Ipsen announced that the US Food and Drug Administration (FDA) had provided the complete response letter (CRL) at the end of last year. The company expects to respond to the agency’s request for further information in the first quarter of 2023.
In terms of what information the FDA is demanding, Ipsen only stated that the request is not for additional efficacy or safety data beyond existing studies. This means that no additional clinical trials will need to take place.
However, the CRL will mean a further six-month review by the FDA, which adds to the complicated journey for palovarotene and Ipsen’s attempts to gain approval for the treatment.
In August 2021, the company withdrew its new drug application (NDA) to the FDA for the treatment, as the agency requested additional analyses and evaluate of data collected in Phase III clinical trials.
On reapplying to the FDA, Ipsen announced that it had received a priority review for palovarotene in June 2022, only for the agency’s most recent decision prolonging the examination of the potential product.
The treatment itself is an investigational treatment for the reduction of new abnormal bone formation (heterotopic ossification) in people living with fibrodysplasia ossificans progressiva (FOP).
FOP is an ‘ultra-rare’ disease, which approximately 400 people living in the US and 900 people globally are affected by.
According to Ipsen, without disease-modifying treatment, people living with FOP may permanently lose the ability to move their neck, back, shoulders, chest, legs and arm joints. The condition results in a median life expectancy of 56 years, as bone formation around the ribcage can lead to breathing problems and cardiorespiratory failure.
There are currently no treatments available in the US to slow the progression of the disease.
“Although this extends the review timeline for palovarotene, we continue to work with the FDA to provide the requested information and believe that investigational palovarotene has the potential to be an innovative treatment to reduce new abnormal bone formation to slow the progression of FOP,” said Howard Mayer, head of R&D for Ipsen.
The treatment is sold in Canada, after it received regulatory approval in January 2022. However, as Ipsen agreed a $1.3bn (€1.23bn) to acquire the treatment and the company that created it, achieving approval in the US would be an important step for the company to make this investment pay off.