The newest category of psoriasis drugs are called biologics, because they are produced by living cells. They are all proteins and therefore must be administered through the skin. All biologics work by suppressing certain specific portions of the immune inflammatory response that are overactive in psoriasis. Available biologic drugs include adalimumab (Humira), infliximab (Remicade), etanercept (Enbrel), ustekinumab (Stelara), secukinumab (Cosentyx), and ixekizumab (Taltz). Newer drugs are in development and no doubt will be available in the near future. As this class of drugs is fairly new, ongoing monitoring and adverse effect reporting continues and long-term safety continues to be monitored. Biologics are all comparatively expensive especially in view of the fact they none of them are curative. Recently, the FDA has attempted to address this problem by permitting the use of "biosimilar" drugs. These drugs are structurally identical to a specific biologic drug and are presumed to produce identical therapeutic responses in human beings to the original, but are produced using different methodology. Biosimilars ought to be available at some fraction of the cost of the original. If this will be an effective approach remains to be seen. The only biosimilar available currently is infliximab (Inflectra). Two other biosimilar drugs have been accepted by the FDA, an etanercept equivalent (Erelzi) and an adalimumab equivalent (Amjevita) -- but currently, neither are available.

    Some biologics are to be administered by self-injections for home use while others are given by intravenous infusions in the doctor's office. Biologics have some screening requirements such as a tuberculosis screening test (TB skin test or PPD test) and other labs prior to starting therapy. As with any drug, side effects are possible with all biologic drugs. Common potential side effects include mild local injection-site reactions (redness and tenderness). There is concern of serious infections and potential malignancy with nearly all biologic drugs. Precautions include patients with known or suspected hepatitis B infection, active tuberculosis, and possibly HIV/AIDS. As a general consideration, these drugs may not be an ideal choice for patients with a history of cancer and patients actively undergoing cancer therapy. In particular, there may be an increased association of lymphoma in patients taking a biologic.

    Biologics are expensive medications ranging in price from several to tens of thousands of dollars per year per person. Their use may be limited by availability, cost, and insurance approval. Not all insurance drug plans may fully cover these drugs for all conditions. Patients need to check with their insurance and may require a prior authorization request for coverage approval. Some of the biologic manufacturers have patient-assistance programs to help with financial issues. Therefore, choice of the right medication for your condition depends on many factors, not all of them medical. Additionally, convenience of receiving the medication and lifestyle may the choice of the right biologic medication.

    Currently, the main classes of biologic drugs for psoriasis are

1. TNF (tumor necrosis factor) blockers；

2. Drugs that interfere with interleukin chemical messengers of inflammation.