Tregzi: FDA Approves Donor Immune Cell Therapy to Lower the Risk of Serious Problems in Adults With Blood Cancer

The FDA has approved a new treatment called Tregzi. It uses a special kind of immune cell called a regulatory T cell, or Treg. Tregzi is for adults with certain high-risk blood cancers who are getting a stem cell transplant from a donor. It is the first treatment to use Treg cells and stem cells from a closely matched donor together. The goal is to help the transplant go well while lowering the risk of a problem called chronic graft-versus-host disease (GVHD).

GVHD is a common problem after a donor stem cell transplant. It happens when the donor’s immune cells attack the healthy tissue of the person who got the transplant. GVHD can range from mild to life-threatening. It may affect the skin, liver, stomach, intestines, and other organs. Acute GVHD usually starts within the first few months after a transplant. Chronic GVHD usually starts later. It can affect several organs for months or years. Preventing chronic GVHD is important. It helps people recover better and have a better quality of life after a transplant.

Tregzi is made of three types of cells taken from a closely matched donor. These are blood-forming stem cells (also called hematopoietic stem and progenitor cells), Tregs, which help calm immune attacks, and conventional T cells (Tcons), which help the immune system recover. Together, these cells aim to lower the risk of long-term GVHD while the immune system heals.

Before you get Tregzi, you receive a strong treatment called a myeloablative regimen. This clears out unhealthy cells so your blood and immune systems can be rebuilt. Tregzi itself is given in a specific order. First, you get Tregs. These help control immune reactions and support recovery. A short time later, you get Tcons. These help your immune system rebuild faster. Over time, the donor stem cells travel to your bone marrow and begin making new blood cells.

Why Was It Approved?

The FDA’s approval was based on a clinical trial of 187 adults with blood cancers, including leukemia or myelodysplastic syndrome. All of them had a matched donor transplant after pretransplant treatment. After one year, about 80% of the patients who got Tregzi were alive without chronic GVHD. This compares to about 40% of patients who got a standard stem cell transplant. Serious chronic GVHD developed in about 13% of patients who got Tregzi compared to 44% of patients who got a standard transplant.

Other results from the study also favored Tregzi. After one year, more patients who received Tregzi were alive (94%) than those who received a standard transplant (83%). Fewer patients died without their cancer coming back when they got Tregzi (3%), compared with a standard transplant (13%). Tregzi also improved the chance of being alive without GVHD or a cancer relapse (63% vs. 31%).

Side effects were similar to those seen after other transplants. Many were related to infections. The most common side effects were mouth soreness, diarrhea, rash, viral or bacterial infections, stomach pain, vomiting, nausea, bleeding, swelling, fungal infections, and acute GVHD.

GVHD can still happen after treatment with Tregzi. Some cases have been life-threatening or deadly. Infusion reactions, including severe allergic reactions, can also happen during or soon after an infusion.

What Do I Need to Know?

Tregzi is made just for you, using cells from your matched donor. You get two infusions on the day of your transplant, and another infusion two to three days later. All doses are given into a vein at a transplant center. You will also get pretransplant treatment before you receive Tregzi.

Before your first and last infusions, you may get acetaminophen and an antihistamine. These help prevent infusion reactions. After your final infusion, you will start one medicine called a calcineurin inhibitor. This medicine helps lower your risk of GVHD.

Signs of GVHD can include a new rash, joint pain, diarrhea, or yellowing of the eyes. Infusion reactions can cause fever, chills, flushing, tiredness, shortness of breath, or dizziness soon after an infusion. Learn these warning signs. Call your health care provider right away if you have any of them.

Sometimes the transplanted cells don’t start working the way they should. This is called primary graft failure. It is rare, but it can be serious.

Tregzi is made using human blood cells. Even with careful screening, there is a small chance that infections could be passed on. Your health care provider will watch for signs of infection, run tests if needed, and treat you if you get an infection.

Doctors do not yet know how this treatment affects a fetus or a breastfeeding infant. If you are pregnant, planning to become pregnant, or breastfeeding, talk with your health care provider.