Overview: Biologics are manufactured through a biological process (rather than chemical process, as in pharmaceutical drugs) using human, animal, or microorganism sources. In Crohn’s and colitis, Biologics bind up inflammatory signals and inhibit the immune system’s ability to attack the bowels.
Types:
- Anti-TNF drugs
- Tumor necrosis factor-alpha (TNF-α) is a proinflammatory cytokine that plays a key role in the inflammatory response and the disease process. Importantly, TNF-α contributes to oxidative stress in inflammation sites.
- Anti-TNF drugs attach to TNF-α to prevent if from causing inflammation
- Remicade (infliximab):
- Infusions (injected slowly into the vein) every 6-8 weeks at a treatment facility
- First biologic used in treatment of Crohn’s and colitis, over 10 years ago
- Engineered from 75% human protein, 25% mouse protein
- Animal protein derived anti-TNF drugs increase risk of reaction, although human proteins can cause a reaction too
- Systemic immunosuppressive
- Entyvio
- Suppresses Tumor necrosis factor-alpha (TNF-α)
- Selective effect on the gut, not a systemic immunosuppressive
- Humira (adalimumab): can choose self-administered shots at home
- Engineered from human protein
- Systemic immunosuppressive
- Cimzia (certolizumab pegol): can choose self-administered shots at home
- Engineered from human protein
- Other biologics (not anti-TNF):
- Tysabri (natalizumab)
- There is another type of protein at inflammation sites that white blood cells use to determine where they should go. This type of biologic blocks these proteins to prevent the white blood cells from getting to the site and causing issues.
- These drugs are highly effective in controlling inflammation and contributing to healing the gut lining (mucosa).
- Before initiating treatment with a Biologic, your doctor will order a hepatitis panel to determine hepatitis infection, particularly hepatitis B. Immunosuppressive drugs, like anti-TNF drugs, put you at higher risk of reactivating hepatitis B, which can be fatal.
- Biologics are fragile proteins that are destroyed by the digestive system so they don’t come in pill or tablet form.
How do they work?
- Biologics are protein antibodies that are designed to target specific immune system molecules (like TNF-α) that play important roles in inflammatory diseases. When the anti-TNF drugs bind these molecules, they prevent them from promoting the inflammatory process.
When are they used?
- Similarly to immunomodulators – considered steroid-sparing, allowing patients to reduce or eliminate their steroid use
- Moderate-severe disease, especially useful for Crohn’s patients with fistulas (can change the natural course of the disease and prevent further complications)
- Typically when other drugs (like 5-ASA or immunomodulators) fail to work
- Can be used as first-line therapy in certain high-risk patients who have aggressive disease
- Not a suitable candidate if you have an infection (like URTI) or a history of cancer or being evaluated for cancer; must be used very carefully in patients with heart failure or other cardiac problems
Side effects:
- Because biologics are protein antibodies, your body can detect that these proteins are intruders and develop its own antibodies against them. This can lead to an allergic reaction or more serious reaction causing shortness of breath, fever, and rash. Sometimes the doctor will premedicate with Tylenol, Benadryl, or a steroid shot to prevent a reaction from happening. If reactions are severe enough, a switch in drugs may occur.
- Injection site reactions can also occur – swelling and redness
- Increased risk of opportunistic infection because of suppressed immune system – fungal lung disease, pneumonia, and severe viral infections
- Increased risk of TB (Tuberculosis), a serious bacterial lung infection – everyone should be TB tested prior to starting biologics
- Slight increased risk of lymphoma (4-6 per 10,000 vs 1 per 10,000 in normal population) – researchers still don’t know why, risk is more pronounced in those that also take a other immunosuppressive medications (like azathioprine) or who have taken anti-TNF drugs for a long time
- Natalizumab activates a virus called JC virus, which causes a fatal brain infection called progressive multifocal encephalopathy (PML). PML is incurable and leads to disability and possibly death.
**Note: Many feel that using biologics is scary because of the side effects and risk of cancer. There are risks and benefits to all decisions, including this one. Risks of infection and cancer can be minimized by proper screening and monitoring.