Hope for people with disease that turns tissue to BONE as three drugs enter clinical trial

People with a rare, genetic disorder that turns tissue into bone may finally have a treatment.

Three experimental drugs are currently being tested in human trials as potential therapies for fibrodysplasia ossificans progressiva (FOP).

Developed by research universities and pharmaceutical companies, the drugs target genes and proteins responsible for the hyperactive bone growth to prevent – and, in some cases, reverse – it.

With any luck, one of them could be approved by the Food and Drug Administration (FDA) by next year, reported STAT News. 

FOP is a rare, genetic disorder in which damaged muscles and soft tissues – such as ligaments and tendons – regrow as bone. 

These new bones eventually form a second skeleton and severely limit sufferers’ ability to move.

It was only in 2006 that researchers discovered FOP is caused by a mutation in the ACVR1 gene, which controls the body’s growth and development of bones and muscles.

Naturally, cartilage is replaced by bone from birth to adolescence. But scientists say that the mutation may leave gene receptors constantly ‘on’, which causes bones to overgrow and joints to fuse together. 

Those with the disorder usually experience their first ‘flare-up’ by age 10. Children with FOP start growing extra bones in their neck and shoulders, proceeding through the body down to the feet. 

According to the National Center for Advancing Transnational Sciences, the disorder occurs in roughly one in 1.6 million newborns.

There are only about 800 people in the world known to have the condtion.

Currently, there is no cure and treatment consists of medications that reduce inflammation and relax the muscles.

Most FOP sufferers are bedridden by the age of 20 and die around age 40.

But, three drugs are in clinical trial with the hope of one that can turn FOP into a manageable condition, Dr Frederick Kaplan, a professor of molecular orthopedic medicine at the University of Pennsylvania, told The Inquirer.

‘I don’t think FOP is going to be any different in concept than common conditions like hypertension, asthma, or diabetes,’ he said.

‘The more targets we have, and the more varied approaches we have, the more successful we’ll be at keeping the disease at bay and changing its natural course.’.

The first drug, called garetosmab, is being developed by Regeneron Pharmaceutical, based in Tarrytown, New York.

It targets activin A, a protein that normally blocks growth. However, studies have shown that it does the exact opposite in those with FOP. and triggers hyperactive bone growth.

In 2015, Regneron showed that garetosmab, which is injected, shut off the signal in mice genetically modified to develop the illness. Currently the drug is being tested on 40 adults, reported STAT News.

The second drug is called palovarotene – originally used to treat lung disease – that has been found in several studies to stop new bone formation in mice with FOP by preventing cartilage from ossifying.   

Canadian biotech company Clementia Pharmaceuticals licensed palovarotene from drug company Roche. In 2016, it announced results from a clinical trial that showed FOP patients saw less bone growth during flare-ups.  

The company is planning to submit a drug application for approval to the FDA before the end of the year.

A third drug, known as BLU-782, targets the FOP gene before it has the ability to attach itself to activin A.

Developer Blueprint Medicines just finished conducting a safety study on the pill and plans to begin testing it on FOP patients next year, according to STAT News.

Whitney Weldon, a 27-year-old from New York City, is one of the FOP patients taking palovarotene and hopes it will help her gain back some of the independence she has lost.

‘I never thought that this would even be a possibility,’ she told STAT News. ‘It would be a lot of happy tears, finding a medication.’