CLINICAL PHARMACOLOGY
Mechanism Of Action
Ixekizumab is a humanized IgG4
monoclonal antibody that selectively binds with the interleukin 17A (IL-17A)
cytokine and inhibits its interaction with the IL-17 receptor. IL-17A is a
naturally occurring cytokine that is involved in normal inflammatory and immune
responses. Ixekizumab inhibits the release of proinflammatory cytokines and
chemokines.
Pharmacodynamics
No formal pharmacodynamic
studies have been conducted with TALTZ.
Pharmacokinetics
The pharmacokinetic (PK)
properties of ixekizumab observed in psoriatic arthritis patients were similar
to the PK properties displayed in plaque psoriasis patients.
Absorption
Following a single subcutaneous dose of 160 mg in subjects
with plaque psoriasis, ixekizumab reached peak mean (±SD) serum concentrations
(Cmax) of 16.2 ±6.6 mcg/mL by approximately 4 days post dose.
Steady-state concentrations were achieved by Week 8
following the 160 mg starting dose and 80 mg every 2 weeks dosing regimen; the
mean ±SD steady-state trough concentration was 9.3 ±5.3 mcg/mL. Steady-state
concentrations were achieved approximately 10 weeks after switching from the 80
mg every 2 weeks dosing regimen to the 80 mg every 4 weeks dosing regimen at
Week 12. The mean ±SD steady-state trough concentration was 3.5 ±2.5 mcg/mL.
In studies of subjects with plaque psoriasis, ixekizumab
bioavailability ranged from 60% to 81% following subcutaneous injection.
Administration of ixekizumab via injection in the thigh achieved a higher
bioavailability relative to that achieved using other injection sites including
the arm and abdomen.
Distribution
The mean (geometric CV%) volume of distribution at
steady-state was 7.11 L (29%) in subjects with plaque psoriasis.
Elimination
The metabolic pathway of ixekizumab has not been
characterized. As a humanized IgG4 monoclonal antibody ixekizumab is expected
to be degraded into small peptides and amino acids via catabolic pathways in
the same manner as endogenous IgG.
The mean systemic clearance was 0.39 L/day (37%) and the
mean (geometric CV%) half-life was 13 days (40%) in subjects with plaque
psoriasis.
Weight
Ixekizumab clearance and volume of distribution increase
as body weight increases.
Dose Linearity
Ixekizumab exhibited dose-proportional pharmacokinetics
in subjects with plaque psoriasis over a dose range from 5 mg (not the
recommended dose) to 160 mg following subcutaneous administration.
Specific Populations
Age: Geriatric Population
Population pharmacokinetic analysis indicated that age
did not significantly influence the clearance of ixekizumab in adult subjects
with plaque psoriasis. Subjects who are 65 years or older had a similar
ixekizumab clearance as compared to subjects less than 65 years old.
Renal Or Hepatic Impairment
No formal trial of the effect of hepatic or renal
impairment on the pharmacokinetics of ixekizumab was conducted.
Drug Interaction Studies
Drug interaction studies have not been conducted with
TALTZ.
Population PK data analyses indicated that the clearance
of ixekizumab was not impacted by concomitant administration of methotrexate,
or by prior exposure to methotrexate or adalimumab in patients with psoriatic
arthritis.
Clinical Studies
Plaque Psoriasis
Three multicenter, randomized, double-blind,
placebo-controlled trials, Trials 1, 2, and 3 (NCT 01474512, NCT 01597245, NCT
01646177), enrolled a total of 3866 subjects 18 years of age and older with
plaque psoriasis who had a minimum body surface area involvement of 10%, a
static Physician Global Assessment (sPGA) score of ≥3 in the overall
assessment (plaque thickness/induration, 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 all three trials, subjects were randomized to either
placebo or TALTZ (80 mg every 2 weeks [Q2W]) for 12 weeks, following a 160 mg
starting dose. In the two active comparator trials (Trials 2 and 3), subjects
were also randomized to receive U.S. approved etanercept 50 mg twice weekly for
12 weeks.
