Of the total number of Infliximab-treated patients in RA and Ps clinical studies, 256 (9.6%) were 65 years old and over, while 17 (0.6%) were 75 years old and over. In these trials, no overall differences in safety or effectiveness were observed between geriatric patients (patients ≥ 65 years old) and younger adult patients (patients 18 to 65 years old). However, the incidence of serious adverse reactions in geriatric patients was higher in both Infliximab and control groups compared to younger adult patients.
Of the total number of Infliximab-treated patients in CD, UC, AS, and PsA clinical studies, 76 (3.2%) were 65 years old and over, while 9 (0.4%) were 75 years old and over. In the CD, UC, AS, and PsA studies, there were insufficient numbers of geriatric patients to determine whether they respond differently from younger adults .
The incidence of serious infections in Infliximab-treated geriatric patients was greater than in Infliximab-treated younger adult patients; therefore close monitoring of geriatric patients for the development of serious infections is recommended [see Warnings and Precautions (5.1), and Adverse Reactions (6.1)].
Single doses up to 20 mg/kg have been administered without any direct toxic effect. In case of overdosage, it is recommended that the patient be monitored for any signs or symptoms of adverse reactions or effects [see Warnings and Precautions (5)] and appropriate symptomatic treatment instituted immediately.
Infliximab, a tumor necrosis factor (TNF) blocker, is a chimeric IgG1κ monoclonal antibody (composed of human constant and murine variable regions). It has a molecular weight of approximately 149.1 kilodaltons. Infliximab is produced by a recombinant murine myeloma cell line, SP2/0.
Infliximab for injection is supplied as a sterile, preservative-free, white, lyophilized powder for intravenous infusion after reconstitution and dilution. Following reconstitution with 10 mL of Sterile Water for Injection, USP, the final concentration is 10 mg/mL and the resulting pH is approximately 7.2. Each single-dose vial contains 100 mg infliximab, dibasic sodium phosphate, dihydrate (6.1 mg), monobasic sodium phosphate, monohydrate (2.2 mg), polysorbate 80 (0.5 mg), and sucrose (500 mg).
Infliximab neutralizes the biological activity of TNFα by binding with high affinity to the soluble and transmembrane forms of TNFα and inhibits binding of TNFα with its receptors. Infliximab does not neutralize TNFβ (lymphotoxin-α), a related cytokine that utilizes the same receptors as TNFα. Biological activities attributed to TNFα include: induction of pro-inflammatory cytokines such as interleukins (IL) 1 and 6, enhancement of leukocyte migration by increasing endothelial layer permeability and expression of adhesion molecules by endothelial cells and leukocytes, activation of neutrophil and eosinophil functional activity, induction of acute phase reactants and other liver proteins, as well as tissue degrading enzymes produced by synoviocytes and/or chondrocytes. Cells expressing transmembrane TNFα bound by infliximab can be lysed in vitro or in vivo. Infliximab inhibits the functional activity of TNFα in a wide variety of in vitro bioassays utilizing human fibroblasts, endothelial cells, neutrophils, B and T-lymphocytes and epithelial cells. The relationship of these biological response markers to the mechanism(s) by which Infliximab exerts its clinical effects is unknown. Anti-TNFα antibodies reduce disease activity in the cotton-top tamarin colitis model, and decrease synovitis and joint erosions in a murine model of collagen-induced arthritis. Infliximab prevents disease in transgenic mice that develop polyarthritis as a result of constitutive expression of human TNFα, and when administered after disease onset, allows eroded joints to heal.
Elevated concentrations of TNFα have been found in involved tissues and fluids of patients with RA, CD, UC, AS, PsA, and Ps. In RA, treatment with Infliximab reduced infiltration of inflammatory cells into inflamed areas of the joint as well as expression of molecules mediating cellular adhesion [E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1)], chemoattraction [IL-8 and monocyte chemotactic protein (MCP-1)] and tissue degradation [matrix metalloproteinase (MMP) 1 and 3]. In CD, treatment with Infliximab reduced infiltration of inflammatory cells and TNFα production in inflamed areas of the intestine, and reduced the proportion of mononuclear cells from the lamina propria able to express TNFα and interferon. After treatment with Infliximab, patients with RA or CD exhibited decreased levels of serum IL-6 and C-reactive protein (CRP) compared to baseline. Peripheral blood lymphocytes from Infliximab-treated patients showed no significant decrease in number or in proliferative responses to in vitro mitogenic stimulation when compared to cells from untreated patients. In PsA, treatment with Infliximab resulted in a reduction in the number of T-cells and blood vessels in the synovium and psoriatic skin lesions as well as a reduction of macrophages in the synovium. In Ps, Infliximab treatment may reduce the epidermal thickness and infiltration of inflammatory cells. The relationship between these pharmacodynamic activities and the mechanism(s) by which Infliximab exerts its clinical effects is unknown.
