Pharmacotherapeutic group: Immunosuppressants, Interleukin inhibitors, ATC code: L04AC12
Mechanism of action
Brodalumab is a recombinant fully human monoclonal immunoglobulin IgG2 antibody that binds with high affinity to human IL-17RA and blocks the biological activities of the pro-inflammatory cytokines IL-17A, IL-17F, IL-17A/F heterodimer, IL-17C and IL-17E (also known as IL-25), resulting in inhibition of the inflammation and clinical symptoms associated with psoriasis. IL-17RA is a protein expressed on the cell surface and is a required component of receptor complexes utilized by multiple IL-17 family cytokines. IL-17 family cytokine levels have been reported to be increased in psoriasis. IL-17A, IL-17F and IL-17A/F heterodimer have pleiotropic activities including the induction of pro-inflammatory mediators such as IL-6, GROα, and G-CSF from epithelial cells, endothelial cells and fibroblasts that promote tissue inflammation. IL-17C has been shown to induce similar responses as IL-17A and IL-17F in keratinocytes. Blocking IL-17RA inhibits IL-17 cytokine-induced responses resulting in normalization of inflammation in the skin.
Pharmacodynamic effects
Elevated levels of IL-17A, IL-17C and IL-17F gene expression are found in psoriatic plaques. Elevated levels of expression of IL-12B and IL-23A, the genes for the two subunits of IL-23, an upstream activator of IL-17A and IL-17F expression, are also found in psoriatic plaques. Treatment with brodalumab in psoriasis patients has been shown to decrease levels of IL-17A and markers of cell proliferation and epidermal thickness in lesional skin biopsies to non-lesional skin biopsy levels up to 12 weeks post-treatment.
Clinical efficacy and safety
The efficacy and safety of brodalumab was assessed in 4373 adult plaque psoriasis patients across three multinational, randomised, double-blind, phase 3, placebo-controlled clinical trials (AMAGINE-1, AMAGINE-2, and AMAGINE-3). AMAGINE-2 and AMAGINE-3 were also active comparator (ustekinumab)-controlled. All three trials included a 12-week placebo-controlled induction phase, a double-blind duration of 52 weeks, and an open-label long-term extension.
Patients enrolled were candidates for systemic therapy, including phototherapy, biologic and non-biologic systemic therapies. Approximately 21% of patients had a history of psoriatic arthritis.
Approximately 30% of patients had previously received a biological and 13% of patients were biological failures.
Patients were predominantly men (70%) and white (91%), with a mean age of 45 years (18 to 86 years), of these 6.4% were ≥65 years of age and 0.3% were >75 years of age. Across treatment groups, the baseline Psoriasis Area Severity Index (PASI) score ranged from 9.4 to 72 (median: 17.4) and baseline involved body surface area (BSA) ranged from 10 to 97 (median: 21). Baseline static Physician Global Assessment (sPGA) score ranged from “3 (moderate)” (58%) to “5 (very severe)” (5%).
AMAGINE-1 was conducted in 661 patients. The trial included a 12-week double-blind, placebo-controlled induction phase followed by a double-blind withdrawal and retreatment phase up to 52 weeks. Patients randomised to brodalumab received 210 mg or 140 mg at Week 0 (day 1), Week 1, and Week 2 followed by same dose every 2 weeks. At Week 12, patients originally randomised to brodalumab who achieved sPGA success (0 or 1) were re-randomised to receive either placebo or continued brodalumab at their induction dose. Patients originally randomised to placebo and those who did not meet the criteria for re-randomisation received brodalumab 210 mg every two weeks beginning at Week 12. Retreatment was available at or after Week 16 for patients with return of disease and rescue treatment was available after 12 weeks of retreatment.
AMAGINE-2 and AMAGINE-3 were identical placebo- and ustekinumab-controlled trials conducted in 1831 and 1881 patients, respectively. Both trials included a 12-week double-blind, placebo- and ustekinumab-controlled induction phase followed by a double-blind maintenance phase up to 52 weeks. Patients randomised to brodalumab in the induction phase received 210 mg or 140 mg at Week 0 (day 1), Week 1, and Week 2 followed by same dose every 2 weeks. Patients randomised to ustekinumab received 45 mg for patients ≤100 kg and 90 mg for patients >100 kg at Weeks 0, 4, and 16 followed by same dose every 12 weeks. At Week 12, patients originally randomised to brodalumab were re-randomised to receive either 210 mg every 2 weeks, or 140 mg every 2 weeks, or 140 mg every 4 weeks, or 140 mg every 8 weeks during the maintenance phase. Patients originally randomised to placebo received brodalumab 210 mg every 2 weeks beginning at Week 12. At Week 12, patients in the ustekinumab group continued to receive ustekinumab and then were switched to brodalumab 210 mg every 2 weeks at Week 52. Rescue treatment was available at or after Week 16 for patients with an inadequate response single sPGA ≥3 or persistent sPGA of 2 over at least a 4-week period.
