CLINICAL PHARMACOLOGY
Mechanism Of Action
Canakinumab is a human monoclonal anti-human IL-1β
antibody of the IgG1/κ isotype. Canakinumab binds to human IL1β and
neutralizes its activity by blocking its interaction with IL-1 receptors, but
it does not bind IL-1α or IL-1 receptor antagonist (IL-1ra).
CAPS refer to rare genetic syndromes generally caused by
mutations in the NLRP-3 [nucleotide-binding domain, leucine rich family (NLR),
pyrin domain containing 3] gene (also known as Cold-Induced Autoinflammatory
Syndrome-1 [CIAS1]). CAPS disorders are inherited in an autosomal dominant
pattern with male and female offspring equally affected. Features common to all
disorders include fever, urticaria-like rash, arthralgia, myalgia, fatigue, and
conjunctivitis.
The NLRP-3 gene encodes the protein cryopyrin, an
important component of the inflammasome. Cryopyrin regulates the protease
caspase-1 and controls the activation of IL-1β. Mutations in NLRP-3 result
in an overactive inflammasome resulting in excessive release of activated
IL-1β that drives inflammation. SJIA is a severe autoinflammatory disease,
driven by innate immunity by means of proinflammatory cytokines such as
IL-1β.
Pharmacodynamics
C-reactive protein and Serum Amyloid A (SAA) are
indicators of inflammatory disease activity that are elevated in patients with CAPS.
Elevated SAA has been associated with the development of systemic amyloidosis
in patients with CAPS. Following ILARIS treatment, CRP and SAA levels normalize
within 8 days. In SJIA the median percent reduction in CRP from baseline to Day
15 was 91%. Improvement in pharmacodynamic markers may not be representative of
clinical response.
Pharmacokinetics
Absorption
The peak serum canakinumab concentration (Cmax) of 16 ±
3.5 mcg/mL occurred approximately 7 days after subcutaneous administration of a
single, 150 mg dose subcutaneously to adult CAPS patients. The mean terminal
half-life was 26 days. The absolute bioavailability of subcutaneous canakinumab
was estimated to be 66%. Exposure parameters (such as AUC and Cmax) increased
in proportion to dose over the dose range of 0.30 to 10 mg/kg given as
intravenous infusion or from 150 to 300 mg as subcutaneous injection.
Distribution
Canakinumab binds to serum IL-1β. Canakinumab volume
of distribution (Vss) varied according to body weight and was estimated to be
6.01 liters in a typical CAPS patient weighing 70 kg, 3.2 liters in a SJIA
patient weighing 33 kg, and 6.34 liters for a Periodic Fever Syndrome (TRAPS,
HIDS/MKD, FMF) patient weighing 70 kg. The expected accumulation ratio was
1.3-fold for CAPS patients and 1.6-fold for SJIA patients following 6 months of
subcutaneous dosing of 150 mg ILARIS every 8 weeks and 4 mg/kg every 4 weeks,
respectively.
Elimination
Clearance (CL) of canakinumab varied according to body
weight and was estimated to be 0.174 L/day in a typical CAPS patient weighing
70 kg, 0.11 L/day in a SJIA patient weighing 33 kg, and 0.17 L/day in a
Periodic Fever Syndrome (TRAPS, HIDS/MKD, FMF) patient weighing 70 kg. There
was no indication of accelerated clearance or time-dependent change in the
pharmacokinetic properties of canakinumab following repeated administration. No
gender-or age-related pharmacokinetic differences were observed after correction
for body weight.
Pediatrics
Pharmacokinetic properties are similar in Periodic Fever
Syndromes (CAPS, TRAPS, HIDS/MKD, FMF) and SJIA pediatric populations. In
patients less than 2 years of age (n=7), the exposure of canakinumab were
comparable to older age groups with the same weight based dose.
In CAPS patients, peak concentrations of canakinumab
occurred between 2 to 7 days following single subcutaneous administration of
ILARIS 150 mg or 2 mg/kg in pediatric patients. The terminal half-life ranged
from 22.9 to 25.7 days, similar to the pharmacokinetic properties observed in
adults.
