Combination Use of Systemic Therapies in Psoriasis: Baseline Characteristics from the Corrona Psoriasis Registry

Beyond this, there were no significant differences in psoriatic disease between the two groups. No discrepancies were observed in psoriasis morphology, years of psoriasis duration, or IGA, PASI, and affected BSA at treatment initiation. One might expect that patients with more widespread skin disease would be prescribed combination therapy with greater frequency, if only to elicit a rapid response before bridging to biologic monotherapy. Combinations of TNF-alpha antagonists with CsA, for instance, reduce response time substantially.^14,15 One possible explanation for these data is that newer biologic agents, such as the IL-17 antagonists (eg, ixekizumab, secukinumab), have a dramatically decreased response time when given as monotherapy. ¹⁶

The only discrepancy in treatment history between the groups was that patients beginning combination therapy were more likely to have previously tried a non-biologic systemic agent. This could be explained by the greater percentage of combination therapy patients who have concomitant PsA, who are likely to have been prescribed non-biologic DMARDs for their rheumatologic disease in the past.

Similarly, few disparities were observed in non-dermatologic comorbid conditions. Patients on combination therapy were no more likely than monotherapy patients to report cardiovascular disease, hypertension, hyperlipidemia, diabetes mellitus, Crohn’s disease, depression, or anxiety. There was a reported history of malignancy in the combination therapy group but not in the monotherapy group. However, as only one of 92 patients in the combination therapy was affected, no meaningful conclusions can be drawn about history of malignancy and the need for combination therapy. Additional information regarding the type and grade of malignancy was unavailable.

Several differences in demographics were noted between the two groups. Patients prescribed combination therapy were an average of 4.4 years older, more likely to self-identify as black, and less likely to be enrolled in commercial insurance plans. The racial disparity is unexpected, as PsA is roughly half as prevalent among Americans who identify as black versus those who identify as white (30% vs 64.5%).¹⁷ However, the clinical significance of this is unclear.

The combination therapy group had a somewhat greater percentage of Medicare enrollees (20% vs 15%) and a significantly greater percentage of Medicaid enrollees (20% vs 7%). While it has been shown that patients with private insurance are more likely to initiate a biologic drug compared to Medicaid patients, there are currently no data on the relative ease of adding a biologic to another systemic therapy.¹⁸ A comparison of PROs between the two groups suggest that the need for combination therapy may be more closely related to impact on quality of life than disease severity or treatment history. Patients starting combination therapy experienced more overall fatigue, missed more hours from work, and had more problems performing activities of daily living than monotherapy patients. There was no significant difference in DLQI score; however, it has also been suggested that the DLQI survey is heavily impacted by cultural background and may not be a useful tool given the demographic differences between our groups.¹⁹

Key limitations of this study are its cross-sectional design and current lack of follow up data. Additionally, participating in the registry is voluntary for both providers and patients, leading to possible selection bias. Another limitation is that the majority of our patients came from the Northeast or the South, with less than a quarter of the cohort coming from the Midwest or the West. Therefore, these results may not be representative of patients on combination therapy across the country. Finally, we do not have data on what percentage of our patients came from urban, suburban, and rural environments.

In this study, patients on combination therapy were more likely to have concomitant PsA. These patients were also more likely to self-identify as black, more likely to report disability, and less likely to have commercial insurance. Key differences in PROs were greater reported fatigue, more missed hours from work, and more problems performing activities of daily living in the combination therapy group. These findings suggest that both medical and demographic factors contribute to a patient’s likelihood to initiate combination systemic therapy for psoriasis. As more follow-up data are obtained from the Corrona Registry, future studies on longitudinal data will assess safety and efficacy of these regimens.

Mark Lebwohl is an employee of Mount Sinai which receives research funds from: Abbvie, Amgen, AstraZeneca, Boehringer Ingelheim, Celgene, Eli Lilly, Incyte, Janssen / Johnson & Johnson, Kadmon, Leo Pharmaceuticals, Medimmune, Novartis, Pfizer, Sciderm, UCB, Ortho-dermatologics, and ViDac. Dr. Lebwohl is also a consultant for Allergan, Almirall, Arcutis, Avotres, Birch biomed, Boehringer-Ingelheim, Bristol Myers Squibb, Cara, Castle Biosciences, Dermavant, Encore, Inozyme, LEO Pharma, Meiji, Menlo, Mitsubishi Pharma, Neuroderm LTD,Pfizer, Promius/Dr. Reddy, Theravance Biopharma, and Verrica. Funding sources: Corrona Psoriasis Registry is sponsored by Corrona LLC, which is funded by AbbVie, Boehringer Ingelheim, Celgene, Valeant, Merck, Eli Lilly and Company, and Novartis Pharmaceutical Corporation. IRB statement: All participating investigators were required to obtain full board approval for conducting research involving human subjects. Sponsor approval and continuing review was obtained through a central institutional review board (IRB; IntegReview, Corrona-PSO-500). For academic investigative sites that did not receive a waiver to use the central IRB, full board approval was obtained from the respective governing IRBs and documentation of approval was submitted to the sponsor before initiating any study procedures. All registry subjects were required to provide written, informed consent before participating.

Mark Lebwohl MD mark.lebwohl@mountsinai.org