Control of allergic rhinitis with MP-AzeFlu: a noninterventional study of a Swedish cohort.

BACKGROUND: The European Union has prioritised allergic rhinitis (AR) control. A visual analogue scale (VAS) has been endorsed as the AR control language and embedded into the most recent MACVIA-ARIA guideline. This study assessed the effectiveness and safety of MP-AzeFlu using a VAS in a real-life study in Sweden. METHODS: 431 patients aged 12 years or over with ARIA-defined moderate to severe AR were included in this multicentre, prospective, non-interventional study and prescribed MP-AzeFlu. Patients assessed symptom severity using a VAS from 0 (not at all bothersome) to 100 mm (very bothersome) on Days 0, 1, 3 and 7, and after approximately 14 days in the morning before using MP-AzeFlu. Patients' perceived level of disease control was assessed on Day 3. The proportion of patients who achieved a defined VAS score cutoff for well- and partly controlled AR was also calculated. RESULTS: MP-AzeFlu reduced mean (SD) VAS score from 67.9 (16.1) mm at baseline to 32.1 (22.8) mm on the last day. Results were consistent irrespective of severity, phenotype, patient age class or previous treatment. By Day 3, 84.0% of patients reported well- or partly controlled symptoms. Overall, 17.7%, 32.2%, 53.8% and 64.2% of patients achieved a 38 mm or greater "well-controlled" VAS score cutoff on Day 1, 3 and 7 and last day, respectively. CONCLUSIONS: MP-AzeFlu provided rapid, effective and sustained symptom control in patients with AR from Sweden in a realworld setting, aligning with EU and MACVIA-ARIA initiatives and supporting the effectiveness of MP-AzeFlu for AR treatment in real life.

A critical review of clinical trials in systemic lupus erythematosus.

One challenge in caring for patients with systemic lupus erythematosus (SLE) is a paucity of approved therapeutics for treatment of the diverse disease manifestations. In the last 60 years, only one drug, belimumab, has been approved for SLE treatment. Critical evaluation of investigator initiated and pharma-sponsored randomized controlled trials (RCTs) highlights barriers to successful drug development in SLE, including disease heterogeneity, inadequate trial size or duration, insufficient dose finding before initiation of large trials, handling of background medications, and choice of primary endpoint. Herein we examine lessons learned from landmark SLE RCTs and subsequent advances in trial design, as well as discuss efforts to address limitations in current SLE outcome measures that will improve detection of true therapeutic responses in future RCTs.

Relative efficiencies of the 7 rheumatoid arthritis Core Data Set measures to distinguish active from control treatments in 9 comparisons from clinical trials of 5 agents.

The 7 Core Data Set measures to assess rheumatoid arthritis (RA) were analysed for their relative efficiencies to distinguish active from control treatments in 9 comparisons of 5 agents, methotrexate, leflunomide, infliximab, adalimumab, and abatacept, in 8 clinical trials. Among the 7 measures, levels of relative efficiencies were in a similar range, highest for the physician global estimate, followed by, in order, patient global estimate, physical function on a health assessment questionnaire (HAQ), pain, swollen joint count (SJC), an acute phase reactant laboratory test - erythrocyte sedimentation (ESR) or C-reactive protein (CRP), and tender joint count (TJC). Comparisons of only 3 measures, SJC and ESR/CRP (regarded as optimal indicators of inflammation) and HAQ function (regarded as most likely to be affected by joint damage and therefore least reversible) indicated relative efficiencies for HAQ function at least as great as for SJC or ESR/CRP, although 8 of the nine comparisons involved patients with disease duration > 6.9 years. The findings indicate a strong rationale for a Core Data Set of 7 measures, as no single measure was clearly superior in relative efficiency in all clinical trials. At the same time, 'objective' laboratory ESR/CRP, TJC and SJC were not superior to 'subjective' global estimates of the physician or patient or patient self-report measures of physical function or pain, to differentiate active from control treatments. The findings challenge a traditional view that laboratory and clinical examination findings are more robust than patient self-report scores and physician global estimates to assess and monitor RA patients.

Biosimilars: how similar?

As patents expire on biological agents for the treatment of rheumatic diseases, we have the opportunity to develop non-proprietary biologic agents, biosimilars. The development and approval of these agents present novel challenges to both pharma and regulatory agencies although there is great promise of high quality, less expensive biologic agents for the treatment of rheumatic diseases. Here, we review the definitions of biosimilars, the regulatory challenges to approval of these agents and the record of approvals of biosimilars to date.

