Feasibility of and patients’ perspective on nilotinib dried blood spot self-sampling

Remote dried blood spot collection for inflammatory markers in older adults is feasible, reliable, and valid

Dried blood spots (DBS) provide a minimally invasive method to assess inflammatory markers and can be collected remotely at-home or in-person in the lab. However, there is a lack of methodological information comparing these different collection methods and in older adults. We investigated the feasibility (including adherence, yield, quality, and participant preferences) and measurement properties (reliability, validity) of remotely collected DBS inflammatory markers in older adults. Participants (N = 167, mean age = 72, range: 60-96 years) collected their own DBS (finger prick on filter paper) during three remote interviews over ∼ 6 months. Within 4-5 days on average of their last remote interview, a subset of 41 participants also attended an in-person lab visit that included a researcher-collected DBS sample, venous blood draw, and survey to assess participant preferences of DBS collection. DBS and venous blood were assayed for CRP, IL-6, and TNF-α. Adherence: 98% of expected DBS samples (493 out of 501) were completed and mailed back to the lab. Yield: 97% of DBS samples were sufficient for all assays. Quality: On average, 0.80 fewer optimal spots (60uL of blood that filled the entire circle) were obtained remotely vs. in-person (p = 0.013), but the number of useable or better spots (at least 30-40uL of blood) did not differ (p = 0.89). Preference: A slight majority of participants (54%) preferred in-person DBS collection. Reliability: DBS test-retest reliabilities were good: CRP (ICC = 0.74), IL-6 (ICC = 0.76), and TNF-α (ICC = 0.70). Validity: Inflammatory levels from DBS correlated strongly with levels from venous blood (r = 0.60-0.99) and correlated as expected with sociodemographic and physical health and function variables. Older adults can remotely collect their own DBS to acquire reliable and valid inflammatory data. Remote DBS collection is highly feasible and may allow for inflammatory markers to be assessed in larger, more representative samples than are possible with lab- or clinic-based research designs.

Self-Sampling by Adolescents at Home: Assessment of the Feasibility to Successfully Collect Blood Microsamples by Inexperienced Individuals

Blood microsampling has increasingly attracted interest in the past decades as a more patient-centric sampling approach, offering the possibility to collect a minimal volume of blood following a finger or arm prick at home. In addition to conventional dried blood spots (DBS), many different devices allowing self-sampling of blood have become available. Obviously, the success of home-sampling can only be assured when (inexperienced) users collect samples of good quality. Therefore, the feasibility of six different microsampling devices to collect capillary blood by inexperienced adolescents at home was evaluated. Participants (n = 95) were randomly assigned to collect blood (dried or liquid) at different time points using four of six different self-sampling devices (i.e., DBS, Mitra volumetric absorptive microsampling (VAMS), Capitainer B, Tasso M20, Minicollect tube and Tasso+ serum separator tube (SST)). The quality of the samples was visually inspected and analytically determined. Moreover, the participants' satisfaction was assessed via questionnaires. Although a majority succeeded based on the visual inspection, the success rate differed largely between the different devices. In general, the lowest success rate was obtained for the Minicollect tubes, although there is an opportunity and need for improvement for the other self-sampling devices as well. Hence, this also emphasizes the importance to assess the quality of samples collected by the target population prior to study initiation. In addition, visual classification by a trained individual was confirmed based on assessment of the analytical variability between replicates. Finally, self-sampling at home was overall (very) positively received by the participants.

Living Well: Protocol for a web-based program to improve quality of life in rural and urban ovarian cancer survivors

BACKGROUND

Ovarian cancer (OC) survivors commonly experience chronic symptoms including anxiety, depression, sleep disturbances, fatigue, physical symptoms, poor health-related quality of life (HRQOL), and a generally poor prognosis. Additionally, factors such as social isolation, stress, and depression are associated with key biological processes promoting tumor progression and poorer survival. Accessible psychosocial interventions to improve HRQOL and clinical outcomes are needed. This need is particularly true in rural settings where survivors may have less access to clinic-based support systems.

