What are monoclonal antibodies?
In the face of a new and devastating disease, it is important to find effective treatments as quickly as possible. With COVID-19, there are numerous ongoing clinical trials involving various drugs. But, to date, only a few effective treatment options have been identified. Most of these treatment options are for patients who are hospitalized. However, there is one type of treatment that can be utilized for individuals with mild to moderate COVID-19 to stave off potential hospitalization. This type of intervention is called monoclonal antibody therapy, and three different monoclonal antibodies have been granted Emergency Use Authorizations (EUAs) from the FDA thus far. Several others are being studied.
So, what are monoclonal antibodies?
Antibodies are proteins that are made by our immune system’s B cells in response to an infection. Monoclonal antibodies are antibodies that have been created in a laboratory and then mass produced to specifically target a virus and block its entry into cells in order to stop an ensuing infection. Monoclonal antibodies are identical to one another and are engineered to have maximal effect at stopping the virus. They work best if given early in the disease course before a person is significantly ill. They offer protection immediately, but this protection is temporary, usually lasting a few months.
What is an Emergency Use Authorization?
It is important to understand that EUAs are not the same as traditional FDA approvals. The usual FDA approval process can take decades, which is not acceptable in a global pandemic emergency. The FDA instead looks at the available evidence and research on a drug, which may be a smaller amount of data than in the traditional process, and decides if that medication’s risks outweigh the benefits. If that ratio appears favorable, then the drug gets granted the EUA. You can think of it as “approval lite.”
What are the three monoclonal antibodies that have EUAs? And why are they so hard to pronounce?
Three monoclonal antibody treatments for COVID-19 have been issued EUAs from the FDA thus far. The names of these medications are difficult to say, and even comedians like Jimmy Fallon have taken notice—he sang a song about the name of one on his show, singing, “Bamlanivimab. It’s made by Eli Lilly, and the name is silly!” Bamlanivimab is the real name of the drug that is made by Eli Lilly, just as the song says. This drug received its EUA in November 2020. Just this month, the FDA gave an EUA to another Eli Lilly drug that is a combination of bamlanivimab with another monoclonal antibody called etesevimab. The third drug available is also a combination of two monoclonal antibodies, and it is made by Regeneron. It is casirivimab/imdevimab, also called the REGN-COV2 cocktail. This drug was in the news when it was given to the former President before it had approval, and it was granted its EUA in November 2020.
These drugs are named according to a specific nomenclature, which makes them hard to pronounce. The stem “mab” stands for monoclonal antibody, while the preceding “vi” stands for viral and represents the antibody’s target source. Then there is the prefix, usually a few syllables, with no particular meaning but can be fun to say such as “bamlani.”
How are these medications administered? What are the side effects?
The monoclonal antibodies are given via an IV infusion over an hour, and patients who receive this drug must be monitored for another hour following the infusion. This step is to watch out for any serious infusion-related reactions, including anaphylaxis (a life-threatening allergic reaction). This process creates logistical challenges, since the treatments are relatively time sensitive and require adequate space and equipment to deliver safely. Since infusion-related reactions can occur, these drugs need to be administered in settings with appropriately trained staff and treatments on hand. Healthcare staff shortages and limited locations to deliver the medications may also be problematic. CVS is currently piloting a program in a few select cities to deliver bamlanivimab infusions to high-risk people in nursing homes and at home by leveraging their infusion care business called Coram. Nurses trained in anaphylactic reactions administer the infusions.
Who is eligible for these drugs?
To be eligible for these drugs, you must have a positive result from a Sars-CoV-2 test and be within 10 days of symptom onset. You must also be high risk for progression to severe disease or hospitalization. These drugs are approved for ages 12 and older in people who have high-risk conditions. Adults who have obesity (BMI 35 and over), diabetes, chronic kidney disease, immunosuppressive disease, or are on immunosuppressive treatment are eligible. Other eligible criteria include age over 65 and age over 55 with cardiovascular disease, high blood pressure, chronic obstructive pulmonary disease or other chronic respiratory conditions. There are more specific criteria for adolescents.
Do these drugs work?
Some preliminary studies of these drugs in individuals with mild to moderate COVID-19 showed a decrease in viral load as well as a decreased need for ER visits and hospitalizations. Other studies have shown a decrease in the need for medical office visits related to COVID-19. The drugs had enough evidence to be granted an EUA, but several of the large guideline groups, including the National Institute of Health (NIH) and Infectious Disease Society of America (IDSA), have said the evidence is insufficient to make a recommendation for their use. Additional studies are ongoing for these drugs that should provide more information, and perhaps stronger recommendations regarding their use. At this time, their use is limited to only high-risk groups.
Regeneron and Eli Lilly have also released some early data via press releases suggesting that these drugs may also prevent symptomatic COVID-19 infection within nursing homes and households. These study results are not definitive and are still ongoing, but early data seems promising. In Regeneron’s study, they reformulated their antibody cocktail as an injection instead of an infusion, which also makes it significantly easier to administer.
Finally, it is not yet known if the current monoclonal antibodies will be effective against new strains of the virus as they emerge. Data on this topic is extremely limited at this time.
Is this drug available everywhere?
Limited distribution is another potential barrier to receiving these drugs. They are currently offered only in select hospitals or infusion centers, so it may or may not be available in your area. If you think you qualify for one of these drugs, you should discuss further with your healthcare provider.
To summarize, monoclonal antibodies are the first medications for outpatient treatment to have EUAs from the FDA. They are given by infusion, and they are for patients with mild to moderate COVID-19 who are at high risk for severe disease or hospitalization. There are currently some challenges with availability and with arranging delivery of the medication. More information is also still needed about their effectiveness. Talk with your healthcare provider early if you become sick with COVID-19 and fall into one of the high-risk categories. And don’t try to say the names of these medications three times fast!