Limitations of current treatments for systemic lupus erythematosus: a patient and physician survey.

An independent cross-sectional survey assessed systemic lupus erythematosus (SLE) disease and treatment burden. Variables included medication classes prescribed, disease activity, flare occurrences, treatment satisfaction, and validated measures of health-related quality of life (HRQoL), fatigue and work productivity. Of 886 eligible patients (mean age 41.3 years, 89% female), 515 completed the survey. One-third reported moderate-to-severe disease activity, and 31% had flared in the last 12 months. Higher severity of disease activity (moderate-to-severe) was associated with ≥ 2 medication classes prescribed and treatment regimens that included corticosteroids (CS) (both p<0.0001). Patients receiving CS reported lower EQ-5D scores (p=0.0019) and higher fatigue levels (p<0.001), and both patients (p=0.0019) and physicians (p=0.0001) were less likely to report satisfaction with treatment regimens including CS. Among responders eligible for work (n=456), severity of disease activity (moderate-to-severe vs. mild) was associated with unemployment (52.9% vs. 40.8%; p=0.0189), greater impairment in work productivity (36% vs. 21%; p=0.0003) and participation in daily activities (41% vs. 21%; p<0.0001). This survey confirms that SLE and current treatment options substantially impair patients' health status and work productivity. Physician- and patient-reported satisfaction with current treatment regimens, despite poorly controlled disease activity, indicate they are resigned to the limitations of available SLE treatment regimens.

A phase II, double-blind, randomised, placebo-controlled study of BMS945429 (ALD518) in patients with rheumatoid arthritis with an inadequate response to methotrexate.

BACKGROUND: Interleukin 6 (IL-6) plays a key role in the inflammatory cascade in rheumatoid arthritis. BMS945429 is a humanised, monoclonal antibody that potently binds IL-6. OBJECTIVE: To conduct aphase II study to determine the efficacy and safety of BMS945429 in patients with active rheumatoid arthritis and an inadequate response to methotrexate. METHODS: Patients were randomised 1:1:1:1 to BMS945429 (80, 160 or 320 mg; administered intravenously) or placebo plus methotrexate during this 16-week, double-blind trial. The primary efficacy end point was the proportion of patients with a 20% improvement in American College of Rheumatology responses (ACR20) at week 12. Additional end points included ACR50 and ACR70 responses and 28-joint Disease Activity Scores (DAS28). RESULTS: Of 127 randomised and treated patients, 116 completed the trial. ACR20 responders at week 12 were 81% (80 mg; p<0.0001 vs placebo), 71% (160 mg; p=0.0005 vs placebo), 82% (320 mg; p<0.0001 vs placebo) and 27% (placebo), respectively. By week 16, 14% (80 mg), 28% (160 mg) and 44% (320 mg) of BMS945429 patients were in DAS28 remission (DAS28 score <2.6). Statistically significant and clinically meaningful improvements in health-related quality of life (HRQoL) were reported in all active treatment groups. Administration of BMS945429 was associated with increases in liver enzymes and in serum cholesterol. There were no serious infections, infusion reactions or apparent immunogenicity. CONCLUSIONS: In this phase II study, BMS945429 was associated with rapid and significant improvements in disease activity and HRQoL in patients with active rheumatoid arthritis and an inadequate response to methotrexate.

A multicenter, randomized controlled trial comparing a single intra-articular injection of Gel-200, a new cross-linked formulation of hyaluronic acid, to phosphate buffered saline for treatment of osteoarthritis of the knee.

OBJECTIVE: To compare the safety and efficacy of a single intra-articular (IA) injection of a new cross-linked hyaluronic acid product, Gel-200, with phosphate buffered saline (PBS, control) in a multi-center randomized controlled trial in patients with symptomatic osteoarthritis (OA) of the knee. DESIGN: Patients were randomized 2:1 to receive a single injection of Gel-200 or PBS, after joint aspiration. The primary measure of effectiveness was Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscores by 100-mm Visual Analog Scale (VAS); secondary outcomes included: total WOMAC, physical function, and stiffness subscores; patient and physician global assessments of disease activity, Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) strict responders, as well as safety of Gel-200. RESULTS: Of 379 patients randomized, safety was evaluated in 377 and efficacy in 375 (98.9% randomized) in the intent-to-treat population. Effectiveness of Gel-200 by WOMAC pain subscores was statistically significant at week 13 (P=0.037). Mean improvements from baseline in WOMAC pain subscores consistently favored Gel-200 at each visit. Effectiveness of Gel-200 treatment was statistically significant over weeks 3-13 by WOMAC total score, physical function, and physician global evaluations (P<0.05). The number of "strict" OMERACT-OARSI responders was statistically significant from weeks 6 to 13 (P=0.022). Adverse events were not significantly different between treatment groups, including serious adverse events considered related to study treatment. CONCLUSIONS: This trial demonstrated that a single injection of Gel-200 was well tolerated and relieved pain associated with symptomatic OA of the knee over 13 weeks. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NTC 00449696.

