Pharmacotherapeutic group: Other dermatological preparations, agents for dermatitis, excluding corticosteroids, ATC code: D11AH09
Mechanism of action
Ruxolitinib is a Janus Kinase (JAK) inhibitor with selectivity for the JAK1 and JAK2 isoforms. Intracellular JAK signalling involves recruitment of STATs (signal transducers and activators of transcription) to cytokine receptors, and subsequent modulation of gene expression. Autoimmune IFNγ producing cytotoxic T lymphocytes are thought to be directly responsible for melanocyte destruction in human vitiligo. Recruitment of cytotoxic lymphocytes to lesional skin is mediated via IFNγ dependent chemokines, such as CXCL10. Downstream signalling of IFNγ is JAK1/2 dependent and treatment with ruxolitinib reduces CXCL10 levels in vitiligo patients.
Clinical efficacy and safety
Efficacy
Two double-blind, randomised, vehicle-controlled studies of identical design (TRuE‑V1 and TRuE‑V2) enrolled a total of 674 patients who have vitiligo on the face and total body vitiligo area (facial and nonfacial) not exceeding 10% BSA, with disease extent at initiation ranging from 3.2% to 10.1% of BSA, aged 12 years and older (10.7% of patients were 12 to 17 years of age and 6.7% were 65 years or older). Females constituted 53.1% of patients, 81.9% of patients were White, 4.7% were Black, and 4.2% were Asian. The majority of patients had Fitzpatrick skin types III, IV, V, or VI (67.5%).
In both studies, patients were randomised 2:1 to treatment with ruxolitinib cream or vehicle twice daily for 24 weeks with affected BSA not exceeding 10%, followed by an additional 28 weeks of treatment with ruxolitinib cream BID for all patients. The primary efficacy endpoint was the proportion of patients achieving a 75% repigmentation in the facial Vitiligo Area Scoring Index (F‑VASI75) at week 24. Key secondary endpoints included the proportions of patients achieving a 90% repigmentation in F‑VASI (F‑VASI90), 50% improvement in total body Vitiligo Area Scoring Index (T‑VASI50), and a Vitiligo Noticeability Scale (VNS) score of 4 or 5 (vitiligo "a lot less noticeable" or "no longer noticeable").
Repigmentation of treated vitiligo lesions and superiority of ruxolitinib cream over vehicle cream were observed for both studies, as demonstrated by statistically significant differences in response rates for F‑VASI75/90, T‑VASI50, and VNS score of 4 or 5 at week 24 (Table 2).
The treatment effect difference from vehicle emerges numerically as early as week 12. Continued repigmentation as assessed by VASI and VNS scores was observed through week 52 for patients who had continuously applied ruxolitinib cream twice daily from baseline. The proportion of patients who achieved F‑VASI75 over the 52‑week treatment period in pooled data from study TRuE‑V1 and TRuE‑V2 are shown in Figure 1.
Similar treatment responses at week 52 are seen for those who crossed over from vehicle to ruxolitinib (Figure 1).
Table 2: Percent of patients with vitiligo achieving the primary and key secondary endpoints at week 24 (intent-to-treat)a
| | TRuE‑V1 | TRuE‑V2 |
| Opzelura | Vehicle | Opzelura | Vehicle |
| (N = 221) | (N = 109) | (N = 222) | (N = 109) |
| F‑VASI75 (%) | 29. 8 | 7. 4 | 30.9 | 11.4 |
| Response rate difference (95% CI) | 22.3b (14.214, 30.471) | - | 19.5c (10.537, 28.420) | - |
| F‑VASI90 (%) | 15. 3 | 2.2 | 16.3 | 1.3 |
| Response rate difference (95% CI) | 13.2d (7.497, 18.839) | - | 15.0e (9.250, 20.702) | - |
| T‑VASI50 (%) | 20.6 | 5.1 | 23.9 | 6.8 |
| Response rate difference (95% CI) | 15.5d (8.339, 22.592) | - | 17.1c (9.538, 24.721) | - |
| VNS 4 or 5 (%) | 24.5 | 3.3 | 20.5 | 4.9 |
| Response rate difference (95% CI) | 21.2c (14.271, 28.143) | - | 15.5d (8.515, 22.561) | - |
a Primary and key secondary outcomes were corrected using multiple imputation method.
b p-value < 0.0001
c p-value < 0.001
d p-value < 0.005
e p-value < 0.01
Figure 1: Proportion of patients achieving F-VASI75 during the 52 week treatment period (Intent to-treat) – pooled data from study TRuE V1 and TRuE V2
At week 52, the observed response rate for F‑VASI90, T‑VASI50 and VNS was 30.3%, 51.1%, and 36.3% respectively for the ITT pooled population.
Durability of response
A Phase 3, double-blind, vehicle-controlled, randomised, withdrawal and treatment-extension study of ruxolitinib cream twice daily enrolled 458 eligible patients with vitiligo who had completed either of the parent studies using ruxolitinib (TRuE-V1 and TRuE-V2; week 52); patients were assigned to either cohort A or B with a follow-up up to 104 weeks.
Cohort A comprised 116 patients who reached ≥ F-VASI90 at week 52 of the parent study. These patients were re-randomised to either ruxolitinib or vehicle (i.e. withdrawal) to study relapse (< F‑VASI75). A relapse occurred in 15% of patients in the ruxolitinib group, and in 29% of patients in the vehicle group. In the latter group, the majority of relapses (9/16) occurred during the first 4 months after stopping ruxolitinib cream. Among the 16 patients in the vehicle group who relapsed and were retreated, re-treatment resulted in a regained F-VASI75 in 12 (75%) patients in a median of 12 weeks and F-VASI90 was regained by 11 (69%) patients in a median of 15 weeks.
Cohort B comprised 342 patients who reached < F-VASI90 at week 52 of the parent study. These patients continued with open-label ruxolitinib treatment; at week 104, among patients originally randomised to ruxolitinib cream twice daily, 66% reached F-VASI75, and 34% reached F-VASI90.
Safety
Safety in the long-term extension study up to 104 weeks cumulatively was consistent with the profile reported in the parent studies up to 52 weeks.
Paediatric population
A total of 72 adolescents (12 to < 18 years; n = 55 ruxolitinib cream, n = 17 vehicle) were included in the pivotal studies. Adolescents showed equal response rates in primary and key secondary endpoints at 24 weeks when treated with ruxolitinib, as compared to adults from 18‑65 years of age.
The Medicines and Healthcare products Regulatory Agency has deferred the obligation to submit the results of studies with Opzelura in one or more subsets of the paediatric population for the treatment of vitiligo (see section 4.2 for information on paediatric use).