Pharmacotherapeutic group: Immunosuppressants, interleukin inhibitors, ATC code: L04AC17
Mechanism of action
Tildrakizumab is a humanised IgG1/k monoclonal antibody that specifically binds to the p19 protein subunit of the interleukin-23 (IL-23) cytokine without binding to IL-12 and inhibits its interaction with the IL-23 receptor.
IL-23 is a naturally occurring cytokine that is involved in inflammatory and immune responses. Tildrakizumab inhibits the release of proinflammatory cytokines and chemokines.
Clinical efficacy and safety
The multicentre, randomised, double-blind, placebo-controlled trials reSURFACE 1 and reSURFACE 2 studies enrolled a total of 1,862 patients 18 years of age and older with plaque psoriasis who had a minimum body surface area involvement of 10%, a Physician Global Assessment (PGA) score of ≥ 3 in the overall assessment (plaque thickness, erythema, and scaling) of psoriasis on a severity scale of 0 to 5, a Psoriasis Area and Severity Index (PASI) score ≥ 12, and who were candidates for phototherapy or systemic therapy.
In these studies, patients were randomised to either placebo or tildrakizumab (including 200 mg and 100 mg at 0, 4 and every twelve weeks thereafter [Q12W]), up to 52 or 64 weeks. In the active comparator study (reSURFACE 2), patients were also randomised to receive etanercept 50 mg twice weekly for 12 weeks, and weekly thereafter up to 28 weeks. Patients who did not respond to etanercept treatment (<75% reduction in PASI from baseline) were switched to tildrakizumab 200 mg Q12W up to 52 weeks, while patients who responded to etanercept were discontinued from the study.
Eligible patients who completed the double-blind periods of reSURFACE 1 and reSURFACE 2 with ≥ 50% improvement in PASI from baseline could participate in open-label extension phases of these studies in order to evaluate the long-term safety and maintenance of efficacy of continuous tildrakizumab treatment. Patients entering the extension periods of reSURFACE 1 and reSURFACE 2 continued treatment at the same dose of tildrakizumab, 100 mg or 200 mg, that they were receiving at week 64 or 52, respectively. Up to 6 years of follow-up data are available.
Overall demographic and baseline characteristics in reSURFACE 1 and reSURFACE 2 studies were consistent across individual trials. Patients were 18 to 82 years old, with a mean age of 45.9 years old. The median baseline PASI score ranged from 17.7 to 18.4 across treatment groups. Baseline PGA score was marked or severe in 33.4% of patients. Of all patients, 35.8% had received prior phototherapy, 41.1% had received prior conventional systemic therapy, 16.7% had received prior biologic therapy for the treatment of plaque psoriasis. A total of 15.4% of study patients had a history of psoriatic arthritis. Mean baseline Dermatology Life Quality Index (DLQI) ranged from 13.0 to 14.8.
Studies reSURFACE 1 and reSURFACE 2 assessed the changes from baseline at Week 12 in the two co-primary endpoints: 1) PASI 75 and 2) PGA of “0” (cleared) or “1” (minimal), with at least a 2-point improvement from baseline. Other evaluated outcomes included the proportion of patients who achieved PASI 90, PASI 100, the proportion of patients with DLQI 0 or 1, and maintenance of efficacy up to 52/64 weeks.
Results obtained at weeks 12, 28 and beyond (up to week 64 in reSURFACE 1 and up to week 52 in reSURFACE 2) are presented in Table 2 and Table 3.