All three trials assessed the changes from baseline to
Week 12 in the two co-primary endpoints: 1) PASI 75, the proportion of subjects
who achieved at least a 75% reduction in the PASI composite score that takes
into consideration both the percentage of body surface area affected and the
nature and severity of psoriatic changes (induration, erythema and scaling)
within the affected regions, and 2) sPGA of “0” (clear) or “1” (minimal), the
proportion of subjects with an sPGA 0 or 1 and at least a 2-point improvement.
Other evaluated outcomes included the proportion of
subjects with an sPGA score of 0 (clear), a reduction of at least 90% in PASI
(PASI 90), a reduction of 100% in PASI (PASI 100), and an improvement of itch
severity as measured by a reduction of at least 4 points on an 11-point itch
Numeric Rating Scale.
Subjects in all treatment groups had a median baseline
PASI score ranging from approximately 17 to 18. Baseline sPGA score was severe
or very severe in 51% of subjects in Trial 1, 50% in Trial 2, and 48% in Trial
3.
Of all subjects, 44% had received prior phototherapy, 49%
had received prior conventional systemic therapy, and 26% had received prior
biologic therapy for the treatment of psoriasis. Of the subjects who had
received prior biologic therapy, 15% had received at least one anti-TNF alpha
agent, and 9% had received an anti-IL 12/IL23. A total of 23% of study subjects
had a history of psoriatic arthritis.
Clinical Response At Week 12
The results of Trials 1, 2, and 3 are presented in Table
2.
Table 2: Efficacy Results at Week 12 in Adults with
Plaque Psoriasis in Trials 1, 2, and 3; NRIa
|
Trial 1 |
Trial 2 |
Trial 3 |
TALTZ 80 mgc Q2W
(N=433) n (%) |
Placebo
(N=431) n (%) |
TALTZ 80 mgc Q2W
(N=351) n (%) |
Placebo
(N=168) n (%) |
TALTZ 80 mgc Q2W
(N=385) n (%) |
Placebo
(N=193) n (%) |
sPGA of “0” (clear) or “1” (minimal)b |
354 (82) |
14 (3) |
292 (83) |
4 (2) |
310 (81) |
13 (7) |
sPGA of “0” (clear) |
160 (37) |
0 |
147 (42) |
1 (1) |
155 (40) |
0 |
PASI 75b |
386 (89) |
17 (4) |
315 (90) |
4 (2) |
336 (87) |
14 (7) |
PASI 90 |
307 (71) |
2 (1) |
248 (71) |
1 (1) |
262 (68) |
6 (3) |
PASI 100 |
153 (35) |
0 |
142 (40) |
1 (1) |
145 (38) |
0 |
a Abbreviations: N = number of patients in the
intent-to-treat population; NRI = Non-Responder Imputation.
b Co-primary endpoints.
cAt Week 0, subjects received 160 mg of
TALTZ. |
Examination of age, gender,
race, body weight, and previous treatment with a biologic did not identify
differences in response to TALTZ among these subgroups at Week 12.
Subjects treated with TALTZ 80
mg Q2W experienced improvement in itch severity when compared to placebo at
Week 12.
An integrated analysis of the
U.S. sites in the two active comparator studies using U.S. approved etanercept,
TALTZ demonstrated superiority to U.S. approved etanercept (50 mg twice weekly)
on sPGA and PASI scores during the 12 week treatment period. The respective
response rates for TALTZ 80 mg Q2W and U.S. approved etanercept 50 mg twice
weekly were: sPGA of 0 or 1 (73% and 27%); PASI 75 (87% and 41%); sPGA of 0
(34% and 5%); PASI 90 (64% and 18%), and PASI 100 (34% and 4%).
Maintenance And Durability Of Response
To evaluate the maintenance and
durability of response, subjects originally randomized to TALTZ and who were
responders at Week 12 (i.e., sPGA of 0 or 1) in Trial 1 and Trial 2 were
re-randomized to an additional 48 weeks of either a maintenance dose of TALTZ
80 mg Q4W (every 4 weeks) or placebo. Non-responders (sPGA >1) at Week 12
and subjects who relapsed (sPGA ≥3) during the maintenance period were
placed on TALTZ 80 mg Q4W.
