ASH 2013: Can New Gene Therapy Help Without Causing Leukemia?

A presentation at the American Society of Hematology meeting demonstrated a very small study indicating that kids with so-called "bubble-boy disease" may benefit from gene therapy without the common side effect of leukemia.

The study was conducted by Sun-Yun Pai, M.D., of the Dana Farber Cancer Institute and Boston's Children's Hospital, and colleagues. Out of nine children under one year old and diagnosed with X-linked severe combined immunodeficiency (SCID) who were given a self-inactivating (SIN) gammaretroviral vector, seven were doing well after three years.

Typically the treatment for SCID involves a stem cell transplant, but finding donors takes a very long time in most cases.

Gene therapy an 'attractive option'

Pai was quoted by MedPage Today as saying:

Without curative therapy such as bone marrow transplantation, these boys die of opportunistic or community-acquired viral infection. Outcomes for boys who do not have well-matched donors are suboptimal. For these patients, gene therapy is an attractive option.

SCID is an otherwise fatal disease and genetic therapy has been attempted in these kids before, but several of them from a French study who were given a different gammaretroviral vector developed T-cell acute lymphoblastic leukemia. One of the patients died while the others recovered. Since the other kids recovered and are said to be doing well, this justified a similar gene therapy approach, but one that tried to eliminate the leukemia risk.

While it appears that Pai's group has done that, it should be added that in the other trial, the kids who developed leukemia developed the disease at the three- to five-year mark, so there's no assurance that kids from this group will not develop the blood cancer too.

Source: MedPage Today