The most expensive drug in the world is approved by the US FDA

The US FDA has approved the world's most expensive drug at a price of 4.25 million USD per dose to treat rare diseases in children .

According to Medical News Today, MLD is a rare genetic disease also known as heterochromatic leukodystrophy (MLD) . Children with MLD will lose the ability to think, move and feel the world around them.

Scientists have sought to create a treatment for the rare genetic disorder MLD. (Photo: Freepik)

On March 18, the US Food and Drug Administration (FDA) approved gene therapy  produced by Orchard Therapeutics, a UK-based company. This is the first treatment in the US for this rare genetic disease , according to Reuters.

The FDA said the therapy is sold under the brand name Libmeldy for $4.25 million , one of the most expensive drugs in the world. This medicine is prescribed to children in the advanced stages of the disease.

Experts based their decision on research from 37 children treated with Lenmeldy in two clinical trials. The results showed that this therapy significantly reduced the risk of severe motor impairment or death. The FDA also warns about the potential risk of leukemia, blood clots or swelling of brain tissue.

Research shows that 1 in 100 children will have MLD due to carrying a faulty gene. In other words, children who carry faulty genes from both parents will have this disease. Therefore, MLD is rare and only affects around 1 in 40,000 babies born in the UK. In the US, it is estimated that less than 50,000 people in the US have this disease.

The MLD gene will produce a faulty version of the enzyme. The job of a healthy enzyme - arylsulfatase A (ARSA ) is to break down fatty acids called sulfatides in the white matter of the brain and spinal cord. Sulfatides are essential components of myelin, the fatty membrane that protects and insulates nerve cells. When the ARSA enzyme does not function normally, sulfatides will accumulate, damaging the myelin layer that protects nerve cells.

Doctors can use bone marrow transplants from healthy donors to treat patients, but this method only slows down the progression of the disease. Another method is to inject the patient with an active enzyme, however this enzyme is a large protein molecule that cannot cross the blood-brain barrier.

Recently, doctors have successfully tested a new gene therapy called atidarsagenee autotemcel , which provides a healthy version of the gene to create enzymes needed by the body.

The doctor will collect stem cells from the patient's bone marrow, and these stem cells will be sent to a laboratory in Italy. Here, doctors use a harmless modified virus to insert healthy copies of the enzyme-producing gene into the stem cell's DNA.

Finally, doctors will inject the repaired stem cells back into the patient's blood. These cells move to the bone marrow, where they begin to produce blood cells capable of making properly functioning enzymes.