Orencia for Psoriatic Arthritis
Dr. Jeffrey Landis, June 2019
Psoriatic arthritis is an inflammatory arthritis associated with psoriasis. Psoriatic arthritis manifests with inflammation in the tendons, tendon attachment sites and in the joints. The inflammation can permanently damage the joints and bones causing deformity and disability.
One of the semi unique features of psoriatic arthritis is dactylitis, also called sausage digits. In this case, the fingers or toes swell to the point the wrinkles in the digit disappear and the digit looks like a sausage. This is mostly due to the swelling of the tendons in the digits.
Another feature is spinal inflammation. Patients will develop a pain in the spine that will get better with movement. They are stiff in the spine for at least 1 hour in the morning. The pain will also wake patients up at night and they will exercise to get the pain to resolve.
Some patients with psoriatic arthritis or psoriasis alone will get eye inflammation called uveitis. In this process, there is inflammation in the eye causing pain, blurriness and eventually blindness if left untreated. This is considered to be an ophthalmologic emergency and patients will need to see an eye doctor that day for treatment or risk going blind in the affected eye.
Patient with both psoriasis and psoriatic arthritis will get nail changes sometimes. The changes are nail pitting and onycholysis. Nail pitting appears as if the nail has been perforated with a needle. Onycholysis is the separation of the nail from the nail bed. This happens when psoriasis affects the nail bed or nail root.
Treatment of psoriasis can be done with steroid creams alone, depending upon the amount of psoriasis a patient has, but large areas of psoriasis and psoriatic arthritis require the use of systemic treatments. These treatments come in different modalities including pills, injections, and infusions. Orencia is unique in its mechanism of action compared to other treatments. Orencia inhibits T-cells by binding CD80 and CD86. Other medications usually affect B-cell activation. This makes Orencia appealing if the patients with psoriasis or psoriatic arthritis are not responding to other treatment modalities.
Orencia comes in an injection or infusion form. Orencia injections are self-injected on a weekly basis. Orencia infusions are given at 0, 2 and 4 weeks and every 4 weeks thereafter. The infusion time is about 45 minutes with premedication to prevent infusion reactions; however, infusion reactions and adverse reactions to Orencia are rare. Side effects can include infection, allergic reaction, bone marrow suppression, MS, and COPD exacerbation. This medication is not for people with COPD.
A unique property about this medication is the malignancy risk. There is no increased risk for a malignancy over placebo in the trials. There was more lung cancer and lymphoma in the Orencia treatment group when compared to the placebo group but the total number of malignancies were similar.
As for the response of the psoriatic arthritis to the Orencia infusions, the response rates to the infusions of Orencia were better than the response rates to the injections of Orencia:
Felt 20% better --> 47% of patients
Felt 50% better --> 25% of patients
Felt 70% better --> 12% of patients