Effective in real world, but less so than in clinical trials
The fact that the patient cohort in the EPIC-HR trial was different from the patients internists see today makes real-world data critical for determining the usefulness of nirmatrelvir-ritonavir in everyday practice, Dr. Smetana said.
A real-world study from Israel conducted during the first Omicron wave (January to March 2022) showed that treatment with nirmatrelvir alone substantially reduced the relative risk of hospitalization in adults older than 65, with no evidence of benefit in adults aged 40-65. Dr. Smetana highlighted that, unlike the EPIC-HR cohort, most patients in the Israeli study had prior immunity due to vaccination or prior SARS-CoV-2 infection.
Many drug-drug interactions, but they can be managed
Nirmatrelvir-ritonavir interacts with many drugs, some of which are commonly used by primary care patients.
To help internists identify drug-drug interactions, Dr. Smetana proposed the use of the Liverpool COVID-19 Drug Interactions Checker, an intuitive tool that can help prescribers identify potential drug-drug interactions, categorize them based on severity, and identify management strategies.
This tool is specific to COVID-19 drugs. The Liverpool group also offers online drug interaction checkers for HIV, hepatitis, and cancer. “We need more tools like this to help improve the safe use of new drugs,” Dr. Smetana said.
To manage drug interactions, according to Dr. Smetana, U.S. treatment guidelines offer the following three options:
- Prescribe an alternative COVID therapy.
- Temporarily withhold concomitant medication if clinically appropriate.
- Adjust the dose of concomitant medication and monitor for adverse effects.
Medication doses that are withheld or modified should be continued through 3 days after completing nirmatrelvir-ritonavir, he added.
Important considerations
Commenting on things to consider for patients with COVID-19, Dr. Smetana said that there is a short window after symptom onset when nirmatrelvir-ritonavir can be prescribed, and safety in pregnancy is not known. There is also uncertainty regarding funding of nirmatrelvir-ritonavir prescriptions after the state of emergency is lifted. He reminded attendees that, although nirmatrelvir-ritonavir is the preferred first-line treatment for high-risk patients, another antiviral agent, molnupiravir, is also available and might be more appropriate for some patients.
He also cautioned about prescribing new drugs off label for indications that are not yet FDA-approved. “We are often stewards of limited resources when new drugs first become available but are not yet in sufficient supply to meet demand. Limiting our prescribing to FDA-approved indications helps to ensure equitable access,” he said.
Dr. Smetana and Dr. Kiefl reported no disclosures.