Nivolumab for locally advanced and metastatic cutaneous squamous cell carcinoma (NIVOSQUACS study)-Phase II data covering impact of concomitant haematological malignancies.

BACKGROUND: Monoclonal antibodies, such as cemiplimab and pembrolizumab, against the programmed death receptor (PD)-1 have become the current standard of care and first-line treatment of advanced cutaneous squamous cell carcinoma (cSCC), proving remarkable clinical benefit and acceptable safety. OBJECTIVES: To assess efficacy and safety of the anti-PD-1 antibody nivolumab in patients with locally advanced and metastatic cSCC. METHODS: Patients received open-label nivolumab 240 mg intravenously every 2 weeks for up to 24 months. Patients with concomitant haematological malignancies (CHMs), either non-progressing or stable under active therapy, were eligible for inclusion. RESULTS: Of 31 patients with a median age of 80 years, 22.6% of patients achieved an investigator assessed complete response, resulting in an objective response rate (ORR) of 61.3% and a disease control rate (DCR) of 64.5%. Progression-free survival (PFS) was 11.1 months, and the median overall survival (OS) was not reached after 24 weeks of therapy. Median follow-up was 23.82 months. Subgroup analysis of the CHM cohort (n = 11; 35%) revealed an ORR of 45.5%, a DCR of 54.5%, a median PFS of 10.9 months, and median OS of 20.7 months. Treatment related adverse events were reported in 58.1% of all patients (19.4% grade 3, the remaining grade 1 or 2). PD-L1 expression and CD-8+ T-cell infiltration did not significantly correlate with clinical response, although a trend towards a shorter PFS of 5.6 months was observed with PD-L1 negativity and low CD8+ intratumoral infiltration. CONCLUSION: This study demonstrated robust clinical efficacy of nivolumab in patients with locally advanced and metastatic cSCCs and a tolerability comparable to data of other anti-PD-1 antibodies. Favourable outcomes were obtained despite involving the oldest hitherto reported study cohort for anti-PD-1 antibodies and a significant proportion of CHM patients prone to high risk tumours and an aggressive course otherwise typically excluded from clinical trials.

Which medical disciplines diagnose and treat melanoma in Europe in 2019? A survey of experts from melanoma centres in 27 European countries.

BACKGROUND AND OBJECTIVES: The incidence of melanoma is increasing. This places significant burden on societies to provide efficient cancer care. The European Cancer Organisation recently published the essential requirements for quality melanoma care. The present study is aimed for the first time to roughly estimate the extent to which these requirements have been met in Europe. MATERIALS AND METHODS: A web-based survey of experts from melanoma centres in 27 European countries was conducted from 1 February to 1 August 2019. Data on diagnostic techniques, surgical and medical treatment, organization of cancer care and education were collected and correlated with national health and economic indicators and mortality-to-incidence ratio (MIR) as a surrogate for survival. Univariate linear regression analysis was performed to evaluate the correlations. SPSS software was used. Statistical significance was set at P < 0.05. RESULTS: The MIR was lower in countries with a high health expenditure per capita and with a higher numbers of general practitioners (GPs) and surgeons (SURG) per million inhabitants. In these countries, GPs and dermatologists (DER) were involved in melanoma detection; high percentage of DER used dermatoscopy and were involved in the follow-up of all melanoma stages; both medical oncologists (ONC) and dermato-oncologists administered systemic treatments; and patients had better access to sentinel lymph node biopsy and were treated within multidisciplinary tumour boards. CONCLUSION: Based on these first estimates, the greater involvement of GPs in melanoma detection; the greater involvement of highly trained DER in dermatoscopy, dermatosurgery, follow-up and the systemic treatment of melanoma; and the provision of ongoing dermato-oncology training for pathologists, SURG, DER and ONC are necessary to provide an optimal melanoma care pathway. A comprehensive analysis of the melanoma care pathway based on clinical melanoma registries will be needed to more accurately evaluate these first insights.

The evolving field of Dermato-oncology and the role of dermatologists: Position Paper of the EADO, EADV and Task Forces, EDF, IDS, EBDV-UEMS and EORTC Cutaneous Lymphoma Task Force.

