Louisville Medicine Volume 69, Issue 9 - Page 21

of neurology , there are mAbs for migraine , multiple sclerosis , neuromelitis optica spectrum disorders and recently Alzheimer ’ s disease . Rheumatoid arthritis , SLE , Crohn ’ s disease and ulcerative colitis are disorders where significant improvement has been noted with the use of mAbs . Other indications include thyroid ophthalmopathy , macular degeneration , asthma , hypercholesterolemia , blood clot prevention after angioplasty , and one for monitoring dabigatran levels in anticoagulation . Skin disorders like psoriasis and atopic dermatitis are other conditions where mAbs have benefited patients dramatically . Infections such as Anthrax , clostridium difficile , HIV , rabies and Ebola are examples where mAbs are being used successfully for providing passive immunity .
More recently , the mAbs were catapulted into prime time by their quick production and use during the COVID-19 pandemic . There has been a rush to find mAbs to control COVID-19 infections in the early stage of the disease to obviate the need for hospitalization . This move has been particularly important for the elderly and the immune-compromised . The FDA approved on an emergency basis several mAbs over the past two years to provide passive immunity to those with mild to moderate infection and later as a post-exposure prophylactic measure . The first to be approved were Casirivimab and imdevimab in November 2020 , followed by bamalanivimab and etesevimab in February 2021 . Sotrovimab was approved in May of 2021 . The primary use of these drugs is to prevent severe disease requiring hospitalization and to provide post-exposure prophylaxis . All these mAbs bind to the spike protein of the virus , potentially preventing the virus from getting a foothold onto the cells . The saga continued with newer mAbs getting authorized for somewhat different indications . Tocilizumab , authorized in June of 2021 is an interleukin-6 receptor antibody , which benefits patients with severe COVID-19 pneumonia . The FDA in December of 2021
FEATURE gave emergency authorization for a combination of tixagevimab and cilgavimab for pre-exposure prophylaxis of COVID-19 in patients who are immune-compromised or those who have severe adverse reaction to COVID-19 vaccines ; given as intramuscular injection , these mAbs are expected to be effective for up to 6 months .
While some of the above-mentioned mAbs have been quite useful in the past for conferring passive immunity against the different COVID-19 variants , the newly identified Omicron with several mutations in the spike protein seems to be able to ignore most of them . According to the manufacturer , sotrovimab is considered effective against Omicron , but it is often in short supply . This is of great concern considering the high transmissibility of this variant . Let us hope that scientists zooming on an epitope of the virus that is highly resistant to mutations may lead to mAbs that will be consistently effective against new variants .
The future is promising for the universe of mAbs , whose indications are steadily expanding . Thinking of George Kohler and Cesar Milstein , the pioneers of mAb technology , I am reminded of Paul de Kruif ’ s prediction almost 95 years ago . In the chapter on Paul Ehrlich in his famous book , Microbe Hunters 1 he writes : “ Of course , it is sure as the sun following the dawn of tomorrow , that the high deeds of the microbe hunters have not come to an end ; there will be others to fashion magic bullets .” As we look forward , we will most certainly need resourceful microbe hunters and magic bullets like the mAbs to continue our fight against the pandemic .
1 . Paul de Kruif : Microbe Hunters . 1926 Harcourt , Brace & World , Inc . New York
Dr . Iyer practices at the Neurodiagnostic Center of Louisville and is a retired professor of neurology at the University of Louisville School of Medicine .
FEBRUARY 2022 19