In SJIA, exposure parameters (such as AUC and Cmax) were
comparable across age groups from 2 years of age and above following
subcutaneous administration of canakinumab 4 mg/kg every 4 weeks.
In TRAPS, HIDS/MKD, and FMF exposure parameter trough
concentrations were comparable across age groups from 2 to less than 20 years
following subcutaneous administration of canakinumab 2 mg/kg every 4 weeks.
Clinical Studies
Treatment Of CAPS
The efficacy and safety of ILARIS for the treatment of
CAPS was demonstrated in CAPS Study 1, a 3-part trial in patients 9 to 74 years
of age with the MWS phenotype of CAPS. Throughout the trial, patients weighing
more than 40 kg received ILARIS 150 mg and patients weighing 15 to 40 kg
received 2 mg/kg. Part 1 was an 8-week open-label, single-dose period where all
patients received ILARIS. Patients who achieved a complete clinical response
and did not relapse by Week 8 were randomized into Part 2, a 24-week
randomized, double-blind, placebo-controlled withdrawal period. Patients who
completed Part 2 or experienced a disease flare entered Part 3, a 16-week
open-label active treatment phase. A complete response was defined as ratings
of minimal or better for physician's assessment of disease activity (PHY) and
assessment of skin disease (SKD) and had serum levels of C-Reactive Protein
(CRP) and Serum Amyloid A (SAA) less than 10 mg/L. A disease flare was defined
as a CRP and/or SAA values greater than 30 mg/L and either a score of mild or
worse for PHY or a score of minimal or worse for PHY and SKD.
In Part 1, a complete clinical response was observed in
71% of patients one week following initiation of treatment and in 97% of
patients by Week 8 (see Table 3 and Figure 1). In the randomized withdrawal
period, a total of 81% of the patients randomized to placebo flared as compared
to none (0%) of the patients randomized to ILARIS. The 95% confidence interval
for treatment difference in the proportion of flares was 53% to 96%. At the end
of Part 2, all 15 patients treated with ILARIS had absent or minimal disease
activity and skin disease (see Table 3).
In a second trial, patients 4 to 74 years of age with
both MWS and FCAS phenotypes of CAPS were treated in an open-label manner.
Treatment with ILARIS resulted in clinically significant improvement of signs
and symptoms and in normalization of high CRP and SAA in a majority of patients
within 1 week.
Table 3: Physician's Global Assessment of Auto
Inflammatory Disease Activity and Assessment of Skin Disease: Frequency Table
and Treatment Comparison in Part 2 (Using LOCF, ITT Population)
|
ILARIS
N=15 |
Placebo
N=16 |
Baseline |
Start of Part 2 (Week 8) |
End of Part 2 |
Start of Part 2 (Week 8) |
End of Part 2 |
Physician's Global Assessment of Auto Inflammatory Disease Activity - n (%) |
Absent |
0/31 (0) |
9/15 (60) |
8/15 (53) |
8/16 (50) |
0/16 (0) |
Minimal |
1/31 (3) |
4/15 (27) |
7/15 (47) |
8/16 (50) |
4/16 (25) |
Mild |
7/31 (23) |
2/15 (13) |
0/15 (0) |
0/16 (0) |
8/16 (50) |
Moderate |
19/31 (61) |
0/15 (0) |
0/15 (0) |
0/16 (0) |
4/16 (25) |
Severe |
4/31 (13) |
0/15 (0) |
0/15 (0) |
0/16 (0) |
0/16 (0) |
Assessment of Skin Disease - n (%) |
Absent |
3/31 (10) |
13/15 (87) |
14/15 (93) |
13/16 (81) |
5/16 (31) |
Minimal |
6/31 (19) |
2/15 (13) |
1/15 (7) |
3/16 (19) |
3/16 (19) |
Mild |
9/31 (29) |
0/15 (0) |
0/15 (0) |
0/16 (0) |
5/16 (31) |
Moderate |
12/31 (39) |
0/15 (0) |
0/15 (0) |
0/16 (0) |
3/16 (19) |
Severe |
1/32 (3) |
0/15 (0) |
0/15 (0) |
0/16 (0) |
0/16 (0) |
Markers of inflammation CRP and SAA normalized within 8
days of treatment in the majority of patients. Normal mean CRP (Figure 1) and
SAA values were sustained throughout CAPS Study 1 in patients continuously
treated with canakinumab. After withdrawal of canakinumab in Part 2 CRP (Figure
1) and SAA values again returned to abnormal values and subsequently normalized
after reintroduction of canakinumab in Part 3. The pattern of normalization of
CRP and SAA was similar.