For responders at Week 12, the
percentage of subjects who maintained this response (sPGA 0 or 1) at Week 60
(48 weeks following re-randomization) in the integrated trials (Trial 1 and
Trial 2) was higher for subjects treated with TALTZ 80 mg Q4W (75%) compared to
those treated with placebo (7%).
For responders at Week 12 who
were re-randomized to treatment withdrawal (i.e., placebo), the median time to
relapse (sPGA ≥3) was 164 days in the integrated trials. Among these
subjects, 66% regained a response of at least 0 or 1 on the sPGA within 12
weeks of restarting treatment with TALTZ 80 mg Q4W.
Psoriasis Involving The Genital
Area
A randomized, double-blind, placebo-controlled trial
(Trial 4) was conducted in 149 adult subjects with plaque psoriasis who had a
minimum body surface area (BSA) involvement of 1%, a sPGA score of ≥3
(moderate psoriasis), a sPGA of Genitalia score of ≥3 (moderate psoriasis
involving the genital area), who failed to respond to or were intolerant of at
least one topical therapy used for treatment of psoriasis affecting the genital
area, and who were candidates for phototherapy and/or systemic therapy.
Subjects had a median baseline PASI score of
approximately 12. Baseline BSA involvement was at least 10% for approximately
60% of the enrolled subjects. Baseline sPGA of Genitalia score was severe or
very severe in approximately 42% of the subjects; baseline sPGA score was severe
or very severe in approximately 47% of the subjects.
Subjects randomized to TALTZ received an initial dose of
160 mg followed by 80 mg every 2 weeks for 12 weeks. The trial evaluated the
primary endpoint of the proportion of subjects who achieved a “0” (clear) or
“1” (minimal) response at Week 12 on sPGA of Genitalia. Other evaluated
outcomes at Week 12 included the proportion of subjects who achieved a sPGA
score of “0” (clear) or “1” (minimal), improvement of genital itch severity as
measured by a reduction of at least 4 points in the 11-point Genital Psoriasis
Symptoms Scale (GPSS) score Itch numeric rating scale (NRS), and the
patient-perceived impact of psoriasis affecting the genital area on limiting
frequency of sexual activity (intercourse or other activities) as measured by
the Genital Psoriasis Sexual Frequency Questionnaire (GenPs-SFQ) Item 2 (In the
past week how often did your genital psoriasis limit the frequency of your
sexual activity?). SFQ Item 2 score ranges from 0 to 4 (0=never, 1=rarely,
2=sometimes, 3=often, 4=always); where higher scores indicate greater
limitations on the frequency of sexual activity in the past week.
The results of Trial 4 are presented in Table 3.
Table 3: Efficacy Results at Week 12 in Adults with
Genital Psoriasis in Trial 4; NRIa
Endpoints |
TALTZ 80 mg Q2Wb
n (%) |
Placebo
n (%) |
Number of subjects randomized |
N=75 |
N=74 |
sPGA of Genitalia “0” (clear) or “1” (minimal) |
55 (73%) |
6 (8%) |
sPGA “0” (clear) or “1” (minimal) |
55 (73%) |
2 (3%) |
Number of subjects with baseline GPSSa Itch NRS Score ≥4 |
N=56 |
N=51 |
GPSS Genital Itch (≥4 point improvement) |
31 (55%) |
3 (6%) |
Number of subjects with baseline GenPs-SFQa Item 2 Score ≥2 |
N=37 |
N=42 |
GenPs-SFQ Item 2 score “0” (never) or “1” (rarely) |
29 (78%) |
9 (21%) |
a Abbreviations: NRI = Non-Responder
Imputation; GPSS = Genital Psoriasis Symptoms Scale; GenPs-SFQ = Genital Psoriasis
Sexual Frequency Questionnaire.
