Normally, the standard FDA review process for potential drugs or biologics takes around 10 months to complete. However, when a drug receives Priority Review status, it means that the FDA will complete the review within 6 months. This designation is often granted to drugs or biologics which would significantly improve the safety and efficacy of treatment for rare or serious conditions over the current standards-of-care. According to Healio, abatacept (Orencia) recently received Priority Review status for moderate to severe acute graft-versus-host disease (GvHD) in patients (6+ years old) who are given hematopoietic stem cell transplantation (HSCT).

Abatacept

So what exactly is abatacept? According to the American College of Rheumatology, this biologic, often given to patients after a disease-modifying anti-rheumatic agent (DMARD) fails, is:

Used to reduce inflammatory symptoms such as swelling, pain, and stiffness [while] expected to stop joint deformities, therefore helping to maintain a range of motion.

In the past, it has been used to treat patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA). Now, researchers are exploring abatacept as a potential therapy for patients with acute GvHD, for which no FDA-approved therapies exist. 

The Clinical Trial

In particular, researchers wanted to understand whether abatacept had benefits for patients receiving unrelated donor HSCT. Currently, up to a whopping 70% of patients receiving HSCT later develop acute GvHD, making the need for treatment options urgent, especially as the immune response may cause long-term tissue or organ damage. 

Within the Phase 2 ABA2 clinical trial, researchers evaluated abatacept for patients at risk of developing acute GvHD. Altogether, there were two separate cohorts in the trial: one which had mismatched unrelated donors and the other with matched unrelated donors. During the trial, patients were treated with a calcineurin inhibitor as well as methotrexate, with certain patients receiving 10mg/kg abatacept on specific days. Findings from the study include:

• Patients treated with abatacept were less likely to develop GvHD within 180 days (6 months) of receiving HSCT. 
• Additionally, abatacept treatment reduced mortality rates and improved overall GvHD-free survival, particularly in the matched unrelated patient population. 

Ultimately, researchers believe that abatacept could be beneficial for patients receiving unrelated donor HSCT, whether matched or unmatched. However, researchers also urge the medical field to encourage increased stem cell donations, especially in underserved populations, to better serve patients across a wide variety of backgrounds.

Graft-versus-Host Disease (GvHD)

After stem cell or bone marrow transplants, some patients may experience a complication known as graft-versus-host disease (GvHD). In short, the donor cells view the host cells as foreign invaders and begin attacking them, causing a variety of health issues. GvHD may be acute (occurring within 6 months following transplantation) or chronic (occurring over 3 months following transplant and lasting throughout life). Symptoms are less likely to occur the closer the match is between patients. These symptoms do differ between chronic and acute GvHD, however. For example, patients with acute GvHD may experience:

• Jaundice (yellowing of the skin and eyes)
• Abdominal pain
• Nausea and vomiting
• Diarrhea
• Skin itchiness or redness

Alternately, symptoms associated with chronic GvHD include:

• Unintended weight loss
• Fatigue
• Muscle weakness
• Dry eyes and/or mouth
• Skin rashes
• Joint pain and stiffness
• Shortness of breath