Figure 1: Mean C-Reactive Protein Levels at the End of
Parts 1, 2 and 3 of CAPS Study 1
Treatment Of Periodic Fever Syndromes: TRAPS, HIDS/MKD, And
FMF
The efficacy and safety of ILARIS for the treatment of
TRAPS, HIDS/MKD, and FMF was demonstrated in a 4-Part study (TRAPS, HIDS/MKD,
and FMF Study 1) consisting of three separate, disease cohorts (TRAPS, HIDS/MKD
and FMF) which enrolled 185 patients aged greater than 28 days. Patients in
each cohort entered a 12-week screening period (Part 1) during which they were
evaluated for the onset of disease flare. Patients aged 2 to 76 years were then
randomized at flare onset into a 16-week double-blind, placebo-controlled
treatment period (Part 2) where they received either 150 mg ILARIS (2 mg/kg for
patients weighing less than or equal to 40 kg) subcutaneously or placebo every
4 weeks. Part 3 and Part 4 of this study are ongoing.
Randomized patients in Part 2 treated with ILARIS whose
disease flare did not resolve, or who had persistent disease activity from Day
8 up to Day 14 (Physician's Global Assessment [PGA] greater than or equal to 2
or C-reactive Protein [CRP] greater than 10 mg/L and no reduction by at least
40% from baseline) received an additional dose of 150 mg (or 2 mg/kg for
patients weighing less than or equal to 40 kg). Patients treated with ILARIS
whose disease flare did not resolve, or who had persistent disease activity
from Day 15 up to Day 28 (PGA greater than or equal to 2 or CRP greater than 10
mg/L and no reduction by at least 70% from baseline), also received an
additional dose of 150 mg (or 2 mg/kg for patients weighing less than or equal
to 40 kg). On or after Day 29, patients treated with ILARIS in Part 2 with PGA
greater than or equal to 2 and CRP greater than or equal to 30 mg/L were also
up-titrated. All up-titrated patients remained at the increased dose of 300 mg
(or 4 mg/kg for patients weighing less than or equal to 40 kg) every 4 weeks.
The primary efficacy endpoint of the randomized, 16-week
treatment period (Part 2) was the proportion of complete responders within each
cohort as defined by patients who had resolution of their index disease flare
at Day 15 and did not experience a new disease flare during the remainder of
the 16-week treatment period. Resolution of the index disease flare (initial
flare at the time of the randomization) was defined at the Day 15 visit as a
Physician's Global Assessment (PGA) Disease Activity score less than 2
(“minimal or no disease”) and C-reactive Protein (CRP) within normal range
(less than or equal to 10 mg/L) or reduction greater than or equal to 70% from
baseline. The key signs and symptoms assessed in the PGA for each condition
were the following: TRAPS: abdominal pain, skin rash, musculoskeletal pain, eye
manifestations; HIDS/MKD: abdominal pain; lymphadenopathy, aphthous ulcers;
FMF: abdominal pain, skin rash, chest pain, arthralgia/arthritis. A new flare
was defined as a PGA score greater than or equal to 2 (“mild, moderate, or
severe disease”) and CRP greater to or equal than 30 mg/L. In the 16-week
treatment period (Part 2), patients who needed dose escalation, who crossed
over from placebo to ILARIS, or who discontinued from the study due to any
reason prior to Week 16 were considered as non-responders.
