Bioanalysis of erlotinib, its O-demethylated metabolites OSI-413 and OSI-420, and other metabolites by liquid chromatography-tandem mass spectrometry with additional ion mobility identification

Pharmacokinetic study of erlotinib in a pregnant woman with advanced non-small cell lung cancer and observation of the effects on the child growth

AIMS

The aim of the study is to report the clinical and pharmacological observations from a pregnant patient treated with erlotinib in the second and third trimesters of pregnancy.

METHODS

Maternal and neonatal blood levels and safety of erlotinib and its metabolites were evaluated. Child development was monitored for 6 years.

RESULTS

A 31-year-old woman with stage IV lung adenocarcinoma with EGFR exon19 deletion began treatment with erlotinib 150 mg/day at 17 weeks of gestation. Although foetal growth retardation and oligohydramnios were observed at several times during the pregnancy, treatment was continued due to the severity of the maternal presentation, with ongoing foetal monitoring. The foetus seemed to tolerate and recover well without specific interventions. A healthy baby boy was delivered at 37 weeks gestation. The child grew and developed without any obvious issues. At last follow-up, at age 6 years, he was attending school at a grade appropriate for his age without health or developmental problems. Blood levels of erlotinib were 397-856 ng/mL at 18-37 weeks of gestation and 1190 ng/mL at 8 weeks postpartum. The blood concentration ratios of OSI-413-to-erlotinib ranged from 0.167 to 0.253 at 18-37 weeks of gestation, excluding 24 weeks, and 0.131 at 8 weeks postpartum. The maternal-to-foetal transfer rate of erlotinib, OSI-420 and OSI-413 were 24.5, 34.8 and 20.3%, respectively.

CONCLUSION

Erlotinib use during the second and third trimester of pregnancy did not seem to cause any untoward effects on the developing foetus, or any long-lasting effects that could be detected during 6 years of follow-up of the child.

Interplay of OATP1A/1B/2B1 uptake transporters and ABCB1 and ABCG2 efflux transporters in the handling of bilirubin and drugs

Transmembrane drug transporters can be important determinants of the pharmacokinetics, efficacy, and safety profiles of drugs. To investigate the potential cooperative and/or counteracting interplay of OATP1A/1B/2B1 uptake transporters and ABCB1 and ABCG2 efflux transporters in physiology and pharmacology, we generated a new mouse model (Bab12), deficient for Slco1a/1b, Slco2b1, Abcb1a/1b and Abcg2. Bab12 mice were viable and fertile. We compared wild-type, Slco1a/1b/2b1-/-, Abcb1a/1b;Abcg2-/- and Bab12 strains. Endogenous plasma conjugated bilirubin levels ranked as follows: wild-type = Abcb1a/1b;Abcg2-/- << Slco1a/1b/2b1-/- < Bab12 mice. Plasma levels of rosuvastatin and fexofenadine were elevated in Slco1a/1b/2b1-/- and Abcb1a/1b;Abcg2-/- mice compared to wild-type, and dramatically increased in Bab12 mice. Although systemic exposure of larotrectinib and repotrectinib was substantially increased in the separate multidrug transporter knockout strains, no additive effects were observed in the combination Bab12 mice. Significantly higher plasma exposure of fluvastatin and pravastatin was only found in Slco1a/1b/2b1-deficient mice. However, noticeable transport by Slco1a/1b/2b1 and Abcb1a/1b and Abcg2 across the BBB was observed for fluvastatin and pravastatin, respectively, by comparing Bab12 mice with Abcb1a/1b;Abcg2-/- or Slco1a/1b/2b1-/- mice. Quite varying behavior in plasma exposure of erlotinib and its metabolites was observed among these strains. Bab12 mice revealed that Abcb1a/1b and/or Abcg2 can contribute to conjugated bilirubin elimination when Slco1a/1b/2b1 are absent. Our results suggest that the interplay of Slco1a/1b/2b1, Abcb1a/1b, and Abcg2 could markedly affect the pharmacokinetics of some, but not all drugs and metabolites. The Bab12 mouse model will represent a useful tool for optimizing drug development and clinical application, including efficacy and safety.