METHODS

The Living Well Study, a cluster-randomized Phase II multi-site clinical trial, is designed to evaluate the efficacy of a group-based, web-delivered psychosocial intervention (Mindful Living) verses a Health Promotion active control (Healthy Lifestyles) in increasing HRQOL and decreasing perceived stress (primary outcomes), depressive mood, anxiety, and fatigue (secondary outcomes) for 256 OC survivors who are <5 years post-primary therapy. Mindful Living targets key concerns of OC survivors and teaches stress reduction skills and coping strategies utilizing cognitive behavioral, mindfulness, and acceptance and commitment therapies. Healthy Lifestyles provides lifestyle information including exercise, nutrition, sleep, and other survivorship topics. Interventions consist of 11 consecutive weekly group sessions lasting 1.5-2 h led by trained facilitators and two booster sessions. Participants complete psychosocial questionnaires at baseline, post-intervention, at 6-months, and at 12-months. A subset completes bloodspots for analysis of inflammatory biology.

CONCLUSION

Easily accessible psychosocial interventions addressing key concerns of OC survivors are an unmet need. The Mindful Living intervention has the potential to substantially enhance HRQOL and decrease distress in OC survivors. Trial registrationclinicaltrials.gov Identifier: NCT04533763.

Stability of steroid hormones in dried blood spots (DBS)

OBJECTIVES

Steroid hormone levels of patients may be monitored via dried blood spot (DBS) sampling at home. Stability of steroid hormones in DBS samples, however, needs to be established.

METHODS

DBS samples from healthy volunteers were collected and stored at various temperatures. Steroid hormone concentrations in DBS were measured directly, at day 2, day 7 and day 14 following storage at 37 °C and after 7 days, 14 days, 3 months and 6 months following storage at -20 °C, 4 °C and room temperature (RT). Cortisol, cortisone, corticosterone, testosterone, androstenedione, and 17-hydroxyprogesterone (17-OHP) were assessed using LC-MS/MS.

RESULTS

All steroids were stable (±15 %) up to 14 days when stored at 37 °C, except for cortisone (only stable until 2 days). All steroids were stable up to 6 months when stored at -20 °C, 4 °C and RT. However, there were some exceptions, for androstenedione at RT (only stable until 7 days), for 17-OHP when stored at -20 °C (only stable until 3 months), for cortisone at RT and 4 °C (only stable until 14 days), and cortisol at RT (only stable until 3 months).

CONCLUSIONS

Overall, we demonstrated stability of steroid hormone concentrations in DBS under various conditions which may be encountered during shipping to the diagnostic laboratory and during long-term storage before analysis.

Pretreatment and analysis techniques development of TKIs in biological samples for pharmacokinetic studies and therapeutic drug monitoring

Tyrosine kinase inhibitors (TKIs) have emerged as the first-line small molecule drugs in many cancer therapies, exerting their effects by impeding aberrant cell growth and proliferation through the modulation of tyrosine kinase-mediated signaling pathways. However, there exists a substantial inter-individual variability in the concentrations of certain TKIs and their metabolites, which may render patients with compromised immune function susceptible to diverse infections despite receiving theoretically efficacious anticancer treatments, alongside other potential side effects or adverse reactions. Therefore, an urgent need exists for an up-to-date review concerning the biological matrices relevant to bioanalysis and the sampling methods, clinical pharmacokinetics, and therapeutic drug monitoring of different TKIs. This paper provides a comprehensive overview of the advancements in pretreatment methods, such as protein precipitation (PPT), liquid-liquid extraction (LLE), solid-phase extraction (SPE), micro-SPE (μ-SPE), magnetic SPE (MSPE), and vortex-assisted dispersive SPE (VA-DSPE) achieved since 2017. It also highlights the latest analysis techniques such as newly developed high performance liquid chromatography (HPLC) and high-resolution mass spectrometry (HRMS) methods, capillary electrophoresis (CE), gas chromatography (GC), supercritical fluid chromatography (SFC) procedures, surface plasmon resonance (SPR) assays as well as novel nanoprobes-based biosensing techniques. In addition, a comparison is made between the advantages and disadvantages of different approaches while presenting critical challenges and prospects in pharmacokinetic studies and therapeutic drug monitoring.