BACKGROUND: The incidence of skin cancers has been increasing steadily over the last decades. Although there have been significant breakthroughs in the management of skin cancers with the introduction of novel diagnostic tools and innovative therapies, skin cancer mortality, morbidity and costs heavily burden the society. OBJECTIVE: Members of the European Association of Dermato-Oncology, European Academy of Dermatology and Venereology, International Dermoscopy Society, European Dermatology Forum, European Board of Dermatovenereology of the European Union of Medical Specialists and EORTC Cutaneous Lymphoma Task Force have joined this effort to emphasize the fundamental role that the specialist in Dermatology-Venereology has in the diagnosis and management of different types of skin cancer. We review the role of dermatologists in the prevention, diagnosis, treatment and follow-up of patients with melanoma, non-melanoma skin cancers and cutaneous lymphomas, and discuss approaches to optimize their involvement in effectively addressing the current needs and priorities of dermato-oncology. DISCUSSION: Dermatologists play a crucial role in virtually all aspects of skin cancer management including the implementation of primary and secondary prevention, the formation of standardized pathways of care for patients, the establishment of specialized skin cancer treatment centres, the coordination of an efficient multidisciplinary team and the setting up of specific follow-up plans for patients. CONCLUSION: Skin cancers represent an important health issue for modern societies. The role of dermatologists is central to improving patient care and outcomes. In view of the emerging diagnostic methods and treatments for early and advanced skin cancer, and considering the increasingly diverse skills, knowledge and expertise needed for managing this heterogeneous group of diseases, dermato-oncology should be considered as a specific subspecialty of Dermatology-Venereology.

ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee.

The European Society for Medical Oncology (ESMO) held a consensus conference on melanoma on 5-7 September 2019 in Amsterdam, The Netherlands. The conference included a multidisciplinary panel of 32 leading experts in the management of melanoma. The aim of the conference was to develop recommendations on topics that are not covered in detail in the current ESMO Clinical Practice Guideline and where available evidence is either limited or conflicting. The main topics identified for discussion were: (i) the management of locoregional disease; (ii) targeted versus immunotherapies in the adjuvant setting; (iii) targeted versus immunotherapies for the first-line treatment of metastatic melanoma; (iv) when to stop immunotherapy or targeted therapy in the metastatic setting; and (v) systemic versus local treatment of brain metastases. The expert panel was divided into five working groups in order to each address questions relating to one of the five topics outlined above. Relevant scientific literature was reviewed in advance. Recommendations were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This manuscript presents the results relating to the management of locoregional melanoma, including findings from the expert panel discussions, consensus recommendations and a summary of evidence supporting each recommendation. All participants approved the final manuscript.

ESMO consensus conference recommendations on the management of metastatic melanoma: under the auspices of the ESMO Guidelines Committee.

The European Society for Medical Oncology (ESMO) held a consensus conference on melanoma on 5-7 September 2019 in Amsterdam, The Netherlands. The conference included a multidisciplinary panel of 32 leading experts in the management of melanoma. The aim of the conference was to develop recommendations on topics that are not covered in detail in the current ESMO Clinical Practice Guideline and where available evidence is either limited or conflicting. The main topics identified for discussion were (i) the management of locoregional disease; (ii) targeted versus immunotherapies in the adjuvant setting; (iii) targeted versus immunotherapies for the first-line treatment of metastatic melanoma; (iv) when to stop immunotherapy or targeted therapy in the metastatic setting; and (v) systemic versus local treatment for brain metastases. The expert panel was divided into five working groups to each address questions relating to one of the five topics outlined above. Relevant scientific literature was reviewed in advance. Recommendations were developed by the working groups and then presented to the entire panel for further discussion and amendment before voting. This manuscript presents the results relating to the management of metastatic melanoma, including findings from the expert panel discussions, consensus recommendations and a summary of evidence supporting each recommendation. All participants approved the final manuscript.

Management of early melanoma recurrence despite adjuvant anti-PD-1 antibody therapy☆.

