Mechanism of Action
Rituximab binds specifically to the antigen CD20 (human
B-lymphocyte-restricted differentiation antigen, Bp35), a hydrophobic
transmembrane protein with a molecular weight of approximately 35 kD located on
pre-B and mature B lymphocytes. The antigen is expressed on > 90% of B-cell
non-Hodgkin's lymphomas (NHL), but the antigen is not found on
hematopoietic stem cells, pro-B-cells, normal plasma cells or other normal
tissues. CD20 regulates an early step(s) in the activation process for cell
cycle initiation and differentiation, and possibly functions as a calcium ion
channel. CD20 is not shed from the cell surface and does not internalize upon
antibody binding. Free CD20 antigen is not found in the circulation.
B cells are believed to play a role in the pathogenesis of
rheumatoid arthritis (RA) and associated chronic synovitis. In this setting, B
cells may be acting at multiple sites in the autoimmune/inflammatory process,
including through production of rheumatoid factor (RF) and other
autoantibodies, antigen presentation, T-cell activation, and/or proinflammatory cytokine production.
Mechanism of Action: The Fab domain of rituximab binds to the CD20 antigen
on B lymphocytes, and the Fc domain recruits immune effector functions to mediate
B-cell lysis in vitro. Possible mechanisms of cell lysis include complement-dependent
cytotoxicity (CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC).
The antibody has been shown to induce apoptosis in the DHL-4 human B-cell lymphoma
line.
Normal Tissue Cross-reactivity: Rituximab binding was observed on lymphoid
cells in the thymus, the white pulp of the spleen, and a majority of B lymphocytes
in peripheral blood and lymph nodes. Little or no binding was observed in the
non-lymphoid tissues examined.
Pharmacodynamics
In NHL patients, administration of Rituxan resulted in
depletion of circulating and tissue-based B cells. Among 166 patients in Study
1, circulating CD19-positive B cells were depleted within the first three weeks
with sustained depletion for up to 6 to 9 months posttreatment in 83% of
patients. B-cell recovery began at approximately 6 months and median B-cell
levels returned to normal by 12 months following completion of treatment.
There were sustained and statistically significant
reductions in both IgM and IgG serum levels observed from 5 through 11 months
following rituximab administration; 14% of patients had IgM and/or IgG serum
levels below the normal range.
In RA patients, treatment with Rituxan induced depletion of
peripheral B lymphocytes, with the majority of patients demonstrating near
complete depletion (CD19 counts below the lower limit of quantification, 20
cells/μl) within 2 weeks after receiving the first dose of Rituxan. The
majority of patients showed peripheral B-cell depletion for at least 6 months.
A small proportion of patients (~4%) had prolonged peripheral B-cell depletion
lasting more than 3 years after a single course of treatment.
Total serum immunoglobulin levels, IgM, IgG, and IgA were
reduced at 6 months with the greatest change observed in IgM. At Week 24 of the
first course of Rituxan treatment, small proportions of patients experienced
decreases in IgM (10%), IgG (2.8%), and IgA (0.8%) levels below the lower limit
of normal. In the experience with Rituxan in RA patients during repeated
rituximab treatment, 23.3%, 5.5%, and 0.5% of the patients experienced
decreases in IgM, IgG, and IgA concentrations below the LLN at any time after
receiving rituximab, respectively. The clinical consequences of decreases in
immunoglobulin levels in RA patients treated with Rituxan are unclear.
Treatment with Rituxan in patients with RA was associated
with reduction of certain biologic markers of inflammation such as
interleukin-6 (IL-6), C-reactive protein (CRP), serum amyloid protein (SAA),
S100 A8/S100 A9 heterodimer complex (S100 A8/9), anti-citrullinated peptide
(anti-CCP), and RF.