Safety issues in the development of treatments for osteoarthritis: recommendations of the Safety Considerations Working Group.

OBJECTIVE: The symptomatic treatment of osteoarthritis (OA) remains to be improved, as many patients do not respond well to current palliative therapies and/or suffer unacceptable adverse events. Given the unmet need for innovative, effective and well-tolerated therapies, it is important to develop the means to estimate the ongoing safety profile of novel therapeutic agents over short- and longer term use. DESIGN: Methods are presented to estimate the number of serious adverse events (SAEs) of interest considered as "acceptable" per 1000 patient-years exposure and to estimate the numbers of patient-years needed in a randomized controlled trial (RCT) to meet objectives. As exposure is increased, more evidence is accrued that the overall risk is within study limits. It is equally important that requirements for delineating the safety of promising new therapies not create barriers that would preclude their development. Therefore, ongoing surveillance of occurrence of SAEs of interest during clinical development is proposed, for example after every incremental 500 patient-years exposure are accrued. RESULTS: This paper and others in this special issue focus on identification of safety signals for symptomatic treatments of OA. Much less information is available for agents aimed at slowing/preventing structural progression but it is expected that a higher risk profile might be considered acceptable in the context of more promising benefit. CONCLUSION: This paper provides a proposal and supporting data for a comprehensive approach for assessing ongoing safety during clinical development of both palliative and disease-modifying therapies for OA.

International consensus for a definition of disease flare in lupus.

The Lupus Foundation of America (LFA) convened an international working group to obtain a consensus definition of disease flare in lupus. With help from the Paediatric Rheumatology International Trials Organization (PRINTO), two web-based Delphi surveys of physicians were conducted. Subsequently, the LFA held a second consensus conference followed by a third Delphi survey to reach a community-wide agreement for flare definition. Sixty-nine of the 120 (57.5%) polled physicians responded to the first survey. Fifty-nine of the responses were available to draft 12 preliminary statements, which were circulated in the second survey. Eighty-seven of 118 (74%) physicians completed the second survey, with an agreement of 70% for 9/12 (75%) statements. During the second conference, three alternative flare definitions were consolidated and sent back to the international community. One hundred and sixteen of 146 (79.5%) responded, with agreement by 71/116 (61%) for the following definition: "A flare is a measurable increase in disease activity in one or more organ systems involving new or worse clinical signs and symptoms and/or laboratory measurements. It must be considered clinically significant by the assessor and usually there would be at least consideration of a change or an increase in treatment." The LFA proposes this definition for lupus flare on the basis of its high face validity.

Elevated liver enzyme tests among patients with rheumatoid arthritis or psoriatic arthritis treated with methotrexate and/or leflunomide.

INTRODUCTION: Potential hepatotoxicity associated with disease-modifying antirheumatic drugs (DMARDs) requires laboratory monitoring. In patients with rheumatoid arthritis (RA) or psoriatic arthritis (PsA), the incidence of elevated alanine aminotransferase/aspartate aminotransferase (ALT/AST) enzymes associated with methotrexate (MTX), leflunomide (LEF) and MTX+LEF versus other DMARDs was examined. METHODS: Patients with RA and PsA enrolled in the Consortium of Rheumatology Researchers of North America (CORRONA) initiating DMARDs were identified. Abnormalities were identified when either was 1- or 2-fold times above the upper limits of normal (ULN). Odds ratios (OR) between MTX/LEF dose and elevated ALT/AST enzymes were estimated using generalised estimating equations. Interaction terms for use of MTX+LEF quantified the incremental risk of the combination compared with each individually. RESULTS: Elevated ALT/AST levels (>1x ULN) occurred in 22%, 17%, 31% and 14% of patients with RA receiving MTX, LEF, MTX+LEF or neither, respectively; elevations were 2.76-fold (95% CI 1.84 to 4.15) more likely in patients with PsA. Elevations >2x ULN occurred in 1-2% of patients on MTX or LEF monotherapy compared with 5% with the combination. After multivariable adjustment and compared with either monotherapy, the combination of MTX and LEF was associated with a greater risk according to MTX dose used as part of the combination: MTX 10-17.5 mg/week, OR 2.91 (95% CI 1.23 to 6.90); MTX > or =20 mg/week, OR 3.98 (95% CI 1.72 to 9.24). CONCLUSIONS: Abnormal ALT/AST levels developed in 14-35% of patients with RA or PsA initiating DMARD therapy. The risks were incrementally greater in those with PsA and in those receiving MTX (> or =10 mg/day) + LEF. These findings should help inform monitoring for potential hepatotoxicity in these patient populations.