BACKGROUND: Anti-programmed cell death protein 1 (PD-1) antibodies (PD1) prolong recurrence-free survival in high-risk resected melanoma; however, approximately 25%-30% of patients recur within 1 year. This study describes the pattern of recurrence, management and outcomes of patients who recur with adjuvant PD1 therapy. PATIENTS AND METHODS: Consecutive patients from 16 centres who recurred having received adjuvant PD1 therapy for resected stage III/IV melanoma were studied. Recurrence characteristics, management and outcomes were examined; patients with mucosal melanoma were analysed separately. RESULTS: Melanoma recurrence occurred in 147 (17%) of ∼850 patients treated with adjuvant PD1. In those with cutaneous melanoma (n = 136), median time to recurrence was 4.6 months (range 0.3-35.7); 104 (76%) recurred during (ON) adjuvant PD1 after a median 3.2 months and 32 (24%) following (OFF) treatment cessation after a median 12.5 months, including in 21 (15%) who ceased early for toxicity. Fifty-nine (43%) recurred with locoregional disease only and 77 (57%) with distant disease. Of those who recurred locally, 22/59 (37%) subsequently recurred distantly. Eighty-nine (65%) patients received systemic therapy after recurrence. Of those who recurred ON adjuvant PD1, none (0/6) responded to PD1 alone; 8/33 assessable patients (24%) responded to ipilimumab (alone or in combination with PD1) and 18/23 (78%) responded to BRAF/MEK inhibitors. Of those who recurred OFF adjuvant PD1, two out of five (40%) responded to PD1 monotherapy, two out of five (40%) responded to ipilimumab-based therapy and 9/10 (90%) responded to BRAF/MEK inhibitors. CONCLUSIONS: Most patients who recur early despite adjuvant PD1 develop distant metastases. In those who recur ON adjuvant PD1, there is minimal activity of further PD1 monotherapy, but ipilimumab (alone or in combination with PD1) and BRAF/MEK inhibitors have clinical utility. Retreatment with PD1 may have activity in select patients who recur OFF PD1.

Talimogene laherparepvec (T-VEC) in advanced melanoma: complete response in a heart and kidney transplant patient. A case report.

Talimogene laherparepvec (T-VEC) is a intralesional oncolytic virotherapy, licensed in the European Union for locoregional advanced melanoma of American Joint Committee on Cancer stages IIIB, IIIC and IVM1a. Organ transplant recipients are currently excluded from all clinical trials dealing with immunotherapies due to the risk of transplant rejection. A 58-year-old white man with a history of heart and kidney transplantation in 2014 was diagnosed with melanoma (Breslow thickness 1·6 mm, stage pT2a) on the left arm in September 2015. In March 2016 he developed in transit metastases, and local therapy with a combination of topical imiquimod (5%) and cryotherapy of individual lesions was initiated. However, in November 2016 therapy was stopped following local progression of the metastases. An interdisciplinary decision to treat the patient with T-VEC was taken. After 11 cycles of T-VEC, the patient showed a complete response. As of June 2018, 11 months after the last treatment cycle of T-VEC, the patient continues to be tumour free. The patient tolerated the therapy well with only mild adverse events and did not show any sign of graft rejection or loss of function of the transplanted organs. We conclude that T-VEC can be a potentially effective and safe treatment in patients with a history of organ transplantation. Nevertheless, due to this special situation, the risks and benefits should always be discussed with an interdisciplinary tumour board.

Access to innovative medicines for metastatic melanoma worldwide: Melanoma World Society and European Association of Dermato-oncology survey in 34 countries.

According to data from recent studies from Europe, a large percentage of patients have restricted access to innovative medicines for metastatic melanoma. Melanoma World Society and European Association of Dermato-oncology conducted a Web-based survey on access to first-line recommended treatments for metastatic melanoma by current guidelines (National Comprehensive Center Network, European Society for Medical Oncology [ESMO] and European Organization for Research and Treatment of Cancer/European Association of Dermato-oncology/European dermatology Forum) among melanoma experts from 27 European countries, USA, China, Australia, Argentina, Brazil, Chile and Mexico from September 1st, 2017 to July 1st, 2018. Data on licencing and reimbursement of medicines and the number of patient treated were correlated with the data on health expenditure per capita (HEPC), Mackenbach score of health policy performance, health technology assessment (HTA), ASCO and ESMO Magnitude of clinical benefit scale (ESMO MCBS) scores of clinical benefit and market price of medicines. Regression analysis for evaluation of correlation between the parameters was carried out using SPSS software. The estimated number of patients without access in surveyed countries was 13768. The recommended BRAFi + MEKi combination and anti-PD1 immunotherapy were fully reimbursed/covered in 19 of 34 (55.8%) and 17 of 34 (50%) countries, and combination anti-CTLA4+anti-PD1 in was fully covered in 6 of 34 (17.6%) countries. Median delay in reimbursement was 991 days, and it was in significant correlation with ESMO MCBS (p = 0.02), median market price (p = 0.001), HEPC and Mackenbach scores (p < 0.01). Price negotiations or managed entry agreements (MEAs) with national authorities were necessary for reimbursement. In conclusion, great discrepancy exists in metastatic melanoma treatment globally. Access to innovative medicines is in correlation with economic parameters as well as with healthcare system performance parameters. Patient-oriented drug development, market access and reimbursement pathways must be urgently found.

