Clinical validation study of dried blood spot for determining everolimus concentration in patients with cancer.

PURPOSE: Everolimus treatment is seriously hampered by its toxicity profile. As a relationship between everolimus exposure and effectiveness and toxicity has been established, early and ongoing concentration measurement can be key to individualize the dose and optimize treatment outcomes. Dried blood spot (DBS) facilitates sampling at a patients' home and thereby eases dose individualization. The aim of this study is to determine the agreement and predictive performance of DBS compared to whole blood (WB) to measure everolimus concentrations in cancer patients. METHODS: Paired DBS and WB samples were collected in 22 cancer patients treated with everolimus and analyzed using UPLC-MS/MS. Bland-Altman and Passing-Bablok analysis were used to determine method agreement. Limits of clinical relevance were set at a difference of ± 25%, as this would lead to a different dosing advice. Using DBS concentration and Passing-Bablok regression analysis, WB concentrations were predicted. RESULTS: Samples of 20 patients were suitable for analysis. Bland-Altman analysis showed a mean ratio of everolimus WB to DBS concentrations of 0.90, with 95% of data points within limits of clinical relevance. Passing-Bablok regression of DBS compared to WB revealed no constant bias (intercept 0.02; 95% CI 0.93-1.35) and a small proportional bias (slope 0.89; 95% CI 0.76-0.99). Predicted concentrations showed low bias and imprecision and 90% of samples had an absolute percentage prediction error of < 20%. CONCLUSIONS: DBS is a valid method to determine everolimus concentrations in cancer patients. This can especially be of value for early recognition of over- or underexposure to enable dose adaptations.

Use of incretin agents and risk of pancreatic cancer: a population-based cohort study.

AIM: To investigate the association between the use of incretin agents and the risk of pancreatic cancer. METHODS: A retrospective population-based cohort study, using data from the Clinical Practice Research Datalink, 2007-2012, was conducted. Patients (n = 182 428) with at least one non-insulin antidiabetic drug (NIAD) prescription and aged ≥18 years during data collection, were matched one-to-one to control patients without diabetes. Multivariable Cox proportional hazards models and a new user design were used to estimate the hazard ratio (HR) of pancreatic cancer in incretin users (n = 28 370) compared with control subjects without diabetes and other NIAD-treated patients. Time-dependent adjustments were made for age, sex, lifestyle, comorbidities and drug use. RESULTS: The mean duration of follow-up was 4.1 years for incretin users. Current NIAD use was associated with a fourfold increased risk of pancreatic cancer [HR 4.28, 95% confidence interval (CI) 3.49-5.24]. This risk was almost doubled among current incretin users as compared with control subjects. Incretin use was not associated with pancreatic cancer when compared with control subjects with diabetes (HR 1.36, 95% CI 0.94-1.96); however, the 'new user' design did show an association between incretin use and pancreatic cancer when compared with control subjects with diabetes. In both cohorts with prevalent and incident users of antidiabetic drugs, the risk of pancreatic cancer almost doubled in those who had recently initiated incretin therapy (up to seven prescriptions), whereas this elevated risk dropped to baseline levels with prolonged use. CONCLUSIONS: We found that incretin use was not associated with pancreatic cancer after adjustment for the severity of the underlying Type 2 Diabetes Mellitus (T2DM). The elevated risk of pancreatic cancer in those recently initiating incretin agents is likely to be caused by protopathic bias or other types of unknown distortion. The presence of considerable confounding by disease severity and the lack of a duration-of-use relationship do not support a causal explanation for the association between incretin agents and pancreatic cancer.

A real-life study on the implementation and effectiveness of exemestane plus everolimus per hospital type in patients with advanced breast cancer. A study of the Southeast Netherlands Advanced Breast Cancer registry.

PURPOSE: We aimed to assess the implementation and effectiveness of exemestane plus everolimus treatment per hospital type in real-life, shortly after approval of everolimus. METHODS: Advanced breast cancer patients treated with exemestane plus everolimus in 2012-2014 were included from the SONABRE registry. Progression-free survival (PFS) and a 12-week conditional PFS (post-hoc) were estimated by Kaplan-Meier method. The multivariable Cox proportional hazards model was performed by type of hospital and adjusted for patient, tumour and treatment characteristics. RESULTS: We included 122 patients, comprising 48 patients treated in academic (N = 1), 56 in teaching (N = 4), and 18 in non-teaching (N = 2) hospitals. The median PFS was 6.3 months (95% Confidence Interval (CI) 4.0-8.6) overall, and 8.5 months (95% CI 7.7-9.3), 4.2 months (95% CI 2.0-6.3), and 5.5 months (95% CI 4.2-6.7) for the patients treated in academic, teaching and non-teaching hospitals, respectively. The adjusted Hazard Ratio (HR) for PFS-events was 1.5 (95% CI 1.0-2.2) and 1.0 (95% CI 0.5-1.9) respectively for patients treated at teaching and non-teaching hospitals versus the academic hospital. The adjusted HR for 12-week conditional PFS-events was not different between hospital types. In the first 12-week treatment period, treatment was discontinued due to early progression in one out of 48 patients in the academic versus nine out of 74 patients in the non-academic hospitals, confirmed by imaging in one and two patients, respectively. CONCLUSIONS: In our study, the median PFS was borderline significantly different between hospital types, possibly the result of a different assessment approach in the first 12-week treatment period.