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Abetimus Trial Data Demonstrates Greater Reduction in Antibody Levels in Systemic Lupus Erythematosus
Dose Dependent Antibody Reduction
The minor changes to the data show a greater reduction from baseline in antibody levels in patients treated with Riquent. The median percent reductions were 100 mg: 18%; 300 mg: 28%; 900 mg: 46% at week 8. In parallel, there was less of an increase above baseline in the antibody levels for the placebo group. As a result, the reductions in median antibody levels between the Riquent treatment groups and the placebo treatment group at week 8 were 100 mg: 30%; 300 mg: 40%; 900 mg: 58% (p=0.0032, p Approximately three times as many patients treated with 900 mg of Riquent (42%) had at least a 50% or greater antibody reduction at week 8 compared with patients treated with 100 mg (13%). Patients reached their maximum reduction after four weeks of treatment at which time separation between doses was also seen.
The analyses assessed the impact of treatment with Riquent on reducing antibodies to dsDNA in 101 patients by measuring the percent of antibody reduction from baseline compared with placebo following weekly treatment with 100 mg, 300 mg or 900 mg of Riquent or placebo. All demographics and baseline characteristics were comparable across dosing groups and there were 16 to 30 patients per treatment group.
Consistent Antibody Reductions
Published data from earlier La Jolla studies indicated that maintaining antibody reductions over time in individual patients was associated with a significantly reduced renal flare rate. The updated data indicate that the higher the Riquent dose, the greater the consistency of response and the greater the magnitude of this response. While more than twice as many 900 mg-treated patients (62%) as 100 mg-treated patients (25%) had a consistent 20% reduction, nearly seven times as many 900 mg-treated patients (42%) had a consistent 40% reduction, compared with 100 mg-treated patients (6%). Nearly twice as many patients on 900 mg as 300 mg had a consistent 50% reduction, but no patients on 100 mg or placebo achieved this level of consistent reduction. A consistent reduction is defined as a patient whose percent antibody reduction exceeded a specified level at weeks 4, 6 and 8.
To date, Riquent has been well tolerated in the ongoing Phase 3 study. The adverse event profile for all patients in the study, including those treated with the 300 mg and 900 mg doses, does not appear to differ from that seen in previous studies where 100 mg of Riquent was the treatment dose.
These data will be presented at the 8th International Congress on SLE in Shanghai in May 2007.
Phase 3 Study Design
The Phase 3 study is designed to assess the ability of Riquent treatment to prevent or delay the time to renal flare in lupus patients with a history of renal disease and with antibodies to dsDNA. A lupus renal flare is a potentially life-threatening increase in inflammation targeting the kidney. A renal flare often requires treatment with immunosuppressive agents which can have severe side effects.
The global study is expected to enroll approximately 730 patients who will be treated weekly with Riquent or placebo. Equal numbers of patients will be treated with 300 mg per week, 900 mg per week or placebo for 12 months. Patient enrollment in this international study recommenced in the third quarter of 2006 and completion of enrollment is targeted for around the end of 2007.
Riquent is being developed to specifically treat lupus renal disease by preventing or delaying renal flares, a leading cause of sickness and death in lupus patients. Riquent has been well tolerated in all 13 clinical trials, with no serious Riquent-related side effects identified to date. Riquent's only known biological activity is the reduction of circulating levels of anti-dsDNA antibodies. Increases in these antibodies are associated with an increased risk of renal flare. Although clinical benefit has not yet been proven, Riquent treatment has significantly reduced these antibody levels in all clinical trials where they were measured.
Source: La Jolla Pharmaceutical Company