Reduced prescription of TNF-inhibitors in chronic arthritis based on therapeutic drug monitoring: A randomized controlled trial

OBJECTIVE

Dosing of tumour necrosis factor-α inhibitors (TNFis) is not personalized causing interindividual variation in serum drug levels; however, dose optimization is not widely implemented. We hypothesized that some patients are overdosed; thus, drug prescription could be reduced by therapeutic drug monitoring (TDM).

METHOD

Independent of disease activity, 239 adults treated for rheumatoid arthritis (n = 99), psoriatic arthritis 15 (n = 48), or spondyloarthritis (n = 92) were recruited for a 48-week prospective, randomized open-label trial. Standard care alone or plus TDM was applied in chronic arthritis patients treated with infliximab (IFX), (n = 81), etanercept (ETN) (n = 79), or adalimumab (ADA) (n = 79). Serum TNFi trough levels assessed at inclusion and every 4 months determined patients within/outside predefined therapeutic intervals, supporting change in prescription or drug switch. The primary endpoint was reduced drug prescription.

RESULTS

Compared to standard care, TDM reduced prescribed IFX [-12% (95% confidence interval -20, -3); p = 0.001] and ETN (-15% (-29, 1); p = 0.01], and prolonged the interdosing intervals of ETN [+235% (38, 432); p = 0.02] and ADA [+28% (6, 51); p = 0.04]. Time to drug switch was accelerated (χ2 = 6.03, p = 0.01). No group differences in adverse events, disease activity, or self-reported outcomes were shown, indicating equally sustained remission.

CONCLUSIONS

TDM reduced prescription of IFX, ETN, and ADA and identified patients benefiting from accelerated drug switch, thereby minimizing treatment failure, risk of toxicity, and unnecessary adverse events.

The improvement of intestinal dysbiosis and hepatic metabolic dysfunction in dextran sulfate sodium-induced colitis mice: effects of curcumin

BACKGROUND AND AIM

Curcumin may have promising application in the prevention and amelioration of inflammatory bowel disease (IBD). However, the underlying mechanisms underpinning the ability of curcumin to interact with the gut and liver in IBD remains to be defined, which is the exploration aim of this study.

METHODS

Mice with dextran sulfate sodium salt (DSS)-induced acute colitis were treated either with 100 mg/kg of curcumin or phosphate buffer saline (PBS). Hematoxylin-eosin (HE) staining, 16S rDNA Miseq sequencing, proton nuclear magnetic resonance (1 H NMR) spectroscopy, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were applied for analysis. Spearman's correlation coefficient (SCC) was utilized to assess the correlation between the modification of intestinal bacteria and hepatic metabolite parameters.

RESULTS

Curcumin supplementation not only prevented further loss of body weight and colon length in IBD mice but also improved diseases activity index (DAI), colonic mucosal injury, and inflammatory infiltration. Meanwhile, curcumin restored the composition of the gut microbiota, significantly increased Akkermansia, Muribaculaceae_unclassified, and Muribaculum, and significantly elevated the concentration of propionate, butyrate, glycine, tryptophan, and betaine in the intestine. For hepatic metabolic disturbances, curcumin intervention altered 14 metabolites, including anthranilic acid and 8-amino-7-oxononanoate while enriching pathways related to the metabolism of bile acids, glucagon, amino acids, biotin, and butanoate. Furthermore, SCC analysis revealed a potential correlation between the upregulation of intestinal probiotics and alterations in liver metabolites.

CONCLUSION

The therapeutic mechanism of curcumin against IBD mice occurs by improving intestinal dysbiosis and liver metabolism disorders, thus contributing to the stabilization of the gut-liver axis.

