News

Organic Anion Transporting Polypeptide 2B1 – More Than a Glass-Full of Drug Interactions

Abstract

The importance of uptake transporters in determining drug disposition is increasingly appreciated. While the focus of regulatory agencies worldwide has been on the hepatic organic anion transporting polypeptides (OATPs)-1B1 and-1B3, there is another isoform of the OATP sub-family, OATP2B1, which should be considered equally relevant. Unlike the other members of the OATP sub-family, OATP2B1 is expressed in multiple organs in humans, including in the intestine and the liver. Similar to other OATPs, OATP2B1 mediates the hepatic and intestinal uptake of many drugs and endogenous compounds. The importance of OATP2B1 in the disposition of many drugs is highlighted by the growing recognition of its role in significant in vivo drug-drug or food-drug interactions. The dramatic changes in drug exposure attributable to inhibition of OATP2B1 highlight the importance of developing a better understanding of the clinical role of OATP2B1. This review aims to provide a thorough summary of the current understanding of the pharmacogenetics, regulation, expression and abundance of OATP2B1 in humans, as well as its clinical relevance in drug-drug and food-drug interactions.

Upcoming release of new features on April 6, 2019!

The DIDB Team will release new features on Saturday April 6, 2019. The release includes the following improvements:

  • Revised home page with a new “Latest NDAs entered” section.
  • Added number of entries (studies) to standard citation info.
  • Added new monograph page for all compounds.
    • This new monograph page combines the previously separate PK summary, QT summary, and monograph into a single page.
    • What was formerly known as “Monograph” is now “DDI summary” and has been renamed throughout application.
    • New monograph page also aggregates some other additional information on each compound such as DIDB defined compound relationships, other properties from DIDB, and some selected external resources.
    • Every compound has a monograph page, but many compounds may not have a DDI, PK, or QT summary, so there may be very little information presented.
  • In Resource Center, added listings of all compounds in each therapeutic class, including DDI risk information.  This new therapeutic class information is a replacement for the DDI risk information which was presented in the Disease section.   The entire Disease section has been removed.
  • In Resource Center, added two new listings – all compounds with DDI Summaries and all compounds with PK Profiles.
  • Removed pdf product labels and replaced with link to Drugs@FDA when an NDA is related to the drug.

Do not hesitate to contact us at didbase@uw.edu if you have any feedback or questions!

Drug-Drug Interactions of Infectious Disease Treatments in Low-Income Countries: A Neglected Topic?

Clin Pharmacol Ther. 2019 Jun; 105(6); 1378-1385.
Published online 2019 Feb 16

Abstract

Despite recent advances in recognizing and reducing the risk of drug-drug interactions (DDIs) in developed countries, there are still significant challenges in managing DDIs in low-income countries (LICs) worldwide. In the treatment of major infectious diseases in these regions, multiple factors contribute to ineffective management of DDIs that lead to loss of efficacy or increased risk of adverse events to patients. Some of these difficulties, however, can be overcome. This review aims to evaluate the inherent complexities of DDI management in LICs from pharmacological standpoints and illustrate the unique barriers to effective management of DDIs, such as the challenges of co-infection and treatment settings. A better understanding of comprehensive drug-related properties, population-specific attributes, such as physiological changes associated with infectious diseases, and the use of modeling and simulation techniques are discussed, as they can facilitate the implementation of optimal treatments for infectious diseases at the individual patient level.

