Haploidentical Transplant

Haploidentical Transplant

A haploidentical transplant is a type of allogeneic bone marrow transplant that uses a half-matched donor. While traditional transplants usually require a 100% HLA match, this procedure utilizes a donor who is a 50% match, significantly expanding the donor pool for patients who cannot find a perfect match in international registries.

When You Should Consider Haploidentical Transplant

• When a 100% HLA-matched sibling or unrelated donor is not available.

• For patients requiring an urgent transplant where a family member can be screened and ready in days.

• When the "mismatch" effect is desired to help new cells identify and eliminate remaining cancer (Graft-vs-Leukemia effect).

• For those who have a biological parent, child, or half-matched sibling available to donate.

Methods of Haploidentical Transplant

• Parental Donation: Utilizing a biological parent as the 50% HLA match.

• Child Donation: Utilizing a biological child as the 50% HLA match.

• Sibling Half-Match: Utilizing a biological sibling who shares half of the inherited HLA markers.

• Post-Transplant Cyclophosphamide (PTCy): A specialized protocol using high-dose chemotherapy after infusion to ensure safety.

How Haploidentical Transplant Is Performed

• Conditioning: Administration of chemotherapy or radiation to eliminate diseased marrow.

• Stem Cell Infusion: Infusing donor stem cells through a central line, similar to a blood transfusion.

• PTCy Administration: Delivering high-dose Cyclophosphamide on days 3 and 4 post-infusion to selectively kill cells that cause rejection.

• Engraftment waiting period: A 2 to 3-week phase where the new cells begin producing white blood cells, red cells, and platelets.

• Immunosuppression: Using specific medications to maintain balance in the new immune system.

Pre-Procedure Preparation

• Identifying and screening a biological family member who is a 50% HLA match.

• Educating the patient on the unique PTCy safety phase following the stem cell infusion.

• Baseline health assessments to ensure the patient can handle the intensive conditioning phase.

• Preparing for a longer hospital stay, typically between 3 to 5 weeks.

Tests Before Haploidentical Transplant

• HLA Typing: Identifying the 50% match markers inherited from parents.

• Donor Screening: Rapid testing and medical clearance of the identified family member.

• Viral Screening: Detailed testing for viruses like CMV, as there is a higher infection risk post-procedure.

• Marrow Assessment: Evaluating the status of the diseased marrow prior to the conditioning phase.

Life After Haploidentical Transplant

• Most patients remain in the hospital for 3 to 5 weeks following the procedure.

• Close outpatient monitoring is required for at least the first 100 days.

• A slightly longer recovery period for the immune system compared to a full-match transplant.

• Ongoing use of immunosuppressant medications to prevent Graft-versus-Host Disease (GVHD).

Benefits of Haploidentical Transplant

• Provides a nearly universal donor source since most people have a half-matched family member.

• Allows for a much faster donor identification and screening process compared to unrelated registries.

• Utilizes the Graft-vs-Leukemia effect, where the mismatch helps kill residual cancer cells.

• Modern PTCy protocols have made half-matched transplants as safe as traditional full-match procedures.