From the Guidelines
Post-transplant cyclophosphamide (CY) is typically administered on days +3 and +4 after allogeneic stem cell transplantation. The standard dosing regimen is 50 mg/kg/day intravenously on each of these two days 1. This timing is critical as it allows donor T cells to be activated by host antigens before the cyclophosphamide selectively depletes these alloreactive T cells. Some key points to consider when administering post-transplant cyclophosphamide include:
- The mechanism works because cyclophosphamide targets proliferating cells, and by days +3 and +4, the alloreactive T cells (which cause graft-versus-host disease) are dividing rapidly while resting T cells (which provide beneficial immune reconstitution) are spared.
- Administration requires adequate hydration before and during treatment, along with mesna for uroprotection to prevent hemorrhagic cystitis.
- Patients should be monitored for myelosuppression, infections, and other cyclophosphamide-related toxicities in the days following administration. It's also worth noting that the use of post-transplant cyclophosphamide has been shown to reduce the risk of acute and chronic graft-versus-host disease while preserving the graft-versus-tumor effect 1. However, the provided study does not directly discuss the administration of post-transplant cyclophosphamide, but rather its potential benefits in reducing the risk of transplant-related complications, such as graft-versus-host disease, in patients receiving anti-PD-1 therapy after allogeneic stem cell transplantation. In clinical practice, post-transplant cyclophosphamide is often used as part of the conditioning regimen to prevent graft-versus-host disease, and its administration on days +3 and +4 is a common practice.
From the Research
Post-Transplant Cyclophosphamide Administration
- Post-transplant cyclophosphamide (PTCy) is administered on specific days after allogenic stem cell transplant to prevent graft-versus-host disease (GVHD) 2, 3, 4, 5, 6.
Days of Administration
- According to the study by 2, cyclophosphamide is given at daily doses of 50 mg/kg on post-transplant 3rd and 4th days.
- The exact days of administration may vary depending on the specific treatment protocol and patient population, but the 3rd and 4th days post-transplant are commonly referenced 2.
Dosage and Combination Therapies
- The dosage of cyclophosphamide can range from 50 mg/kg to 100 mg/kg, with some studies exploring reduced doses to minimize toxicities 4.
- Cyclophosphamide is often used in combination with other immunosuppressive agents, such as cyclosporine, sirolimus, and antithymocyte globulin, to enhance its efficacy in preventing GVHD 2, 3, 6.