Yes, Cimzia (certolizumab pegol) is a biologic medication. The FDA classifies it as a TNF blocker, placing it in the same drug class as other well-known biologics like Humira (adalimumab) and Enbrel (etanercept). What sets Cimzia apart is its unusual structure: it’s built from only a fragment of an antibody rather than a whole one, and it’s coated with a polymer that changes how it behaves in the body.
What Makes Cimzia a Biologic
Biologics are medications made from living cells rather than synthesized through chemical processes like traditional drugs. Cimzia is a lab-engineered antibody fragment designed to target a specific protein called TNF-alpha, one of the body’s key drivers of inflammation. When TNF-alpha is overactive, it fuels the chronic inflammation behind conditions like rheumatoid arthritis, Crohn’s disease, and psoriasis. Cimzia binds to TNF-alpha and neutralizes it, reducing that inflammatory cascade.
What makes Cimzia structurally unique among TNF blockers is that it uses only a piece of an antibody (called a Fab’ fragment) rather than a complete antibody molecule. Full antibodies have a tail region known as the Fc portion, which can trigger certain immune responses like activating the complement system or causing cells to attack tagged targets. Cimzia lacks this tail entirely, meaning it blocks TNF-alpha without triggering those additional immune pathways.
The antibody fragment is also coated with polyethylene glycol (PEG), a process called PEGylation. This coating increases the drug’s half-life so it stays active longer, improves its solubility, and may reduce the chance of the immune system recognizing the drug as foreign and mounting a response against it.
Conditions Cimzia Treats
Cimzia is FDA-approved for several inflammatory conditions in adults. These include rheumatoid arthritis, Crohn’s disease, psoriatic arthritis, ankylosing spondylitis (a type of inflammatory spinal arthritis), non-radiographic axial spondyloarthritis, and plaque psoriasis. It is not approved for use in children.
How Well It Works
In clinical trials for rheumatoid arthritis, Cimzia produced meaningful improvement in a majority of patients. When combined with methotrexate, 59% of patients on Cimzia achieved at least a 20% improvement in joint symptoms at 24 weeks, compared to just 14% on placebo. More substantial improvement (50% or greater) was reached by 37% of patients on Cimzia versus 8% on placebo.
Results for psoriatic arthritis were similarly strong. At 24 weeks, 64% of patients on Cimzia achieved at least 20% improvement in joint symptoms, compared to 24% on placebo. Nearly half (44%) saw 50% or greater improvement.
How It’s Given
Cimzia is a subcutaneous injection, meaning it goes just under the skin rather than into a vein. Treatment starts with a loading phase: three doses of 400 mg given at weeks 0, 2, and 4. Each 400 mg dose is split into two separate 200 mg injections. After the loading phase, maintenance dosing for rheumatoid arthritis is typically 200 mg every two weeks, though 400 mg every four weeks is an alternative. For Crohn’s disease, the maintenance dose is 400 mg every four weeks.
The medication needs to be stored in a refrigerator between 2°C and 8°C (about 36°F to 46°F). If needed, it can stay at room temperature for up to 7 days, which is helpful for travel or temporary situations where refrigeration isn’t available.
Pregnancy Considerations
Cimzia’s lack of an Fc region has a practical benefit during pregnancy. Full antibodies cross the placenta through a transport system that recognizes the Fc tail. Because Cimzia doesn’t have one, it largely doesn’t cross. A study published in the Annals of the Rheumatic Diseases found that 13 out of 14 infants had no detectable Cimzia in their blood at birth. The one infant with a measurable level had a trace amount, with an infant-to-mother ratio of just 0.0009. No infants had detectable levels at 4 or 8 weeks of age. This makes Cimzia a notable option among TNF blockers for people who need to manage active inflammatory disease during pregnancy.
Side Effects and Safety Warnings
Like all TNF blockers, Cimzia carries a boxed warning for serious infections and malignancy. Because the drug suppresses part of the immune system, it increases the risk of infections that can lead to hospitalization. The most concerning include tuberculosis (including reactivation of dormant TB), invasive fungal infections, and opportunistic bacterial or viral infections. You’ll be tested for latent tuberculosis before starting treatment and monitored periodically during it.
The boxed warning also notes that lymphoma and other cancers, some fatal, have been reported in children and adolescents treated with TNF blockers as a class. Heart failure is another serious risk the label highlights.
The most common, less severe side effects in clinical trials were upper respiratory infections, rash, and urinary tract infections, each occurring in 7% or more of patients and at higher rates than placebo. If you develop a serious infection while on Cimzia, treatment is stopped.