Post-transplant cyclophosphamide (PTCy) is, as the name implies, cyclophosphamide chemotherapy given after the stem cell transplant (SCT). For example, it is often administered on Day +3 or Day +4 in many preparative regimens. It prevents T cell–mediated graft-versus-host disease (GVHD) and minimizes allograft rejection.
Background of PTCy Research
Research of PTCy began in human leukocyte antigen (HLA)–mismatched haploidentical (haplo) donor setting. Starting in this patient population was due to the knowledge that if the match between a patient’s HLA markers and the donor’s is closer, the outcomes are better for the patient. Logically, since a haplo is an exactly one-half match, patients receiving a haplo transplant are at higher risk for GVHD development than those receiving a mismatched unrelated donor (MMUD) transplant.
- Haplo: 50% match (5/10 or 6/12)
- MMUD: not a complete match (ranging from 6/10 to 9/10 or 7/12 to 11/12)
More recent studies show that PTCy can overcome barriers related to HLA-MMUD allogeneic transplant.
New Study Results of PTCy vs. Standard of Care
Researchers from the Sylvester Comprehensive Care Center in Miami, Florida, and Memorial Sloan Kettering Cancer Center in New York presented their results of using PTCy in HLA-MMUD transplant at the 2022 Tandem Transplantation & Cellular Therapy Meetings. This study compared the standard of care of tacrolimus, methotrexate, and anti-thymocyte globulin (ATG) versus PTCy, mycophenolate mofetil (MMF), and tacrolimus or sirolimus. What is unique about this study from all the other studies on PTCy is its patient population. Of note, 57.8% (more than one half) of their subjects were racial/ethnic minorities.
Although they did not analyze the data based on race/ethnicity, the 2 groups (standard of care vs. PTCy) were well matched for SCT indication, high-risk disease, and SCT comorbidity index. More patients receiving PTCy received a bone marrow graft (50% vs. 26%; P=.01) and more than 1 locus HLA-mismatched grafts (30.5% vs 2.2%, P=.001). PTCy after MMUD SCT resulted in superior 1-year GVHD-free, relapse-free survival than the ATG-based GVHD prophylaxis. Their results indicate that PTCy is the better method to prevent GVHD after MMUD SCT with either bone marrow or peripheral blood–derived stem cells.
Importance of Diversity in Clinical Trials
Diversity, equity, and inclusion in clinical trials is a national initiative. The goal is to make clinical trials representative of the patients that a community serves. Therefore, in this study, the researchers in Miami—where there is a large minority population—achieved diverse participation representative of their community. The FDA notes that:
“Ensuring people from diverse backgrounds join clinical trials is key to advancing health equity. … People from racial and ethnic minority and other diverse groups are underrepresented in clinical research. This is a concern because people of different ages, races, and ethnicities may react differently to certain medical products.”
Oncology Nursing Call to Action
Oncology nurses may be in roles supporting clinical research, such as a research nurse or transplant coordinator. They can help increase diversity in clinical trials involving SCTs and cellular therapy. First, nurses can educate patients about clinical trials with culturally appropriate communication. Second, they need to recognize barriers that make it difficult for patients to enroll or participate in clinical trials. And finally, nurses should explore ways to break down those barriers to promote diversification in clinical research. Oncology nurses everywhere can be advocates and educators to improve minority participation in clinical trials.
2022 Tandem Meetings, Transplant & Cellular Therapy Poster 406
Post-Transplant Cyclophosphamide (PTCy) is Associated with Superior Gvhd-Free Relapse-Free Survival (GRFS) in HLA-Mismatched Unrelated Donor (MMUD) Hematopoietic Cell Transplantation.