Development and Bioequivalence of 3D-Printed Medication at the Point-of-Care: Bridging the Gap Toward Personalized Medicine.

Personalized medicine is currently hampered by the lack of flexible drug formulations. Especially for pediatric patients, manual compounding of personalized drug formulations by pharmacists is required. Three-Dimensional (3D) printing of medicines, which enables small-scale manufacturing at the point-of-care, can fulfill this unmet clinical need. This study investigates the feasibility of developing a 3D-printed tablet formulation at the point-of-care which complies to quality requirements for clinical practice, including bioequivalence. Development, manufacturing, and quality control of the 3D-printed tablets was performed at the manufacturing facility and laboratory of the department of Clinical Pharmacy and Toxicology at Leiden University Medical Center. Sildenafil was used as a model drug for the tablet formulation. Along with the 3D-printed tablets a randomized, an open-label, 2-period, crossover, single-dose clinical trial to assess bioequivalence was performed in healthy adults. Bioequivalence was established if areas under the plasma concentration curve from administration to the time of the last quantifiable concentration (AUC0-t ) and maximum plasma concentration (Cmax ) ratios were within the limits of 80.00-125.00%. The manufacturing process provided reproducible 3D-printed tablets that adhered to quality control requirements and were consequently used in the clinical trial. The clinical trial was conducted in 12 healthy volunteers. The 90% confidence intervals (CIs) of both AUC0-t and Cmax ratios were within bioequivalence limits (AUC0-t 90% CI: 87.28-104.14; Cmax 90% CI: 80.23-109.58). For the first time, we demonstrate the development of a 3D-printed tablet formulation at the point-of-care that is bioequivalent to its marketed originator. The 3D printing of personalized formulations is a disruptive technology for compounding, bridging the gap toward personalized medicine.

The Oral Pheneticillin Absorption Test: An Accurate Method to Identify Patients with Inadequate Oral Pheneticillin Absorption.

Severe streptococcal infections are commonly treated with intravenous followed by oral penicillin (pheneticillin) therapy. However, switching from iv to oral therapy is complicated by the variability in oral pheneticillin absorption. We employed an Oral Absorption Test (OAT) for pheneticillin to identify patients in whom oral pheneticillin absorption is poor. Out of 84 patients 30 patients (36%) were identified as insufficient absorbers. Treatment failure due to pheneticillin malabsorption can be avoided by performing an OAT, and these patients should be treated by another antibiotic, which is known to be absorbed well.

Optimizing the dose in cancer patients treated with imatinib, sunitinib and pazopanib.

AIM: Fixed dose oral tyrosine kinase inhibitors imatinib, sunitinib and pazopanib show a high interpatient variability in plasma exposure. A relationship between plasma exposure and treatment outcome has been established, which supports the rationale for dose optimization of these drugs. The aim of this study was to monitor how many patients reached adequate trough levels after therapeutic drug monitoring-based dose optimization in daily practice. METHODS: A cohort study was performed in patients treated with imatinib, sunitinib or pazopanib of whom follow-up drug levels were measured between August 2012 and April 2016. Patients' characteristics were collected by reviewing electronic patient records. Drug levels were measured using high-performance liquid chromatography coupled with tandem mass spectrometry and trough levels were estimated using a predefined algorithm. Dose interventions were proposed based on trough levels. RESULTS: In total, 396 trough levels were determined in 109 patients. Median sample frequency per patient was 3. During the first measurement only 38% of patients showed trough levels within the predefined target ranges despite standard dosing; 52% of the patients showed drug levels below and 10% above the target range. In 35 out of 41 patients (85%) dose interventions led to adequate trough levels. Eventually, 64% of the total cohort reached adequate trough levels. CONCLUSIONS: Dose optimization proved an effective tool to reach adequate trough levels in patients treated with imatinib, sunitinib and pazopanib. The percentage of patients with adequate trough levels increased from 38 to 64%. Therapeutic drug monitoring may add to the improvement of efficacy and reduction of toxicity and costs of these treatments.