Patients randomized in the TRAPS cohort (N=46) were aged
2 to 76 years (median age at baseline: 15.5 years) and of this population,
57.8% did not have fever at baseline. Randomized TRAPS patients were those with
chronic or recurrent disease activity defined as 6 flares per year (median
number of flares per year: 9.0) with PGA greater than or equal to 2 and CRP
greater than 10 mg/L (median CRP at baseline: 112.5 mg/L). In the TRAPS cohort,
11/22 (50.0%) patients randomized to ILARIS 150 mg every 4 weeks received
up-titration to 300 mg every 4 weeks during the 16-week treatment period, while
21/24 (87.5%) patients randomized to placebo crossed over to ILARIS.
Patients randomized in the HIDS/MKD cohort (N=72) were
aged 2 to 47 years (median age at baseline: 11.0 years) and of this population,
41.7% did not have fever at baseline. Randomized HIDS/MKD patients were those
with a confirmed diagnosis of HIDS according to known genetic MVK/enzymatic
(MKD) findings, and documented prior history of greater than or equal to 3
febrile acute flares within a 6 month period (median number of flares per year:
12.0) when not receiving prophylactic treatment and during the study, had
active HIDS flares defined as PGA greater than or equal to 2 and CRP greater
than 10 mg/L (median CRP at baseline: 113.5 mg/L). In the HIDS/MKD cohort,
19/37 (51.4%) patients randomized to ILARIS 150 mg every 4 weeks received
up-titration to 300 mg every 4 weeks during the 16-week treatment period, while
31/35 (88.6%) patients randomized to placebo crossed over to ILARIS.
Patients randomized in the FMF cohort (N=63) were aged 2
to 69 years (median age at baseline: 18.0 years) and of this population, 76.2%
did not have fever at baseline. Randomized FMF patients were those with
documented active disease despite colchicine therapy or documented intolerance
to effective doses of colchicine. Patients had active disease defined as at
least one flare per month (median number of flares per year: 18.0) and CRP
greater than 10 mg/L (median CRP at baseline: 94.0 mg/L). Patients were allowed
to continue their stable dose of colchicine without change. Of the 63
randomized patients, 55 (87.3%) were taking concomitant colchicine therapy on
or after randomization. In the FMF cohort, 10/31 (32.3%) patients randomized to
ILARIS 150 mg every 4 weeks received up-titration to 300 mg every 4 weeks
during the 16-week treatment period, while 27/32 (84.4%) patients randomized to
placebo crossed over to ILARIS.
For the primary efficacy endpoint, ILARIS was superior to
placebo in the proportion of TRAPS, HIDS/MKD, and FMF patients who resolved
their index disease flare at Day 15 and had no new flare over the 16 weeks of
treatment from the time of the resolution of the index flare (see Table 4).
Table 4: Proportion of TRAPS, HIDS/MKD, and FMF
Patients Who Achieved a Complete Response (Resolution of Index Flare by Day 15
and Maintained Through Week 16)
Cohort |
ILARIS 150 mg |
Placebo |
Treatment comparison |
n/N (%) |
n/N (%) |
Odds Ratio 95% CI |
p-value |
TRAPS |
10/22 (45.5%) |
2/24 (8.3%) |
9.17 (1.51, 94.61) |
0.005 |
HIDS/MKD |
13/37 (35.1%) |
2/35 (5.7%) |
8.94 (1.72, 86.41) |
0.002 |
FMF |
19/31 (61.3%) |
2/32 (6.3%) |
23.75 (4.38, 227.53) |
< 0.0001 |
n=number of patients with the response; N=number of
patients evaluated for that response in each cohort; CI: Confidence Interval. |
At Day 15, a higher proportion of ILARIS-treated patients
compared to placebo-treated patients experienced resolution of their index
flare in all disease cohorts (see Table 5).