Table 2: Overview of the main efficacy results
| | AMAGINE-1 | AMAGINE-2 and AMAGINE-3 |
| | Placebo | Brodalumab 210 mg Q2W | Placebo | Brodalumab 210 mg Q2W | Ustekinumab |
| n-randomised | 220 | 222 | 624 | 1236 | 613 |
| n-completed Week 12 | 209 | 212 | 601 | 1205 | 594 |
| n-in maintenance | 84 | 83 | NA | 339 | 590 |
| n-completed Week 52 | 2 | 74 | NA | 236 | 300 |
| PASI | | | | | |
| PASI Baseline score (mean±SD) | 19.7±7.7 | 19.4±6.6 | 20.2±8.4 | 20.3±8.3 | 20.0±8.4 |
| PASI 75 Week 12 (%) | 3 | 83* | 7 | 86* | 70* |
| PASI 75 Week 52 (%) | 0 | 87* | NA | 65 | 48 |
| sPGA (%) | | | | | |
| sPGA 0 or 1 Week 12 | 1 | 76* | 4 | 79* | 59* |
| sPGA 0 or 1 Week 52 | 0 | 83* | NA | 65 | 45 |
| PSI | | | | | |
| PSIBaseline score (mean±SD) | 19.0±6.7 | 18.9±6.7 | 18.8±6.9 | 18.7±7.0 | 18.8±6.9 |
| PSIresponder Week 12 (%) | 4 | 61* | 7 | 64* | 54* |
| Q2W = every 2 weeks PSI = Psoriasis Symptom Inventory. PSI responder: total score ≤8 with no item scores >1; SD: standard deviation. Non-responder imputation is used to impute missing data. Due to re-randomisation to other explored dose regimens, n-in maintenance is substantially lower than n-randomised in several arms. The maintenance phase in AMAGINE-2 and -3 did not include placebo. *p-value vs. corresponding placebo, adjusted for stratification factors <0.001 |
PASI 75 response at 2 weeks ranged between 20% and 25% in the Phase 3 trials compared to placebo (0% to 0.6%) and ustekinumab (3% to 3.5%).
Figure 1: PASI 100 during induction and maintenance phase for brodalumab and ustekinumab (AMAGINE-2 and AMAGINE-3, pooled)
In all three clinical trials, examination of age, gender, race, use of prior systemic or photo therapy, use of prior biologics, and biologic failures did not identify differences in response in all key endpoints [PASI 75, PASI 100, sPGA success (0 or 1), and sPGA clear (0)] to brodalumab among these subgroups.
Along with primary efficacy endpoints, clinically important improvements were observed in Psoriasis Scalp Severity Index (PSSI) at Week 12 (AMAGINE-1) and in Nail Psoriasis Severity Index (NAPSI) at Week 12 and 52 (AMAGINE-1,-2, and -3).
Quality of life/patient reported outcomes
The proportion of patients who achieved a Psoriasis Symptom Inventory (PSI) score of 0 (not at all) or 1 (mild) on every item (itch, burning, stinging, pain, redness, scaling, cracking and flaking) at Week 12 are shown in Table 2.
The percentage of patients that at Week 12 achieved a DLQI (Dermatology Life Quality Index) score of 0 or 1 was 56%, 61%, 59% in the brodalumab 210 mg group and 5%, 5%, 7% in the placebo group in AMAGINE-1, -2 and -3, respectively (adjusted p-value <0.001) and 44% in the ustekinumab groups (AMAGINE-2 and -3).
Paediatric population
The European Medicines Agency has deferred the obligation to submit the results of studies with brodalumab in plaque psoriasis in one or more subsets of the paediatric population in plaque psoriasis (see section 4.2 for information on paediatric use).