Search

Background and Objectives: MCLA-128 is a bispecific monoclonal antibody targeting the HER2 and HER3 receptors and is in development to overcome HER3-mediated resistance to anti-HER2 therapies. The aims of this analysis were to characterize the population pharmacokinetics of MCLA-128 in patients with various solid tumors, to evaluate patient-related factors that affect the disposition of MCLA-128, and to assess whether flat dosing is appropriate., Methods: MCLA-128 concentration data following intravenous administration were collected in a phase I/II clinical trial. Pharmacokinetic data were analyzed using non-linear mixed-effects modeling. Different compartmental models were evaluated. Various body size parameters including body weight, body surface area, and fat-free mass were evaluated as covariates in addition to age, sex, HER2 status, and tumor burden., Results: In total, 1115 serum concentration measurements were available from 116 patients. The pharmacokinetics of MCLA-128 was best described by a two-compartment model with linear and non-linear (Michaelis-Menten) clearance. Fat-free mass significantly affected the linear clearance and volume of distribution of the central compartment of MCLA-128, explaining 8.4% and 5.6% of inter-individual variability, respectively. Tumor burden significantly affected the non-linear clearance capacity. Simulations demonstrated that dosing based on body size parameters resulted in similar area under the plasma concentration-time curve for a dosing interval (AUC 0-τ ), maximum and trough concentrations of MCLA-128, compared to flat dosing., Conclusions: This analysis demonstrated that the pharmacokinetics of MCLA-128 exhibits similar disposition characteristics to other therapeutic monoclonal antibodies and that a flat dose of MCLA-128 in patients with various solid tumors is appropriate.

Background: Olaparib, a potent oral poly(ADP-ribose) polymerase inhibitor, is partially renally cleared. We investigated the pharmacokinetics and safety of olaparib in patients with mild or moderate renal impairment to provide dosing recommendations., Methods: This phase I open-label study assessed the pharmacokinetics, safety and tolerability of single-dose, oral 300-mg olaparib tablets in adults (aged 18-75 years) with solid tumours. Patients had normal renal function, or mild or moderate renal impairment (estimated creatinine clearance ≥ 81, 51-80 or 31-50 mL/min, respectively). Blood was collected for 96 h, and urine samples collected for 24 h post-dose. Patients could continue taking olaparib 300 mg twice daily for a long-term safety assessment., Results: Overall, 44 patients received one or more doses of olaparib and 38 were included in the pharmacokinetic assessment. Patients with mild renal impairment had an area under the curve geometric least-squares mean ratio of 1.24 (90% confidence interval 1.06-1.47) and a geometric least-squares mean maximum plasma concentration ratio of 1.15 (90% confidence interval 1.04-1.27) vs. those with normal renal function. In patients with moderate renal impairment, the geometric least-squares mean ratio for the area under the curve was 1.44 (90% confidence interval 1.10-1.89) and for the maximum plasma concentration was 1.26 (90% confidence interval 1.06-1.48) vs. those with normal renal function. No new safety signals were detected in patients with mild or moderate renal impairment., Conclusions: In patients with mild renal impairment, the small increase in exposure to olaparib was not considered clinically relevant. In patients with moderate renal impairment, exposure to olaparib increased by 44%; thus, these patients should be carefully monitored and the tablet dose should be adjusted to 200 mg twice daily., Clinical Trials Registration: NCT01894256.

Oral anti-hormonal drugs are essential in the treatment of breast and prostate cancer. It is well known that the interpatient variability in pharmacokinetic exposure is high for these agents and exposure-response relationships exist for many oral anti-hormonal drugs. Yet, they are still administered at fixed doses. This could lead to underdosing and thus suboptimal efficacy in some patients, while other patients could be overdosed resulting in unnecessary side effects. Therapeutic drug monitoring (TDM), individualized dosing based on measured blood concentrations of the drug, could therefore be a valid option to further optimize treatment. In this review, we provide an overview of relevant clinical pharmacokinetic and pharmacodynamic characteristics of oral anti-hormonal drugs in oncology and translate these into practical guidelines for TDM. For some agents, TDM targets are not well established yet and as a reference the median pharmacokinetic exposure could be targeted (exemestane: minimum plasma concentration (C min ) 4.1 ng/mL and enzalutamide: C min 11.4 mg/L). However, for most drugs, exposure-efficacy analyses could be translated into specific targets (abiraterone: C min 8.4 ng/mL, anastrozole: C min 34.2 ng/mL, and letrozole: C min 85.6 ng/mL). Moreover, prospective clinical trials have shown TDM to be feasible for tamoxifen, for which the exposure-efficacy threshold of its active metabolite endoxifen is 5.97 ng/mL. Based on the available data, we therefore conclude that individualized dosing based on drug concentrations is feasible and promising for oral anti-hormonal drugs and should be developed further and implemented into clinical practice.