Mechanisms and Clinical Significance of Pharmacokinetic-Based Drug-Drug Interactions With Drugs Approved by the U.S. Food and Drug Administration in 2017

Abstract

Pharmacokinetic-based drug-drug interaction (DDI) data for drugs approved by the U.S. Food and Drug Administration in 2017 (N = 34) were analyzed using the University of Washington Drug Interaction Database. The mechanisms and clinical relevance of these interactions were characterized based on information from new drug application reviews. CYP3A inhibition and induction explained most of the observed drug interactions (new drugs as victims or as perpetrators), and transporters mediated about half of all DDIs, alone or with enzymes. Organic anion transporting polypeptide (OATP)1B1/1B3 played a significant role, mediating more than half of the drug interactions with area under the time-plasma curve (AUC) changes ≥5-fold. As victims, five new drugs were identified as sensitive substrates: abemeciclib, midostaurin, and neratinib for CYP3A and glecaprevir and voxilaprevir for OATP1B1/1B3. As perpetrators, three drugs were considered strong inhibitors: ribociclib for CYP3A, glecaprevir/pibrentasvir for OATP1B1/1B3, and sofosbuvir/velpatasvir/voxilaprevir for OATP1B1/1B3 and breast cancer resistance protein. No strong inducer of enzymes or transporters was identified. DDIs with AUC changes ≥5-fold and almost all DDIs with AUC changes 2- to 5-fold had dose recommendations in their respective drug labels. A small fraction of DDIs with exposure changes <2-fold had a labeling impact, mostly related to drugs with narrow therapeutic indices. As with drugs approved in recent years, all drugs found to be sensitive substrates or strong inhibitors of enzymes or transporters were among oncology or antiviral treatments, suggesting a serious risk of DDIs in these patient populations for whom effective therapy is already complex because of polytherapy.

Identification and Evaluation of Clinical Substrates of Organic Anion Transporting Polypeptides 1B1 and 1B3

Clin Transl Sci. 2019 Jul; 12(4): 379-387
Published online 2019 Feb 01

Abstract

Organic anion transporting polypeptides (OATPs) 1B1 and 1B3 facilitate the uptake of drugs and endogenous compounds into the liver. In recent years, the impact of these transporters on drug-drug interactions (DDIs) has become a focus of research, and the evaluation of their role in drug disposition is recommended by regulatory agencies worldwide.1-3 Although sensitive substrates of OATP1B1/1B3 have been identified in the literature and probe drugs have been proposed by regulatory agencies, there is no general consensus on the ideal in vivo substrate for clinical DDI studies as analysis may be confounded by contribution from other metabolic and/or transport pathways.1-3 A thorough analysis of the available in vitro and in vivo data regarding OATP1B1/1B3 substrates was performed using the in vitro, clinical, and pharmacogenetic modules in the University of Washington Drug Interaction Database. A total of 34 compounds were identified and further investigated as possible clinical substrates using a novel indexing system. By analyzing the compounds for in vivo characteristics, including sensitivity to inhibition by known OATP1B1/1B3 inhibitors, selectivity for OATP1B1/1B3 compared with other transport and metabolic pathways, and safety profiles, a total of six compounds were identified as potential clinical markers of OATP1B1/1B3 activity.

Developing User Personas to Aid in the Design of a User-Centered Natural Product-Drug Interaction Information Resource for Researchers

Abstract

Pharmacokinetic interactions between natural products and conventional drugs can adversely impact patient outcomes. These complex interactions present unique challenges that require clear communication to researchers. We are creating a public information portal to facilitate researchers’ access to credible evidence about these interactions. As part of a user-centered design process, three types of intended researchers were surveyed: drug-drug interaction scientists, clinical pharmacists, and drug compendium editors. Of the 23 invited researchers, 17 completed the survey. The researchers suggested a number of specific requirements for a natural product-drug interaction information resource, including specific information about a given interaction, the potential to cause adverse effects, and the clinical importance. Results were used to develop user personas that provided the development team with a concise and memorable way to represent information needs of the three main researcher types and a common basis for communicating the design’s rationale.

New features have been implemented!

The following new features have been implemented:

  • New DRUG query where you can find all studies in DIDB for a given compound, including in vitro transporter data
  • Unified in vivo measurement types across all study types
  • Unified citation tree view of all in vivo studies
  • Measurement types now displayed in their proper subscript formats
  • Tree view now more easily viewable on phones
  • New “In Vivo Other Mechanism” sub-type of “PD interaction”

Do not hesitate to contact us if you have any questions or suggestions!