NIH guidelines recommend the use of Casirivimab plus Imdevimab for post-exposure prophylaxis of COVID-19
While Vaccine remains the mainstay of protection against Coronavirus Disease 2019 (COVID-19), a recent update from the National Institute of Health (NIH), US provides a major step in dealing with Post-Exposure Prophylaxis in individuals who are at high risk of COVID-19 and have been exposed to the severe acute respiratory syndrome coronavirus 2 (SARS- CoV‐2).
In a recent update released on October 19, 2021, following the panel's recommendation The COVID-19 Treatment Guidelines, the NIH has recommended the use of antibody cocktails of Casirivimab 600 mg plus imdevimab 600 mg for post-exposure prophylaxis of SARS-CoV-2 Infection(1,2).
According to the panel, the doses should be administered as soon as possible and preferably within 7 days of high-risk exposure. The patient should be observed for at least 1 hour after the injections or infusion. (3)
Earlier in October 2021, the Panel recommended the use of anti-SARS-CoV-2 monoclonal antibodies (mAbs) for the treatment of mild to moderate COVID-19 and for post-exposure prophylaxis (PEP) of SARS-CoV-2 infection in individuals who are at high risk for progression to severe COVID-19 as outlined in the Food and Drug Administration Emergency Use Authorizations (EUAs) issued for the anti-SARS-CoV-2 mAbs. (2)
According to the panel recommendation, Casirivimab 600 mg plus imdevimab 600 mg is to be administered as subcutaneous injections (SC) or an intravenous (IV) infusion.2 Casirivimab and imdevimab are the recombinant human monoclonal antibodies (mAbs) that bind to non-overlapping epitopes of the spike protein receptor-binding domain (RBD) of SARS-CoV-2.
The Journey- From USFDA to NIH guidelines
The move comes in consonance with the USFDA giving its EUA to the cocktail Drug. On 10th August 2021, the US FDA has revised the emergency use authorization (EUA) for REGEN-COV (casirivimab and imdevimab antibody cocktail) authorizing REGEN-COV for emergency use as post-exposure prophylaxis (prevention) for COVID-19 in adults and pediatric individuals (12 years of age and older weighing at least 40 kg) who are at high risk for progression to severe COVID-19, including hospitalization or death.
Following the USFDA approval, the panel of the NIH went through the evidence consisting of randomized, placebo-controlled trials in non-hospitalized patients who had mild to moderate COVID-19 symptoms and certain risk factors for disease progression. The evidence showed that the use of anti-SARS-CoV-2 mAb therapy reduced the risk of hospitalization and death, following which the panel in its October 7 report gave the following recommendations:(4)
● Prioritizing the treatment of COVID-19 over PEP of SARS-CoV-2 infection; and
● Prioritizing anti-SARS-CoV-2 mAb therapy for unvaccinated or incompletely vaccinated individuals and vaccinated individuals who are not expected to mount an adequate immune response (e.g., individuals who are immunocompromised or on immunosuppressive medications or individuals aged ≥65 years).
Initially, the Panel called for prioritization strategies to adopt when logistical constraints can make it difficult to administer anti-SARS-CoV-2 mAb therapy to all eligible patients, and later updated its previous statement on the prioritization of anti-SARS-CoV-2 mAbs to recommend that, in addition to the prioritization, clinicians consider prioritizing the use of anti-SARS-CoV-2 mAb therapy for patients at highest risk of clinical progression.
The EUA criteria have been broadened to include patients with a body mass index (BMI) of 25 or above, pregnant patients, and racial/ethnic factors. Also, patients with medical high-risk conditions such as sickle cell anemia, asthma cardiovascular disease, and disorders of neurological development are now eligible at any age above 12 years. (2)
Both the FDA and the NIH guidelines specify that the cocktail is not authorized for pre-exposure prophylaxis to prevent COVID-19 before being exposed to SARS- CoV-2 virus, and is authorized for use only after the exposure of the virus.
Far-reaching implications especially for the medical fraternity
While all the organizations specify that these drugs are not a substitute for vaccination, the cocktail provides a strong hope for individuals who are at high risk and have had exposure to the virus. With their inclusion in the guidelines Early intervention with the cocktail, can come to the rescue to patients and also importantly, healthcare workers who repeatedly come in the contact with the virus and stand the risk of disease that has claimed millions of lives across the world.
4. Updated Statemnt on the Prioritization of Anti-SARS-CoV-2 mAbs | COVID-19 Treatment Guidelines (nih.gov)