Table 2. Summary of response rates in studies reSURFACE 1 and reSURFACE 2
| | Week 12 (2 doses)* | Week 28 (3 doses)* |
| 200 mg | 100 mg | Placebo | Etanercept | 200 mg | 100 mg | Etanercept |
| reSURFACE1 |
| Number of patients | 308 | 309 | 154 | - | 298 | 299 | - |
| PASI 75a (%) | 62.3†b | 63.8†b | 5.8b | - | 81.9c | 80.4c | - |
| PGA of “clear” or “minimal” with ≥2 grade improvement from Baselinea (%) | 59.1†b | 57.9†b | 7.1b | - | 69.1c | 66.0c | - |
| PASI 90 (%) | 35.4†b | 34.6†b | 2.6b | - | 59.0c | 51.6c | - |
| PASI 100 (%) | 14.0†b | 13.9†b | 1.3b | - | 31.5c | 23.5c | - |
| DLQI Score 0 or 1 (%) | 44.2† | 41.5 † | 5.3 | - | 56.7c | 52.4c | - |
| reSURFACE2 |
| Number of patients | 314 | 307 | 156 | 313 | 299 | 294 | 289 |
| PASI 75a (%) | 65.6†‡b | 61.2†‡b | 5.8b | 48.2b | 72.6‡b | 73.5‡b | 53.6b |
| PGA of “clear” or “minimal” with ≥2 grade improvement from Baselinea (%) | 59.2†¥b | 54.7†b | 4.5b | 47.6b | 69.2‡b | 64.6‡b | 45.3b |
| PASI 90 (%) | 36.6†‡b | 38.8†‡b | 1.3b | 21.4b | 57.7‡c | 55.5‡c | 29.4 c |
| PASI 100 (%) | 11.8†‡b | 12.4†‡b | 0 | 4.8b | 27.0‡c | 22.8‡c | 10.7c |
| DLQI Score 0 or 1 (%) | 47.4†¥ | 40.2† | 8.0 | 35.5 | 65.0‡c | 54.1‡c | 39.4c |
a Co-primary efficacy endpoint at week 12.
b Non-responder imputation for missing data.
c No imputation for missing data.
*The number of doses administered refers only to tildrakizumab groups.
n = number of patients in the full analysis set for which data was available, after imputation when applicable.
p-values calculated using the Cochran-Mantel-Haenszel (CMH) test stratified by body weight (≤90 kg, >90 kg) and prior exposure to biologic therapy for psoriasis (yes/no).
† p≤0.001 versus placebo; ‡ p≤0.001 versus etanercept; ¥ p≤0.05 versus etanercept.
Maintenance of response
The maintenance of response in studies reSURFACE 1 and reSURFACE 2 are presented in Table 3. Maintenance and durability of PASI 90 response over time is presented in Figure 1.
Table 3. Maintenance of response in studies reSURFACE 1 and reSURFACE 2
| | Long term responsea,b |
| 200 mg | 100 mg |
| reSURFACE 1 | Week 28 | Week 64 | Week 28 | Week 64 |
| Number of patients | 116 | 114 | 115 | 112 |
| PGA of “clear” or “minimal” with ≥2 grade improvement from Baseline (%) | 80.2 | 76.3 | 80.9 | 61.6 |
| PASI 90 (%) | 70.7 | 74.6 | 65.2 | 58.0 |
| PASI 100 (%) | 38.8 | 40.4 | 25.2 | 32.1 |
| reSURFACE 2 | Week 28 | Week 52 | Week 28 | Week 52 |
| Number of patients | 108 | 105 | 213 | 204 |
| PGA of “clear” or “minimal” with ≥2 grade improvement from Baseline (%) | 88.0 | 84.8 | 84.0 | 79.4 |
| PASI 90 (%) | 75.0 | 81.9 | 74.2 | 78.4 |
| PASI 100 (%) | 34.3 | 46.7 | 30.2 | 35.3 |
a Long-term response in patients who were responders (had achieved at least PASI 75) to tildrakizumab at week 28.
b No imputation for missing data.
Figure 1. Maintenance and durability of PASI 90 response. Proportion of patients with PASI 90 response over time up to week 64 (full analysis set part 3*)

Patients randomised to tildrakizumab 100 mg or tildrakizumab 200 mg in Part 1 who were PASI 75 responders at week 28 (reSURFACE1).
*No imputation of missing data.
**These patients were switched to placebo at week 28.
Of the patients who completed the double-blind period, 506 (79%) in reSURFACE 1 and 730 (97%) in reSURFACE 2 entered the extension period. Across studies, at least 76% of patients who had a PASI 90 response at the end of double-blind period, maintained a PASI 90 response during the extension period, when tildrakizumab 100 mg or 200 mg treatment was continued during a period of 192 weeks (Figure 2 and Figure 3).
