Psoriatic arthritis is a chronic inflammatory arthropathy associated with psoriasis. A recent review found that about 20% of patients with psoriasis have psoriatic arthritis. Updated guidelines for treatment of psoriatic arthritis have recently been published.

The FDA has approved the human interleukin (IL)-12 and -23 antagonist ustekinumab (Stelara – Janssen Biotech) for treatment of moderately to severely active Crohn's disease in adults who were intolerant of or whose disease was unresponsive to treatment with immunomodulators or corticosteroids, or a tumor necrosis factor (TNF) inhibitor. Ustekinumab was approved earlier for treatment of psoriasis and psoriatic arthritis.

View the Table: Some Drug Interactions with Drugs for IBD

The FDA has approved tofacitinib (toe” fa sye’ ti nib; Xeljanz – Pfizer), an oral Janus kinase (JAK) inhibitor, for treatment of adults with moderately to severely active rheumatoid arthritis (RA) who have had an inadequate response to or are intolerant of methotrexate. Ruxolitinib (Jakafi) is the only other JAK inhibitor available in the US; it is FDA-approved for treatment of myelofibrosis.

Tildrakizumab-asmn (Ilumya – Sun), an interleukin (IL)-23 antagonist, has been approved by the FDA for treatment of adults with moderate to severe plaque psoriasis who are candidates for systemic therapy or phototherapy. Tildrakizumab is the second selective IL-23 antagonist to be approved for this indication; guselkumab (Tremfya) was the first.

Natalizumab (Tysabri - Elan and Biogen) is a monoclonal antibody approved for induction and maintenance treatment of moderate to severe Crohn's disease (CD) refractory to conventional therapies and inhibitors of tumor necrosis factor (TNF). Initially approved in 2004 for the treatment of multiple sclerosis (MS), natalizumab was temporarily withdrawn from the market after 3 patients developed progressive multifocal leukoencephalopathy (PML). It is now available for treatment of both MS and CD through a restricted distribution program.

The FDA has approved the interleukin (IL)-6 inhibitor sarilumab (Kevzara – Sanofi) for second-line treatment of adults with moderately to severely active rheumatoid arthritis (RA). It is the second IL-6 inhibitor to be approved for this indication; tocilizumab (Actemra) was approved earlier.

Rheumatoid arthritis (RA) is prevalent in 0.5% of adults in the US; it is about 2.5 times more common in women than in men. Guidelines for treatment of RA from the American College of Rheumatology were recently updated. The goal of treatment is to minimize disease activity and prevent irreversible joint damage.

Mild to moderate plaque psoriasis can be treated with topical drugs and phototherapy. Patients with moderate to severe disease generally require systemic therapy. Guidelines for the treatment of psoriasis with topical therapy, phototherapy, and systemic drugs have recently been published.

The May 5, 2008 article (Med Lett Drugs Ther 2008; 50:34) on the approval of natalizumab (Tysabri) for treatment of Crohn's disease in the "Adverse Effects" section on page 35 included the statement: "post-marketing hepatotoxicity, sometimes fatal or requiring liver transplantation, has occurred." Actually, no fatal hepatotoxicity or liver transplantation has been reported to date. The FDA warning about post-marketing hepatotoxicity with Tysabri that was the basis for our statement said: "The combination of transaminase elevations and elevated bilirubin without evidence of obstruction is...