The U.S. Food and Drug Administration approved certolizumab pegol (Cimzia), a drug previously approved to treat Crohn’s disease, to also treat moderate to severe rheumatoid arthritis.

Certolizumab pegol belongs to a class of biologic drugs that block an inflammatory protein called tumor necrosis factor alpha, or TNF-alpha. Other drugs in this category include etanercept (Enbrel), infliximab (Remicade), adalimumab (Humira) and golimumab (Simponi), which was approved last month.

Cimzia’s molecule is slightly different from the other drugs in its class, however, because it is pegylated, or coated, a process that, in theory, should help it slip by the body’s immune system more easily and may make it less likely to cause an infusion reaction.

Pegylation may also help the drug work more quickly. According to UCB, the Belgian company that makes certolizumab pegol, when used in conjunction with methotrexate, patients in clinical trials for Cimzia reported a reduction in symptoms as early as the first week.

Certolizumab pegol is administered with at-home injections, which can be given every two or four weeks.

UCB also worked with industrial designers OXO Products, the same company behind the Good Grips line of kitchen tools, to redesign the syringe that patients use to administer the drug. Noting that the design of the classic syringe, which is very difficult for some arthritis patients to use, had not changed substantially in a century, UCB worked with OXO to add features like an extra large loop at the top which make it more patient-friendly. The new device has earned the Arthritis Foundation’s Ease-of-Use Commendation.