Pharmacokinetics
Pharmacokinetics were characterized in 203 NHL patients
receiving 375 mg/m² rituximab weekly by IV infusion for 4 doses. The mean Cmax
increased with each successive infusion and was 486 mcg/mL (range, 78-997
mcg/mL) following the fourth infusion. Peak and trough serum levels of
rituximab were inversely correlated with pretreatment circulating CD19-positive
B cells and tumor burden. Rituximab was detectable in the serum of patients 3
to 6 months after completion of treatment.
The pharmacokinetic profile of rituximab when administered
as 6 infusions of 375 mg/m² in combination with 6 cycles of CHOP chemotherapy
was similar to that seen with rituximab alone.
Based on a population pharmacokinetic analysis of data from
298 NHL patients who received rituximab once weekly or once every three weeks,
the estimated median terminal elimination half-life was 22 days (range, 6.1 to
52 days). Patients with higher CD19-positive cell counts or larger measurable
tumor lesions at pretreatment had a higher clearance. However, dose adjustment
for pretreatment CD19 count or size of tumor lesion is not necessary. Age and
gender had no effect on the pharmacokinetics of rituximab.
Following administration of 2 doses of rituximab in patients
with RA, the mean (± S.D.; % CV) concentrations after the first infusion
(Cmax first) and second infusion (Cmax second) were 157 (± 46; 29%) and 183 (±
55; 30%) mcg/mL, and 318 (± 86; 27%) and 381 (± 98; 26%) mcg/mL for the 2 ×
500 mg and 2 × 1000 mg doses, respectively.
Based on a population pharmacokinetic analysis of data from
2005 RA patients who received rituximab, the estimated clearance of Rituxan was
0.335 L/day; volume of distribution was 3.1 L and mean terminal elimination half-life
was 18.0 days (range, 5.17 to 77.5days). Age, weight and gender had no effect
on the pharmacokinetics of rituximab in RA patients.
The pharmacokinetics of rituximab have not been studied in
children and adolescents. No formal studies were conducted to examine the
effects of either renal or hepatic impairment on the pharmacokinetics of
rituximab.
Animal Toxicology and/or Pharmacology
Reproductive Toxicology Studies
An embryo-fetal developmental toxicity study was performed
on pregnant cynomolgus monkeys. Pregnant animals received rituximab via the
intravenous route during early gestation (organogenesis period; post-coitum
days 20 through 50). Rituximab was administered as loading doses on postcoitum
(PC) Days 20, 21 and 22, at 15, 37.5 or 75 mg/kg/day, and then weekly on PC
Days 29, 36, 43 and 50, at 20, 50 or 100 mg/kg/week. The 100 mg/kg/week dose
resulted in 80% of the exposure (based on AUC) of those achieved following a
dose of 2 grams in humans. Rituximab crosses the monkey placenta. Exposed
offspring did not exhibit any teratogenic effects but did have decreased
lymphoid tissue B cells.
A subsequent pre- and postnatal reproductive toxicity study
in cynomolgus monkeys was completed to assess developmental effects including
the recovery of B cells and immune function in infants exposed to rituximab in
utero. Animals were treated with a loading dose of 0, 15, or 75 mg/kg every day
for 3 days, followed by weekly dosing with 0, 20, or 100 mg/kg dose. Subsets of
pregnant females were treated from PC Day 20 through postpartum Day 78, PC Day
76 through PC Day 134, and from PC Day 132 through delivery and postpartum Day
28. Regardless of the timing of treatment, decreased B cells and
immunosuppression were noted in the offspring of rituximab-treated pregnant
animals. The B-cell counts returned to normal levels, and immunologic function
was restored within 6 months postpartum.
Clinical Studies
Relapsed or Refractory, Low-Grade or Follicular, CD20-Positive, B-Cell NHL
The safety and effectiveness of Rituxan in relapsed,
refractory CD20+ NHL were demonstrated in 3 single-arm studies enrolling 296
patients.
