Journal of clinical pharmacology
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Randomized Controlled Trial Multicenter Study
Studying the antiemetic effect of vitamin B6 for morning sickness: pyridoxine and pyridoxal are prodrugs.
Vitamin B6 has been known to possess antiemetic effects since 1942. This water soluble compound has several forms in the circulation including pyridoxine, pyridoxal, and pyridoxal phosphate. The active antiemetic form of vitamin B6 is unknown. ⋯ With Diclectin® exhibiting a significant antiemetic effect in pregnancy, serum concentrations of pyridoxine were unmeasurable in almost all patients and those of pyridoxal were undetectable in half of patients. In contrast, PLP was measurable at sustained, stable steady-state levels in all patients. Our data suggest that there is a correlation between PLP levels and PUQE score of morning sickness symptoms when pyridoxine and pyridoxal levels are undetectable, and hence they might be prodrugs of PLP, which may be the active antiemetic form of vitamin B6.
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Randomized Controlled Trial Multicenter Study
Systemic pharmacokinetics and cerebrospinal fluid uptake of intravenous ceftriaxone in patients with amyotrophic lateral sclerosis.
The cephalosporin antibiotic ceftriaxone was evaluated as a potential therapeutic agent for the treatment of amyotrophic lateral sclerosis (ALS). The pharmacokinetics (PK) of ceftriaxone in plasma and cerebrospinal fluid (CSF) were investigated in 66 participants in a previously reported clinical trial. Their mean age was 51 years, and 65% were male. ⋯ CSF PK analysis, determined through sparse CSF sampling, indicated apparent entry and elimination half-life values of 1.0 and 34 hours, respectively. With both dosage regimens, CSF concentrations were maintained above the target threshold of 1.0 µM (0.55 µg/mL) as determined from in vitro models. The plasma and CSF PK profiles of ceftriaxone were used as a basis for planning the Phase 3 clinical trial of ceftriaxone in ALS.
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Randomized Controlled Trial Multicenter Study
Population exposure-response model to support dosing evaluation of ixekizumab in patients with chronic plaque psoriasis.
Ixekizumab (LY2439821), a humanized immunoglobulin G subclass 4 (IgG4) monoclonal antibody that selectively binds and neutralizes interleukin (IL) 17A has demonstrated efficacy in the treatment of psoriasis. A population pharmacokinetics-pharmacodynamics model was developed using NONMEM 7.2 to describe the temporal relationship between ixekizumab concentrations and absolute Psoriasis Area and Severity Index (PASI) scores from a phase 2 dose-finding study in chronic plaque psoriasis. The objective was to inform dose-selection for further development. ⋯ The population pharmacokinetics of ixekizumab was characterized by a two-compartment model, while the exposure-response relationship was characterized using an indirect response model that described the pharmacological effects of ixekizumab and placebo in the form of inhibition of the formation of psoriatic skin lesions. PASI 75 responder status at the Week 12 primary endpoint was found to be a significant covariate on the concentration producing half maximal effect (EC50 ). While the results suggested patient may have different levels of sensitivity to ixekizumab, it is possible that nonresponder patients assigned to lower doses of ixekizumab may potentially become responders to ixekizumab if given doses that yield adequate exposures.
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Randomized Controlled Trial Multicenter Study Comparative Study
Comparing the pharmacokinetics of doxylamine/pyridoxine delayed-release combination in nonpregnant women of reproductive age and women in the first trimester of pregnancy.
Although Diclectin (doxylamine/pyridoxine delayed-released combination) is widely used in Canada, its pharmacokinetics (PK) during pregnancy has never been described. The objective of this study was to compare the PK of doxylamine/pyridoxine delayed-released combination in pregnant versus nonpregnant women. The apparent clearances (CL) of doxylamine and pyridoxal 5'-phosphate (PLP; the active metabolite of vitamin B(6) ) during the first-trimester pregnancy in women who participated in a Diclectin randomized trial were compared with those of healthy, adult, nonpregnant women who participated in a voluntary PK trial. ⋯ There was no difference in the apparent CL of doxylamine in women in their first trimester of pregnancy when compared with nonpregnant women on day 4 (median = 196.7 vs 249.5 mL/h/kg, respectively, P = .065), day 8 (median = 248.4 vs 249.5 mL/h/kg, respectively, P = .82), and day 15 (median = 200.9 vs 249.5 mL/h/kg, respectively, P = .55). No difference was found in the apparent CL of PLP on day 15 (median = 342.3 vs 314.7 mL/h/kg, respectively, P = .92). There was no pregnancy-induced effect in the apparent CL of either doxylamine or PLP in women during the first trimester of pregnancy despite the existence of morning sickness.
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Trastuzumab is a key component of treatment for human epidermal growth factor receptor 2 (HER2)-positive breast cancer in both the early and metastatic settings. It is administered intravenously, with between 17 and 52 infusions in standard regimens over 1 year. Intravenous administration of trastuzumab requires substantial time commitments for patients and health care professionals and can result in patient discomfort. ⋯ A subcutaneous trastuzumab dose of 8 mg/kg was found to result in exposure comparable with the intravenous trastuzumab dose of 6 mg/kg. The subcutaneous formulation was well tolerated, with a trend toward fewer adverse events versus intravenous administration; most adverse events were mild in intensity. These results support an ongoing phase III efficacy and safety study comparing a fixed subcutaneous trastuzumab dose with intravenous trastuzumab administration.