In adults, single intravenous (IV) infusions of 3 mg/kg to 20 mg/kg (two times the maximum recommended dose for any indication) showed a linear relationship between the dose administered and the maximum serum concentration. The volume of distribution at steady state was independent of dose and indicated that infliximab was distributed primarily within the vascular compartment. Pharmacokinetic results for single doses of 3 mg/kg to 10 mg/kg in RA, 5 mg/kg in CD, and 3 mg/kg to 5 mg/kg in Ps indicate that the median terminal half-life of infliximab is 7.7 to 9.5 days.
Following an initial dose of Infliximab, repeated infusions at 2 and 6 weeks resulted in predictable concentration-time profiles following each treatment. No systemic accumulation of infliximab occurred upon continued repeated treatment with 3 mg/kg or 10 mg/kg at 4- or 8-week intervals. Development of antibodies to infliximab increased infliximab clearance. At 8 weeks after a maintenance dose of 3 to 10 mg/kg of Infliximab, median infliximab serum concentrations ranged from approximately 0.5 to 6 mcg/mL; however, infliximab concentrations were not detectable (<0.1 mcg/mL) in patients who became positive for antibodies to infliximab. No major differences in clearance or volume of distribution were observed in patient subgroups defined by age, weight, or gender. It is not known if there are differences in clearance or volume of distribution in patients with marked impairment of hepatic or renal function.
Infliximab pharmacokinetic characteristics (including peak and trough concentrations and terminal half-life) were similar in pediatric (aged 6 to 17 years) and adult patients with CD or UC following the administration of 5 mg/kg of Infliximab.
A 6-month study in CD-1 mice was conducted to assess the tumorigenic potential of cV1q anti-mouse TNFα, an analogous antibody. No evidence of tumorigenicity was observed in mice that received intravenous doses of 10 mg/kg or 40 mg/kg cV1q given weekly. The relevance of this study for human risk is unknown. No impairment of fertility or reproductive performance indices were observed in male or female mice that received cV1q, an analogous mouse antibody, at intravenous doses up to 40 mg/kg given weekly.
Active Crohn’s Disease in Adults
The safety and efficacy of single and multiple doses of Infliximab were assessed in 2 randomized, double-blind, placebo-controlled clinical studies in 653 adult patients with moderate to severely active CD [Crohn’s Disease Activity Index (CDAI) ≥220 and ≤400] with an inadequate response to prior conventional therapies. Concomitant stable doses of aminosalicylates, corticosteroids and/or immunomodulatory agents were permitted and 92% of patients continued to receive at least one of these medications.
In the single-dose trial of 108 adult patients, 16% (4/25) of placebo patients achieved a clinical response (decrease in CDAI ≥70 points) at Week 4 vs. 81% (22/27) of patients receiving 5 mg/kg Infliximab (p<0.001, two-sided, Fisher’s Exact test). Additionally, 4% (1/25) of placebo patients and 48% (13/27) of patients receiving 5 mg/kg Infliximab achieved clinical remission (CDAI<150) at Week 4.
In a multidose trial (ACCENT I [Study Crohn’s I]), 545 adult patients received 5 mg/kg at Week 0 and were then randomized to one of three treatment groups; the placebo maintenance group received placebo at Weeks 2 and 6, and then every 8 weeks; the 5 mg/kg maintenance group received 5 mg/kg at Weeks 2 and 6, and then every 8 weeks; and the 10 mg/kg maintenance group received 5 mg/kg at Weeks 2 and 6, and then 10 mg/kg every 8 weeks. Patients in response at Week 2 were randomized and analyzed separately from those not in response at Week 2. Corticosteroid taper was permitted after Week 6.
At Week 2, 57% (311/545) of patients were in clinical response. At Week 30, a significantly greater proportion of these patients in the 5 mg/kg and 10 mg/kg maintenance groups achieved clinical remission compared to patients in the placebo maintenance group (Table 3).
Additionally, a significantly greater proportion of patients in the 5 mg/kg and 10 mg/kg Infliximab maintenance groups were in clinical remission and were able to discontinue corticosteroid use compared to patients in the placebo maintenance group at Week 54 (Table 3).
|Single 5-mg/kg Dose *||Three-Dose Induction †|
|Placebo Maintenance||Infliximab Maintenance q8 wks|
|5 mg/kg||10 mg/kg|
|P -value ‡||0.022||0.001|
|Patients in remission able to discontinue corticosteroid use §||11%||25%||34%|
|P -value ‡||0.059||0.005|
Patients in the Infliximab maintenance groups (5 mg/kg and 10 mg/kg) had a longer time to loss of response than patients in the placebo maintenance group (Figure 1). At Weeks 30 and 54, significant improvement from baseline was seen among the 5 mg/kg and 10 mg/kg Infliximab-treated groups compared to the placebo group in the disease-specific inflammatory bowel disease questionnaire (IBDQ), particularly the bowel and systemic components, and in the physical component summary score of the general health-related quality of life questionnaire SF-36.
