Dosing Interval for Tixagevimab/Cilgavimab (Evusheld)
The FDA has amended its Emergency Use Authorization (EUA) for the investigational long-acting monoclonal antibodies tixagevimab and cilgavimab (Evusheld – AstraZeneca) to recommend repeat dosing every 6 months in patients who require ongoing protection against COVID-19.1 Evusheld is authorized for IM pre-exposure prophylaxis of COVID-19 in persons ≥12 years old who weigh ≥40 kg and have either a history of a severe adverse reaction that prevents their vaccination against COVID-19 or moderate or severe immune compromise.2
The revision was based on pharmacologic modeling data, which suggest that tixagevimab and cilgavimab retain activity against currently circulating variants of SARS-CoV-2 (including the Omicron variants BA.2, BA.2.12.1, BA.4, and BA.5) for 6 months after administration of a 300-mg dose of each antibody.2
The recommended dosage of Evusheld is 300 mg of tixagevimab and 300 mg of cilgavimab given as two consecutive IM injections once every 6 months. Patients should be monitored for at least 1 hour after administration. Evusheld should not be used for treatment or post-exposure prophylaxis of COVID-19, or within 2 weeks after administration of a COVID-19 vaccine.2
- FDA. FDA authorizes revisions to Evusheld dosing. June 29, 2022. Available at: https://bit.ly/3K5AcNc. Accessed July 11, 2022.
- FDA. Fact sheet for health care providers: Emergency Use Authorization for Evusheld (tixagevimab co-packaged with cilgavimab). June 2022. Available at: https://bit.ly/3IWpQjg. Accessed July 11, 2022.
Prescription of Paxlovid by Pharmacists
The FDA has amended its Emergency Use Authorization (EUA) for Paxlovid (Pfizer), the investigational oral antiviral drug nirmatrelvir copackaged with oral ritonavir, to allow for it to be prescribed by licensed pharmacists in certain situations.1 Paxlovid is authorized for oral treatment of mild to moderate COVID-19 in high-risk outpatients ≥12 years old who weigh at least 40 kg.2,3 NIH guidelines list it as the treatment of choice for COVID-19 in high-risk adult outpatients.4
The amendment to the EUA allows pharmacists to provide Paxlovid to eligible patients for whom they can review measurements of renal and hepatic function (obtained within the last 12 months) and a list of prescription and nonprescription medications currently being taken.
Paxlovid is not recommended for use in patients with severe renal impairment (eGFR <30 mL/min) or severe hepatic impairment (Child-Pugh C); dosage adjustments are recommended in patients with moderate renal impairment (eGFR ≥30 to <60 mL/min).3 The drug is contraindicated for use with strong CYP3A4 inducers,5 or with drugs that are highly dependent on CYP3A for clearance and are associated with serious or life-threatening events at elevated serum concentrations (e.g., amiodarone, midazolam). According to the revised EUA, if other medications in the patient’s regimen must be modified because of a potential interaction, the patient should be referred to their healthcare provider.
- FDA News Release. Coronavirus (COVID-19) update: FDA authorizes pharmacists to prescribe Paxlovid with certain limitations. July 6, 2022. Available at: https://bit.ly/3RelGau. Accessed July 11, 2022.
- FDA. Fact sheet for health care providers: Emergency Use Authorization for Paxlovid. July 6, 2022. Available at: https://bit.ly/3sTNGqh. Accessed July 11, 2022.
- Paxlovid for treatment of COVID-19. Med Lett Drugs Ther 2022; 64:9.
- NIH. COVID-19 treatment guidelines. Therapeutic management of nonhospitalized adults with COVID-19. April 8, 2022. Available at: https://bit.ly/3w5TdLB. Accessed July 11, 2022.
- Inhibitors and inducers of CYP enzymes, P-glycoprotein, and other transporters. Med Lett Drugs Ther 2021 October 20 (epub). Available at: medicalletter.org/downloads/CYP_PGP_Tables.pdf.