b At Week 0, subjects received 160 mg of TALTZ, followed by 80 mg
every 2 weeks for 12 weeks. |
Psoriatic Arthritis
The safety and efficacy of
TALTZ were assessed in 679 patients, in 2 randomized, double-blind,
placebo-controlled studies (PsA1 and PsA2) in adult patients, age 18 years and
older with active psoriatic arthritis (at least 3 swollen and at least 3 tender
joints) despite non-steroidal anti-inflammatory drug (NSAID), corticosteroid or
disease modifying anti-rheumatic drug (DMARD) therapy. Patients in these
studies had a diagnosis of PsA for at least 6 months across both studies. At
baseline, 60% and 23% of the patients had enthesitis and dactylitis,
respectively. In PsA2, all patients discontinued previous treatment with
anti-TNFα agents due to either inadequate response or intolerance. In
addition, approximately 47% of patients from both studies had concomitant
methotrexate (MTX) use.
PsA1 Study (NCT 01695239)
evaluated 417 biologic-naive patients, who were treated with either TALTZ 160
mg at Week 0 followed by 80 mg every 2 weeks (Q2W) or 4 weeks (Q4W), adalimumab
40 mg every 2 weeks, or placebo. PsA2 Study (NCT 02349295) evaluated 363
anti-TNFα experienced patients, who were treated with TALTZ 160 mg at Week
0 followed by 80 mg every 2 or 4 weeks, or placebo. Patients receiving placebo
were re-randomized to receive TALTZ (80 mg every 2 or 4 weeks) at Week 16 or
Week 24 based on responder status. The primary endpoint was the percentage of
patients achieving an ACR20 response at Week 24.
Clinical Response
In both studies, patients
treated with TALTZ 80 mg Q2W or 80 mg Q4W demonstrated a greater clinical
response including ACR20, ACR50, and ACR70 compared to placebo at Week 24
(Table 4). In PsA2, responses were seen regardless of prior anti-TNFα
exposure.
Table 4: Responsesa at Week 12 and 24; NRIb
|
PsA1 - anti-TNFα naive |
PsA2 - anti-TNFα - experienced |
TALTZ 80 mgc Q4W
(N=107) |
Placebo
(N=106) |
Difference from placebo (95% CI) |
TALTZ 80 mgc Q4W
(N=122) |
Placebo
(N=118) |
Difference from placebo (95% CI) |
ACR20 response |
Week 12 (%) |
57 |
31 |
26
(13, 39) |
50 |
22 |
28
(16, 40) |
Week 24 (%) |
58 |
30 |
28
(15, 41) |
53 |
20 |
34
(22, 45) |
ACR50 response |
Week 12 (%) |
34 |
5 |
29
(19, 39) |
31 |
3 |
28
(19, 37) |
Week 24 (%) |
40 |
15 |
25
(14, 37) |
35 |
5 |
30
(21, 40) |
ACR70 response |
Week 12 (%) |
15 |
0 |
15
(8, 22) |
15 |
2 |
13
(6, 20) |
Week 24 (%) |
23 |
6 |
18
(9, 27) |
22 |
0 |
22
(15, 30) |
a Patients who met escape criteria (less than
20% improvement in tender and swollen joint counts) at Week 16 or had missing
data at Week 24 were considered non-responders at Week 24.
b Abbreviations: N = number of patients in the intent-to-treat
population; NRI = Non-Responder Imputation.
cAt Week 0, patients received 160 mg of TALTZ. |
The percentage of patients
achieving ACR20 response by visit is shown in Figure 1.
Figure 1: Percent of Patients Achieving ACR20 Responsea
in PsA1 Through Week 24
a Patients who met escape criteria (less than
20% improvement in tender and swollen joint counts) at Week 16 or had missing
data at Week 24 were considered non-responders at Week 24.
The improvements in the
components of the ACR response criteria are shown in Table 5.