Efficacy, safety, and immunological effects of a 2-year immunotherapy with Depigoid birch pollen extract: a randomized, double-blind, placebo-controlled study.

BACKGROUND: Rhinoconjunctivitis due to birch pollen sensitization is common in Northern Europe. A depigmented polymerized birch pollen extract - Depigoid has been developed for immunotherapy. OBJECTIVE: To evaluate its clinical efficacy, safety, and effects on immunological parameters. METHODS: Sixty-one patients aged 7-69 years were included in a randomized, double-blind, placebo-controlled trial of subcutaneous immunotherapy (SCIT) using depigmented polymerized birch pollen extract. SCIT consisted of four increasing doses at 7-day intervals, followed by maintenance injections of 500 DPP (corresponding to 30 microg Bet v1 before depigmentation) at 6-week intervals for 18 months. The primary outcome was the combined symptom and medication score during the 2006 birch pollen season. The frequency of peripheral blood mononuclear cells (PBMC)producing IL-4, IL-10, IL-12, and IL-13 was assessed in a subgroup of patients by ELISPOT assay. RESULTS: After 18 months of treatment, the median combined symptom and medication score (upper/lower quartile) of treated patients was significantly lower than those on placebo: 8.0 (5.8-10.3) and 12.6 (8.6-16.2), respectively (P=0.004). Systemic reactions occurred in 29 patients (12 active, 17 placebo), were grades 1 or 2, and none required specific treatment. After 18 months of treatment, mean serum concentrations of specific IgE increased significantly in both groups (P<0.0001) whereas serum concentrations of both specific IgG1 and IgG4 only increased significantly in the SCIT group (P=0.002) and not in the placebo group. The seasonal increase in numbers of IL-4- and IL-13-producing PBMC was blunted by immunotherapy. CONCLUSIONS: SCIT with depigmented polymerized birch pollen extract significantly reduced symptom and medication scores when compared with the placebo, was well tolerated, and resulted in immunological changes comparable with those of native pollen extracts.

Unmet needs in ankylosing spondylitis patients receiving tumour necrosis factor inhibitor therapy; results from a large multinational real-world study.

BACKGROUND: Symptoms and comorbidities of ankylosing spondylitis (AS) considerably reduce health-related quality of life (HRQoL) and ability to work. This real-world study assessed rates of tumour necrosis factor inhibitor (TNFi) use and switching, treatment failure, and associations between failing TNFi and HRQoL, work productivity and activity impairment (WPAI). METHODS: AS patients and their treating physicians completed questionnaires capturing patient demographics, clinical status, TNFi treatment history, reasons for switching TNFi, HRQoL and WPAI. Current TNFi was determined as "failing" if, after ≥3 months, physician-rated disease severity had worsened, remained severe, was "unstable/deteriorating", physicians were dissatisfied with disease control and/or did not consider treatment a "success". RESULTS: The analysis included 2866 AS patients from 18 countries. Of 2795 patients with complete treatment data, 916 (32.8%) patients had never received TNFi therapy, 1623 (58.1%) patients were receiving their 1st TNFi and 200 (7.2%) patients had ever received ≥2 TNFi (treatment switch). Primary or secondary lack of efficacy were the commonest reasons for switching, and the mean delay in switching after primary lack of efficacy was 11.1 months. 232 (15.4%) patients on TNFi were currently "failing" who, compared to those with treatment success, reported poorer HRQoL: 5-dimension EuroQoL (EQ-5D-3 L): 0.63 vs. 0.78; Medical Outcomes Study Short-Form Health Survey version 2 (SF-36v2) mental component summary (MCS): 41.8 vs. 46.3; physical component summary (PCS): 40.2 vs. 45.1; impaired work productivity: 46.4% vs. 25.0%; and activity: 44.5% vs. 29.6%; all P < 0.001. CONCLUSIONS: Among AS patients, switching TNFi is uncommon and delayed by nearly 1 year despite primary lack of efficacy. Patients currently failing TNFi experience worse physical function, HRQoL and work productivity.

