Fast Facts for Board Review
Biologics for Psoriasis
As part of our commitment to resident education, Cutis is excited to offer this monthly section with board-relevant, easy-to-review...
IL-17 Inhibitors
Ixekizumab
Ixekizumab (Eli Lilly and Company), a monoclonal inhibitor of IL-17A, is the most recently approved psoriasis biologic on the market and has been cleared for use in adults with moderate to severe plaque psoriasis. Recommended dosing is 160 mg (given in two 80-mg subcutaneous injections via an autoinjector or prefilled syringe) at week 0, followed by an 80-mg injection at weeks 2, 4, 6, 8, 10, and 12, and then 80 mg every 4 weeks thereafter. The FDA approved ixekizumab in March 2016 following favorable results of several phase 3 trials: UNCOVER-1, UNCOVER-2, and UNCOVER-3.7,8
In UNCOVER-1, 1296 participants were randomized to 1 of 2 ixekizumab treatment arms—160 mg starting dose at week 0, 80 mg every 2 or 4 weeks thereafter—or placebo.7 At week 12, 89.1%, 82.6%, and 3.9% achieved PASI 75, respectively (P<.001 for both). Importantly, high numbers of participants also achieved PASI 90 (70.9% in the 2-week group and 64.6% in the 4-week group vs 0.5% in the placebo group [P<.001]) and PASI 100 (35.3% and 33.6% vs 0%, respectively [P<.001]), suggesting high rates of disease clearance.7
UNCOVER-2 (N=1224) and UNCOVER-3 (N=1346) investigated the same 2 dosing regimens of ixekizumab compared to etanercept 50 mg biweekly and placebo.8 At week 12, the percentage of participants achieving PASI 90 in UNCOVER-2 was 70.7%, 59.7%, 18.7%, and 0.6%, respectively, and 68.1%, 65.3%, 25.7%, and 3.1%, respectively, in UNCOVER-3 (P<.0001 for all comparisons to placebo and etanercept). At week 12, PASI 100 results also showed striking superiority, with 40.5%, 30.8%, 5.3%, and 0.6% of participants, respectively, in UNCOVER-2, and 37.7%, 35%, 7.3%, and 0%, respectively, in UNCOVER-3, achieving complete clearance of disease (P<.0001 for all comparisons to placebo and etanercept). Responses to ixekizumab were observed as early as weeks 1 and 2, while no participants in the etanercept and placebo treatment groups achieved comparative efficiency.8
In an extension of UNCOVER-3, efficacy increased from week 12 to week 60 according to PASI 90 (68%–73% in the 2-week group; 65%–72% in the 4-week group) and PASI 100 measures (38%–55% in the 2-week group; 35%–52% in the 4-week group).7
The most common AEs associated with ixekizumab treatment from weeks 0 to 12 occurred at higher rates in the 2-week and 4-week ixekizumab groups compared to placebo, including nasopharyngitis (9.5% and 9% vs 8.7%, respectively), upper respiratory tract infection (4.4% and 3.9% vs 3.5%, respectively), injection-site reaction (10% and 7.7% vs 1%, respectively), arthralgia (4.4% and 4.3% vs 2.9%, respectively), and headache (2.5% and 1.9% vs 2.1%, respectively). Infections, including candidal, oral, vulvovaginal, and cutaneous, occurred in 27% of the 2-week dosing group and 27.4% of the 4-week dosing group compared to 22.9% of the placebo group during weeks 0 to 12, with candidal infections in particular occurring more frequently in the active treatment groups and exhibiting dose dependence. Other AEs of special interest that occurred among all ixekizumab-treated participants (n=3736) from weeks 0 to 60 were cardiovascular and cerebrovascular events (22 [0.6%]), inflammatory bowel disease (11 [0.3%]), non–skin cancer malignancy (14 [0.4%]), and nonmelanoma skin cancer (20 [0.5%]). Neutropenia occurred at higher rates in ixekizumab-treated participants (9.3% in the 2-week group and 8.6% in the 4-week group) compared to placebo (3.3%) and occurred in 11.5% of all ixekizumab participants over 60 weeks.7
Brodalumab
