Long-term safety of mepolizumab for the treatment of hypereosinophilic syndromes.

BACKGROUND: Hypereosinophilic syndromes (HESs) are chronic disorders that require long-term therapy to suppress eosinophilia and clinical manifestations. Corticosteroids are usually effective, yet many patients become corticosteroid refractory or develop corticosteroid toxicity. Mepolizumab, a humanized monoclonal anti-IL-5 antibody, showed corticosteroid-sparing effects in a double-blind, placebo-controlled study of FIP1L1/PDGFRA-negative, corticosteroid-responsive subjects with HESs. OBJECTIVE: We evaluated long-term safety and efficacy of mepolizumab (750 mg) in HES. METHODS: MHE100901 is an open-label extension study. The primary end point was the frequency of adverse events (AEs). Optimal dosing frequency, corticosteroid-sparing effect of mepolizumab, and development of antimepolizumab antibodies were also explored. RESULTS: Seventy-eight subjects received 1 to 66 mepolizumab infusions each (including mepolizumab infusions received in the placebo-controlled trial). Mean exposure was 251 weeks (range, 4-302 weeks). The most common dosing interval was 9 to 12 weeks. The incidence of AEs was 932 events per 100 subject-years in the first year, declining to 461 events per 100 subject-years after 48 months. Serious AEs, including 1 death, were reported by the investigator as possibly due to mepolizumab in 3 subjects. The median daily prednisone dose decreased from 20.0 to 0 mg in the first 24 weeks. The median average daily dose for all subjects over the course of the study was 1.8 mg. Sixty-two percent of subjects were prednisone free without other HES medications for ≥ 12 consecutive weeks. No neutralizing antibodies were detected. Twenty-four subjects withdrew before study completion for death (n = 4), lack of efficacy (n = 6), or other reasons. CONCLUSION: Mepolizumab was well tolerated and effective as a long-term corticosteroid-sparing agent in PDGFRA-negative HES.

Treatment of patients with the hypereosinophilic syndrome with mepolizumab.

BACKGROUND: The hypereosinophilic syndrome is a group of diseases characterized by persistent blood eosinophilia, defined as more than 1500 cells per microliter with end-organ involvement and no recognized secondary cause. Although most patients have a response to corticosteroids, side effects are common and can lead to considerable morbidity. METHODS: We conducted an international, randomized, double-blind, placebo-controlled trial evaluating the safety and efficacy of an anti-interleukin-5 monoclonal antibody, mepolizumab, in patients with the hypereosinophilic syndrome. Patients were negative for the FIP1L1-PDGFRA fusion gene and required prednisone monotherapy, 20 to 60 mg per day, to maintain a stable clinical status and a blood eosinophil count of less than 1000 per microliter. Patients received either intravenous mepolizumab or placebo while the prednisone dose was tapered. The primary end point was the reduction of the prednisone dose to 10 mg or less per day for 8 or more consecutive weeks. RESULTS: The primary end point was reached in 84% of patients in the mepolizumab group, as compared with 43% of patients in the placebo group (hazard ratio, 2.90; 95% confidence interval [CI], 1.59 to 5.26; P<0.001) with no increase in clinical activity of the hypereosinophilic syndrome. A blood eosinophil count of less than 600 per microliter for 8 or more consecutive weeks was achieved in 95% of patients receiving mepolizumab, as compared with 45% of patients receiving placebo (hazard ratio, 3.53; 95% CI, 1.94 to 6.45; P<0.001). Serious adverse events occurred in seven patients receiving mepolizumab (14 events, including one death; mean [+/-SD] duration of exposure, 6.7+/-1.9 months) and in five patients receiving placebo (7 events; mean duration of exposure, 4.3+/-2.6 months). CONCLUSIONS: Our study shows that treatment with mepolizumab, an agent designed to target eosinophils, can result in corticosteroid-sparing for patients negative for FIP1L1-PDGFRA who have the hypereosinophilic syndrome. (ClinicalTrials.gov number, NCT00086658 [ClinicalTrials.gov].).

Placebo response in two long-term randomized psoriasis studies that were negative for rosiglitazone.

BACKGROUND: Previous research has suggested that the thiazolidinedione rosiglitazone may possess anti-psoriatic activity. OBJECTIVE: To compare the efficacy and safety of rosiglitazone with that of placebo in the treatment of chronic plaque psoriasis. METHODS: Two large-scale, randomized, double-blind, multicenter studies (study A, n = 1563; study B, n = 1032) were conducted over 52 weeks (plus optional 44 weeks safety extension) in an outpatient setting. The subjects (aged 18-75 years) had moderate-to-severe chronic plaque psoriasis affecting >or=10% body surface area (BSA) with plaques of any elevation above normal-appearing skin (or >or=6% BSA involvement with marked elevation) and had not used phototherapy during the previous month or thiazolidinediones within the previous 3 months. Rosiglitazone was administered as 2, 4, or 8 mg tablets once daily. The main outcome measure was the proportion of subjects achieving >or=75% improvement from baseline in the Psoriasis Area and Severity Index (PASI 75) at week 26. RESULTS: Rosiglitazone was well tolerated but no more effective than placebo for moderate-to-severe chronic plaque psoriasis. However, there was a large placebo response unrelated to concomitant rescue medication. Interestingly, subjects had been advised to expect a long period before onset of action. At week 26 and across both studies for subjects receiving placebo, the PASI 75 was 9% (48/506) and the PASI 50 (proportion of subjects who achieved at least 50% improvement from baseline) was 27% (135/506). In addition, few subjects withdrew from placebo or rosiglitazone treatment because of 'lack of efficacy' and the majority persisted in the year-long study. CONCLUSION: While these large-scale, robust studies demonstrated that rosiglitazone is not active in psoriasis, they also showed that for a large proportion of subjects receiving placebo, the expectation of a successful treatment, the favorable adverse effect profile of the drug, and the supportive environment of a clinical study conferred beneficial effects. These results may have implications for the design of future placebo-controlled studies in patients with psoriasis.