Table 5: Efficacy results in
ACR Components at Week 12 and 16
|
PsA1 |
PsA2 |
TALTZ 80 mga Q4W
(N=107) |
Placebo
(N=106) |
TALTZ 80 mga Q4W
(N=122) |
Placebo
(N=118) |
No. of Swollen Joints |
Baseline |
11.4 |
10.6 |
13.1 |
10.3 |
Mean Change at Week 12 |
-6.2 |
-3.2 |
-5.8 |
-2.6 |
Mean Change at Week 16 |
-6.2 |
-3.0 |
-7.4 |
-2.6 |
No. of Tender Joints |
Baseline |
20.5 |
19.2 |
22.0 |
23.0 |
Mean Change at Week 12 |
-10.3 |
-3.5 |
-9.4 |
-5.4 |
Mean Change at Week 16 |
-9.7 |
-4.0 |
-10.1 |
-3.0 |
Patient’s Assessment of Pain |
Baseline |
60.1 |
58.5 |
63.9 |
63.9 |
Mean Change at Week 12 |
-26.6 |
-9.1 |
-29.8 |
-11.9 |
Mean Change at Week 16 |
-26.1 |
-10.6 |
-30.1 |
-12.3 |
Patient Global Assessment |
Baseline |
62.7 |
61.1 |
66.4 |
64.1 |
Mean Change at Week 12 |
-29.7 |
-11.1 |
-34.5 |
-10.7 |
Mean Change at Week 16 |
-30.4 |
-13.2 |
-35.3 |
-15.7 |
Physician Global Assessment |
Baseline |
57.6 |
55.9 |
60.3 |
58.9 |
Mean Change at Week 12 |
-34.0 |
-16.6 |
-34.4 |
-15.9 |
Mean Change at Week 16 |
-35.5 |
-16.5 |
-32.9 |
-9.7 |
Disability Index (HAQ-DI)b |
Baseline |
1.2 |
1.2 |
1.2 |
1.2 |
Mean Change at Week 12 |
-0.4 |
-0.1 |
-0.4 |
-0.1 |
Mean Change at Week 16 |
-0.4 |
-0.1 |
-0.5 |
-0.1 |
CRP (mg/L) |
Baseline |
12.8 |
15.1 |
17.0 |
12.1 |
Mean Change at Week 12 |
-8.8 |
-3.2 |
-11.4 |
-4.3 |
Mean Change at Week 16 |
-9.3 |
-3.2 |
-11.2 |
-5.9 |
a At Week 0, subjects received 160 mg of
TALTZ.
b Disability Index of the Health Assessment Questionnaire; 0 = best,
3 = worst, measures the patient’s ability to perform the
following: dress/groom, arise, eat, walk, reach, grip, maintain hygiene, and maintain
daily activity. |
Treatment with TALTZ resulted
in improvement in dactylitis and enthesitis in patients with pre-existing
dactylitis or enthesitis.
Treatment with TALTZ 80 mg Q4W
resulted in an improvement in psoriatic skin lesions in patients with PsA.
Radiographic Response
Radiographic changes were
assessed in PsA1. Inhibition of progression of structural damage was assessed
radiographically and expressed as the change in modified total Sharp score
(mTSS) at Week 16, compared to baseline. The total Sharp score was modified for
psoriatic arthritis by addition of hand distal interphalangeal (DIP) joints.
TALTZ 80 mg Q4W inhibited the progression
of structural joint damage (mTSS) compared to placebo at Week 16. The adjusted
mean change from baseline in the mTSS was 0.13 for TALTZ 80 mg Q4W and 0.36 for
placebo (difference in means TALTZ minus placebo: -0.23, 95% CI: (-0.42,
-0.04)).
Physical Function
TALTZ treated patients showed
improvement in physical function compared to patients treated with placebo as
assessed by the Health Assessment Questionnaire-Disability Index (HAQ-DI) at
Week 12 and 24. In both studies, the proportion of HAQ-DI responders
(≥0.35 improvement in HAQ-DI score) was greater in the TALTZ 80 mg Q4W
groups compared to placebo at week 12 and 24.
Other Health-Related Outcomes
General health status was
assessed by the Short Form health survey (SF-36). At Week 12 in PsA1 and PsA2,
patients treated with TALTZ showed greater improvement from baseline in the
SF-36 physical component summary (PCS) score compared to patients treated with
placebo but this improvement was not consistent in both studies for the SF-36
mental component summary (MCS) score. At Week 12, there was consistent evidence
of effect in the physical-functioning, role-physical, bodily-pain, and general
health domains but not in the social-functioning, role-emotional, vitality, and
mental health domains.