Beyond the BRAFV600E hotspot: biology and clinical implications of rare BRAF gene mutations in melanoma patients.

BRAF gene mutations can be found in approximately 50% of melanomas, but the most common BRAF mutation leads to substitution at residue 600 of the protein, from valine to glutamic acid. BRAFV600E occurs in up to 95% of all melanoma cases and can be successfully blocked by using a combination of BRAF- and MEK inhibitors. The wider availability of next-generation sequencing is revealing more non-V600 BRAF mutations, and the clinical implications of these mutations are widely unknown. In this review, we will discuss the biology of the MAPK pathway and the different types of BRAF mutations as well as their effect on MEK activation. Current literature will be reviewed including in vitro data, case reports and case series.

More than 5000 patients with metastatic melanoma in Europe per year do not have access to recommended first-line innovative treatments.

BACKGROUND: Despite the efficacy of innovative treatments for metastatic melanoma, their high costs has led to disparities in cancer care among different European countries. We analysed the availability of these innovative therapies in Europe and estimated the number of patients without access to first-line recommended treatment per current guidelines of professional entities such as the European Society for Medical Oncology (ESMO), the European Organisation for Research and Treatment of Cancer (EORTC), the European Association of Dermato-Oncology (EADO), and European Dermatology Forum (EDF). MATERIALS AND METHODS: Web-based online survey was conducted in 30 European countries with questions about the treatment schedules from 1st May 2015 to 1st May 2016: number of metastatic melanoma patients, registration and reimbursement of innovative medicines (updated data, as of 1st October 2016), percentage of patients treated and availability of clinical studies and compassionate-use programmes. RESULTS: The recommended BRAF inhibitor (BRAFi) + MEK inhibitor (MEKi) combination was both registered and fully reimbursed in 9/30 (30%) countries, and in 13/30 (43%) (all from Eastern Europe) not reimbursed. First-line immunotherapy with anti-PD1 antibodies was registered and fully reimbursed in 14/30 (47%) countries, while in 13/30 (43%) (all from Eastern Europe) not reimbursed. It was estimated that in Europe 19,600 patients with metastatic melanoma are treated, and 5238 (27%) do not have access to recommended first-line therapy. Significant correlation was found between human development index (HDI, UNDP report 2015), (r = 0.662; p < 0.001), health expenditure per capita (r = 0.695; p < 0.001) and the Mackenbach score of health policy performance (r = 0.765; p < 0.001) with the percentage of patients treated with innovative medicines and a number of reimbursed medicines. CONCLUSIONS: Great discrepancy exists in metastatic melanoma treatment across Europe. It is crucial to increase the awareness of national and European policymakers, oncological societies, melanoma patients' associations and pharma industry.

Erythema nodosum-like lesions during BRAF inhibitor therapy: Report on 16 new cases and review of the literature.

IMPORTANCE: BRAF inhibitors have been licensed for the therapy of BRAF-mutated melanoma. Recently, inflammatory skin lesions clinically resembling erythema nodosum have been reported as therapy side-effects that may lead to treatment discontinuation. OBJECTIVE: To identify and characterize cases with BRAF inhibitor-associated erythema nodosum-like inflammatory skin lesions and development of an algorithm for their management. DESIGN AND SETTING: Retrospective chart review of melanoma patients treated with BRAF inhibitors in 14 departments of Dermatology in Germany and Austria and PubMed search for cases in the literature. RESULTS: Sixteen patients were identified who developed erythema nodosum-like lesions under BRAF inhibitor therapy; 14 had received vemurafenib and two dabrafenib plus trametinib. The most frequently involved body sites were the legs. Histopathology was performed in five cases and revealed panniculitis in three and vasculitis in two patients respectively. Arthralgia and fever were associated symptoms in 44% and 31% of patients respectively. Inflammatory symptoms led to discontinuation of treatment in three patients, while in the majority of cases symptomatic management was sufficient. Skin lesions finally resolved despite continued BRAF inhibitor therapy in seven patients. In the literature, 19 additional patients with similar cutaneous appearance under BRAF inhibitors could be identified. An algorithm for the management of such lesions is proposed. CONCLUSION: Erythema nodosum-like skin lesions histologically correspond to panniculitis and/or vasculitis. Symptomatic treatment may be sufficient. However, additional work-up and interruption of BRAF inhibitor therapy may be necessary in severe cases which are commonly associated with systemic symptoms.