Citizens' perspectives on relocating care: a scoping review

BACKGROUND

Healthcare systems around the world are facing large challenges. There are increasing demands and costs while at the same time a diminishing health workforce. Without reform, healthcare systems are unsustainable. Relocating care, for example, from hospitals to sites closer to patients' homes, is expected to make a key contribution to keeping healthcare sustainable. Given the significant impact of this initiative on citizens, we conducted a scoping review to provide insight into the factors that influence citizens' attitudes towards relocating care.

METHOD

A scoping review was conducted. The search was performed in the following databases: Pubmed, Embase, Cinahl, and Scopus. Articles had to include relocating healthcare and citizens' perspectives on this topic and the articles had to be about a European country with a strong primary care system. After applying the inclusion and exclusion criteria, 70 articles remained.

RESULTS

Factors positively influencing citizens' attitudes towards relocating care included: convenience, familiarity, accessibility, patients having more control over their disease, and privacy. Factors influencing negative attitudes included: concerns about the quality of care, familiarity, the lack of physical examination, contact with others, convenience, and privacy. Furthermore, in general, most citizens preferred to relocate care in the studies we found, especially from the hospital to care provided at home.

CONCLUSION

Several factors influencing the attitude of citizens towards relocating care were found. These factors are very important when determining citizens' preferences for the location of their healthcare. The majority of studies in this review reported that citizens are in favour of relocating care. In general citizens' perspectives on relocating care are very often missing in articles. It was significant that very few studies on relocation from the hospital to the general practitioner were identified.

Development and evaluation of serological screening based on one dried plasma spot for HIV, syphilis, and HCV

BACKGROUND

In the effort to prevent and control HIV/AIDS, China has established a national sentinel surveillance system. However, some sentinel sites face limitations in environmental resources and accessibility, prompting the exploration of alternative sample strategies. Dried plasma spots (DPS) samples are viewed as promising alternatives to traditional plasma samples due to their advantages, including sample stability, easy storage, and convenient transport. This study aims to develop a method for screening HIV, Treponema pallidum (TP), and Hepatitis C Virus (HCV) using DPS samples and assess their performance.

METHODS

Based on existing commercial assay kits, a detection method was established through the optimization of experimental parameters, including the amount of plasma on filter paper, the volume of elution solution applied to dried plasma spots, the size of dried plasma spots, elution solution volume, elution solution components, elution temperature, and elution time. A series of laboratory evaluation panels were constructed for laboratory assessments, including the laboratory basic panel, laboratory interference panel, and laboratory precision panel. Additionally, clinical samples were used for evaluation.

RESULTS

Optimal conditions for DPS sample extraction were: plasma volume, 100 µL; DPS size, whole spot; eluent volume, 500 µL; eluent, PBS with 1‰ Tween20; elution time, 2 h; elution temperature, room temperature. A total of 619 paired plasma/DPS samples were tested by both methods. The DPS-based ELISA method exhibited 100% sensitivity/specificity for HIV, 98.6%/100% for TP, and 99.6%/100% for HCV. Kappa values between the plasma samples and DPS samples were 100% for HIV, 99% for TP, and 100% for HCV. The DPS-based ELISA method failed to detect 1 HCV mono-infected sample and TP in 1 HIV/HCV/TP co-infected sample. For the HIV/HCV/TP co-infected sample, the S/CO in the plasma sample was 2.143 and in the DPS sample was 0.5. For HCV, the S/CO (sample OD/cut-off) was 3.049 in the plasma sample and 0.878 in the DPS sample.

CONCLUSIONS

A single DPS, following one-time standardized processing, can be used to detect HIV, HCV, and TP. Researching and establishing laboratory testing methods better suited for China's sentinel surveillance have significant practical applications in improving HIV testing in resource-constrained environments.

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.

Reliability and feasibility of home-based dried blood spot in therapeutic drug monitoring: a systematic review and meta-analysis

PURPOSE

Dried blood spot (DBS) is one of promising home sampling methods for therapeutic drug monitoring (TDM). However, the associated reliability and feasibility (including yield, adherence, and preference), which are criteria for the promotion of home-based DBS, remain unknown. This systematic review and meta-analysis aimed to evaluate the reliability and feasibility of TDM using DBS sampling.

