Enzyme replacement therapy (abbreviated ERT) is a rather large market that addresses many rare diseases. Oftentimes, patients with these diseases have a genetic defect whereby their body either does not produce a protein at all or their body produces an incorrectly functioning protein. This can lead to devastating consequences. For example, Pompe Disease (also known as acid alpha-glucosidase (GAA) deficiency among other names) is the result of genetic variations of the GAA gene resulting in the accumulation of glycogen causing damage to muscles. Patients can develop difficulty moving and breathing on their own, requiring invasive interventions to sustain life. While such invasive interventions help manage the symptoms and clinical decline for patients with Pompe disease, they do not address the biological defect. This is where the pharmacologic intervention of ERT comes in. Pompe disease has a therapy, Lumizyme, which is a laboratory produced form of human acid alpha-glucosidase (the defective enzyme in Pompe disease). The idea here is that the missing enzyme is administered to the patient to replace what they are unable to produce, which in the case of Pompe disease, slows the accumulation of glycogen and damage.
Theoretically, ERT can pose as a significant, constant revenue stream for companies as patients on therapy would continue throughout their life until they either pass away or a new therapy that has better data is approved. This is offset by the rather rarity that many of these diseases occur. Here is a 2013 document that highlights the FDA approved ERTs at that time. This segment of biopharma is estimated to generate global revenues of $7.7 billion in 2020, and grow at a rate of 7.7% annually from 2019 to 2026. There are several very large companies that produce ERT (like Genzyme and Pfizer), however there is another name that specializes in this type of therapy, BioMarin (ticker BMRN). With a market cap of ~$15 billion, BioMarin is significantly smaller than the larger mega-cap companies and presents a diversified pipeline of products and technologies. A review of the MS Money Moves FDA Calendar in the Intel Hub shows that there is currently one ERT under review at the FDA. This is Sanofi’s avalglucosidase alfa, which is being developed for the treatment of Pompe disease. Overall, ERT can represent a solid revenue stream for a company if approved. However, the production of these products can be technically complicated which requires an experienced management team to ensure the product withstands the scrutiny of the FDA when it comes time to submit the application to the FDA.