Continuing innovations in immunotherapy research are opening the doors to new and effective approaches to address previously untreatable diseases and conditions. One rare disease that directly affects the immune system is adenosine deaminase (ADA) deficiency. Some may be familiar with the 1970s movie “The Boy in the Plastic Bubble,” essentially about a child with ADA deficiency. This rare inherited disorder causes severe combined immunodeficiency and leaves the person without adequate protection from microorganisms, even those that normally would not cause disease in people with normally functioning immune systems. Most babies affected by ADA deficiency have very short lifespans of two years or less.
The ADA protein is necessary to protect lymphocytes from destruction by a by-product of DNA break down, deoxyadenosine. The ADA protein converts the lymphocyte-destroying deoxyadenosine into the nontoxic deoxyinosine. Due to ADA gene mutations, the ADA enzyme does not function correctly or is absent leading to ADA deficiency, lymphocyte destruction, and the severe combined immunodeficiency.
A new drug developed by GlaxoSmithKline to address ADA, Strimvelis, was named the Drug Discovery of the Year 2018 by the British Pharmacological Society. Strimvelis consists of autologous CD34+ stem cells containing a retroviral vector that encodes CD34+ stem cell ADA. That is, a patient’s own CD34+ stem cells are transduced with a functional ADA gene then reintroduced into the patient. Treatment with CD34+ stem cells containing a functional ADA gene allows the patient to replicate mature lymphocytes that can produce the ADA protein. This therapy is particularly beneficial for those who cannot be matched with a bone-marrow transplant donor and is the world’s first licensed stem cell gene therapy.
This development in gene and immunotherapy provides the exciting prospect of the ability to fix a life-threatening rare disease and represents an example of the massive advantages of this therapeutic approach. Its application may extend to other less rare disorders that are based on genetic defects or deficiencies. Countless numbers of patients can be relieved of life-long therapies and drugs and experience drastically improved life-expectancy and quality.
British Pharmacological Society’s Drug Discovery of the Year 2018 Announced. (2018). Technology Networks. Retrieved 23 January 2018, from https://www.technologynetworks.com/tn/news/british-pharmacological-societys-drug-discovery-of-the-year-2018-announced-295261