What is ADA-SCID?1
Adenosine deaminase severe combined immune deficiency (ADA-SCID) is an ultra-rare, inherited genetic disorder, caused by a deficiency in the adenosine deaminase (ADA) enzyme, that is often fatal if left untreated. The ADA enzyme is most active in lymphocytes, a type of white blood cell that is a key part of the body’s immune system.
ADA-SCID results from defects in the ADA gene, which reduce or eliminate the amount of ADA enzyme activity and increase the risk of severe and recurring infections.
How common is ADA-SCID?
ADA-SCID is an ultra-rare disease. It is estimated to occur in approximately one in 200,000 to one in one million newborns around the world.
At what age is ADA-SCID diagnosed?2
ADA-SCID is typically diagnosed within the first few months of life. Diagnosis is made through a simple blood test which measures ADA enzyme activity and/or through genetic testing for the gene mutations in a patient with suspected or proven SCID. Sometimes, SCID/ADA-SCID is diagnosed later in childhood in less severely affected individuals using the same testing as in infants.
Why is early diagnosis important?2,3,4
Without early diagnosis and effective treatment, babies with ADA-SCID usually die from infections before they reach age two. Treatment is most successful in infants who have not yet experienced serious infections.
Why are babies with ADA-SCID particularly vulnerable?1,2,4
Babies born with more severe genetic defects that lead to SCID do not have sufficient immune function to combat effectively, infections from bacteria, viruses, or fungi. These babies do not respond to vaccines, and live virus vaccines can establish infections, rarely. Additionally, these babies produce no protective immune response from the vaccines.
Is there a screening test for ADA-SCID? Is it required in the U.S.?2,5
Today, all 50 states, the District of Columbia, and Puerto Rico are screening newborns for SCID. Newborn screening may not find less severe cases of ADA deficiency.
What is Revcovi?6
Revcovi is a new enzyme replacement therapy (ERT) for the treatment of adenosine deaminase deficiency severe combined immune deficiency (ADA-SCID) in pediatric and adult patients.
How is Revcovi different than Adagen?
Revcovi is a PEGylated recombinant adenosine deaminase (rADA) enzyme that has been developed to replace the bovine ADA (nADA) that is used in the manufacture of Adagen® (pegademase bovine injection). PEG is polyethylene glycol, a substance that is used to increase the half-life of a linked molecule. Revcovi is the product of recombinant technology, thus eliminating the need to source the adenosine deaminase (ADA) enzyme from animals.
What is a recombinant protein?
A recombinant protein is a protein that results from the expression of genetically-engineered DNA molecules within living cells.
Why was Revcovi developed?
Due to the reduced supply of the naturally-derived bovine ADA (nADA), Leadiant Biosciences, Inc. (LBI) invested in research and development to identify an alternative method to produce the enzyme. Leadiant’s manufacturing partner no longer produces the bovine sourced enzyme needed to make Adagen. In order to ensure that patients continue to receive this life-sustaining enzyme replacement therapy, Leadiant developed a new source enzyme through recombinant technology. Revcovi is a PEGylated recombinant adenosine deaminase (rADA) enzyme developed to replace the animal source (bovine) ADA (nADA).
How often are injections needed?6
The dosing schedule for Revcovi will vary from patient to patient. Your healthcare provider will provide an individualized treatment and schedule.
How long is treatment with Revcovi needed?
The duration of treatment with Revcovi will vary depending on the patient’s individual treatment plan as determined by a healthcare provider. Infants may be treated with Revcovi for a limited period of time while they are preparing for either hematopoietic stem cell transplant or hematopoietic stem cell gene therapy. Patients with ADA-SCID who are not candidates or who have failed hematopoietic stem cell gene therapy or hematopoietic stem cell transplant may be treated with Revcovi for life. Consult with your physician to see what is right for you or your child.
- Whitmore KV, Gaspar HB. Adenosine deaminase deficiency – more than just an immunodeficiency. Front Immunol. 2016; 7:314. doi: 10.3389/fimmu.2016.00314.
- Hershfield M. Adenosine deaminase deficiency. Gene Reviews [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK1483/. Initially posted October 2006; updated March 2017. Accessed January 8, 2019.
- AlKhater SA. Approach to the child with recurrent infections. J Family Community Med. 2009;16(3):77-82.
- Blaese MR, Winkelstein JA, eds. Patient & Family Handbook for Primary Immunodeficiency Diseases. 5th ed. Towson, MD: Immune Deficiency Foundation; 2007.
- IDF SCID Newborn Screening Campaign. Immune Deficiency Foundation. https://primaryimmune.org/idf-advocacy-center/idf-scid-newborn-screening-campaign. Accessed January 9, 2019.
- Revcovi™ (elapegademase-lvlr) Injection prescribing information. Leadiant Biosciences, Inc.; 2018.
Revcovi (elapegademase-lvlr) is indicated for the treatment of adenosine deaminase severe combined immune deficiency (ADA-SCID) in pediatric and adult patients.
Important safety information
Warnings and precautions:
- Injection site bleeding in patients with thrombocytopenia: Increased risk of local bleeding in patients with thrombocytopenia; should not be used if thrombocytopenia is severe.
- Delay in improvement of immune function: Protect immune deficient patients from infections until improvement in immune function.
The most commonly reported adverse reactions were cough and vomiting.
In addition, the following post-marketing reports for the same class of enzyme replacement therapy used in the treatment of ADA-SCID, may also be seen with Revcovi treatment:
- Hematologic events: hemolytic anemia, autoimmune hemolytic anemia, thrombocythemia, thrombocytopenia and autoimmune thrombocytopenia
- Dermatological events: injection site erythema, urticaria
Important monitoring information:
Treatment with Revcovi should be monitored by measuring trough plasma ADA activity and trough dAXP levels for maintenance of therapeutic targets. If a persistent decline in plasma ADA activity occurs, immune function and clinical status should be monitored closely, and precautions should be taken to minimize the risk of infection.
Please refer to Revcovi’s Full Prescribing Information.