Organic anion-transporting polypeptide 2B1 knockout and humanized mice; insights into the handling of bilirubin and drugs

Organic anion transporting polypeptide 2B1 (OATP2B1/SLCO2B1) facilitates uptake transport of structurally diverse endogenous and exogenous compounds. To investigate the roles of OATP2B1 in physiology and pharmacology, we established and characterized Oatp2b1 knockout (single Slco2b1^-/- and combination Slco1a/1b/2b1^-/-) and humanized hepatic and intestinal OATP2B1 transgenic mouse models. While viable and fertile, these strains exhibited a modestly increased body weight. In males, unconjugated bilirubin levels were markedly reduced in Slco2b1^-/- compared to wild-type mice, whereas bilirubin monoglucuronide levels were modestly increased in Slco1a/1b/2b1^-/- compared to Slco1a/1b^-/- mice. Single Slco2b1^-/- mice showed no significant changes in oral pharmacokinetics of several tested drugs. However, markedly higher or lower plasma exposure of pravastatin and the erlotinib metabolite OSI-420, respectively, were found in Slco1a/1b/2b1^-/- compared to Slco1a/1b^-/- mice, while oral rosuvastatin and fluvastatin behaved similarly between the strains. In males, humanized OATP2B1 strains showed lower conjugated and unconjugated bilirubin levels than control Slco1a/1b/2b1-deficient mice. Moreover, hepatic expression of human OATP2B1 partially or completely rescued the impaired hepatic uptake of OSI-420, rosuvastatin, pravastatin, and fluvastatin in Slco1a/1b/2b1^-/- mice, establishing an important role in hepatic uptake. Expression of human OATP2B1 in the intestine was basolateral and markedly reduced the oral availability of rosuvastatin and pravastatin, but not of OSI-420 and fluvastatin. Neither lack of Oatp2b1, nor overexpression of human OATP2B1 had any effect on fexofenadine oral pharmacokinetics. While these mouse models still have limitations for human translation, with additional work we expect they will provide powerful tools to further understand the physiological and pharmacological roles of OATP2B1.

Ritonavir-Boosted Exposure of Kinase Inhibitors: an Open Label, Cross-over Pharmacokinetic Proof-of-Concept Trial with Erlotinib

Background

Although kinase inhibitors (KIs) are generally effective, their use has a large impact on the current health care budget. Dosing strategies to reduce treatment costs are warranted. Boosting pharmacokinetic exposure of KIs metabolized by cytochrome P450 (CYP)3A4 with ritonavir might result in lower doses needed and subsequently reduces treatment costs. This study is a proof-of-concept study to evaluate if the dose of erlotinib can be reduced by co-administration with ritonavir.

Methods

In this open-label, cross-over study, we compared the pharmacokinetics of monotherapy erlotinib 150 mg once daily (QD) (control arm) with erlotinib 75 mg QD plus ritonavir 200 mg QD (intervention arm). Complete pharmacokinetic profiles at steady-state were taken up to 24 h after erlotinib intake for both dosing strategies.

Results

Nine patients were evaluable in this study. For the control arm, the systemic exposure over 24 h, maximum plasma concentration and minimal plasma concentration of erlotinib were 29.3 μg*h/mL (coefficient of variation (CV):58%), 1.84 μg/mL (CV:60%) and 1.00 μg/mL (CV:62%), respectively, compared with 28.9 μg*h/mL (CV:116%, p = 0.545), 1.68 μg/mL (CV:68%, p = 0.500) and 1.06 μg/mL (CV:165%, p = 0.150) for the intervention arm. Exposure to the metabolites of erlotinib (OSI-413 and OSI-420) was statistically significant lower following erlotinib plus ritonavir dosing. Similar results regarding safety in both dosing strategies were observed, no grade 3 or higher adverse event was reported.

Conclusions

Pharmacokinetic exposure at a dose of 75 mg erlotinib when combined with the strong CYP3A4 inhibitor ritonavir is similar to 150 mg erlotinib. Ritonavir-boosting is a promising strategy to reduce erlotinib treatment costs and provides a rationale for other expensive therapies metabolized by CYP3A4.