Ustekinumab has a higher drug survival rate than adalimumab, etanercept and infliximab, confirms a study of plaque psoriasis patients published in the Journal of Cutaneous Medicine and Surgery.
The study, published earlier this year, shows that the dosage is the main factor that may be associated with differing survival rates. And, plaque psoriasis patients tend to stay on the interleukin (IL)-12/23 inhibitor ustekinumab longer than they do on TNF inhibitors, the study showed.
The findings, which were published in the January/February issue of the journal, support previous studies showing that ustekinumab has the highest survival rate compared to other biologics, said principal investigator Kim A. Papp, M.D., research director, Probity Medical Research Inc., Ontario. "This is the first time where we see these sorts of numbers ― hundreds of patients ― out of two practices, with heavily edited data sets."
This was a retrospective analysis of 882 patients treated at two Canadian practices between July 2003 and June 2016. Patients may have had psoriatic arthritis in addition to plaque psoriasis. Biologic therapy was chosen to treat plaque psoriasis.
Investigators excluded patients on treatment they initially received in a clinical study, as well as those enrolled in clinical trials. Additionally, researchers excluded IL-17 inhibitors because its relatively recent approval for psoriasis in Canada obviated the possibility of long-term survival data.
The mean survival times for ustekinumab, adalimumab, etanercept and infliximab was 68 months, 33 months, 28 months and 23 months, respectively. The differences between survival times of each biologic therapy versus ustekinumab were statistically significant (adalimumab and etanercept: p<0.001; infliximab: p= 0.005). Female gender positively predicted drug survival: with a hazard ratio of 1.23 (95 percent confidence interval: 1.04-1.45; p= 0.017), women were less likely to discontinue treatment or switch biologics.
Consistent with other studies, ustekinumab also posted the highest cumulative survival rates after years one through five. However, these survival rates were lower than those reported elsewhere, write Dr. Papp and colleagues. They found two- and four-year ustekinumab survival rates of 0.74 and 0.60, respectively, versus 0.856 and 0.755 in a 398-patient study published in the November 2016 Australian Journal of Dermatology.
The patient population of this study was considerably larger that of many national biologic drug registries such as the Danish DANBIO database.
"For many of the registries, the drivers for keeping patients on a drug are quite different than the ability of the drug to maintain efficacy. Our study reflects what's happening in the real world," he said.
To a lesser degree, the study also reveals a difference between the two practices studied. "One practice had slightly better persistency. And that difference occurred solely because patients were exposed to a higher level of drug across the board. It's a strategy that will allow you to eke more benefit or a longer period of benefit from a drug," Dr. Papp said.
The study says nothing about how to manage patients. "It tells you what you can expect to see, and it depends somewhat on one’s practice. Nonetheless, ustekinumab showed the greatest persistency," he said.
"If you really wanted to get a good estimate of what the drugs can do in a broader sense, we need to incorporate more patients and add additional sites to get a more uniform assessment of how a large population behaves when they're in a collection of practices," Dr. Papp said.
With larger numbers of patients, "we can start to play with other factors: Are there any trends or characteristics of the way patients are treated that might either increase or decrease their persistency on a drug? With a large enough cohort, you could even start to look at safety signals."
Accordingly, Dr. Papp and colleagues have invited several larger practices to join them for an upcoming study. "Assuming we can get even a modicum of funding, I believe we will move forward to try and plug that gap." The goal is to collect and analyze data for 12,000-18,000 patients, taking additional therapies, over the next approximately 18 months.
Luvneet Verma, Julia N Mayba MD, Melinda J Gooderham MD, Ankush Verma, Kim A Papp MD. "Persistency of Biologic Therapies for Plaque Psoriasis in 2 Large Community Practices," Journal of Cutaneous Medicine and Surgery. January/February 2018.