Patient Population

Four hundred and fifty-one patients completed the baseline survey and were included in the analysis (Table 1). Of these, 361 patients completed two surveys, one survey while on original ixekizumab and another after switching to citrate-free ixekizumab; and 90 patients completed a survey after initiating citrate-free ixekizumab (i.e., had no prior ixekizumab use). Most patients were White (85.4%), had PsO and/or PsA (91.8%), and were 45.3 years of age on average. Over half the patients had no prior biologic use in the past 2 years (53.2%), while some had used one prior biologic (28.6%) or two or more biologics (18.2%).

Table 1 Baseline demographics and clinical characteristicsSatisfaction with Injection Experience for Patients Who Switched from Original to Citrate-Free Ixekizumab

Overall, significantly more patients reported feeling very or somewhat satisfied with their first injection experience with citrate-free ixekizumab compared to original ixekizumab (83.9% vs. 71.7% respectively; p = 0.0001) (Fig. 2). The percentage of patients receiving original ixekizumab who were very or somewhat satisfied with their first injection was similar for different treatment durations: ≤ 1 month (n = 40, 70.0%), 2–5 months (n = 151, 70.2%), and 6–12 months (n = 170, 73.5%) (p = 0.7768). Most patients who switched from original ixekizumab were definitely or mostly willing to continue using citrate-free ixekizumab (93.9%) as well as to recommend it to others (93.4%) (Fig. 3 and Fig. 4). Additionally, most patients (94.2%) who switched from original to citrate-free ixekizumab preferred citrate-free ixekizumab or had no preference (Fig. 5).

Fig. 2

Overall satisfaction with first injection of citrate-free ixekizumab and first injection of the original ixekizumab

Fig. 3

Willingness to continue using citrate-free ixekizumab among participants who had switched from the original ixekizumab

Fig. 4

Willingness to recommend citrate-free ixekizumab to a friend or family member among participants who had switched from the original ixekizumab

Fig. 5

Preference for ixekizumab by formulation among participants who had switched from the original ixekizumab

Subgroup Analysis by Indication for Patients Who Switched from Original to Citrate-Free Ixekizumab

For those with PsO and PsO + PsA, significantly more patients were very or somewhat satisfied with their first injection experience with citrate-free ixekizumab compared to their first injection experience with original ixekizumab (PsO n = 141/160, 88.1% vs. n = 125/160, 78.1%, respectively, p = 0.0245; PsO + PsA n = 95/118, 80.5% vs. n = 79/118, 66.9%, respectively, p = 0.0261) (Fig. 6). In general, the percentage of patients that were very or somewhat satisfied with their first injection experience with citrate-free and original ixekizumab was similar for patients with PsA as well as those with AS + nr-axSpA; however, these findings were not statistically significant (PsA n = 44/52, 84.6% vs. n = 36/52, 69.2%, respectively, p = 0.1021; AS + nr-axSpA n = 23/31, 74.2% vs. n = 19/31, 61.3%, respectively, p = 0.4155).

Fig. 6

Overall satisfaction with citrate-free ixekizumab injection and the original ixekizumab injection by indication. AS, ankylosing spondylitis; AxSpA, axial spondyloarthritis; PsA, psoriatic arthritis; PsO, psoriasis

At least 93% of patients who switched from the original ixekizumab were definitely or mostly willing to continue using citrate-free ixekizumab, regardless of the indication (range from n = 149, 93.1% PsO only to n = 30, 96.8% AS + nr-axSpA), and at least 90% of patients were definitely or mostly willing to recommend citrate-free ixekizumab to others (range from n = 49, 94.2% PsA only to n = 28, 90.3% AS + nr-axSpA). Most patients preferred citrate-free ixekizumab or had no preference, regardless of the indication (range from n = 47, 90.3% PsA only to n = 31, 100.0% AS + nr-axSpA).

Subgroup Analysis by Prior Biologic Use Status for Patients Who Switched from Original to Citrate-Free Ixekizumab

For those who did not use biologics prior to ixekizumab in the past 2 years, significantly more patients were very or somewhat satisfied with their first injection experience with citrate-free ixekizumab compared to their first injection experience with original ixekizumab (n = 173, 89.2% vs. n = 151, 77.8%, respectively; p = 0.0038) (Fig. 7). A similar difference in the proportion of patients who were very or somewhat satisfied was seen for those who used one or two or more biologics in the previous 2 years; however, these findings were not statistically significant. At least 93% of patients who switched from original ixekizumab were definitely or mostly willing to continue using citrate-free ixekizumab, regardless of biologic use in the previous 2 years (range from n = 181, 93.3% no prior biologics to n = 67, 95.7% ≥ 2 biologics), and at least 91% of patients were definitely or mostly willing to recommend the citrate-free ixekizumab to others (range from n = 64, 91.4% ≥ 2 biologics to n = 183, 94.3% no prior biologics). Nearly all patients preferred citrate-free ixekizumab or had no preference regardless of biologic status (n = 182, 93.8% no prior biologics; n = 91, 93.8% one prior biologic; and n = 67, 95.7% ≥ 2 biologics).

Fig. 7

Overall satisfaction with first injection of citrate-free ixekizumab and first injection of the original ixekizumab formulation by prior biologic use

Satisfaction with Injection Experience for Patients Initiating Citrate-Free Ixekizumab Without Prior Ixekizumab Use

Among patients who had not been previously exposed to ixekizumab, 74.5% reported feeling very or somewhat satisfied with their first injection experience with citrate-free ixekizumab (Fig. 8). Most patients were definitely or mostly willing to continue using citrate-free ixekizumab (94.5%) and were definitely or mostly willing to recommend it to others (78.9%) (Fig. 9).

Fig. 8

Overall satisfaction with the first injection of citrate-free ixekizumab in patients initiating ixekizumab

Fig. 9

Willingness to use and recommend ixekizumab in patients initiating ixekizumab