CHMP Recommends Authorization of Phenylketonuria Treatment

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The CHMP has recommended for authorization a new medicine for patients aged 16 years and older with phenylketonuria-Palynziq (pegvaliase).

The European Medicines Agency’s (EMA’s) Committee for Medicinal Products for Human Use (CHMP) has recommended for authorization a new medicine for patients aged 16 years and older with phenylketonuria-Palynziq (pegvaliase).

Phenylketonuria is a rare inherited metabolic disease where those suffering from it do not have the required enzyme to break down phenylalanine, commonly found in foods containing protein. If phenylalanine builds up it in the blood, it can impact the brain and nervous system, potentially causing neurological and psychiatric disorders.

There is no cure for phenylketonuria, with patients required to adhere to strict diets of phenylalanine-containing foods using medication to help manage the disease. Only one other treatment has been authorized within the European Union for phenylketonuria management.

Palynziq is recommended for use in patients with excessive levels, greater than 600 µmol/L, of phenylalanine in the blood irrespective of prior management with available treatments. It works through a novel mode of action, whereby a pegylated recombinant phenylalanine ammonia lyase, contained within the treatment, breaks down phenylalanine with the expectation of preventing its accumulation in the body.

During the Phase III clinical trials of the treatment, most patients who were administered with the medicine had blood phenylalanine levels ≤ 600 µmol/L after 18 months of treatment. Additionally, the study results showed that after continued long-term treatment improvements in psychiatric and cognitive symptoms were experienced.


Common side effects seen during the trials were arthralgia and injection site reactions including erythema and rash. Most of the side effects were mild to moderate but there were a small proportion (5.6%) of patients who experienced acute hypersensitivity reactions. As a result, the CHMP required some specific measures to be taken by the company in order to minimize the risk.

The opinion of the CHMP will be sent to the European Commission for the adoption of a decision on an EU-wide marketing authorization. The application for Palynziq was submitted by BioMarin International.

Source: EMA