated as AUC(t0-20), was between 5.5 (+/-43%) and 200 (+/-66%)-fold higher than the systemic exposure. Loco-regional exposure to gemcitabine was statistically higher in presence of stringent hypoxia (P < 0.01 for C (max) and AUC(t0-20), both normalised to the gemcitabine dose). Toxicities were acceptable considering the complexity of the procedure and were mostly hepatic; it was not possible to differentiate the respective contributions of systemic and regional exposures. A significant correlation (P < 0.05) was found between systemic C (max) of gemcitabine and the nadir of both leucocytes and neutrophils. CONCLUSIONS: Regional exposure to gemcitabine-the current standard drug for advanced adenocarcinoma of the pancreas-can be markedly enhanced using an optimised hypoxic stop-flow perfusion technique, with acceptable toxicities up to a dose of 1,125 mg/m(2). However, the activity of gemcitabine under hypoxic conditions is not as firmly established as that of other drugs such as mitomycin C, melphalan or tirapazamine. Further studies of this investigational modality, but with bioreductive drugs, are therefore warranted first to evaluate the tolerance in a phase I study and later on to assess whether it does improve the response to chemotherapy.

The role of interval nodes in sentinel lymph node mapping and dissection for melanoma patients.

UNLABELLED: In sentinel node (SN) biopsy, an interval SN is defined as a lymph node or group of lymph nodes located between the primary melanoma and an anatomically well-defined lymph node group directly draining the skin. As shown in previous reports, these interval SNs seem to be at the same metastatic risk as are SNs in the usual, classic areas. This study aimed to review the incidence, lymphatic anatomy, and metastatic risk of interval SNs. METHODS: SN biopsy was performed at a tertiary center by a single surgical team on a cohort of 402 consecutive patients with primary melanoma. The triple technique of localization was used-that is, lymphoscintigraphy, blue dye, and gamma-probe. Otolaryngologic melanoma and mucosal melanoma were excluded from this analysis. SNs were examined by serial sectioning and immunohistochemistry. All patients with metastatic SNs were recommended to undergo a radical selective lymph node dissection. RESULTS: The primary locations of the melanomas included the trunk (188), an upper limb (67), or a lower limb (147). Overall, 97 (24.1%) of the 402 SNs were metastatic. Interval SNs were observed in 18 patients, in all but 2 of whom classic SNs were also found. The location of the primary was truncal in 11 (61%) of the 18, upper limb in 5, and lower limb in 2. One patient with a dorsal melanoma had drainage exclusively in a cervicoscapular area that was shown on removal to contain not lymph node tissue but only a blue lymph channel without tumor cells. Apart from the interval SN, 13 patients had 1 classic SN area and 3 patients 2 classic SN areas. Of the 18 patients, 2 had at least 1 metastatic interval SN and 2 had a classic SN that was metastatic; overall, 4 (22.2%) of 18 patients were node-positive. CONCLUSION: We found that 2 of 18 interval SNs were metastatic: This study showed that preoperative lymphoscintigraphy must review all known lymphatic areas in order to exclude an interval SN.

Long-term protective effect of mature DC-LAMP+ dendritic cell accumulation in sentinel lymph nodes containing micrometastatic melanoma.

PURPOSE: In a previous immunohistochemical study of dendritic cells (DC) in sentinel lymph nodes (SLN) draining regressing melanomas, we found that the accumulation of mature DC-LAMP(+) DCs in SLNs was associated with local expansion of antigen-specific memory effector CTLs and the absence of metastasis in downstream lymph nodes. The aim of this study was to investigate the prognostic importance of the maximal density of mature DCs in SLNs. EXPERIMENTAL DESIGN: A total of 458 consecutive patients with micrometastatic melanoma within SLNs were eligible for analysis. The maximal density of mature DC-LAMP(+) DCs was evaluated by three independent observers and categorized into three classes (<100, 100 to <200, and >or=200/mm(2)). RESULTS: There was excellent interobserver reproducibility for maximum density of mature DC-LAMP(+) DC scores (kappa score = 0.82). There were differences in the maximal density scores and staining intensity according to the treating melanoma center (P < 0.001). The higher the mature DC density in the SLN is, the longer is the duration of survival [P = 0.047; hazard ratio, 0.70; 95% confidence interval, 0.50-1.00]. Adjusted by thickness and ulceration, the prognostic importance of DC density was lower (P = 0.36). CONCLUSION: This study is the first to report the prognostic value of DC-LAMP(+) DC counts in SLNs containing metastatic melanoma. Patients with a high density of mature DCs (>or=200/mm(2)) have the lowest risk of death. It also provides evidence that a lack of maturation in the SLNs is important in biological facilitation of melanoma progression.

