2022 White Paper on Recent Issues in Bioanalysis: ICH M10 BMV Guideline & Global Harmonization; Hybrid Assays; Oligonucleotides & ADC; Non-Liquid & Rare Matrices; Regulatory Inputs (Part 1A - Recommendations on Mass Spectrometry, Chromatography and Sample Preparation, Novel Technologies, Novel Modalities, and Novel Challenges, ICH M10 BMV Guideline & Global Harmonization Part 1B - Regulatory Agencies' Inputs on Regulated Bioanalysis/BMV, Biomarkers/CDx/BAV, Immunogenicity, Gene & Cell Therapy and Vaccine)

The 16th Workshop on Recent Issues in Bioanalysis (16th WRIB) took place in Atlanta, GA, USA on September 26-30, 2022. Over 1000 professionals representing pharma/biotech companies, CROs, and multiple regulatory agencies convened to actively discuss the most current topics of interest in bioanalysis. The 16th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on the ICH M10 BMV final guideline (focused on this guideline training, interpretation, adoption and transition); mass spectrometry innovation (focused on novel technologies, novel modalities, and novel challenges); and flow cytometry bioanalysis (rising of the 3rd most common/important technology in bioanalytical labs) were the special features of the 16th edition. As in previous years, WRIB continued to gather a wide diversity of international, industry opinion leaders and regulatory authority experts working on both small and large molecules as well as gene, cell therapies and vaccines to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance, and achieving scientific excellence on bioanalytical issues. This 2022 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2022 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1A) covers the recommendations on Mass Spectrometry and ICH M10. Part 1B covers the Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine. Part 2 (LBA, Biomarkers/CDx and Cytometry) and Part 3 (Gene Therapy, Cell therapy, Vaccines and Biotherapeutics Immunogenicity) are published in volume 15 of Bioanalysis, issues 15 and 14 (2023), respectively.

Acute and Chronic Effects of Rifampin on Letermovir Suggest Transporter Inhibition and Induction Contribute to Letermovir Pharmacokinetics

Rifampin has acute inhibitory and chronic inductive effects that can cause complex drug-drug interactions. Rifampin inhibits transporters including organic-anion-transporting polypeptide (OATP)1B and P-glycoprotein (P-gp), and induces enzymes and transporters including cytochrome P450 3A, UDP-glucuronosyltransferase (UGT)1A, and P-gp. This study aimed at separating inhibitory and inductive effects of rifampin on letermovir disposition and elimination (indicated for cytomegalovirus prophylaxis in hematopoietic stem cell transplant recipients). Letermovir is a substrate of UGT1A1/3, P-gp, and OATP1B, with its clearance primarily mediated by OATP1B. Letermovir (single-dose) administered with rifampin (single-dose) resulted in increased letermovir exposure through transporter inhibition. Chronic coadministration with rifampin (inhibition plus potential OATP1B induction) resulted in modestly decreased letermovir exposure versus letermovir alone. Letermovir administered 24 hours after last rifampin dose (potential OATP1B induction) resulted in markedly decreased letermovir exposure. These data suggest rifampin may induce transporters that clear letermovir; the modestly reduced letermovir exposure with chronic rifampin coadministration likely reflects the net effect of inhibition and induction. OATP1B endogenous biomarkers coproporphyrin (CP) I and glycochenodeoxycholic acid-sulfate (GCDCA-S) were also analyzed; their exposures increased after single-dose rifampin plus letermovir, consistent with OATP1B inhibition and prior reports of inhibition by rifampin alone. CP I and GCDCA-S exposures were substantially reduced with letermovir administered 24 hours after the last dose of rifampin versus letermovir plus chronic rifampin coadministration, This study suggests that OATP1B induction may contribute to reduced letermovir exposure after chronic rifampin administration, although given the complexity of letermovir disposition, alternative mechanisms are not fully excluded.

A Microdose Cocktail to Evaluate Drug Interactions in Patients with Renal Impairment

Renal impairment (RI) is known to influence the pharmacokinetics of nonrenally eliminated drugs, although the mechanism and clinical impact is poorly understood. We assessed the impact of RI and single dose oral rifampin (RIF) on the pharmacokinetics of CYP3A, OATP1B, P-gp, and BCRP substrates using a microdose cocktail and OATP1B endogenous biomarkers. RI alone had no impact on midazolam (MDZ), maximum plasma concentration (C_max ), and area under the curve (AUC), but a progressive increase in AUC with RI severity for dabigatran (DABI), and up to ~2-fold higher AUC for pitavastatin (PTV), rosuvastatin (RSV), and atorvastatin (ATV) for all degrees of RI was observed. RIF did not impact MDZ, had a progressively smaller DABI drug-drug interaction (DDI) with increasing RI severity, a similar 3.1-fold to 4.4-fold increase in PTV and RSV AUC in healthy volunteers and patients with RI, and a diminishing DDI with RI severity from 6.1-fold to 4.7-fold for ATV. Endogenous biomarkers of OATP1B (bilirubin, coproporphyrin I/III, and sulfated bile salts) were generally not impacted by RI, and RIF effects on these biomarkers in RI were comparable or larger than those in healthy volunteers. The lack of a trend with RI severity of PTV and several OATP1B biomarkers, suggests that mechanisms beyond RI directly impacting OATP1B activity could also be considered. The DABI, RSV, and ATV data suggest an impact of RI on intestinal P-gp, and potentially BCRP activity. Therefore, DDI data from healthy volunteers may represent a worst-case scenario for clinically derisking P-gp and BCRP substrates in the setting of RI.

