(18)F-FDG PET patterns and BAL cell profiles in pulmonary sarcoidosis.

PURPOSE: Bronchoalveolar lavage (BAL) and (18)F-fluorodeoxyglucose ((18)F-FDG) PET can both demonstrate sarcoid activity. To assess whether metabolic activity imaged by (18)F-FDG PET represents signs of disease activity as reflected by BAL, (18)F-FDG PET patterns were compared with BAL cell profiles. METHODS: In this retrospective analysis, 77 newly diagnosed pulmonary sarcoidosis patients underwent BAL and (18)F-FDG PET. Based on (18)F-FDG PET, patients were diagnosed with exclusively mediastinal/hilar activity (group A) and activity in the lung parenchyma (group B). Per group, BAL lymphocytes (%), CD4/CD8 ratio, CD103(+)CD4(+)/CD4(+) ratio and neutrophils (%) were compared with the extent of metabolic activity expressed as the maximum standardized uptake value (SUV(max)). Additionally, SUV(max) and BAL parameters per radiographic stage were analysed. RESULTS: Overall, the SUV(max) in the lung parenchyma correlated with neutrophils and SUV(max) of the mediastinum/hila correlated with the CD4/CD8 ratio. In both groups, a significant, negative correlation between the SUV(max) of the mediastinum/hila and the CD103(+)CD4(+)/CD4(+) ratio was found. In group B, the SUV(max) of the mediastinum/hila correlated with the CD4/CD8 ratio, while the SUV(max) in the lung parenchyma correlated with the CD103(+)CD4(+)/CD4(+) ratio and neutrophils. Significant differences were found in the SUV(max), CD4/CD8 ratio, CD103(+)CD4(+)/CD4(+) ratio and neutrophils between the radiographic stages. The SUV(max) of the lung parenchyma was positively related to the radiographic stage, while the SUV(max) of the mediastinum/hila and CD4/CD8 ratio were inversely related. CONCLUSION: (18)F-FDG PET correlates with the CD4/CD8 ratio and neutrophils, suggesting that (18)F-FDG PET represents this specific cell profile in BAL. High SUV(max) values of the lung parenchyma may therefore correlate with more severe parenchymal involvement, particularly when accompanied by a low SUV(max) of the mediastinum/hila

Vemurafenib plus cobimetinib in unresectable stage IIIc or stage IV melanoma : Response monitoring and resistance prediction with positron emission tomography and tumor characteristics (REPOSIT): Study protocol of a phase II, open-label, multicenter study

Background: In patients with BRAFV600 mutated unresectable stage IIIc or metastatic melanoma, molecular targeted therapy with combined BRAF/MEK-inhibitor vemurafenib plus cobimetinib has shown a significantly improved progression-free survival and overall survival compared to treatment with vemurafenib alone. Nevertheless, the majority of BRAFV600 mutation-positive melanoma patients will eventually develop resistance to treatment. Molecular imaging with 18F-Fluorodeoxyglucose (18F-FDG) PET has been used to monitor response to vemurafenib in some BRAFV600 mutated metastatic melanoma patients, showing a rapid decline of 18F-FDG uptake within 2 weeks following treatment. Furthermore, preliminary results suggest that metabolic alterations might predict the development of resistance to treatment. 18F-Fluoro-3'-deoxy-3'L-fluorothymidine (18F-FLT), a PET-tracer visualizing proliferation, might be more suitable to predict response or resistance to therapy than 18F-FDG. Methods: This phase II, open-label, multicenter study evaluates whether metabolic response to treatment with vemurafenib plus cobimetinib in the first 7 weeks as assessed by 18F-FDG/18F-FLT PET can predict progression-free survival and whether early changes in 18F-FDG/18F-FLT can be used for early detection of treatment response compared to standard response assessment with RECISTv1.1 ceCT at 7 weeks. Ninety patients with BRAFV600E/K mutated unresectable stage IIIc/IV melanoma will be included. Prior to and during treatment all patients will undergo 18F-FDG PET/CT and in 25 patients additional 18F-FLT PET/CT is performed. Histopathological tumor characterization is assessed in a subset of 40 patients to unravel mechanisms of resistance. Furthermore, in all patients, blood samples are taken for pharmacokinetic analysis of vemurafenib/cobimetinib. Outcomes are correlated with PET/CT-imaging and therapy response. Discussion: The results of this study will help in linking PET measured metabolic alterations induced by targeted therapy of BRAFV600 mutated melanoma to molecular changes within the tumor. We will be able to correlate both 18F-FDG and 18F-FLT PET to outcome and decide on the best modality to predict long-term remissions to combined BRAF/MEK-inhibitors. Results coming from this study may help in identifying responders from non-responders early after the initiation of therapy and reveal early development of resistance to vemurafenib/cobimetinib. Furthermore, we believe that the results can be fundamental for further optimizing individual patient treatment. Trial registration:Clinicaltrials.govidentifier: NCT02414750. Registered 10 April 2015, retrospectively registered

Vemurafenib plus cobimetinib in unresectable stage IIIc or stage IV melanoma : Response monitoring and resistance prediction with positron emission tomography and tumor characteristics (REPOSIT): Study protocol of a phase II, open-label, multicenter study

Background: In patients with BRAFV600 mutated unresectable stage IIIc or metastatic melanoma, molecular targeted therapy with combined BRAF/MEK-inhibitor vemurafenib plus cobimetinib has shown a significantly improved progression-free survival and overall survival compared to treatment with vemurafenib alone. Nevertheless, the majority of BRAFV600 mutation-positive melanoma patients will eventually develop resistance to treatment. Molecular imaging with 18F-Fluorodeoxyglucose (18F-FDG) PET has been used to monitor response to vemurafenib in some BRAFV600 mutated metastatic melanoma patients, showing a rapid decline of 18F-FDG uptake within 2 weeks following treatment. Furthermore, preliminary results suggest that metabolic alterations might predict the development of resistance to treatment. 18F-Fluoro-3'-deoxy-3'L-fluorothymidine (18F-FLT), a PET-tracer visualizing proliferation, might be more suitable to predict response or resistance to therapy than 18F-FDG. Methods: This phase II, open-label, multicenter study evaluates whether metabolic response to treatment with vemurafenib plus cobimetinib in the first 7 weeks as assessed by 18F-FDG/18F-FLT PET can predict progression-free survival and whether early changes in 18F-FDG/18F-FLT can be used for early detection of treatment response compared to standard response assessment with RECISTv1.1 ceCT at 7 weeks. Ninety patients with BRAFV600E/K mutated unresectable stage IIIc/IV melanoma will be included. Prior to and during treatment all patients will undergo 18F-FDG PET/CT and in 25 patients additional 18F-FLT PET/CT is performed. Histopathological tumor characterization is assessed in a subset of 40 patients to unravel mechanisms of resistance. Furthermore, in all patients, blood samples are taken for pharmacokinetic analysis of vemurafenib/cobimetinib. Outcomes are correlated with PET/CT-imaging and therapy response. Discussion: The results of this study will help in linking PET measured metabolic alterations induced by targeted therapy of BRAFV600 mutated melanoma to molecular changes within the tumor. We will be able to correlate both 18F-FDG and 18F-FLT PET to outcome and decide on the best modality to predict long-term remissions to combined BRAF/MEK-inhibitors. Results coming from this study may help in identifying responders from non-responders early after the initiation of therapy and reveal early development of resistance to vemurafenib/cobimetinib. Furthermore, we believe that the results can be fundamental for further optimizing individual patient treatment. Trial registration:Clinicaltrials.govidentifier: NCT02414750. Registered 10 April 2015, retrospectively registered