METHODS

In this study, a combination of MeSH and free terms for (dried blood spot*[title/abstract])AND ("Drug Monitoring"[Mesh])AND(home OR venous)was surveyed using EMBASE, PubMed, Cochrane Library, and Web of Science upon gathering published. we registered this study protocol with the International Prospective Registry of Systematic Reviews (CRD42021247559).

RESULTS

Approximately half (35/75) of the evaluations reported good agreement between DBS and plasma, and the results for drugs with poor agreement may be improved using a haematocrit-based physiological equation. The yield and adherence to home-based DBS exceeded 87%, and questionnaire-based preference for DBS was 77%.

CONCLUSIONS

DBS may be a reliable and feasible home sampling method; however, it requires intricate design and evaluation before implementation.

At-home dried blood spot (DBS) collection to increase population heterogeneity representation in pediatric research: An ECHO study

Self-collection of dried blood samples (DBS) in the participant's home provides an alternative to university/hospital visits for research and has the potential to improve the representation of population heterogeneity in research. This study aimed to assess the feasibility of guardian and/or self-DBS collection in healthy youth in the lab and home. Guardians/youth [N = 140; females = 63; M _age = 8.73, SD _age = 3.56] who enrolled in a longitudinal study of typical development were asked during a lab visit to provide a DBS. Upon providing a sample, the participants were asked if they would be willing to self-collect in the home and return the sample via the post office. Of those asked to provide a sample in the lab, 82% consented and 18% declined, with a significant difference in age but no significant difference in sex, ethnicity, race, or family income. Of those who provided a sample in the lab, 75% were willing to self-collect DBS in the home, with no significant difference in demographic variables between them. We report a quality assessment and DNA extraction results from a subset of samples. The results demonstrate a high feasibility of DBS collection from healthy youth for research purposes both in the laboratory and in the home across different demographic variables. Developmental researchers should consider including this approach in their studies to increase population heterogeneity representation.

Feasibility of community at-home dried blood spot collection combined with pooled reverse transcription PCR as a viable and convenient method for malaria epidemiology studies

Background

Many Plasmodium infections in endemic regions exist at densities below the limit of detection of standard diagnostic tools. These infections threaten control efforts and may impact vaccine and therapeutic drug studies. Simple, cost-effective methods are needed to study the natural history of asymptomatic submicroscopic parasitaemia. Self-collected dried blood spots (DBS) analysed using pooled and individual quantitative reverse transcription polymerase chain reaction (qRT-PCR) provide such a solution. Here, the feasibility and acceptability of daily at-home DBS collections for qRT-PCR was studied to better understand low-density infections.

Methods

Rapid diagnostic test (RDT)-negative individuals in Katakwi District, northeastern Uganda, were recruited between April and May 2021. Venous blood samples and clinic-collected DBS were taken at enrollment and at four weekly clinic visits. Participants were trained in DBS collection and asked to collect six DBS weekly between clinic visits. Opinions about the collection process were solicited using daily Diary Cards and a Likert scale survey at the final study visit. Venous blood and DBS were analysed by Plasmodium 18S rRNA qRT-PCR. The number of participants completing the study, total DBS collected, and opinions of the process were analysed to determine compliance and acceptability. The human internal control mRNA and Plasmodium 18S rRNA were evaluated for at-home vs. clinic-collected DBS and venous blood to assess quality and accuracy of at-home collected samples.

Results

One-hundred two adults and 29 children were enrolled, and 95 and 26 completed the study, respectively. Three individuals withdrew due to pain or inconvenience of procedures. Overall, 96% of participants collected ≥ 16 of 24 at-home DBS, and 87% of DBS contained ≥ 40 µL of blood. The procedure was well tolerated and viewed favourably by participants. At-home collected DBS were acceptable for qRT-PCR and showed less than a one qRT-PCR cycle threshold shift in the human control mRNA compared to clinic-collected DBS. Correlation between Plasmodium falciparum 18S rRNA from paired whole blood and DBS was high (R = 0.93).

Conclusions

At-home DBS collection is a feasible, acceptable, and robust method to obtain blood to evaluate the natural history of low-density Plasmodium infections by qRT-PCR.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04239-x.