Brodalumab (Valeant Pharmaceuticals International, Inc) is a human monoclonal antibody targeting the IL-17A receptor currently under review for FDA approval after undergoing phase 3 trials. The first of these trials, AMAGINE-1, showed efficacy of subcutaneous brodalumab (140 or 210 mg administered every 2 weeks with an extra dose at week 1) compared to placebo in 661 participants.9 At week 12, 60%, 83%, and 3%, respectively, achieved PASI 75; 43%, 70%, and 1%, respectively, achieved PASI 90; and 23%, 42%, and 1%, respectively, achieved PASI 100 (P<.001 for all respective comparisons to placebo). These effects were retained through 52 weeks of treatment. The median time to complete disease clearance in participants reaching PASI 100 was 12 weeks. Conversely, participants who were re-randomized to placebo after week 12 of brodalumab treatment relapsed within weeks to months.9
AMAGINE-2 and AMAGINE-3 further demonstrated the efficacy of brodalumab (140 or 210 mg every 2 weeks with extra dose at week 1) compared to ustekinumab (45 or 90 mg weight-based standard dosing) and placebo in 1831 participants, respectively.10 In AMAGINE-2, 49% of participants in the 140-mg group (P<.001 vs placebo), 70% in the 210-mg group (P<.001 vs placebo), 47% in the ustekinumab group, and 3% in the placebo group achieved PASI 90 at week 12. Similarly, in AMAGINE-3, 52% of participants in the 140-mg group (P<.001), 69% in the 210-mg group (P<.001), 48% in the ustekinumab group, and 2% in the placebo group achieved PASI 90. Impressively, complete clearance (PASI 100) at week 12 occurred in 26% of the 140-mg group (P<.001 vs placebo), 44% of the 210-mg group (P<.001 vs placebo), and 22% of the ustekinumab group compared to 2% of the placebo group in AMAGINE-2, with similar rates in AMAGINE-3. Brodalumab was significantly superior to ustekinumab at the 210-mg dose by PASI 90 measures (P<.001) in both studies and at the 140-mg dose by PASI 100 measures (P=.007) in AMAGINE-3 only.10
Common AEs were nasopharyngitis, upper respiratory tract infection, headache, and arthralgia, all occurring at grossly similar rates (49%–60%) across all experimental groups in AMAGINE-1, AMAGINE-2, and AMAGINE-3 during the first 12-week treatment period.9,10 Brodalumab treatment groups had high rates of specific interest AEs compared to ustekinumab and placebo groups, including neutropenia (0.8%, 1.1%, 0.3%, and 0%, respectively) and candidal infections (0.8%, 1.3%, 0.3%, and 0.3%, respectively). Induction phase (weeks 0–12) depression rates were concerning, with 6 cases each in AMAGINE-2 (4 [0.7%] in the 140-mg group, 2 [0.3%] in the 210-mg group) and AMAGINE-3 (4 [0.6%] in the 140-mg group, 2 [0.3%] in the 210-mg group). Cases of neutropenia were mild, were not associated with major infection, and were transient or reversible. Depression rates after 52 weeks of treatment were 1.7% (23/1567) of brodalumab participants in AMAGINE-2 and 1.8% (21/1613) in AMAGINE-3. Three participants, all on constant 210-mg dosing through week 52, attempted suicide with 1 completion10; however, because no other IL-17 inhibitors were associated with depression or suicide in other trials, it has been suggested that these cases were incidental and not treatment related.12 An FDA advisory panel recommended approval of brodalumab in July 2016 despite ongoing concerns of depression and suicide.13
Conclusion
The robust investigation into IL-23 and IL-17 inhibitors to treat plaque psoriasis has yielded promising results, including the unprecedented rates of PASI 100 achievement with these new biologics. Risankizumab, ixekizumab, and brodalumab have demonstrated superior efficacy in trials compared to ustekinumab. Tildrakizumab has shown low disease relapse after drug cessation. Ixekizumab and brodalumab have shown high rates of total disease clearance. Thus far, safety findings for these pipeline biologics have been consistent with those of ustekinumab. With ixekizumab approved in 2016 and brodalumab under review, new options in biologic therapy will offer patients and clinicians greater choices in treating severe and recalcitrant psoriasis.