Background: The mammalian target of rapamycin (mTOR) inhibitor everolimus is used in the treatment of breast cancer, neuroendocrine tumors, and renal cancer. The approved 10 mg once-daily dose is associated with considerable adverse effects and it has been suggested that these are associated with the maximum concentration (C max ) of everolimus. Twice-daily dosing might be an alternative strategy with improved tolerability; however, a direct pharmacokinetic comparison of 10 mg once-daily with 5 mg twice-daily dosing is lacking., Methods: We performed a prospective, randomized, pharmacokinetic, crossover trial comparing everolimus 10 mg once daily with 5 mg twice daily. Patients received the first dose schedule for 2 weeks and then switched to the alternative regimen for 2 weeks. Pharmacokinetic sampling was performed on days 14 and 28., Results: Eleven patients were included in the study, of whom 10 were evaluable for pharmacokinetic analysis. On the 10 mg once-daily schedule, C max , minimum concentration (C min ), and area under the concentration-time curve from time zero to 24 h (AUC 24 ) were 61.5 ng/mL [mean percentage coefficient of variation (CV%) 29.6], 9.6 ng/mL (CV% 35.0), and 435 ng h/mL (CV% 28.1), respectively. Switching to the 5 mg twice-daily schedule resulted in a reduction of C max to 40.3 ng/mL (CV% 46.6) (p = 0.013), while maintaining AUC 24 at 436 ng h/mL (CV% 34.8) (p = 0.952). C min increased to 13.7 ng/mL (CV% 53.9) (p = 0.018). The overall reduction in C max was 21.2 ng/mL, or 32.7%. The C max /C min ratio was reduced from 6.44 (CV% 36.2) to 3.18 (CV% 35.5) (p < 0.001)., Conclusions: We demonstrated that switching from a once-daily to a twice-daily everolimus dose schedule reduces C max without negatively impacting C min or AUC 24 . These results merit further investigation of the twice-daily schedule in an effort to reduce everolimus toxicity while maintaining treatment efficacy., Registration: This trial was registered in the EurdaCT database (2014-004833-25) and the Netherlands Trial Registry (NTR4908).

Breast cancer is a heterogeneous disease, manifesting in a broad differentiation in phenotypes and morphologic profiles, resulting in variable clinical behavior. Between 10 and 20% of all breast cancers are triple negative. Triple-negative breast cancer (TNBC) lacks the expression of human epidermal growth factor receptor 2 (HER2) and hormone receptors; therefore, to date, chemotherapy remains the backbone of treatment. TNBC tends to be aggressive and has a high histological grade, resulting in a poor 5-year prognosis. It has a high prevalence of BRCA1 mutations and an increased Ki-67 expression. This subtype usually responds well to taxanes and/or platinum compounds and poly (ADP-ribose) polymerase (PARP) inhibitors. Studies with PARP inhibitors have demonstrated promising results in the treatment of BRCA-mutated breast and ovarian cancer, and PARP inhibitors have been studied as monotherapy and in combination with cytotoxic therapy or radiotherapy. PARP inhibitor efficacy on poly (ADP-ribose) polymer (PAR) formation in vivo can be quantified by pharmacodynamic assays that measure PAR activity in peripheral blood mononuclear cells (PBMC). Biomarkers such as TP53, ATM, PALB2 and RAD51C might be prognostic or predictive indicators for treatment response, and could also provide targets for novel treatment strategies. In summary, this review provides an overview of the treatment options for basal-like TNBC, including PARP inhibitors, and focuses on the pharmacotherapeutic options in these patients.

This review describes the pharmacokinetic properties of the systemically administered antileishmanial drugs pentavalent antimony, paromomycin, pentamidine, miltefosine and amphotericin B (AMB), including their absorption, distribution, metabolism and excretion and potential drug-drug interactions. This overview provides an understanding of their clinical pharmacokinetics, which could assist in rationalising and optimising treatment regimens, especially in combining multiple antileishmanial drugs in an attempt to increase efficacy and shorten treatment duration. Pentavalent antimony pharmacokinetics are characterised by rapid renal excretion of unchanged drug and a long terminal half-life, potentially due to intracellular conversion to trivalent antimony. Pentamidine is the only antileishmanial drug metabolised by cytochrome P450 enzymes. Paromomycin is excreted by the kidneys unchanged and is eliminated fastest of all antileishmanial drugs. Miltefosine pharmacokinetics are characterized by a long terminal half-life and extensive accumulation during treatment. AMB pharmacokinetics differ per drug formulation, with a fast renal and faecal excretion of AMB deoxylate but a much slower clearance of liposomal AMB resulting in an approximately ten-fold higher exposure. AMB and pentamidine pharmacokinetics have never been evaluated in leishmaniasis patients. Studies linking exposure to effect would be required to define target exposure levels in dose optimisation but have only been performed for miltefosine. Limited research has been conducted on exposure at the drug's site of action, such as skin exposure in cutaneous leishmaniasis patients after systemic administration. Pharmacokinetic data on special patient populations such as HIV co-infected patients are mostly lacking. More research in these areas will help improve clinical outcomes by informed dosing and combination of drugs.

Pazopanib is an inhibitor of the vascular endothelial growth factor receptor, platelet-derived growth factor receptor, fibroblast growth factor receptor and stem cell receptor c-Kit, and has been approved for the treatment of renal cell carcinoma and soft tissue sarcoma. The pharmacokinetics of pazopanib are complex and are characterized by pH-dependent solubility, large interpatient variability and low, non-linear and time-dependent bioavailability. Exposure to pazopanib is increased by both food and coadministration of ketoconazole, but drastically reduced by proton pump inhibitors. Studies have demonstrated relationships between systemic exposure to pazopanib and toxicity, such as hypertension. Furthermore, a strong relationship between pazopanib trough level ≥20 mg/L and both tumor shrinkage and progression-free survival has been established. At the currently approved daily dose of 800 mg, approximately 20% of patients do not reach this threshold and may be at risk of suboptimal treatment. As a result of this, clinical trials have explored individualized pazopanib dosing, which demonstrate the safety and feasibility of individualized pazopanib dosing based on trough levels. In summary, we provide an overview of the complex pharmacokinetic and pharmacodynamic profiles of pazopanib and, based on the available data, we propose optimized dosing strategies.