Microsampling to support pharmacokinetic clinical studies in pediatrics

BACKGROUND

Conventional sampling for pharmacokinetic clinical studies requires removal of large blood volumes from patients. This can result in a physiological/emotional burden for children. Microsampling to support pharmacokinetic clinical studies in pediatrics may reduce this burden.

METHODS

Parents/guardians and bedside nurses completed a questionnaire describing their perception of the use of microsampling compared to conventional sampling to collect blood samples, based on their child's participation or their own role within a paired-sample pharmacokinetic clinical study. Responses were based on a seven-point Likert scale and were analyzed using frequency distributions.

RESULTS

Fifty-one parents/guardians and seven bedside nurses completed a questionnaire. Parents/guardians (96%) and bedside nurses (100%) indicated that microsampling was highly acceptable and recommended as a method for collecting blood samples for pediatric patients. Responding to a question about the child indicating pain during the blood sampling procedure, 61% of parent/guardians reported no pain in their children, 14% remained neutral, and 26% reported that their child indicated pain; 71% of the bedside nurses slightly agreed that the children indicated pain.

CONCLUSIONS

This study strongly suggests that parents/guardians and bedside nurses prefer microsampling to conventional sampling to conduct pediatric pharmacokinetic clinical studies. Employing microsampling may support increased participation by children in these studies.

IMPACT

Pharmacokinetic clinical studies require the withdrawal of blood samples at multiple times during a dosing interval. This can result in a physiological or emotional burden, particularly for neonates or pediatric patients. Microsampling offers an important opportunity for pharmacokinetic clinical studies in vulnerable patient populations, where smaller sample volumes can be collected. However, microsampling is not commonly used in clinical studies. Understanding the perceptions of parents/guardians and bedside nurses about microsampling may ascertain if this technique offers an improvement to conventional blood sample collection to perform pharmacokinetic clinical studies for pediatric patients.

Therapeutic Drug Monitoring of Tyrosine Kinase Inhibitors Using Dried Blood Microsamples

Therapeutic drug monitoring (TDM) of tyrosine kinase inhibitors (TKIs) is not yet performed routinely in the standard care of oncology patients, although it offers a high potential to improve treatment outcome and minimize toxicity. TKIs are perfect candidates for TDM as they show a relatively small therapeutic window, a wide inter-patient variability in pharmacokinetics and a correlation between drug concentration and effect. Moreover, most of the available TKIs are susceptible to various drug-drug interactions and medication adherence can be checked by performing TDM. Plasma, obtained via traditional venous blood sampling, is the standard matrix for TDM of TKIs. However, the use of plasma poses some challenges related to sampling and stability. The use of dried blood microsamples can overcome these limitations. Collection of samples via finger-prick is minimally invasive and considered convenient and simple, enabling sampling by the patients themselves in their home-setting. The collection of small sample volumes is especially relevant for use in pediatric populations or in pharmacokinetic studies. Additionally, working with dried matrices improves compound stability, resulting in convenient and cost-effective transport and storage of the samples. In this review we focus on the different dried blood microsample-based methods that were used for the quantification of TKIs. Despite the many advantages associated with dried blood microsampling, quantitative analyses are also associated with some specific difficulties. Different methodological aspects of microsampling-based methods are discussed and applied to TDM of TKIs. We focus on sample preparation, analytics, internal standards, dilution of samples, external quality controls, dried blood spot specific validation parameters, stability and blood-to-plasma conversion methods. The various impacts of deviating hematocrit values on quantitative results are discussed in a separate section as this is a key issue and undoubtedly the most widely discussed issue in the analysis of dried blood microsamples. Lastly, the applicability and feasibility of performing TDM using microsamples in a real-life home-sampling context is discussed.

