Researchers to test use of ‘viral specific’ T-cells to target toxic viruses in children

Michael Pulsipher, MD, of the Children's Center for Cancer and Blood Diseases at Children's Hospital Los Angeles, along with Michael Keller, MD from Children's National Health System in Washington, DC, have been awarded $4.8 million by the California Institute for Regenerative Medicine (CIRM) to study the use of a new T-cell therapy to help fight active viral infections in children with severe immune deficiencies. In what will be the largest multi-center pediatric clinical trial of this kind to date, investigators will test the feasibility of using "viral specific" T-cells that are engineered to target three common and potentially toxic viruses: Epstein-Bar virus (EBV), cytomegalovirus (CMV) and adenovirus.

In healthy individuals infections with EBV, CMV and adenovirus cause fatigue, sore muscles, sore throat and swollen glands, but after a short period they recover. For children with weakened immune systems, however, infection with these viruses can lead to severe organ damage or death.

"When patients have severe inherited immune deficiencies or are intensely immune suppressed after a bone marrow transplant, standard antiviral medications are sometimes not enough and patients can die from common viral infections," explained Pulsipher. "Patients often need at least some function of their own immune systems in addition to antiviral medications in order to clear these infections, but sometimes the patient's own T-cells are not up to the task."

Previous studies have demonstrated success in restoring immunity against a particular virus by using donor T-cells that are engineered to target a specific virus for therapy following BMT.

For the new clinical trial, Pulsipher, Keller and their collaborators will use T-cells from healthy donors that have been trained and expanded to target the viruses, then preserved in a donor "bank" for use in the trial. The cells are then individually matched to specific patients based upon their genetic make-up and the viral infection they are experiencing, and shipped to individual centers for infusion. After infusion, the virus-specific targeted T-cells can not only control the active infection, but can help prevent other infections.

"It is our hope that with these trained T-cells, we can help the most vulnerable patients fight off life-threatening viral infections," said Keller. "By offering a 'donor' bank, we are significantly expanding the reach of this therapy and increasing access to even more children, which is extremely exciting."

"Our study design is to use a multi-virus T-cell therapy to reconstitute immunity against all three of these viruses," said Pulsipher. "Restoring immunity against multiple viruses simultaneously provides patients with protection from severe viral infections and reduces the need for continued prophylaxis with pharmacotherapy drugs after transplant which can have adverse effects."

The study, which is expected to include up to 30 centers, will be run through the Pediatric Blood and Marrow Transplant Consortium (PBMTC) Operations Center at CHLA and was developed and is being performed in collaboration with the Primary Immune Deficiency Treatment Consortium (PIDTC). Cell manufacturing for use in the clinical trial will be conducted by the Program for Cell Enhancement and Technologies for Immunotherapy (CETI) of the Children's National Health System.