Figure 2. Percentage of patients who maintained a PASI 90 response by visit in the open-label extension of reSURFACE 1 (Full Analysis Set, Extension Period*)

*Among PASI 90 responders at the end of the double-blind study period. No imputation of missing data.
Note: Visit week is nominal, as study participants had a window of up to approximately 12 weeks from week 64 to begin the extension.
Figure 3. Percentage of patients who maintained a PASI 90 response by visit in the open-label extension of reSURFACE 2 (Full Analysis Set, Extension Period*)
*Among PASI 90 responders at the end of the double-blind study period. No imputation of missing data.
Quality of life/patient-reported outcomes
At week 12 and across studies, tildrakizumab was associated with statistically significant improvement in health-related quality of life as assessed by the DLQI (Table 2). Improvements were maintained over time with at week 52, 63.7% (100 mg) and 73.3% (200 mg) in reSURFACE 1, and 68.8% (100 mg) and 72.4% (200 mg) in reSURFACE 2 of patients who were PASI 75 responders at week 28 having a DLQI of 0 or 1.
Plaque psoriasis of the scalp
A randomised, placebo-controlled study evaluated the efficacy and safety of tildrakizumab in 231 patients with moderate to severe plaque psoriasis of the scalp, defined as an Investigator's Global Assessment (IGA) modified (mod) 2011 scalp score ≥3, Psoriasis Scalp Severity Index (PSSI) score ≥12, and ≥30% of scalp surface area (SSA) affected at baseline. At week 16, tildrakizumab treatment compared to placebo was associated with a statistically significant improvement in both endpoints the IGA mod 2011 0 or 1 scalp only response (49% versus 7%) and PSSI 90 response (56% versus 4%). These effects were sustained for tildrakizumab patients who continued treatment up to week 52.
Nail psoriasis
A randomised, placebo-controlled study evaluated the efficacy and safety of tildrakizumab in 99 adults with moderate to severe plaque psoriasis who had moderate to severe nail psoriasis, defined as a modified Nail Psoriasis Severity Index (mNAPSI) score of ≥20 and at least 50% nail destruction. Patients were randomised to tildrakizumab 100 mg administered at week 0, week 4, and every Q12W thereafter, or placebo up to 28 weeks. Tildrakizumab demonstrated a statistically significant treatment benefit in patients with moderate to severe nail psoriasis (Table 4).
Table 4. Efficacy Outcomes at Week 28
| Endpoint | Tildrakizumab 100 mg Q12W N=51 | Placebo N=48 | Response Difference (95% CI) |
| mNAPSI 75, n (%) | 13 (25.5)a | 2 (4.2)a | 22.0% (7.97, 36.06)b |
| Mean change in total-fingernail mNAPSI | -21.8 | -7.7 | -14.1 (-19.86, -8.42)c |
aNon-responder imputation for missing data.
bResponse difference and CI were calculated using Miettinen-Nurminen, stratified by body weight and prior anti-TNF agent exposure.
cMMRM model included fixed effects for treatment, visit, treatment by visit interaction, prior use of TNF-alpha inhibitors, body weight class, and prior anti-TNF agent exposures.
Immunogenicity
In pooled Phase 2b and Phase 3 analyses, 7.3% of tildrakizumab-treated patients developed antibodies to tildrakizumab up to week 64. Of the subjects who developed antibodies to tildrakizumab, 38% (22/57 patients) had neutralizing antibodies. This represents 2.8% of all subjects receiving tildrakizumab.
In pooled phase 3 analyses, 8.3% of tildrakizumab-treated patients developed antibodies to tildrakizumab up to 420 weeks of treatment. Of the tildrakizumab-treated patients who developed antibodies to tildrakizumab, 35% (36/102 patients) had antibodies that were classified as neutralizing, which represents 2.9% of all tildrakizumab-treated patients.
The development of neutralizing antibodies to tildrakizumab was associated with lower serum tildrakizumab concentrations.
Paediatric population
The European Medicines Agency has deferred the obligation to submit the results of studies with Ilumetri in one or more subsets of the paediatric population in the treatment of plaque psoriasis (see section 4.2 for information on paediatric use).