Volumetric absorptive microsampling as a suitable tool to monitor tyrosine kinase inhibitors

Therapeutic drug monitoring (TDM) of tyrosine kinase inhibitors (TKIs) shows significant potential in guiding personalized anticancer treatment. Dried blood microsampling could be a valuable alternative for traditional plasma sampling to provide TDM results faster and to reach a wider audience. Sample collection is easy and patient friendly as only a small volume of blood is collected via a fingerprick. This enables the possibility of home sampling by the patients themselves. Therefore, an LC-MS/MS method was developed and validated for the quantification of bosutinib, dasatinib, gilteritinib, ibrutinib, imatinib, midostaurin, nilotinib and ponatinib in dried blood samples collected via volumetric absorptive microsampling (VAMS). A VAMS device collects a fixed volume of blood (± 10 µL), irrespective of the sample's hematocrit (Hct). During method validation, special attention was paid to the possible impact of Hct (range 0.18-0.55) on matrix effect (ME), robustness of the extraction, and accuracy of the method. The method was successfully validated based on international guidelines in terms of calibration curves, precision (within-run CV 2.20-14.8%; between-run CV 2.40-12.3%), accuracy (within-run bias 0.34-12.5%; between-run bias -0.15 to 16.2%), carry-over and selectivity. IS-compensated ME and recovery were Hct independent and no significant impact of Hct on the accuracy of the TKI quantifications was observed. All TKIs were stable in VAMS samples stored at -20 °C, 4 °C and room temperature for at least 4 weeks and for 2 days at 60 °C (except ibrutinib). Lastly, we demonstrated a good agreement between liquid blood obtained from patients on TKI treatment and VAMS samples prepared from that venous blood. As this implies that there is no methodological impact of liquid versus dried blood analysis, the presented method can be applied in clinical follow-up studies for determining TKIs in (capillary) VAMS samples with varying Hct levels.

Validation of dried blood spot sample modifications to two commercially available COVID-19 IgG antibody immunoassays

Aim: Coronavirus disease 2019 antibody testing often relies on venous blood collection, which is labor-intensive, inconvenient and expensive compared with finger-stick capillary dried blood spot (DBS) collection. The purpose of our work was to determine if two commercially available anti-severe acute respiratory syndrome coronavirus 2 enzyme-linked immunosorbent assays for IgG antibodies against spike S1 subunit and nucleocapsid proteins could be validated for use with DBS. Materials & methods: Kit supplied reagents were used to extract DBS, and in-house DBS calibrators were included on every run. Results: Positive/negative concordance between DBS and serum was 100/99.3% for the spike S1 subunit assay and 100/98% for the nucleocapsid assay. Conclusion: Validation of the DBS Coronavirus disease 2019 IgG antibody assays demonstrated that serum and DBS can produce equivalent results with minimal kit modifications.

Barriers and opportunities for the clinical implementation of therapeutic drug monitoring in oncology

There are few fields of medicine in which the individualisation of medicines is more important than in the area of oncology. Under-dosing can have significant ramifications due to the potential for therapeutic failure and cancer progression; by contrast, over-dosing may lead to severe treatment-limiting side effects, such as agranulocytosis and neutropenia. Both circumstances lead to poor patient prognosis and contribute to the high mortality rates still seen in oncology. The concept of dose individualisation tailors dosing for each individual patient to ensure optimal drug exposure and best clinical outcomes. While the value of this strategy is well recognised, it has seen little translation to clinical application. However, it is important to recognise that the clinical setting of oncology is unlike that for which therapeutic drug monitoring (TDM) is currently the cornerstone of therapy (e.g. antimicrobials). Whilst there is much to learn from these established TDM settings, the challenges presented in the treatment of cancer must be considered to ensure the implementation of TDM in clinical practice. Recent advancements in a range of scientific disciplines have the capacity to address the current system limitations and significantly enhance the use of anticancer medicines to improve patient health. This review examines opportunities presented by these innovative scientific methodologies, specifically sampling strategies, bioanalytics and dosing decision support, to enable optimal practice and facilitate the clinical implementation of TDM in oncology.

Response and Adherence to Nilotinib in Daily practice (RAND study): an in-depth observational study of chronic myeloid leukemia patients treated with nilotinib

Introduction

This comprehensive observational study aimed to gain insight into adherence to nilotinib and the effect of (non)adherence on exposure (C_min) and treatment outcomes.

Methods

Chronic myeloid leukemia (CML) patients using nilotinib were followed for 12 months. Adherence was measured by Medication Event Monitoring System (MEMS), pill count, and Medication Adherence Report Scale (MARS-5). Nilotinib C_min and patient-reported outcomes (i.e., quality of life, side effects, beliefs, satisfaction) were measured at baseline, 3, 6, and 12 months.