Use of "spydergrams" to present and interpret SF-36 health-related quality of life data across rheumatic diseases.

The Medical Outcomes Study Short Form-36 (SF-36) is a generic measure of health-related quality of life (HRQOL), validated and cross-culturally translated, which has been extensively utilised in rheumatology. In randomised controlled trials and observational studies, SF-36 provides rich data regarding HRQOL; but as typically portrayed, patterns of disease and treatment-associated effects can be difficult to discern. "Spydergrams" offer a simplified means to visualise complex results across all domains of SF-36 in a single figure: depicting disease and population-specific patterns of decrements in HRQOL compared with age and gender-matched normative data, as well as providing a tool for interpreting complex treatment-associated or longitudinal changes. Utilising spydergrams as a standard format to illustrate and report changes in SF-36 across different rheumatic diseases can greatly facilitate analyses and interpretations of clinical trial results, as well as providing patients an accessible means to compare baseline scores and treatment-associated improvements with normative data from individuals without arthritis. Furthermore, SF-6D utility scores based on mean changes across all eight domains of SF-36 are suggested as a quantitative means of summarising changes illustrated by spydergrams, offering a universal metric for cost-effectiveness analyses of therapeutic interventions.

Efficacy and safety of certolizumab pegol plus methotrexate in active rheumatoid arthritis: the RAPID 2 study. A randomised controlled trial.

BACKGROUND: Certolizumab pegol is a PEGylated tumour necrosis factor inhibitor. OBJECTIVE: To evaluate the efficacy and safety of certolizumab pegol versus placebo, plus methotrexate (MTX), in patients with active rheumatoid arthritis (RA). METHODS: An international, multicentre, phase 3, randomised, double-blind, placebo-controlled study in active adult-onset RA. Patients (n = 619) were randomised 2:2:1 to subcutaneous certolizumab pegol (liquid formulation) 400 mg at weeks 0, 2 and 4 followed by 200 mg or 400 mg plus MTX, or placebo plus MTX, every 2 weeks for 24 weeks. The primary end point was ACR20 response at week 24. Secondary end points included ACR50 and ACR70 responses, change from baseline in modified Total Sharp Score, ACR core set variables and physical function. RESULTS: Significantly more patients in the certolizumab pegol 200 mg and 400 mg groups achieved an ACR20 response versus placebo (p< or =0.001); rates were 57.3%, 57.6% and 8.7%, respectively. Certolizumab pegol 200 and 400 mg also significantly inhibited radiographic progression; mean changes from baseline in mTSS at week 24 were 0.2 and -0.4, respectively, versus 1.2 for placebo (rank analysis p< or =0.01). Certolizumab pegol-treated patients reported rapid and significant improvements in physical function versus placebo; mean changes from baseline in HAQ-DI at week 24 were -0.50 and -0.50, respectively, versus -0.14 for placebo (p< or =0.001). Most adverse events were mild or moderate, with low incidence of withdrawals due to adverse events. Five patients developed tuberculosis. CONCLUSION: Certolizumab pegol plus MTX was more efficacious than placebo plus MTX, rapidly and significantly improving signs and symptoms of RA and physical function and inhibiting radiographic progression. TRIAL REGISTRATION NUMBER: NCT00175877.

Efficacy and safety of certolizumab pegol monotherapy every 4 weeks in patients with rheumatoid arthritis failing previous disease-modifying antirheumatic therapy: the FAST4WARD study.