Study 1
A multicenter, open-label, single-arm study was conducted in
166 patients with relapsed or refractory, low-grade or follicular, B-cell NHL
who received 375 mg/m² of Rituxan given as an intravenous infusion weekly for 4
doses. Patients with tumor masses > 10 cm or with > 5000 lymphocytes/μL
in the peripheral blood were excluded from the study.
Results are summarized in Table 3. The median time to onset
of response was 50 days. Disease-related signs and symptoms (including
B-symptoms) resolved in 64% (25/39) of those patients with such symptoms at
study entry.
Study 2
In a multicenter, single-arm study, 37 patients with
relapsed or refractory, low-grade NHL received 375 mg/m² of Rituxan weekly for
8 doses. Results are summarized in Table 3.
Study 3
In a multicenter, single-arm study, 60 patients received 375
mg/m² of Rituxan weekly for 4 doses. All patients had relapsed or refractory,
low-grade or follicular, B-cell NHL and had achieved an objective clinical
response to Rituxan administered 3.8-35.6 months (median 14.5 months)
prior to retreatment with Rituxan. Of these 60 patients, 5 received more than
one additional course of Rituxan. Results are summarized in Table 3. Bulky
Disease
In pooled data from Studies 1 and 3, 39 patients with bulky (single
lesion > 10 cm in diameter) and relapsed or refractory, low-grade NHL
received Rituxan 375 mg/m² weekly for 4 doses. Results are summarized in Table
3.
Table 3 : Summary of Rituxan Efficacy Data by Schedule and
Clinical Setting
| |
Study 1
Weekly × 4
N = 166 |
Study 2
Weekly × 8
N = 37 |
Study 1 and Study 3 Bulky disease,
Weekly × 4
N = 39a |
Study 3
Retreatment,
Weekly × 4
N = 60 |
| Overall Response Rate |
48% |
57% |
36% |
38% |
| Complete Response Rate |
6% |
14% |
3% |
10% |
| Median Duration of Responseb, c,d |
11.2 |
13.4 |
6.9 |
15.0 |
| (Months) [Range] |
[1.9 to 42.1+] |
[2.5 to 36.5+] |
[2.8 to 25.0+] |
[3.0 to 25.1+] |
a Six of these patients are included in the first
column. Thus, data from 296 intent-to-treat patients are provided in this
table.
b Kaplan-Meier projected with observed range.
c “+” indicates an ongoing response.
d Duration of response: interval from the onset of response
to disease progression. |
Previously Untreated, Follicular, CD20-Positive, B-Cell NHL
Study 4
A total of 322 patients with previously untreated follicular
NHL were randomized (1:1) to receive up to eight 3-week cycles of CVP
chemotherapy alone (CVP) or in combination with Rituxan 375 mg/m² on Day 1 of
each cycle (R-CVP) in an open-label, multicenter study. The main outcome
measure of the study was progression-free survival (PFS) defined as the time
from randomization to the first of progression, relapse, or death.
Twenty-six percent of the study population was > 60 years
of age, 99% had Stage III or IV disease, and 50% had an International
Prognostic Index (IPI) score ≥ 2. The results for PFS as determined by a
blinded, independent assessment of progression are presented in Table 4. The
point estimates may be influenced by the presence of informative censoring. The
PFS results based on investigator assessment of progression were similar to
those obtained by the independent review assessment.
Table 4 : Efficacy Results in Study 4
| |
Study Arm |
R-CVP
N=162 |
CVP
N=160 |
| Median PFS (years)a |
2.4 |
1.4 |
| Hazard ratio (95% CI)b |
0.44 |
(0.29, 0.65) |
a p < 0.0001, two-sided stratified log-rank
test.
b Estimates of Cox regression stratified by center. |
Non-Progressing Low-Grade, CD20-Positive, B-Cell NHL Following First-Line
CVP Chemotherapy
Study 5
A total of 322 patients with previously untreated low-grade,
B-cell NHL who did not progress after 6 or 8 cycles of CVP chemotherapy were
enrolled in an open-label, multicenter, randomized trial. Patients were
randomized (1:1) to receive Rituxan 375 mg/m² intravenous infusion, once weekly
for 4 doses every 6 months for up to 16 doses or no further therapeutic
intervention. The main outcome measure of the study was progression-free
survival defined as the time from randomization to progression, relapse, or
death. Thirty-seven percent of the study population was > 60 years of age,
99% had Stage III or IV disease, and 63% had an IPI score ≥ 2.