Results

Sixty-eight patients (57.5 ± 15.0 years, 49% female) participated. Median adherence to nilotinib (MEMS and pill count) was ≥ 99% and adherence < 90% was rare. Self-reported nonadherence (MARS-5) increased in the first year of treatment to a third of patients. In line with the strong beliefs in the necessity of taking nilotinib, forgetting to take a dose was more prevalent than intentionally adjusting/skipping doses. Nilotinib C_min were generally above the therapeutic target in 95% of patients. Patients reported a variety of side effects, of which fatigue was most frequent. The mean C_min was higher in patients who reported severe itching and fatigue. The overall 1-year MMR rate ranged from 47 to 71%.

Conclusion

Substantial nonadherence (< 90%) to nilotinib was rare and nilotinib C_min were generally above the therapeutic target. Lack of response in our group of patients was not related to nonadherence or inadequate C_min. Nevertheless, a considerable number of patients experienced difficulties in adhering to the twice daily fasted dosing regimen, emphasizing the importance of continuous support of medication adherence in CML.

Clinical trial registration

NTR3992 (Netherlands Trial Register, www.trialregister.nl)

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02910-3) contains supplementary material, which is available to authorized users.

Volumetric absorptive microsampling and dried blood spot microsampling vs. conventional venous sampling for tacrolimus trough concentration monitoring

Objectives

Monitoring tacrolimus blood concentrations is important for preventing allograft rejection in transplant patients. Our hospital offers dried blood spot (DBS) sampling, giving patients the opportunity to sample a drop of blood from a fingerprick at home, which can be sent to the laboratory by mail. In this study, both a volumetric absorptive microsampling (VAMS) device and DBS sampling were compared to venous whole blood (WB) sampling.

Methods

A total of 130 matched fingerprick VAMS, fingerprick DBS and venous WB samples were obtained from 107 different kidney transplant patients by trained phlebotomists for method comparison using Passing-Bablok regression. Bias was assessed using Bland-Altman. A multidisciplinary team pre-defined an acceptance limit requiring >80% of all matched samples within 15% of the mean of both samples. Sampling quality was evaluated for both VAMS and DBS samples.

Results

32.3% of the VAMS samples and 6.2% of the DBS samples were of insufficient quality, leading to 88 matched samples fit for analysis. Passing-Bablok regression showed a significant difference between VAMS and WB, with a slope of 0.88 (95% CI 0.81–0.97) but not for DBS (slope 1.00; 95% CI 0.95–1.04). Both VAMS (after correction for the slope) and DBS showed no significant bias in Bland-Altman analysis. For VAMS and DBS, the acceptance limit was met for 83.0% and 96.6% of the samples, respectively.

Conclusions

VAMS sampling can replace WB sampling for tacrolimus trough concentration monitoring, but VAMS sampling is currently inferior to DBS sampling, both regarding sample quality and agreement with WB tacrolimus concentrations.

Food-effect study of nilotinib in chronic myeloid leukaemia (NiFo study): Enabling dose reduction and relief of treatment burden

Objectives

Taking advantage of its food‐dependent bioavailability, the present study investigated the effect of a reduced dose taken with real‐life meals on the pharmacokinetics (PK) of nilotinib in chronic myeloid leukaemia (CML) patients.

Methods

Nilotinib was taken fasted (300 mg BID, days 1‐4) or with real‐life meals (200 mg BID, days 5‐11). Rich sampling (days 1, 3, 8, 11) allowed for non‐compartmental PK analysis. Nilotinib exposure (AUC_0–12 h ‐C_min ‐C_max) and its intra‐ and interpatient variability were compared between the two regimens. Adverse events were recorded by means of a patient diary and ECG monitoring.

Results

Fifteen patients aged 40‐74 years participated. Nilotinib PK following 200 mg BID taken with a meal strongly resembled that of 300 mg BID taken fasted (C_min percentile (P)10‐P90: 665‐1404 ng/mL and 557‐1743 ng/mL, respectively). Meals delayed nilotinib absorption. Intra‐ and interpatient variability were not increased by intake with meals. Nilotinib with food was well tolerated.