Abstract 118: The Effect of CETP Inhibition With Anacetrapib on the Metabolism of PCSK9

Introduction

Inhibition of CETP activity with anacetrapib has been associated with a significant reduction in low density lipoprotein (LDL)-cholesterol (C) levels both as a monotherapy and in combination with a statin. We recently reported that this reduction in LDL-C is due to a significant increase in the fractional clearance rate (FCR) of LDL apoB. One potential mechanism by which anacetrapib could influence LDL apoB clearance is through effects on PCSK9 metabolism. We conducted kinetic studies on PCSK9 to determine if a change in the metabolism of PCSK9 is responsible for the reduction in LDL-C levels following treatment with anacetrapib.

Methods

Moderately hyperlipidemic volunteers (n=39) were enrolled in a fixed-sequence study: 75% were on atorvastatin (20mg/day) plus placebo and 25% were on double placebo for four weeks. Following this baseline period subjects added anacetrapib (100 mg/day) to their background treatment for 8 weeks. Studies using D3 leucine tracer were performed at the end of each treatment period to determine the kinetics PCSK9.

Results

Statin treated subjects had lower LDL-C levels (84 vs 118 mg/dL) and higher PCSK9 levels (234 vs. 208 ng/mL) at baseline than subjects on placebo. The difference in PCSK9 was due to a higher PCSK9 production rate (PR) (19.7 vs. 16.7 ug/kg/day) but similar PCSK9 FCR (1.87 vs. 1.78 pools/day). Adding anacetrapib to background treatment was associated with a significant reduction in LDL cholesterol (~ -35%) and apoB levels (~ 20%) in both panels. Anacetrapib had no significant effect on PCSK9 levels in either of the background treatment groups. Consistent with the lack of change in PCSK9 levels, there was no effect of anacetrapib on the PR (18.1 vs. 19.3 ug/kg/day) or FCR of PCSK9 (1.82 vs. 1.93 pools/day).

Conclusion

These results indicate that in our study population the increase in LDL FCR observed in response to anacetrapib treatment is not likely to be related to changes in the metabolism of PCSK9.

Abstract 329: Mechanism by Which Anacetrapib Lowers Plasma Lipoprotein (a) Concentration

Objective: Anacetrapib, a CETP inhibitor, was previously shown to decrease plasma lipoprotein (a) [Lp(a)] levels by 35-40% in subjects also taking a statin. Thus, anacetrapib is an efficacious Lp(a)-lowering agent. The goal of this study was to define the mechanism by which anacetrapib lowers plasma Lp(a) levels.

Methods: 39 moderately hyperlipidemic volunteers were enrolled in a fixed-sequence study, in which 75% were on atorvastatin 20mg/day, plus placebo for four weeks (period 1), and then atorvastatin plus anacetrapib (100 mg/day) for 8 weeks (period 2). The other 25% of the subjects received double placebo for four weeks, and then placebo plus anacetrapib for 8 weeks. Turnover studies using D3-leucine were performed at the end of each period. The present analysis utilized samples from a subset of subjects (n=12) who had plasma Lp(a) levels greater than 10 nM at the end of period 1 and had a greater than 10% reduction in Lp(a) by the end of period 2. The fractional synthetic rate (FSR:equal to fractional catabolic rate at steady state) of mature Lp(a), isolated from a D:1.019-1.21 g/ml density interval, was determined from the enrichment of a leucine-containing peptide specific to apo(a). The production rate (PR) of mature Lp(a) was calculated from the FSR and the Lp(a) pool size. To date, we have calculated the FSR and PR in 4 participants.

Results: Baseline Lp(a) mean levels were 45.7 ± 6.3nM in the entire group and 56.5 ± 33.6nM in the 12 qualifying subjects. Anacetrapib lowered Lp(a) by 43 ± 22% in the 12 subjects and 21 ±12% in the 4 subjects with turnover data. In these 4 subjects, the reduction in mature Lp(a) was associated with a 24% reduction in FSR and a 41% reduction in PR. Lp(a) kinetics analyses of the remaining 8 subjects are in progress.

Conclusion: These preliminary results suggest that anacetrapib decreases Lp(a) levels by significantly decreasing the production of mature Lp(a). Additional analyses are planned to determine if the reduced production of Lp(a) results from decreased entry of Lp(a) into plasma or reduced conversion of a precursor form to the mature Lp(a).

Risk of neural tube defects in relation to maternal fertility and fertility drug use

In a case-control study to investigate whether women who use drugs to induce ovulation are at increased risk of conception of a child with a neural tube defect, 571 women who had a fetus or child with a neural tube defect, 546 women who had a fetus or child with other abnormalities, and 573 women who had an apparently normal fetus or child were questioned about infertility, fertility drug use, and related obstetric problems. The rate of maternal fertility drug use around the time of conception was not significantly higher for neural tube defects than for other abnormalities (odds ratio 1.28; 95% confidence interval 0.39, 4.51) or no abnormalities (odds ratio 0.80; 95% Cl 0.27, 2.27). Fertility drug use at any time was not significantly more frequent for neural tube defects than for other abnormalities (odds ratio 1.37; 95% Cl 0.70, 2.74) or no abnormalities (odds ratio 1.05; 95% Cl 0.56, 1.98).