Background: Drug-drug interaction (DDIs) are evaluated using pharmacokinetic (PK) simulation models, clinical studies, and scientific publications throughout drug development. DDIs with Norvir (ritonavir) and combination products (eg, Kaletra [lopinavir/ritonavir]) containing ritonavir as a PK enhancer are relevant, because these drugs could affect exposures of CYP3A4 substrates. Application of algorithms proactively identified recently approved drugs, which potentially cause adverse outcomes when given with drugs containing ritonavir.
Methods: An evidence-based medicine technology platform was used to identify newly approved products. PK-related information from the products' prescribing information was reviewed to identify DDIs with ritonavir. Algorithms were used to further evaluate PK, clinical, and postmarketing information pertinent to the interaction to determine if prescribing information required revision.
Results: From January 1, 2014, through December 31, 2015, 39 newly approved drugs were identified as having potential interactions with Norvir and/or Kaletra. Ten drugs were excluded, 19 drugs went through initial screening, and 10 drugs underwent in-depth algorithm-based analyses for DDIs. No changes to prescribing information for Norvir or Kaletra were recommended from evaluation of the DDIs. Regulatory concurrence with AbbVie decisions was 93.1% (27/29, 93.1%); in 6.9% (2/29, 6.9%) of the evaluated interactions, at least 1 local regulatory authority disagreed with recommendations, requiring label changes to incorporate the DDI information.
Conclusions: This proactive algorithmic approach identifies and complements existing methods used to detect DDIs with newly approved products. Additionally, this approach facilitates timely communication of risks to patients and healthcare providers via label revisions, publications, or other regulatory communications.
Keywords: CYP3A4; algorithm; drug-drug interaction; evidence-based medicine technology platform; prescribing information.