Figure 1: Kaplan-Meier Estimate of the Proportion of Adults with CD Who Had Not Lost Response Through Week 54 (Study Crohn’s I)
In a subset of 78 patients who had mucosal ulceration at baseline and who participated in an endoscopic substudy, 13 of 43 patients in the Infliximab maintenance group had endoscopic evidence of mucosal healing compared to 1 of 28 patients in the placebo group at Week 10. Of the Infliximab-treated patients showing mucosal healing at Week 10, 9 of 12 patients also showed mucosal healing at Week 54.
Patients who achieved a response and subsequently lost response were eligible to receive Infliximab on an episodic basis at a dose that was 5 mg/kg higher than the dose to which they were randomized. The majority of such patients responded to the higher dose. Among patients who were not in response at Week 2, 59% (92/157) of Infliximab maintenance patients responded by Week 14 compared to 51% (39/77) of placebo maintenance patients. Among patients who did not respond by Week 14, additional therapy did not result in significantly more responses [see Dosage and Administration (2)].
Fistulizing Crohn’s Disease in Adults
The safety and efficacy of Infliximab were assessed in 2 randomized, double-blind, placebo-controlled studies in adult patients with fistulizing CD with fistula(s) that were of at least 3 months duration. Concurrent use of stable doses of corticosteroids, 5-aminosalicylates, antibiotics, MTX, 6-mercaptopurine (6-MP) and/or azathioprine (AZA) was permitted.
In the first trial, 94 adult patients received 3 doses of either placebo or Infliximab at Weeks 0, 2 and 6. Fistula response (≥50% reduction in number of enterocutaneous fistulas draining upon gentle compression on at least 2 consecutive visits without an increase in medication or surgery for CD) was seen in 68% (21/31) of patients in the 5 mg/kg Infliximab group (P =0.002) and 56% (18/32) of patients in the 10 mg/kg Infliximab group (P =0.021) vs. 26% (8/31) of patients in the placebo arm. The median time to onset of response and median duration of response in Infliximab-treated patients was 2 and 12 weeks, respectively. Closure of all fistulas was achieved in 52% of Infliximab-treated patients compared with 13% of placebo-treated patients (P <0.001).
In the second trial (ACCENT II [Study Crohn’s II]), adult patients who were enrolled had to have at least 1 draining enterocutaneous (perianal, abdominal) fistula. All patients received 5 mg/kg Infliximab at Weeks 0, 2 and 6. Patients were randomized to placebo or 5 mg/kg Infliximab maintenance at Week 14. Patients received maintenance doses at Week 14 and then every 8 weeks through Week 46. Patients who were in fistula response (fistula response was defined the same as in the first trial) at both Weeks 10 and 14 were randomized separately from those not in response. The primary endpoint was time from randomization to loss of response among those patients who were in fistula response.
Among the randomized patients (273 of the 296 initially enrolled), 87% had perianal fistulas and 14% had abdominal fistulas. Eight percent also had rectovaginal fistulas. Greater than 90% of the patients had received previous immunosuppressive and antibiotic therapy.
At Week 14, 65% (177/273) of patients were in fistula response. Patients randomized to Infliximab maintenance had a longer time to loss of fistula response compared to the placebo maintenance group (Figure 2). At Week 54, 38% (33/87) of Infliximab-treated patients had no draining fistulas compared with 22% (20/90) of placebo-treated patients (P =0.02). Compared to placebo maintenance, patients on Infliximab maintenance had a trend toward fewer hospitalizations.
Figure 2: Life Table Estimates of the Proportion of Adult CD Patients Who Had Not Lost Fistula Response Through Week 54 (Study Crohn’s II)
Patients who achieved a fistula response and subsequently lost response were eligible to receive Infliximab maintenance therapy at a dose that was 5 mg/kg higher than the dose to which they were randomized. Of the placebo maintenance patients, 66% (25/38) responded to 5 mg/kg Infliximab, and 57% (12/21) of Infliximab maintenance patients responded to 10 mg/kg.
Patients who had not achieved a response by Week 14 were unlikely to respond to additional doses of Infliximab.
Similar proportions of patients in either group developed new fistulas (17% overall) and similar numbers developed abscesses (15% overall).
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