Pretherapeutic laboratory findings, extent of metastasis and choice of treatment as prognostic markers in ocular melanoma- a single centre experience.

BACKGROUND: Uveal melanoma is the most common intraocular neoplasm with a high tendency to metastasize predominantly to the liver. Prognostic parameters for progression and overall survival are not well defined. The aim of this study was to assess the value of pretherapeutic serum levels of C-reactive protein (CRP), lactate dehydrogenase, albumin and fibrinogen in patients with uveal melanoma and to evaluate their significance as prognostic parameters for survival. METHODS: Forty-nine patients with metastatic uveal melanoma treated between 2000 and 2010 were retrospectively analysed. The potential influence of levels of CRP, lactate dehydrogenase, fibrinogen and albumin as well as other commonly known prognostic variables on progression-free and overall survival were investigated. RESULTS: Patients' age and treatment with systemic chemotherapy were the only variables to show significant influences on progression-free and overall survival in a univariate analysis. Multivariate analysis confirmed the influence of these variables on progression-free survival, presence of metastasis, pretherapeutic CRP levels and treatment with systemic chemotherapy were associated with overall survival. CONCLUSION: In this patient cohort elevated pretherapeutic CRP and extent of metastasis are independent prognostic factors for decreased overall survival, whereas treatment with systemic chemotherapy showed a significant association with improved overall survival.

Sentinel node status in melanoma patients is not predictive for overall survival upon multivariate analysis.

Sentinel lymph node biopsy (SLNB) has become a widely accepted standard procedure in the staging of patients with cutaneous melanoma and absence of clinical lymph node metastases, although there is no final proof that SLNB influences overall survival in these patients. This study investigated the accuracy of SLNB and the clinical outcome of patients after a mean follow-up of 22 months. Between 1998 and 2003, SLNB was performed in 309 consecutive patients. Patients with one or more positive sentinel lymph nodes (SLNs) were subjected to selective lymphadenectomy (SL). Survival analyses were performed using the Kaplan-Meier approach. A Cox proportional-hazard analysis was used for univariate and multivariate analysis to explore the effect of variables on survival. Sentinel lymph nodes were identified in 299 of 309 patients (success rate: 96.8%). Of these, 69 (23%) had a positive SLN. The false-negative rate was 9.2%. Recurrence of disease to the regional lymph node basin (3.0%) and to the locoregional skin (2.6%) was rare in SLN-negative patients in contrast to SLN-positive patients (7.2 and 17.4%, respectively). The 3-year overall survival was 93 and 83% for SLN-negative and SLN-positive patients, respectively. Upon multivariate analysis, SLN status (P<0.001), Breslow thickness (P<0.02) and ulceration (P<0.026) were all found to be independent prognostic factors with respect to disease-free survival, whereas Breslow thickness proved to be the only significant factor with respect to overall survival.

Perilesional injection of r-GM-CSF in patients with cutaneous melanoma metastases.

Based on evidence that granulocyte-macrophage colony stimulating factor (GM-CSF) induces a potent systemic antitumor immunity, we tested recombinant GM-CSF in advanced melanoma. Seven patients with histologically confirmed cutaneous melanoma metastases were treated with perilesional intracutaneous injections of recombinant GM-CSF and observed for a follow-up time of 5 y. All but two patients had a decrease in the total number of metastases. At the end of the 5 y follow-up three of the seven patients are still alive with only one patient receiving other than surgical therapy, and one patient died tumor free at the age of 93. The remaining three patients died from progressive melanoma. Perilesional intradermal GM-CSF therapy resulted in a mean survival time of 33 mo. The treatment was well tolerated and no side-effects other than local erythema at the injection sites and mild drowsiness were seen. Immunohistochemical analysis with staining for CD14 and GM-CSF receptor demonstrated an increased infiltration of monocytes into both injected and noninjected cutaneous melanoma metastases compared with lesions excised prior to the initiation of therapy. The same was true for CD4- and CD8-positive lymphocytes. This phenomenon, together with GM-CSF-induced leukocyte counts of more than 20,000 during therapy, support the possible impact of a systemic over a locally induced reaction by GM-CSF. To our knowledge this is the first report that intracutaneously injected GM-CSF results in long-lasting reduction of melanoma metastases.