There was a reduction in the risk of progression, relapse,
or death (hazard ratio estimate in the range of 0.36 to 0.49) for patients randomized
to Rituxan as compared to those who received no additional treatment.
Diffuse Large B-Cell NHL (DLBCL)
The safety and effectiveness of Rituxan were evaluated in
three randomized, active-controlled, open-label, multicenter studies with a
collective enrollment of 1854 patients. Patients with previously untreated
diffuse large B-cell NHL received Rituxan in combination with cyclophosphamide,
doxorubicin, vincristine, and prednisone (CHOP) or other anthracycline-based
chemotherapy regimens.
Study 6
A total of 632 patients age ≥ 60 years with DLBCL
(including primary mediastinal B-cell lymphoma) were randomized in a 1:1 ratio
to treatment with CHOP or R-CHOP. Patients received 6 or 8 cycles of CHOP, each
cycle lasting 21 days. All patients in the R-CHOP arm received 4 doses of
Rituxan 375 mg/m² on Days 7 and 3 (prior to Cycle 1) and 48-72 hours
prior to Cycles 3 and 5. Patients who received 8 cycles of CHOP also received
Rituxan prior to Cycle 7. The main outcome measure of the study was progression-free
survival, defined as the time from randomization to the first of progression,
relapse, or death. Responding patients underwent a second randomization to
receive Rituxan or no further therapy.
Among all enrolled patients, 62% had centrally confirmed DLBCL histology, 73% had Stage III-IV disease, 56% had IPI scores ≥ 2,
86% had ECOG performance status of < 2, 57% had elevated LDH levels, and 30%
had two or more extranodal disease sites involved. Efficacy results are
presented in Table 5. These results reflect a statistical approach which allows
for an evaluation of Rituxan administered in the induction setting that
excludes any potential impact of Rituxan given after the second randomization.
Analysis of results after the second randomization in Study 6 demonstrates that
for patients randomized to R-CHOP, additional Rituxan exposure beyond induction
was not associated with further improvements in progression-free survival or
overall survival.
Study 7
A total of 399 patients with DLBCL, age ≥ 60 years,
were randomized in a 1:1 ratio to receive CHOP or R-CHOP. All patients received
up to eight 3-week cycles of CHOP induction; patients in the R-CHOP arm
received Rituxan 375 mg/m² on Day 1 of each cycle. The main outcome measure of
the study was event-free survival, defined as the time from randomization to
relapse, progression, change in therapy, or death from any cause. Among all
enrolled patients, 80% had Stage III or IV disease, 60% of patients had an
age-adjusted IPI ≥ 2, 80% had ECOG performance status scores < 2, 66%
had elevated LDH levels, and 52% had extranodal involvement in at least two
sites. Efficacy results are presented in Table 5.
Study 8
A total of 823 patients with DLBCL, aged 18-60 years,
were randomized in a 1:1 ratio to receive an anthracycline-containing
chemotherapy regimen alone or in combination with Rituxan. The main outcome
measure of the study was time to treatment failure, defined as time from
randomization to the earliest of progressive disease, failure to achieve a
complete response, relapse, or death. Among all enrolled patients, 28% had
Stage III-IV disease, 100% had IPI scores of ≤ 1, 99% had ECOG
performance status of < 2, 29% had elevated LDH levels, 49% had bulky
disease, and 34% had extranodal involvement. Efficacy results are presented in
Table 5.