Conclusion

With support of therapeutic drug monitoring, the use of a reduced 200 mg nilotinib dose with real‐life meals seems feasible and safe. Future (confirmatory) studies should further explore the usefulness of nilotinib dosing together with food, including the relationship with treatment efficacy as well as long‐term effects on quality of life.

Clinical Trial Registration: NTR5000 (Netherlands Trial Register, www.trialregister.nl).

Effects, costs and implementation of monitoring kidney transplant patients' tacrolimus levels with dried blood spot sampling: A randomized controlled hybrid implementation trial

Aims

Dried blood spot (DBS) home sampling allows monitoring creatinine levels and tacrolimus trough levels as an alternative for blood sampling in the hospital, which is important in kidney transplant patient follow‐up. This study aims to assess whether DBS home sampling results in decreased patient travel burden and lower societal costs.

Methods

In this single‐centre randomized controlled hybrid implementation trial, adult kidney transplant patients were enrolled. The intervention group (n = 25) used DBS home sampling on top of usual care in the first 6 months after transplantation. The control group (n = 23) received usual care only. The primary endpoint was the number of outpatient visits. Other endpoints were costs per patient, patient satisfaction and implementation.

Results

There was no statistically significant difference in the average number of outpatient visits between the DBS group (11.2, standard deviation: 1.7) and the control group (10.9, standard deviation: 1.4; P = .48). Average costs per visit in the DBS group were not significantly different (€542, 95% confidence interval €316–990) compared to the control group (€533, 95% confidence interval €278–1093; P = .66). Most patients (n = 19/23, 82.6%) were willing to perform DBS home‐sampling if this would reduce the number of hospital visits. Only 55.9% (n = 143/256) of the expected DBS samples were received and 1/5 analysed on time (n = 52/256).

Conclusion

Adult kidney transplant patients are willing to perform DBS home sampling. However, to decrease patient travel burden and costs in post‐transplant care, optimization of the logistical process concerning mailing and analysis of DBS samples is crucial.

Development of a dried blood spot sampling method towards therapeutic monitoring of radotinib in the treatment of chronic myeloid leukaemia

WHAT IS KNOWN AND OBJECTIVE

Dried blood spot (DBS) sampling is a minimally invasive method of blood sampling that enables monitoring of drug concentrations to be more convenient. This study aimed at developing a DBS sampling method for an accurate and precise prediction of radotinib plasma concentrations (C_p ) in patients with chronic myeloid leukaemia (CML).

METHODS

Dried blood spot and venous blood samples were simultaneously collected from fifty CML patients who had been receiving radotinib for at least a week. Radotinib concentrations were measured using a high-performance liquid chromatographic method with tandem mass spectrometric detection. Unmeasured C_p was predicted directly based on a Deming regression between DBS concentrations (C_DBS ) and C_p . Unmeasured C_p was also predicted from C_DBS corrected by each patient's haematocrit (Hct). Both prediction methods were evaluated for their accuracy and precision using Deming regression and Bland-Altman analysis.

RESULTS AND DISCUSSION

The Deming regression equation between C_DBS and C_p was obtained as follows: C_p  = 1.34∙C_DBS  + 4.26 (r²  = .97). C_p was directly predictable using C_p,pred1  = 1.34∙C_DBS  + 4.26. With Hct correction, C_p was alternatively predictable using C_p,pred2  = C_DBS / (1-Hct + Hct² ). The slopes of Deming regression line between predicted and measured C_p were 0.99 and 1.02 for the direct and Hct-corrected method, respectively. The mean biases (accuracy) were -0.44% and 1.6% with the 95% limits of agreement (precision) of -22.4% to 21.5% and -20.5% to 23.7%, respectively. More than 93% of predicted and measured C_p pairs had their differences within 20% of the mean of each pair in both methods.

WHAT IS NEW AND CONCLUSIONS

Radotinib C_DBS are highly correlated with radotinib C_p. Radotinib C_p can be accurately and precisely predicted from C_DBS using direct or Hct-corrected prediction methods. Both appear to be appropriate for the therapeutic monitoring of radotinib in patients with CML.