Gene Therapy

Latest News in Gene Therapy

An Update on Gene Therapy for Hemophilia

Answers to common questions about this potentially game-changing treatment. Read more.

Gene Therapy Candidates Face ‘Once in a Lifetime’ Choice

People with hemophilia considering gene therapy are wrestling with concerns including the cost of treatment and variations in results. Read more.

Green Bay Resident Became First Wisconsinite to Receive Gene Therapy Treatment for Hemophilia A.

A Green Bay resident became the first Wisconsinite to receive a gene therapy treatment for hemophilia A since it was approved by the FDA in June. Read more.

First Sickle Cell Patient to Receive Gene Therapy Featured in NYT

Sickle cell disease is linked to an abnormality in the hemoglobin protein, which normally helps carry oxygen throughout the body via red blood cells. This causes red blood cells, normally disc shaped and flexible enough to travel smoothly in the body, to become rigid and misshapen to resemble a “C” or sickle. Read more.

FDA Approves Second Hemophilia B Gene Therapy Product.

The U.S. Food and Drug Administration (FDA) has approved BEQVEZ™ (Pfizer, Inc.), a new hemophilia B gene therapy product. The therapy is administered as a one-time intravenous infusion to stimulate the long-term production of clotting factor IX (FIX) and prevent bleeding. This represents the second hemophilia B gene therapy product to be approved in the U.S. – the first was approved in the fall of 2022. Read more.

Gene Therapy

Genes contain DNA — the code that controls much of the body’s form and function. DNA
controls everything from hair color and height to breathing, walking and digesting food. Genes
that don’t work properly can cause disease. Sometimes these genes are called mutations.

Gene therapy aims to fix a faulty gene or replace it with a healthy gene to try to cure disease or
make the body better able to fight disease. It holds promise as a treatment for a wide range of
diseases, such as cancer, cystic fibrosis, heart disease, diabetes, hemophilia and AIDS.

The U.S. Food and Drug Administration (FDA) has approved gene therapy products for several
conditions, including cancer, spinal muscular atrophy, hemophilia and sickle cell disease. But for
most people, gene therapy is available only as part of a clinical trial.

Clinical trials are research studies that help healthcare professionals find out whether a gene
therapy approach is safe for people. Clinical trials also help healthcare professionals learn how
gene therapy affects the body. (Source: Mayo Clinic, 2024)

What is gene therapy?

Gene therapy is a treatment where new working genes are introduced into a person’s cells to
fight disease. In the case of hemophilia, the new genes give the body instructions on how to
make factor. There are different kinds of gene therapy, including gene transfer, gene editing,
and cell therapy.

How does gene therapy work in hemophilia?

A working gene has clear instructions that tell the cell how to make factor. In gene therapy, a
working gene is carried into the liver cells of a person with hemophilia. Once the working gene
reaches the cells, they should begin producing factor.

What is a Vector?

At this time, gene therapy focused on treating hemophilia uses viral vectors. A vector is a virus
that has been changed to remove the illness-causing (viral) material. It is used as a carrier to
bring the new, working genes into a person’s cells. Viral vectors are used in gene therapy
because they are very effective at getting into cells.

What vectors are being used in gene therapy for hemophilia?

The most commonly used vectors in hemophilia are called adeno-associated viruses, or AAV.
These vectors do not carry any infectious material, meaning they do not cause viral infections.
They are used to deliver working genes into liver cells in the body so that they can start
producing clotting factor.

What are the differences between gene editing, gene transfer and cell therapy?

Gene transfer puts genetic information into a vector, which then carries the working copy of a
gene to a person’s cells. Once inside the cell, the new, working gene allows the cell to start
making factor.

Gene editing tries to “fix” the part of a gene that isn’t working. By editing the genetic directions,
the cell can then start to make factor.

Cell therapy transfers cells that work well into a person to treat disease. These cells are
created to produce clotting factors. They are contained in specific materials that prevent them
from attack by the patient’s immune system. These cells are implanted inside the body and will
help the individual make their own factor.

What is CRISPR?

CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats. CRISPR is a
way to edit a non-working gene. Instead of bringing new copies of the working gene using a
vector, as in gene transfer, CRISPR actually tries to fix the patient’s non-working gene within the

One way to think about the difference between gene transfer and CRISPR is to pretend you
have a table with two broken legs. With gene transfer, someone would bring you a new,
unbroken table. The old table would remain without being of any use. With CRISPR, someone
would fix the two broken legs still attached to your table. The table would still be the original
table but now improved and working. While CRISPR is exciting science, federal laws currently
prevent the use of CRISPR in humans.

Visit the National Bleeding Disorders Foundation website for answers to the most common questions asked about gene therapy for hemophilia including:

Source: National Bleeding Disorders Foundation, 2024