Table 5 : Efficacy Results in Studies 6, 7, and 8
| Main outcome |
Study 6
(n =632) |
Study 7
(n =399) |
Study 8
(n =823) |
| R-CHOP |
CHOP |
R-CHOP |
CHOP |
R-Chemo |
Chemo |
| Progression-free survival (years) |
Event-free survival (years) |
Time to treatment failure (years) |
| Median of main outcome measure |
3.1 |
1.6 |
2.9 |
1.1 |
NEb |
NEb |
| Hazard ratiod |
0.69a |
0.60a |
0.45a |
| Overall survival at 2 yearsc |
74% |
63% |
69% |
58% |
95% |
86% |
| Hazard ratiod |
0.72a |
0.68a |
0.40a |
a Significant at p < 0.05, 2-sided.
b NE = Not reliably estimable.
c Kaplan-Meier estimates.
d R-CHOP vs. CHOP. |
In Study 7, overall survival estimates at 5 years were 58% vs. 46% for R-CHOP
and CHOP, respectively.
Rheumatoid Arthritis (RA)
Reducing Signs and Symptoms: Initial and Re-Treatment Courses
The efficacy and safety of Rituxan were evaluated in two
randomized, double-blind, placebo-controlled studies of adult patients with
moderately to severely active RA who had a prior inadequate response to at
least one TNF inhibitor. Patients were 18 years of age or older, diagnosed with
active RA according to American College of Rheumatology (ACR) criteria, and had
at least 8 swollen and 8 tender joints.
In RA Study 1, patients were randomized to receive either
Rituxan 2 x 1000 mg + MTX or placebo + MTX for 24 weeks. Further courses of
Rituxan 2 x 1000 mg + MTX were administered in an open label extension study at
a frequency determined by clinical evaluation, but no sooner than 16 weeks
after the preceding course of Rituxan. In addition to the IV premedication,
glucocorticoids were administered orally on a tapering schedule from baseline
through Day 14. The proportions of patients achieving ACR 20, 50, and 70
responses at Week 24 of the placebo-controlled period are shown in Table 6.
In RA Study 2, all patients received the first course of
Rituxan 2 x 1000 mg + MTX. Patients who experienced ongoing disease activity
were randomized to receive a second course of either Rituxan 2 x 1000 mg + MTX
or placebo + MTX, the majority between Weeks 24-28. The proportions of
patients achieving ACR 20, 50, and 70 responses at Week 24, before the
re-treatment course, and at Week 48, after retreatment, are shown in Table 6.
Table 6 : ACR Responses in Study 1 and Study 2 (Percent of
Patients) (Modified Intent-to-Treat Population)
| Response |
Inadequate Response to TNF Antagonists |
Study 1
24 Week Placebo-Controlled (Week 24) |
Study 2
Placebo-Controlled Retreatment (Week 24 and Week 48) |
Placebo +
MTX
n = 201 |
Rituxan +
MTX
n = 298 |
Treatment Difference
(Rituxan – Placebo)c
(95% CI) |
Response |
Placebo + MTX
Retreatment
n = 157 |
Rituxan + MTX
Retreatment
n = 318 |
Treatment Difference
(Rituxan – Placebo) a , b, c
(95% CI) |
| ACR20 |
ACR20 |
|
Week 24
|
18% |
51% |
33%
(26%, 41%) |
Week 24
|
48% |
45% |
NA |
|
Week 48
|
45% |
54% |
11%
(2%, 20%) |
| ACR50 |
ACR50 |
|
Week 24
|
5% |
27% |
21%
(15%, 27%) |
Week 24
|
27% |
21% |
NA |
|
Week 48
|
26% |
29% |
4%
(-4%, 13%) |
| ACR70 |
ACR70 |
|
Week 24
|
1% |
12% |
11%
(7%, 15%) |
Week 24
|
11% |
8% |
NA |
|
Week 48
|
13% |
14% |
1%
(-5%, 8%) |
a In Study 2, all patients received
a first course of Rituxan 2 x 1000 mg. Patients who experienced ongoing
disease activity were randomized to receive a second course of either
Rituxan 2 x 1000 mg + MTX or placebo + MTX at or after Week 24.