Combination of transient lymphodepletion with busulfan and fludarabine and peptide vaccination in a phase I clinical trial for patients with advanced melanoma.

Taking advantage of homeostatic mechanisms to boost tumor-specific cellular immunity is raising increasing interest in the development of therapeutic strategies in the treatment of melanoma. Here, we have explored the potential of combining homeostatic proliferation, after transient immunosuppression, and antigenic stimulation of Melan-A/Mart-1 specific CD8 T-cells. In an effort to develop protocols that could be readily applicable to the clinic, we have designed a phase I clinical trial, involving lymphodepleting chemotherapy with Busulfan and Fludarabine, reinfusion of Melan-A specific CD8 T-cell containing peripheral blood mononuclear cells (exempt of growth factors), and Melan-A peptide vaccination. Six patients with advanced melanoma were enrolled in this outpatient regimen that demonstrated good feasibility combined with low toxicity. Consistent depletion of lymphocytes with persistent increased CD4/CD8 ratios was induced, although the proportion of circulating CD4 regulatory T-cells remained mostly unchanged. The study of the immune reconstitution period showed a steady recovery of whole T-cell numbers overtime. However, expansion of Melan-A specific CD8 T-cells, as measured in peripheral blood, was mostly inconsistent, accompanied with marginal phenotypic changes, despite vaccination with Melan-A/Mart-1 peptide. On the clinical level, 1 patient presented a partial but objective antitumor response following the beginning of the protocol, even though a direct effect of Busulfan/Fludarabine cannot be completely ruled out. Overall, these data provide further ground for the development of immunotherapeutic approaches to be both effective against melanoma and applicable in clinic.

Pretreatment levels of peripheral neutrophils and leukocytes as independent predictors of overall survival in patients with American Joint Committee on Cancer Stage IV Melanoma: results of the EORTC 18951 Biochemotherapy Trial.

PURPOSE: An elevated count of blood neutrophils and monocytes recently was shown independently to predict short survival in patients with stage IV melanoma undergoing interleukin-2-based immunotherapy. In this study, we aimed to validate this finding in a large cohort of stage IV melanoma patients. PATIENTS AND METHODS: For this retrospective prognostic study, the data from the European Organisation for the Research and Treatment of Cancer 18951 study were used. Patients were randomly assigned between treatment with dacarbazine, cisplatin, and interferon alfa with or without interleukin-2. Counts of neutrophils and leukocytes were analyzed together with other known prognostic factors: serum lactate dehydrogenase, performance status, metastatic site, and sex. Two multivariate prognostic factor analyses were carried out in the model: one with leukocyte counts and one with neutrophil counts. RESULTS: A total of 363 patients were randomly assigned and baseline blood neutrophil and leukocyte counts were available from 316 and 350 patients, respectively. A high neutrophil count (> 7.5 x 10(9)/L) was an independent prognostic factor for short overall survival (hazard ratio [HR], 1.5; 95% CI, 1.1 to 2.1; P = 0.02), and a high leukocyte count (> 10 x 10(9)/L) was an independent prognostic factor of both short overall survival (HR, 1.7; 95% CI, 1.3 to 2.4; P = 0.0005) and short progression-free survival (HR, 1.5; 95% CI, 1.1 to 2.1; P = 0.008). CONCLUSION: A high pretreatment count of neutrophils in blood was confirmed as an independent prognostic factor for short overall survival in stage IV melanoma patients undergoing interleukin-2-based immunotherapy. Furthermore, a high count of leukocytes was an independent prognostic factor for short overall survival and progression-free survival. Both parameters should be useful as stratification factors in clinical trials.

IL-12 controls cytotoxicity of a novel subset of self-antigen-specific human CD28+ cytolytic T cells.

Activated CD8 T cells develop cytotoxicity against autologous cells bearing foreign Ags and self/tumor Ags. However, self-specific cytolysis needs to be kept under control to avoid overwhelming immunopathology. After peptide vaccination of melanoma patients, we studied molecular and functional properties of T cell subsets specific for the self/tumor Ag Melan-A/MART-1. Ex vivo analysis revealed three Ag-specific effector memory (EM) populations, as follows: CD28-negative EM (EM28(-)) T cells strongly expressing granzyme/perforin, and two EM28(+) subsets, one with high and the other with low level expression of these cytotoxic proteins. For further functional characterization, we generated 117 stable CD8 T cell clones by ex vivo flow cytometry-based sorting of these subsets. All EM28(-)-derived clones lysed target cells with high efficacy. In contrast, EM28(+)-derived clones were heterogenous, and could be classified in two groups, one with high and the other with low killing capacity, correlating with granzyme/perforin expression. High and low killer phenotypes remained surprisingly stable for several months. However, strongly increased granzyme expression and cytotoxicity were observed after exposure to IL-12. Thus, the data reveal a newly identified subset of CD28(+) conditional killer T cells. Because CD28 can mediate strong costimulatory signals, tight cytotoxicity control, as shown in this study through IL-12, may be particularly important for subsets of T cells expressing CD28.