BACKGROUND: Tumour necrosis factor alpha (TNFalpha) is a proinflammatory cytokine involved in the pathogenesis of rheumatoid arthritis (RA). Treatment with TNFalpha inhibitors reduces disease activity and improves outcomes for patients with RA. This study evaluated the efficacy and safety of certolizumab pegol 400 mg, a novel, poly-(ethylene glycol) (PEG)ylated, Fc-free TNFalpha inhibitor, as monotherapy in patients with active RA. METHODS: In this 24-week, multicentre, randomised, double-blind, placebo-controlled study, 220 patients previously failing > or =1 disease-modifying antirheumatic drug (DMARD) were randomised 1:1 to receive subcutaneous certolizumab pegol 400 mg (n = 111) or placebo (n = 109) every 4 weeks. The primary endpoint was 20% improvement according to the American College of Rheumatology criteria (ACR20) at week 24. Secondary endpoints included ACR50/70 response, ACR component scores, 28-joint Disease Activity Score Erythrocyte Sedimentation Rate 3 (DAS28(ESR)3), patient-reported outcomes (including physical function, health-related quality of life (HRQoL), pain and fatigue) and safety. RESULTS: At week 24, the ACR20 response rates were 45.5% for certolizumab pegol 400 mg every 4 weeks vs 9.3% for placebo (p<0.001). Differences for certolizumab pegol vs placebo in the ACR20 response were statistically significant as early as week 1 through to week 24 (p<0.001). Significant improvements in ACR50, ACR components, DAS28(ESR)3 and all patient-reported outcomes were also observed early with certolizumab pegol and were sustained throughout the study. Most adverse events were mild or moderate and no deaths or cases of tuberculosis were reported. CONCLUSIONS: Treatment with certolizumab pegol 400 mg monotherapy every 4 weeks effectively reduced the signs and symptoms of active RA in patients previously failing > or =1 DMARD compared with placebo, and demonstrated an acceptable safety profile. TRIAL REGISTRATION NUMBER: NCT00548834.

Health care utilization in patients with spondyloarthropathies.

OBJECTIVE: To study health care utilization in veterans with SpAs. METHODS: In a postal survey of 70,508 veterans in Veterans Integrated Service Network (VISN)-13 from 1 October 1996 to 31 March 1998, demographics, smoking status and performance of activities of daily living (ADLs) were queried. Databases provided ICD-9 codes for AS, PsA and ReA; comorbidities; demographics; and health care utilization post-survey in respondents. Multivariable linear/logistic regression compared out- and inpatient health care utilization in SpA vs non-SpA, and its predictors in SpA. RESULTS: A total of 1001 veteran respondents had diagnoses of SpA: AS, n = 154; PsA, n = 814; ReA, n = 33. Veterans with AS, PsA and ReA, respectively, had significantly higher adjusted annual medical specialty (2.8, 3.6 and 3 vs 1.5; P < 0.0001), surgical care (3.3, 2.7 and 3.2 vs 1.9; P < 0.0001) and primary care visits (3.4, 3.0 and 2.3 vs 2.7, P = 0.024). Multivariable-adjusted analyses showed that more ADL limitations and higher comorbidity were associated with higher in- and outpatient health care utilization in PsA and none of the predictors were significantly associated with utilization in AS. CONCLUSIONS: After adjustment for differences in demographics and comorbidities, more outpatient health resource utilization was observed in SpA patients. Further studies should focus on what leads to this increase in utilization, and whether any modifiable factors can be introduced to reduce health care utilization in PsA patients.

The size of the disease relevant IgE antibody fraction in relation to 'total-IgE' predicts the efficacy of anti-IgE (Xolair) treatment.

BACKGROUND: Some patients with allergic asthma treated with anti-IgE (Xolair) do not become symptom free. Better criteria for response assessment than allergy skin tests or IgE determination are needed. The impact of the size of the disease relevant allergen-specific IgE antibody fraction, i.e. the percentage of IgE antibody of total IgE, was evaluated in cat allergic patients treated with the recommended doses of Xolair. Results were measured as changes in basophil allergen threshold sensitivity (CD-sens). METHODS: In a double-blind placebo controlled trial 20 patients with a high (>3.8%) and 18 with a low (<1%) percentage of IgE antibodies to cat were given Xolair for 16 weeks and the change in CD-sens was compared to 11 and 10 patients, respectively, in each group receiving placebo. RESULTS: The CD-sens dropped significantly in both the high (P < 0.001) and low (P < 0.001) group on Xolair but did not change significantly after placebo. For Xolair-treated patients, at the end of the trial there was a highly significant (P < 0.001) difference in CD-sens between the high group, where no patients, and the low group, where 13/18 patients, had become negative. CONCLUSIONS: The currently recommended doses of Xolair very efficiently eliminate IgE antibodies if the IgE antibody fraction is <1% of total IgE but has not enough effect on allergen sensitivity if the fraction is >3-4%. Further studies will show if increased doses of Xolair would help also these patients, who seem to represent about 1/3 of the patient population.