b Since all patients received a first course of Rituxan, no
comparison between Placebo + MTX and Rituxan + MTX is made at Week 24.
c For Study 1, weighted difference stratified by region (US,
rest of the world) and Rheumatoid Factor (RF) status (positive > =
20 IU/mL, negative < 20 IU/mL) at baseline; For Study 2, weighted difference
stratified by RF status at baseline and > =20% improvement from baseline
in both SJC and TJC at Week 24 (Yes/No). |
Improvement was also noted for all components of ACR response following treatment
with Rituxan, as shown in Table 7.
Table 7 : Components of ACR Response at Week 24 in Study
1 (Modified Intent-to-Treat Population)
| Parameter (median) |
Inadequate Response to TNF Antagonists |
Placebo+ MTX
(n = 201) |
Rituxan+ MTX
(n = 298) |
| Baseline |
Wk 24 |
Baseline |
Wk 24 |
| Tender Joint Count |
31.0 |
27.0 |
33.0 |
13.0 |
| Swollen Joint Count |
20.0 |
19.0 |
21.0 |
9.5 |
| Physician Global Assessmenta |
71.0 |
69.0 |
71.0 |
36.0 |
| Patient Global Assessmenta |
73.0 |
68.0 |
71.0 |
41.0 |
| Paina |
68.0 |
68.0 |
67.0 |
38.5 |
| Disability Index (HAQ)b |
2.0 |
1.9 |
1.9 |
1.5 |
| CRP (mg/dL) |
2.4 |
2.5 |
2.6 |
0.9 |
a Visual Analogue Scale: 0 = best, 100 = worst.
b Disability Index of the Health Assessment Questionnaire:
0 = best, 3 = worst. |
The time course of ACR 20 response for Study 1 is shown in Figure 1. Although
both treatment groups received a brief course of intravenous and oral glucocorticoids,
resulting in similar benefits at Week 4, higher ACR 20 responses were observed
for the Rituxan group by Week 8. A similar proportion of patients achieved these
responses through Week 24 after a single course of treatment (2 infusions) with
Rituxan. Similar patterns were demonstrated for ACR 50 and 70 responses.
Figure 1 : Percent of Patients Achieving ACR 20 Response
by Visit* Study 1 (Inadequate Response to TNF Antagonists)
*The same patients may not have responded at each time
point.
Radiographic Response
In RA Study 1, structural joint damage was assessed
radiographically and expressed as changes in Genant-modified Total Sharp Score
(TSS) and its components, the erosion score (ES) and the joint space narrowing
(JSN) score. Rituxan + MTX slowed the progression of structural damage compared
to placebo + MTX after 1 year as shown in Table 8.
Table 8 : Mean Radiographic Change From Baseline to 104 Weeks
| Parameter |
Inadequate Response to TNFAntagonists |
| Rituxan 2 x 1000 mg + MTXb |
Placebo + MTXc |
Treatment Difference (Placebo – Rituxan) |
95% CI |
| Change during First Year |
| TSS |
0.66 |
1.78 |
1.12 |
(0.48, 1.76) |
| ES |
0.44 |
1.19 |
0.75 |
(0.32, 1.18) |
| JSN Score |
0.22 |
0.59 |
0.37 |
(0.11, 0.63) |
| Change during Second Yeara |
| TSS |
0.48 |
1.04 |
- |
- |
| ES |
0.28 |
0.62 |
- |
- |
| JSN Score |
0.20 |
0.42 |
- |
- |
a Based on radiographic scoring following 104
weeks of observation.
b Patients received up to 2 years of treatment with Rituxan
+ MTX.
c Patients receiving Placebo + MTX. Patients receiving Placebo+
MTX could have received retreatment with Rituxan + MTX from Week 16 onward. |
In RA Study 1 and its open-label extension, 70% of patients initially randomized
to Rituxan + MTX and 72% of patients initially randomized to placebo + MTX were
evaluated radiographically at Year 2. As shown in Table 8, progression of structural
damage in Rituxan + MTX patients was further reduced in the second year of treatment.
