Clinical validation and assessment of feasibility of volumetric absorptive microsampling (VAMS) for monitoring of nilotinib, cabozantinib, dabrafenib, trametinib, and ruxolitinib.

Volumetric absorptive microsampling (VAMS) has emerged as a minimally invasive alternative to conventional sampling. However, the applicability of VAMS must be investigated clinically. Therefore, the feasibility of at-home sampling was investigated for the kinase inhibitors nilotinib, cabozantinib, dabrafenib, trametinib and ruxolitinib and evaluated regarding the acceptance of at-home microsampling, sample quality of at-home VAMS and incurred sample stability. In addition, clinical validation including three different approaches for serum level predictions was performed. For this purpose, VAMS and reference serum samples were collected simultaneously. Conversion of VAMS to serum concentration was based either on a linear regression model, a hematocrit-dependent formula, or using a correction factor. During the study period 591 VAMS were collected from a total of 59 patients. The percentage of patients who agreed to perform VAMS at home ranged from 50.0 % to 84.6 % depending on the compound. 93.1 % of at-home VAMS were collected correctly. Regarding the drug stability in dried capillary blood, no stability issues were detected between on-site and at-home VAMS. Linear regression showed a strong correlation between VAMS and reference serum concentrations for nilotinib, cabozantinib, dabrafenib and ruxolitinib (r 0.9427 - 0.9674) and a moderate correlation for trametinib (r 0.5811). For clinical validation, the acceptance criteria were met for all three approaches for three of the five kinase inhibitors. Predictive performance was not improved by using individual hematocrit instead of population hematocrit and was largely independent of conversion model. In conclusion, VAMS at-home has been shown to be feasible for use in routine clinical care and serum values could be predicted based on the measured VAMS concentration for nilotinib, cabozantinib, and dabrafenib.

Blinatumomab: a CD19/CD3 bispecific T cell engager (BiTE) with unique anti-tumor efficacy.

Blinatumomab is a member of a novel class of T cell-engaging bispecific antibodies, so-called Bispecific T cell Engager (BiTEs). It is directed against the B cell differentiation antigen CD19 and intended for treatment of B cell malignancies. In clinical phase I/II trials, blinatumomab showed remarkable single-agent activity in patients with relapsed and/or refractory (R/R) non-Hodgkin lymphoma and R/R B cell precursor acute lymphoblastic leukemia (B-precursor ALL). Cytokine release syndrome and neurological side effects were dose-limiting. Adverse effects were well manageable and transient in nature. Based on results of an international phase II trial, blinatumomab received FDA approval for the treatment of R/R B-precursor ALL in December 2014. Ongoing and future trials will contribute to further optimization of blinatumomab-based T cell therapy and have to show that integration of blinatumomab in current and innovative treatment protocols improves overall survival and quality of life of patients with B cell malignancies.