At the start of April 2021, the Food and Drug Administration (FDA) approved Regeneron Pharmaceutical’s Praluent (alirocumab), a treatment for patients aged 18+ with a rare genetic condition called homozygous familial hypercholesterolemia (HoFH). According to the FDA’s announcement, Praluent should not be used as a monotherapy. However, the treatment is designed and approved to be used in conjunction with other HoFH therapies.
According to Regeneron:
PRALUENT is a human monoclonal antibody.
Monoclonal antibodies are laboratory-created proteins which mimic our immune system’s ability to fight foreign invaders. In this case, Praluent inhibits or stops proprotein convertase subtilisin kexin type 9 (PCSK9), which controls LDL receptors. Normally, PCKS9 works to control LDL receptors so that a certain amount of cholesterol is being removed from the blood. However, patients with HoFH often have defective LDL receptors. By inhibiting PCSK9, Praluent allows LDL receptors to more quickly remove cholesterol.
Initially, the drug was approved in 2015 for patients with cardiovascular disease and primary hyperlipidemia. Now, for patients with HoFH, Praluent is subcutaneously administered every 2 weeks. According to data sourced from a clinical trial, Praluent is relatively safe, effective, and well-tolerated. 69 patients enrolled in the trial. Bi-weekly, 24 patients received a placebo while the remaining patients were administered 150mg Praluent. Altogether, patients who received Praluent saw an average 27% reduction in cholesterol. Alternately, those receiving a placebo saw higher cholesterol levels.
Although the drug was relatively well-tolerated, some adverse reactions did occur. These included:
- The common cold
- Hypersensitivity / allergic reactions
- Injection site reactions
- The flu
Homozygous Familial Hypercholesterolemia (HoFH)
Familial hypercholesterolemia (FH) is a form of treatment-resistant high cholesterol which can cause severe health impacts. Patients with homozygous familial hypercholesterolemia (HoFH) have an even rarer and more severe form of this condition. An estimated 1 in every 250,000-300,000 people has HoFH. Altogether, this condition is inherited. There are multiple genetic mutations which can result in HoFH. However, they all share something in common: the mutations code for LDL (low-density lipoprotein) receptors which normally remove cholesterol from the blood. A child must receive two defective copies (one from each parent) to have HoFH. Patients with HoFH may have cholesterol levels up to 4x higher than normal. Without treatment, HoFH can progress and cause heart disease.
Outside of very high cholesterol levels, additional symptoms include:
- Chest pain
- Rapid heartbeat
- Shortness of breath / difficulty breathing
- Calf cramps
- Xanthomas (yellow, waxy patches on the skin)
- Xanthelasmas (yellow fat deposits under the skin)
- White or gray corneal circles