Table 5: Resolution of Index Flare (Full Analysis Set)
Variable |
Resolution at Day 15* |
ILARIS 150 mg every 4 weeks
n/N (%) |
Placebo
n/N (%) |
TRAPS |
14/22 (63.6%) |
5/24 (20.8%) |
HIDS/MKD |
24/37 (64.9%) |
13/35 (37.1%) |
FMF |
25/31 (80.7%) |
10/32 (31.3%) |
n=number of patients with the response; N=number of
patients evaluated for that response in each cohort
*Resolution of index disease flare (PGA less than 2 and CRP less than or equal
to 10 mg/L or reduction greater than or equal to 70% from baseline) |
There was supportive evidence of efficacy for ILARIS at
Day 15, as compared to placebo, for the components of the primary endpoint, CRP
and PGA Disease Activity score, as well as for the secondary endpoint Serum
Amyloid A (SAA) level (see Table 6).
Table 6: Proportion of TRAPS, HIDS/MKD, and FMF
Patients Achieving PGA Less Than 2, CRP Less Than or Equal To 10 mg/L and SAA
Less Than or Equal To 10 mg/L at Day 15*
Variable |
TRAPS |
HIDS/MKD |
FMF |
ILARIS 150 mg
n/N (%) |
Placebo
n/N (%) |
Treatment comparison Odds Ratio 95% CI |
ILARIS 150 mg
n/N (%) |
Placebo
n/N (%) |
Treatment comparison Odds Ratio 95% CI |
ILARIS 150 mgn/N (%) |
Placebo
n/N (%) |
Treatment comparison Odds Ratio 95% CI |
PGA Less Than 2 |
14/22 (63.6%) |
8/24 (33.3%) |
4.06 (1.12, 14.72) |
26/37 (70.3%) |
14/35 (40.0%) |
3.42 (1.28, 9.16) |
27/31 (87.1%) |
13/32 (40.6%) |
10.07 (2.78, 36.49) |
CRP Less Than or equal to 10 mg/L |
13/22 (59.1%) |
8/24 (33.3%) |
3.88 (1.05, 14.26) |
25/37 (67.6%) |
9/35 (25.7%) |
6.05 (2.14, 17.12) |
28/31 (90.3%) |
9/32 (28.1%) |
22.51 (5.41, 93.62) |
SAA |
7/22 |
2/24 |
5.06 (0.92, |
10/37 |
4/35 |
2.94 (0.82, |
13/31 |
5/32 |
3.73 (1.11, |
Less Than or Equal to 10 mg/L |
(31.8%) |
(8.3%) |
27.91) |
(27.0%) |
(11.4%) |
10.53) |
(41.9%) |
(15.6%) |
12.52) |
n=number of patients with the response; N=number of patients
evaluated for that response in each cohort; CI: Confidence Interval.
*Ilaris-treated patients who up-titrated or discontinued prior to Day 15 and
placebo-treated patients who switched over to Ilaris or discontinued prior to
Day 15 were classified as non-responders. |
Treatment Of SJIA
The efficacy of ILARIS for the treatment of active SJIA
was assessed in 2 phase 3 studies (SJIA Study 1 and SJIA Study 2). Patients
enrolled were aged 2 to less than 20 years (mean age at baseline: 8.5 years)
with a confirmed diagnosis of SJIA at least 2 months before enrollment (mean
disease duration at baseline: 3.5 years). Patients had active disease defined
as greater than or equal to 2 joints with active arthritis (mean number of
active joints at baseline: 15.4), documented spiking, intermittent fever (body
temperature greater than 38°C) for at least 1 day within 1 week before study
drug administration, and CRP greater than 30 mg/L (normal range less than 10
mg/L) (mean CRP at baseline: 200.5 mg/L). Patients were allowed to continue
their stable dose of methotrexate, corticosteroids, and/or NSAIDs without
change, except for tapering of the corticosteroid dose as per study design in
SJIA Study 2 (see below).
SJIA Study 1 was a randomized, double-blind,
placebo-controlled, single-dose 4-week study assessing the short-term efficacy
of ILARIS in 84 patients randomized to receive a single subcutaneous dose of 4
mg/kg ILARIS or placebo (43 patients received ILARIS and 41 patients received
placebo). The primary objective of this study was to demonstrate the superiority
of ILARIS versus placebo in the proportion of patients who achieved at least
30% improvement in an adapted pediatric American College of Rheumatology (ACR)
response criterion which included both the pediatric ACR core set (ACR30
response) and absence of fever (temperature less than or equal to 38°C in the
preceding 7 days) at Day 15.
