Combined physicochemical and functional assessment of pertuzumab integrity supports extended in-use stability.

Pertuzumab (Perjeta®) is a monoclonal antibody approved for the treatment of HER2-positive breast cancer. Before treatment, the concentrate must be diluted to obtain the ready-to-use infusion solution. Data on the storage stabilities of these preparations are lacking but important for all healthcare professionals in the area of outpatient chemotherapy. The aim of this study was to investigate the storage stability of the ready-to-use infusion bags and the concentrates from once-opened vials over a period of up to 42 days. For a comprehensive and unambiguous assessment of pertuzumab's integrity, a panel of orthogonal analytical methods was employed, including a newly established mass spectrometry-based peptide mapping procedure along with a reporter gene assay for monitoring cellular bioactivity. The herein presented data showed that the ready-to-use infusion solutions stored at 4 ± 2°C and at 20 ± 3°C without light protection, as well as the undiluted Perjeta® concentrates stored at 4 ± 2°C, were physicochemically stable and biologically active for 28 days. These results might eventually allow for infusion preparations in advance, thus improving the quality of patient care as well as the economic usage of pertuzumab.

Frequency and Types of Pathological Upper Gastrointestinal Endoscopy Findings in Clinically Healthy Individuals.

BACKGROUND AND OBJECTIVE: Beyond its application for diagnostics in patients, esophagogastroduodenoscopy (EGD) is used to assess gastrointestinal drug effects in clinical trials, where the interpretation of any pathological findings depends on the respective background variability. The objective of this analysis was to characterize the occurrence of pathological findings in the upper gastrointestinal tract in symptom-free healthy individuals. METHODS: A baseline EGD was performed in clinically healthy individuals in three clinical trials aimed to assess gastrointestinal tolerability of drugs. Pathological findings were described by type (redness, erosion, ulcer or other), number, size and location, and by clinical relevance as assessed by the endoscopist. Characteristics of volunteers were tested as potential covariates. RESULTS: A total of 294 EGDs were assessed. Characteristics of individuals were as follows: 257 (87.4%) males, age (mean ± SD) 32.0 ± 8.1 years, body weight 76.0 ± 10.6 kg, body mass index (BMI) 24.0 ± 2.5 kg/m2, 200 consumed alcohol, 250 (of 290 where this information was available) consumed caffeine and 39 (of 152) were smokers, 30 (of 151) tested positive for H. pylori. Any pathological finding was present in 79.6%. Clinically relevant findings occurred in 44.2%, mainly erosions (39.1%). Nine stomach ulcers were observed. Only age and BMI had a statistically significant relationship to overall pathological findings [age 3.4 years higher (p = 0.027), and BMI 1.6 kg/m2 higher (p < 0.001); for clinically relevant vs no findings]. CONCLUSION: Upper gastrointestinal tract mucosal lesions, including those assessed as clinically relevant, are frequent in clinically healthy individuals, impeding the assessment of causality for both disease and drug effects on gastrointestinal health.

Drug cocktail interaction study on the effect of the orally administered lavender oil preparation silexan on cytochrome P450 enzymes in healthy volunteers.

UNLABELLED: This cocktail study evaluated the interaction potential of the oral lavender oil preparation silexan with major P450 (cytochrome P450) enzymes. SUBJECTS AND METHODS: Sixteen healthy male or female Caucasians completed this double-blind, randomized, 2-fold crossover study. Silexan (160 mg) or placebo were administered once daily for 11 days. Additionally, on day 11 of both study periods, 150 mg caffeine (CYP1A2), 125 mg tolbutamide (CYP2C9), 20 mg omeprazole (CYP2C19), 30 mg dextromethorphan-HBr (CYP2D6), and 2 mg midazolam (CYP3A4) were administered orally. Formal interaction was excluded if the 90% confidence interval (CI) for the silexan over placebo ratios for phenotyping metrics (primary: AUC(0-t)) was within a 0.70-1.43 range. RESULTS: According to the AUC(0-t) comparisons, silexan had no relevant effect on CYP1A2, 2C9, 2D6, and 3A4 activity. Secondary phenotyping metrics confirmed this result. Mean ratios for all omeprazole-derived metrics were close to unity. The 90% CI for the AUC(0-t) ratio of omeprazole but not for omeprazole/5-OH-omeprazole plasma ratio 3 hours post-dose or omeprazole/5-OH-omeprazole AUC(0-t) ratio (secondary CYP2C19 metrics) was above the predefined threshold of 1.43, probably caused by the inherent high variability of omeprazole pharmacokinetics. Silexan and the phenotyping drugs were well tolerated. Repeated silexan (160 mg/day) administration has no clinically relevant inhibitory or inducing effects on the CYP1A2, 2C9, 2C19, 2D6, and 3A4 enzymes in vivo.

