Alternative donor BMT using PTCy may be a promising first-line therapy for acquired severe aplastic anemia

This research, carried out at the Sidney Kimmel Cancer Center at Johns Hopkins University, revisits the treatment paradigm for severe aplastic anemia (SAA). Researchers propose bone marrow transplant (BMT) with a haploidentical (haplo) donor and post-transplant cyclophosphamide (PTCy) graft-versus-host disease (GVHD) prevention as a primary therapy rather than a fallback option after immunosuppressive therapy (IST) failure. The findings indicate that the use of haplo BMT with PTCy expands access to transplant across various populations and yields promising survival rates. This method could mark a significant shift in treatment strategies, benefiting especially the racially and ethnically diverse patient groups with SAA.

Download a PDF of the study highlights and citation.

Background

SAA, caused by an autoimmune attack on hematopoietic stem cells, leads to a sharp decrease in blood cells. Without treatment, mortality rates can surge to 70% within two years. Though IST is the conventional first-line treatment, its long-term success rates hover below 40%, with many patients requiring a subsequent BMT. Given the potential complications stemming from prolonged IST usage and the benefits of BMT, the study recommends BMT as a primary treatment strategy for SAA, specifically using haplo BMT with PTCy as GVHD prevention.

Study Details

The study spanned from August 2016 to July 2020 and included 20 patients initially, with 7 additional patients treated post-trial. Eligibility criteria included a confirmed SAA diagnosis, no prior IST exposure, and the absence of certain disorders. The study prioritized related haplo donors and did not conduct unrelated donor searches. Patients' median follow-up duration was approximately 41 months.

Results

Of the 27 patients included (52% male, median age 25), 92% exhibited overall survival at intervals of 1, 2 and 3 years, exceeding previous data. Adjustments to the total body irradiation dose (400 cGy improved over 200 cGy) enhanced success rates, with 88.9% achieving sustained engraftment. Acute and chronic GVHD rates were below 10%. Remarkably, 96% of patients reached neutrophil recovery by day 28, with platelet and red blood cell recoveries also showing promising results. Two patients faced severe viral infections, resulting in graft losses. However, as of the last follow-up, all surviving patients were in complete remission.

Key Takeaways

This study marks a transformative approach in SAA treatment, shedding light on the advantages of using haplo BMT with PTCy GVHD prevention over the traditional IST, especially considering the latter's low long-term success rate.

The findings underscore the need to revisit the role of BMT in treating SAA, particularly for those patients without an available sibling donor. Importantly, this new method drastically enhances both access to and outcomes of treatment for racially and ethnically diverse patients diagnosed with SAA. With this paradigm shift, early BMT consultation and referrals become more critical, and as the research landscape evolves, more patients will hopefully have the opportunity to access and benefit from this innovative care approach.

DeZern AE, et al., Published in Blood