Concordance of genotype for polymorphisms in DNA isolated from peripheral blood and colorectal cancer tumor samples.

BACKGROUND & AIM: Results from different pharmacogenetic association studies in colorectal cancer are often conflicting. Both peripheral blood and formalin-fixed, paraffin-embedded (FFPE) tissue are routinely used as DNA source. This could cause bias due to somatic alterations in tumor tissue, such as loss of heterozygosity. We therefore compared genotypes in DNA from peripheral blood and FFPE colorectal tumor samples for SNPs with putative influence on the cytotoxicity of chemotherapy. MATERIALS & METHODS: Eleven SNPs in nine genes involved in anticancer drug metabolism or efficacy were determined in matched samples from blood and FFPE tissue of colorectal tumors by pyrosequencing and TaqMan(®) techniques. The κ-statistic was calculated to assess concordance. RESULTS: A total of 149 paired FFPE tissue and EDTA blood DNA samples were available for comparison. Overall, 20 out of 1418 genotypes were discordant (1.4%); in ten cases, loss of heterozygosity could not be ruled out. Only GSTP1 showed significant discordance between FFPE tissue and blood genotype (κ = 0.947; 95% CI: 0.896-0.998). CONCLUSION: FFPE tissue-derived DNA can be used as a valid proxy for germline DNA for a selection of SNPs in (retrospective) pharmacogenetic association studies in colorectal cancer. However, for future studies, genotyping of blood-derived DNA is preferred.

Clinical and pharmacogenetic factors associated with irinotecan toxicity.

Irinotecan is a topo-isomerase-I inhibitor with broad antitumor activity in solid tumors. Its use may lead to severe toxicities, predominantly neutropenia and diarrhea which can be life-threatening. This review discusses clinical determinants and pharmacogenetic factors associated with irinotecan toxicity. Age, performance status, co-medication and elevated transaminases have been associated with increased risk of diarrhea or neutropenia. Also, elevated bilirubin levels, due to liver impairment, conjugation disorders or UGT1A1 *28 genotype, have been associated with increased incidence of grades 3 intestinal toxicity and neutropenia. UGT1A1 *28 homozygosity is strongly associated with irinotecan-induced neutropenia and polymorphisms in the transporting peptides ABCB1 and OATP1B1 have also been associated with gastrointestinal toxicity and irinotecan pharmacokinetics, respectively. In the irinotecan product label, it is advised to reduce the irinotecan starting dose for UGT1A1 *28 homozygotes. However, due to the lack of prospective data, it is yet unknown whether dose reduction leads to reduced toxicity or altered antitumor effect. Combined toxicity analysis reveals that most patients experiencing grade 3-4 diarrhea and/or neutropenia are not homozygous for UGT1A1 *28. Future studies should combine pharmacogenetics with clinical determinants such as performance status and co-medication as to predict irinotecan toxicity and to develop predefined dosing algorithms.

Multiplex pyrosequencing of two polymorphisms in DNA repair gene XRCC1.

DNA repair enzymes play a pivotal role in platinum-based chemotherapy. Within the gene encoding for the base excision repair enzyme XRCC1, several nonsynonymous polymorphisms have been identified. It has been shown that the Arg399Gln single-nucleotide polymorphism results in a polymorphic enzyme that is less capable of initiating DNA repair. We developed a multiplex pyrosequence assay to simultaneously detect two nonsynonymous polymorphisms within the XRCC1 gene. Both of these polymorphisms resulted in amino acid changes: G/A in codon 399 changes Arg into Gln, and deletion of A in the second position of codon 576 results in a stopcodon. We established the frequency of these mutations in 270 patients suffering from colorectal cancer. Allele frequencies of G in second position of codon 399 and A in the second position codon 576 are 61.1 and 99.6%, respectively, in these patients. This fast and reliable method allows for simultaneous detection of the infrequent mutant C or CT alleles instead of the A deletion at codon 576. The method may be used in pharmacogenetic studies of platinum-based chemotherapy.