Pediatric ACR responses are defined by achieving levels
of percentage improvement (30%, 50%, and 70%) from baseline in at least 3 of
the 6 core outcome variables, with worsening of greater than or equal to 30% in
no more than one of the remaining variables. Core outcome variables included a
physician global assessment of disease activity, parent or patient global
assessment of well-being, number of joints with active arthritis, number of
joints with limited range of motion, CRP, and functional ability (Childhood
Health Assessment Questionnaire-CHAQ).
Percentages of patients by pediatric ACR response are
presented in Table 7.
Table 7: Pediatric ACR Response at Days 15 and 29
|
Day 15 |
Day 29 |
ILARIS
N=43 |
Placebo
N=41 |
Weighted Difference1 (95% CI)2 |
ILARIS
N=43 |
Placebo
N=41 |
Weighted Difference1 (95% CI)2 |
ACR30 |
84% |
10% |
70% (56%, 84%) |
81% |
10% |
70% (56%, 84%) |
ACR50 |
67% |
5% |
65% (50%, 80%) |
79% |
5% |
76% (63%, 88%) |
ACR70 |
60% |
2% |
64% (49%, 79%) |
67% |
2% |
67% (52%, 81%) |
1Weighted difference is the difference between
the ILARIS and placebo response rates, adjusted for the stratification factors
(number of active joints, previous response to anakinra, and level of oral
corticosteroid use)
2CI: confidence interval for the weighted difference
N: Number of patients |
Results for the components of the pediatric ACR core set
were consistent with the overall ACR response results, for systemic and
arthritic components including the reduction in the total number of active
joints and joints with limited range of motion. Among the patients who returned
for a Day 15 visit, the mean change in patient pain score (0 to 100 mm visual
analogue scale) was -50.0 mm on ILARIS (N=43), as compared to +4.5 mm on
placebo (N=25). The mean change in pain score among ILARIS-treated patients was
consistent through Day 29. All patients treated with ILARIS had no fever at Day
3 compared to 87% of patients treated with placebo.
SJIA Study 2 was a randomized, double-blind,
placebo-controlled, withdrawal study of flare prevention by ILARIS in patients
with active SJIA. Flare was defined by worsening of greater than or equal to
30% in at least 3 of the 6 core Pediatric ACR response variables combined with
improvement of greater than or equal to 30% in no more than 1 of the 6
variables, or reappearance of fever not due to infection for at least 2
consecutive days. The study consisted of 2 major parts. One hundred
seventy-seven patients were enrolled in the study and received 4 mg/kg ILARIS
subcutaneously every 4 weeks in Part I and 100 of these patients continued into
Part II to receive either ILARIS 4 mg/kg or placebo subcutaneously every 4
weeks.
Corticosteroid Dose Tapering
Of the total 128 patients taking corticosteroids who
entered the open-label portion of Study 2, 92 attempted corticosteroid
tapering. Fifty-seven (62%) of the 92 patients who attempted to taper were able
to successfully taper their corticosteroid dose and 42 (46%) discontinued
corticosteroids.
Time to Flare
Part II was a randomized withdrawal design to demonstrate
that the time to flare was longer with ILARIS than with placebo. Follow-up
stopped when 37 events had been observed resulting in patients being followed
for different lengths of time. The probability of experiencing a flare over
time in Part II was statistically lower for the ILARIS treatment group than for
the placebo group (Figure 2). This corresponded to a 64% relative reduction in
the risk of flare for patients in the ILARIS group as compared to those in the
placebo group (hazard ratio of 0.36; 95% CI: 0.17 to 0.75).
Figure 2: Kaplan-Meier Estimates of the Probability to
Stay Flare-Free in Part II of SJIA Study 2 by Treatment
Very few patients were followed for more than 48 weeks