Chemosensitisation of malignant melanoma by BCL2 antisense therapy.

BACKGROUND: Chemoresistance of malignant melanoma has been linked to expression of the proto-oncogene BCL2. Antisense oligonucleotides (ASO) targeted against BCL2 mRNA decreased BCL2 protein concentrations, increased tumour-cell apoptosis, and led to tumour responses in a mouse xenotransplantation model when combined with systemic dacarbazine. This phase I-II clinical study investigated the combination of BCL2 ASO (augmerosen, Genasense, G3139) and dacarbazine in patients with advanced malignant melanoma expressing BCL2. METHODS: In a within-patient dose-escalation protocol, 14 patients with advanced malignant melanoma were given augmerosen intravenously or subcutaneously in daily doses of 0.6-6.5 mg/kg plus standard dacarbazine treatment (total doses up to 1000 mg/m2 per cycle). Toxicity was scored by common toxicity criteria. Plasma augmerosen concentrations were assayed by high-performance liquid chromatography. In serial tumour biopsy samples, BCL2 protein concentrations were measured by western blotting and tumour-cell apoptosis was assessed. FINDINGS: The combination regimen was well tolerated, with no dose-limiting toxicity. Haematological abnormalities were mild to moderate. Lymphopenia was common, but no febrile neutropenia occurred. Higher doses of augmerosen were associated with transient fever. Four patients had liver-function abnormalities that resolved within 1 week. Steady-state plasma concentrations of augmerosen were attained within 24 h, and increased with administered dose. By day 5, daily doses of 1.7 mg/kg and higher led to a median 40% decrease in BCL2 protein in melanoma samples compared with baseline, concomitantly with increased tumour-cell apoptosis, which was greatly increased after dacarbazine treatment. Six patients have shown antitumour responses (one complete, two partial, three minor). The estimated median survival of all patients now exceeds 12 months. INTERPRETATION: Systemic administration of augmerosen downregulated the target BCL2 protein in metastatic cancer. Such downregulation of BCL2, combined with standard anticancer therapy, offers a new approach to the treatment of patients with resistant neoplasms.

Negative chronotropic effects of fentanyl attenuate beneficial effects of dobutamine on oxygen metabolism: hemodynamic and pharmacokinetic interactions.

Opioids are well known to cause cardiovascular depression. The aim of the present investigation was to determine whether an interaction of opioid derivatives with catecholamines might be involved in these hemodynamic alterations. Six comatose patients were enrolled into a prospective, nonrandomized pilot trial. All patients first received a continuous i.v. infusion of dobutamine (10 microgram. kg-1. min-1) paralleled by continuous administration of midazolam (0.4 mg. kg-1. h-1); thereafter, fentanyl was added i.v. (4 microgram. kg-1. h-1). Hemodynamic parameters as well as dobutamine and endogenous catecholamines plasma levels were determined. The mean arterial blood pressure did not change significantly during the whole study period. The continuous administration of dobutamine (steady-state plasma concentrations: 217 +/- 118 ng. ml-1) increased the beta1-adrenergic receptor-mediated hemodynamic parameters such as heart rate, stroke volume index, cardiac index, and oxygen delivery index (p <.05). The concomitant administration of fentanyl decreased the heart rate-dependent hemodynamic parameters (p <.05), suggesting that fentanyl antagonizes the chronotropic effects of dobutamine. In parallel, dobutamine plasma levels increased significantly (275 +/- 165 ng. ml-1; p <.05). Noteworthy, after administration of fentanyl, oxygen delivery and consumption index returned to baseline values. Radioligand binding experiments on rat cardiac ventricular microsomes ruled out a direct interaction of fentanyl with beta-adrenergic receptors and, more importantly, a fentanyl-induced inhibition of beta-adrenergic receptor G protein coupling. Our observations suggest that fentanyl inhibits the frequency-related hemodynamic changes induced by dobutamine. The underlying mechanism is independent of beta-adrenergic receptors, but is powerful enough to abolish the salutary effect of dobutamine on oxygen delivery and consumption.