New generation vaccine induces effective melanoma-specific CD8+ T cells in the circulation but not in the tumor site.

Although increasing evidence suggests that CTL are important to fight the development of some cancers, the frequency of detectable tumor-specific T cells is low in cancer patients, and these cells have generally poor functional capacities, compared with virus-specific CD8(+) T cells. The generation with a vaccine of potent CTL responses against tumor Ags therefore remains a major challenge. In the present study, ex vivo analyses of Melan-A-specific CD8(+) T cells following vaccination with Melan-A peptide and CpG oligodeoxynucleotides revealed the successful induction in the circulation of effective melanoma-specific T cells, i.e., with phenotypic and functional characteristics similar to those of CTL specific for immunodominant viral Ags. Nonetheless, the eventual impact on tumor development in vaccinated melanoma donors remained limited. The comprehensive study of vaccinated patient metastasis shows that vaccine-driven tumor-infiltrating lymphocytes, although activated, still differed in functional capacities compared with blood counterparts. This coincided with a significant increase of FoxP3(+) regulatory T cell activity within the tumor. The consistent induction of effective tumor-specific CD8(+) T cells in the circulation with a vaccine represents a major achievement; however, clinical benefit may not be achieved unless the tumor environment can be altered to enable CD8(+) T cell efficacy.

A novel approach to characterize clonality and differentiation of human melanoma-specific T cell responses: spontaneous priming and efficient boosting by vaccination.

Despite major progress in T lymphocyte analysis in melanoma patients, TCR repertoire selection and kinetics in response to tumor Ags remain largely unexplored. In this study, using a novel ex vivo molecular-based approach at the single-cell level, we identified a single, naturally primed T cell clone that dominated the human CD8(+) T cell response to the Melan-A/MART-1 Ag. The dominant clone expressed a high-avidity TCR to cognate tumor Ag, efficiently killed tumor cells, and prevailed in the differentiated effector-memory T lymphocyte compartment. TCR sequencing also revealed that this particular clone arose at least 1 year before vaccination, displayed long-term persistence, and efficient homing to metastases. Remarkably, during concomitant vaccination over 3.5 years, the frequency of the pre-existing clone progressively increased, reaching up to 2.5% of the circulating CD8 pool while its effector functions were enhanced. In parallel, the disease stabilized, but subsequently progressed with loss of Melan-A expression by melanoma cells. Collectively, combined ex vivo analysis of T cell differentiation and clonality revealed for the first time a strong expansion of a tumor Ag-specific human T cell clone, comparable to protective virus-specific T cells. The observed successful boosting by peptide vaccination support further development of immunotherapy by including strategies to overcome immune escape.

Efficiency of recombinant human TNF in human cancer therapy.

Recombinant human tumour necrosis factor (TNF) has a selective effect on angiogenic vessels in tumours. Given that it induces vasoplegia, its clinical use has been limited to administration through isolated limb perfusion (ILP) for regionally advanced melanomas and soft tissue sarcomas of the limbs. When combined with the alkylating agent melphalan, a single ILP produces a very high objective response rate. In melanoma, the complete response (CR) rate is around 80% and the overall objective response rate greater than 90%. In soft tissue sarcomas that are inextirpable, ILP is a neoadjuvant treatment resulting in limb salvage in 80% of the cases. The CR rate averages 20% and the objective response rate is around 80%. The mode of action of TNF-based ILP involves two distinct and successive effects on the tumour-associated vasculature: first, an increase in endothelium permeability leading to improved chemotherapy penetration within the tumour tissue, and second, a selective killing of angiogenic endothelial cells resulting in tumour vessel destruction. The mechanism whereby these events occur involves rapid (of the order of minutes) perturbation of cell-cell adhesive junctions and inhibition of alphavbeta3 integrin signalling in tumour-associated vessels, followed by massive death of endothelial cells and tumour vascular collapse 24 hours later. New, promising approaches for the systemic use of TNF in cancer therapy include TNF targeting by means of single chain antibodies or endothelial cell ligands, or combined administration with drugs perturbing integrin-dependent signalling and sensitizing angiogenic endothelial cells to TNF-induced death.