Mesalazine pharmacokinetics and NAT2 phenotype.

BACKGROUND: Mesalazine undergoes extensive metabolism by N-acetylation. While there is some evidence for an involvement of N-acetyltransferase (NAT) type 1, a potential role of NAT type 2 (NAT2) in vivo has not been tested. METHODS: In two studies in healthy young Caucasians, NAT2 phenotyping was carried out using a caffeine metabolic ratio in urine 4-6 h postdose. In study A, 1,000 mg mesalazine doses were given thrice daily for 5 days, and urine and blood samples were drawn during the last dosing interval. In study B, a 1,000 mg single dose was given, and samples were taken for 48 h postdose. Pharmacokinetics of mesalazine and N-acetylmesalazine (LC-MS/MS) were calculated by noncompartmental methods. RESULTS: NAT2 phenotype could be allocated unequivocally in 21 slow and 5 rapid acetylators in study A, and in 9 slow and 8 rapid acetylators in study B. Geometric mean (CV%) values in study A for slow [rapid] acetylators were as follows: mesalazine AUC 11.1 microg/mL.h (51%) [12.0 microg/mL.h (52%)], N-acetylmesalazine AUC 27.7 microg/mL.h (32%) [30.5 microg/mL.h (27%)], mesalazine Ae 8.53% (89%) [9.03% (52%)], N-acetylmesalazine Ae 31.4% (46%) [32.2 (41%)]. Values in study B were as follows: mesalazine AUC 3.45 microg/mL.h (113%) [2.36 microg/mL.h (87%)], N-acetylmesalazine AUC 21.3 microg/mL.h (29%) [18.0 microg/mL.h (39%)], mesalazine Ae 0.2% (256%) [0.1% (359%)], N-acetylmesalazine Ae 30.9% (44%) [18.1% (84%)]. Higher AUC and Ae values for mesalazine in steady state study indicate saturation of mesalazine metabolism. Statistics provided no evidence for a true difference in mesalazine pharmacokinetics between slow and rapid acetylators, and no significant correlation between NAT2 activity and any mesalazine pharmacokinetic parameter was found. CONCLUSION: NAT2 has no major role in human metabolism of mesalazine in vivo.

The effect of silymarin on oral nifedipine pharmacokinetics.

Silibinin, the main component of silymarin (a milk thistle extract used for treatment of liver injury), has been shown to inhibit CYP3A4 in human liver microsomes. The present study was conducted to examine whether inhibition of CYP3A4 by silymarin is also present IN VIVO. Immediate release nifedipine (10 mg) was administered as a CYP3A4 test drug either alone or with co-administration of silymarin (280 mg administered 10 hours and 1.5 hours prior to the administration of nifedipine) to 16 healthy male volunteers (mean age 27 years, mean body weight 77 kg). Nifedipine and silibinin concentrations were quantified by HPLC, heart rate and blood pressure were monitored for safety reasons. Pharmacokinetic parameters were calculated by non-compartmental methods, and the potential interaction by silymarin was handled as an equivalence problem. We found that nifedipine AUC was 1.13-fold higher (90 % CI, 0.97- to 1.32-fold) in the silymarin period, C (max) values were 0.70-fold (90 % CI, 0.39- to 1.27-fold) of those of the reference period, with a trend to delayed absorption in the silymarin period. Intraindividual variability especially for C (max) (intrasubject CV 120 %) was unexpectedly high. There was no meaningful effect on hemodynamic parameters. In conclusion, our data suggest that co-administration of silymarin does not considerably change the extent of absorption or metabolism of nifedipine but may decrease the absorption rate. Silymarin thus is not a potent CYP3A4 inhibitor IN VIVO.