Following 2 years of treatment with Rituxan + MTX, 57% of
patients had no progression of structural damage. During the first year, 60% of
Rituxan + MTX treated patients had no progression, defined as a change in TSS
of zero or less compared to baseline, compared to 46% of placebo + MTX treated
patients. In their second year of treatment with Rituxan + MTX, more patients
had no progression than in the first year (68% vs. 60%), and 87% of the Rituxan
+ MTX treated patients who had no progression in the first year also had no
progression in the second year.
Lesser Efficacy of 500 Vs. 1000 mg Treatment Courses for Radiographic Outcomes
RA Study 3 is a randomized, double-blind, placebo-controlled
study which evaluated the effect of placebo + MTX compared to Rituxan 2 x 500
mg + MTX and Rituxan 2 x 1000 mg + MTX treatment courses in MTX-naïve RA
patients with moderately to severely active disease. Patients received a first
course of two infusions of rituximab or placebo on Days 1 and 15. MTX was
initiated at 7.5 mg/week and escalated up to 20 mg/week by week 8 in all three
treatment arms. After a minimum of 24 weeks, patients with ongoing disease
activity were eligible to receive re-treatment with additional courses of their
assigned treatment. After one year of treatment, the proportion of patients
achieving ACR 20/50/70 responses were similar in both Rituxan dose groups and
were higher than in the placebo group. However, with respect to radiographic
scores, only the Rituxan 1000 mg treatment group demonstrated a statistically significant
reduction in TSS: a change of 0.36 units compared to 1.08 units for the placebo
group, a 67% reduction.
Physical Function Response
RA Study 4 is a randomized, double-blind, placebo-controlled
study in adult RA patients with moderately to severely active disease with
inadequate response to MTX. Patients were randomized to receive an initial
course of Rituxan 500 mg, Rituxan 1000 mg, or placebo in addition to background
MTX.
Physical function was assessed at Weeks 24 and 48 using the Health Assessment
Questionnaire Disability Index (HAQ-DI). From baseline to Week 24, a greater
proportion of Rituxan-treated patients had an improvement in HAQ-DI of at least
0.22 (a minimal clinically important difference) and a greater mean HAQ-DI improvement
compared to placebo, as shown in Table 10. HAQ-DI results for the Rituxan 500
mg treatment group were similar to the Rituxan 1000 mg treatment group; however
radiographic responses were not assessed (see Dosing Precaution in the Radiographic
Responses section above). These improvements were maintained at 48 weeks.
Table 9 : Improvement from Baseline in Health Assessment
Questionnaire Disability Index (HAQ-DI) at Week 24 in Study 4
| |
Placebo
+ MTX
n = 172 |
Rituxan
2 x 1000 mg + MTX
n = 170 |
Treatment Difference
(Rituxan – CI) Placebo)b
(95% CI) |
| Mean Improvement from Baseline |
0.19 |
0.42 |
0.23
(0.11, 0.34) |
| Percent of patients with “Improved” score (Change from Baseline ≥
MCID)a |
48% |
58% |
11%
(0%, 21%) |
a Minimal Clinically Important Difference: MCID
for HAQ = 0.22.
b Adjusted difference stratified by region (US, rest of the
world) and rheumatoid factor (RF) status (positive > = 20 IU/mL, negative
< 20 IU/mL) at baseline |
Last updated on RxList: 11/6/2009