Long-term efficacy of fixed-dose omalizumab for patients with severe chronic spontaneous urticaria.

BACKGROUND: Treatment of chronic urticaria is challenging because many patients are refractory to or experience adverse effects with conventional therapy. Recently, short-term efficacy of omalizumab has been demonstrated. OBJECTIVE: To determine both the short- and long-term efficacy of omalizumab in the treatment of chronic urticaria. METHODS: Sixteen patients with severe chronic spontaneous urticaria at our center received omalizumab, 150 mg every 2 to 4 weeks, between 2010 and 2011. Disease severity was measured by urticaria activity scores before the first injection, during treatment, and at most recent follow-up, ranging from 9 to 24 months. Duration of therapy was determined individually for each patient. In this retrospective analysis, outcome measures include number of treatments required to induce remission and long-term remission sustainability. RESULTS: Ten patients had remission of urticaria after their first injection (62%). Four patients required 2 to 6 treatments to achieve remission. Two patients discontinued treatment after 2 injections. Of the 14 patients who initially benefited (88%), 4 remain in remission more than 9 months after their last treatments. Seven patients continue to achieve remission with maintenance omalizumab, dosed at intervals appropriate for individual remission duration. Three patients became refractory and discontinued treatment (19%). CONCLUSION: Omalizumab is an effective treatment for inducing and maintaining long-term remission for patients with severe chronic urticaria. Onset of remission is rapid, although duration is variable, with some patients requiring maintenance treatment. Large-scale randomized trials are necessary to confirm our findings that support the long-term efficacy of anti-IgE therapy for the treatment of this disease.

Characterization of Cannabis sativa allergens.

BACKGROUND: Allergic sensitization to Cannabis sativa is rarely reported, but the increasing consumption of marijuana has resulted in an increase in the number of individuals who become sensitized. To date, little is known about the causal allergens associated with C sativa. OBJECTIVE: To characterize marijuana allergens in different components of the C sativa plant using serum IgE from marijuana sensitized patients. METHODS: Serum samples from 23 patients with a positive skin prick test result to a crude C sativa extract were evaluated. IgE reactivity was variable between patients and C sativa extracts. IgE reactivity to C sativa proteins in Western blots was heterogeneous and ranged from 10 to 70 kDa. Putative allergens derived from 2-dimensional gels were identified. RESULTS: Prominent IgE reactive bands included a 23-kDa oxygen-evolving enhancer protein 2 and a 50-kDa protein identified to be the photosynthetic enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase. Additional proteins were identified in the proteomic analysis, including those from adenosine triphosphate synthase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and luminal binding protein (heat shock protein 70), suggesting these proteins are potential allergens. Deglycosylation studies helped refine protein allergen identification and demonstrated significant IgE antibodies against plant oligosaccharides that could help explain cross-reactivity. CONCLUSION: Identification and characterization of allergens from C sativa may be helpful in further understanding allergic sensitization to this plant species.

Effect of ketotifen premedication on adverse reactions during peanut oral immunotherapy.

BACKGROUND: Oral immunotherapy (OIT) has shown promise in inducing desensitization for food allergy. However, there are safety concerns regarding the frequency and severity of adverse events during food OIT. OBJECTIVE: To evaluate the effect of Ketotifen premedication on adverse reactions during peanut OIT. METHODS: A randomized single blind placebo controlled pilot study was performed. Peanut OIT was performed using a previously published protocol. Ketotifen was up-titrated to 2 mg twice daily over two weeks (week -2 to 0), followed by a peanut OIT initial escalation day (day 1). Ketotifen was administered from week 0-4 of peanut OIT; reactions to peanut OIT doses were recorded by clinic staff and subject diary. RESULTS: Six subjects (median age 10 years, peanut IgE >100kUA/L) were enrolled, 4 randomized to Ketotifen, 2 to placebo. The most common side effect of Ketotifen was fatigue (9% during up-titration). The rate of reaction per peanut OIT dose was lower for subjects on ketotifen (K) compared to placebo (P) during initial escalation on day 1 (K: 22% (8/36) vs. P: 67% (12/18)); week 0-4 build-up doses (K: 75% (3/4) vs. P: 100% (2/2)); and week 0-4 home doses (K: 50% (54/108) vs. P: 82% (27/33)). The rate of gastrointestinal symptoms per peanut OIT dose was also lower for subjects on ketotifen during initial escalation on day 1 (K: 17% (6/36) vs. P: 61% (11/18)); week 0-4 build-up doses (K: 75% (3/4) vs P: 100% (2/2)); and week 0-4 home doses (K: 46% (50/108) vs. P: 82% (27/33)). CONCLUSIONS: Ketotifen premedication is well tolerated and reduces the rate of gastrointestinal symptoms during peanut OIT. These findings require confirmation in a larger study of Ketotifen premedication used throughout peanut OIT. CLINICAL TRIALS NUMBER: NCT0162515.

Examination of genetic variants involved in generation and biodisposition of kinins in patients with angioedema.

BACKGROUND: Angioedema (AE) is idiopathic in the majority of cases. We studied patients with AE for genetic variants of proteins involved with bradykinin generation and biodisposition. METHODS: One hundred sixty one patients with AE were recruited at a university hospital clinic. Patients were categorized according to the proposed pathogenesis of AE: low C1 inhibitor (C1-INH) and C4 levels, autoimmune disease, cancer, angiotensin-converting enzyme (ACE) inhibitor-induced, nonsteroidal antiinflammatory drug (NSAID)-induced, or idiopathic. In addition, each patient had a blood sample analyzed for a complement profile and enzymes (C1-INH and C4). Fifty-two of the patients were tested for genetic variants in factor XII, plasminogen-activator inhibitor-1 (PAI-1), ACE, and aminopeptidase P (APP). RESULTS: The cause of angioedema was identified in 59/161 (37%) of the cases: 3 (2%) patients had a low plasma C1-INH and C4; 20 (12%) were ACE inhibitor-induced; 12 (7%) were associated with autoimmune disorders; 7 (4%) were associated with malignancy; and 17 (11%) were associated with NSAIDs. In the remaining 102 (63%) patients the cause of angioedema was idiopathic. Of 52 patients with genetic analysis, 13 (25%) had a genetic variant in APP, 10 (19%) in ACE, 13 (25%) in PAI-1, and 0 in Factor XII. CONCLUSIONS: In addition to related diseases and medications causing AE, certain genetic variants encoding proteins involved in bradykinin generation and/or catabolism pathways may be involved in the pathogenesis of AE.