Ross E. Rocklin

Dupilumab in Persistent Asthma with Elevated Eosinophil Levels

BACKGROUND Moderate-to-severe asthma remains poorly treated. We evaluated the efficacy and safety of dupilumab (SAR231893/REGN668), a fully human monoclonal antibody to the alpha subunit of the interleukin-4 receptor, in patients with persistent, moderate-to-severe asthma and elevated eosinophil levels. METHODS We enrolled patients with persistent, moderate-to-severe asthma and a blood eosinophil count of at least 300 cells per microliter or a sputum eosinophil level of at least 3% who used medium-dose to high-dose inhaled glucocorticoids plus long-acting beta-agonists (LABAs). We administered dupilumab (300 mg) or placebo subcutaneously once weekly. Patients were instructed to discontinue LABAs at week 4 and to taper and discontinue inhaled glucocorticoids during weeks 6 through 9. Patients received the study drug for 12 weeks or until a protocol-defined asthma exacerbation occurred. The primary end point was the occurrence of an asthma exacerbation; secondary end points included a range of measures of asthma control. Effects on various type 2 helper T-cell (Th2)-associated biomarkers and safety and tolerability were also evaluated. RESULTS A total of 52 patients were assigned to the dupilumab group, and 52 patients were assigned to the placebo group. Baseline characteristics were similar in the two groups. Three patients had an asthma exacerbation with dupilumab (6%) versus 23 with placebo (44%), corresponding to an 87% reduction with dupilumab (odds ratio, 0.08; 95% confidence interval, 0.02 to 0.28; P<0.001). Significant improvements were observed for most measures of lung function and asthma control. Dupilumab reduced biomarkers associated with Th2-driven inflammation. Injection-site reactions, nasopharyngitis, nausea, and headache occurred more frequently with dupilumab than with placebo. CONCLUSIONS In patients with persistent, moderate-to-severe asthma and elevated eosinophil levels who used inhaled glucocorticoids and LABAs, dupilumab therapy, as compared with placebo, was associated with fewer asthma exacerbations when LABAs and inhaled glucocorticoids were withdrawn, with improved lung function and reduced levels of Th2-associated inflammatory markers. (Funded by Sanofi and Regeneron Pharmaceuticals; ClinicalTrials.gov number, NCT01312961.).

Dupilumab Treatment in Adults with Moderate-to-Severe Atopic Dermatitis

BACKGROUND Dupilumab, a fully human monoclonal antibody that blocks interleukin-4 and interleukin-13, has shown efficacy in patients with asthma and elevated eosinophil levels. The blockade by dupilumab of these key drivers of type 2 helper T-cell (Th2)-mediated inflammation could help in the treatment of related diseases, including atopic dermatitis. METHODS We performed randomized, double-blind, placebo-controlled trials involving adults who had moderate-to-severe atopic dermatitis despite treatment with topical glucocorticoids and calcineurin inhibitors. Dupilumab was evaluated as monotherapy in two 4-week trials and in one 12-week trial and in combination with topical glucocorticoids in another 4-week study. End points included the Eczema Area and Severity Index (EASI) score, the investigators global assessment score, pruritus, safety assessments, serum biomarker levels, and disease transcriptome. RESULTS In the 4-week monotherapy studies, dupilumab resulted in rapid and dose-dependent improvements in clinical indexes, biomarker levels, and the transcriptome. The results of the 12-week study of dupilumab monotherapy reproduced and extended the 4-week findings: 85% of patients in the dupilumab group, as compared with 35% of those in the placebo group, had a 50% reduction in the EASI score (EASI-50, with higher scores in the EASI indicating greater severity of eczema) (P<0.001); 40% of patients in the dupilumab group, as compared with 7% in the placebo group, had a score of 0 to 1 (indicating clearing or near-clearing of skin lesions) on the investigators global assessment (P<0.001); and pruritus scores decreased (indicating a reduction in itch) by 55.7% in the dupilumab group versus 15.1% in the placebo group (P<0.001). In the combination study, 100% of the patients in the dupilumab group, as compared with 50% of those who received topical glucocorticoids with placebo injection, met the criterion for EASI-50 (P=0.002), despite the fact that patients who received dupilumab plus glucocorticoids used less than half the amount of topical glucocorticoids used by those who received placebo plus the topical medication (P=0.16). Adverse events, such as skin infection, occurred more frequently with placebo; nasopharyngitis and headache were the most frequent adverse events with dupilumab. CONCLUSIONS Patients treated with dupilumab had marked and rapid improvement in all the evaluated measures of atopic dermatitis disease activity. Side-effect profiles were not dose-limiting. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov numbers, NCT01259323, NCT01385657, NCT01639040, and NCT01548404.).

Generation of Antigen-Specific Suppressor Cells during Allergy Desensitization

We used a suppressor-cell assay to study a possible mechanism of allergy desensitization. Before specific immunotherapy, blood mononuclear cells from 20 patients with ragweed hayfever failed to exhibit suppressor activity in vitro after stimulation by ragweed antigen E. However, when the 10 patients with allergic rhinitis had been desensitized by injections of ragweed extract, their mononuclear cells specifically suppressed a ragweed proliferative response six and 12 months after desensitization was begun (31 per cent and 48 per cent suppression, respectively). Suppressor mononuclear cells were not detected in 10 control subjects of in 10 patients with ragweed hayfever who were not desensitized. When mononuclear cells taken from treated patients were passed over columns containing insolubilized histamine, antigen-specific suppressor cells that could be activated by ragweed antigen were depleted. These results indicate that antigen-specific suppressor cells, probably bearing histamine receptors, are generated during desensitization to allergy and may be partly responsible for the efficacy of this therapy.

Cellular Sensitivity to Collagen in Rheumatoid Arthritis

We examined patients with rheumatoid arthritis for cellular sansitivity to native human Types I, II and III collagens. Mononuclear cells from 50 patients with rheumatoid arthritis, 21 with other inflammatory arthritides, 20 with osteoarthritis and 20 normal subjects were evaluated for the in vitro production of leukocyte inhibitory factor in response to collagen and a control antigen, streptokinase-streptodornase. By this assay, cells from 37 (74 per cent) and 39 (78 per cent) of the patients with rheumatoid arthritis responded to Types II and III collagens, respectively. In contrast, cells from the 41 patients with other kinds of arthritis and the normal group did not produce this lymphokine to collagens. There was no response to Type I collagen or to denatured alpha chains of these collagens. All four groups responded equivalently to streptokinase-streptodornase. These data demonstrate that most patients with rheumatoid arthritis exhibit cellular sensitivity to Types II and III collagens.

The Influence of Histamine on Immune and Inflammatory Responses

Publisher Summary The fact that histamine can influence the immune process at different stages and that it can influence different subpopulations of cells at concentrations that probably exist in vivo during physiologic and pathologic events indicates that it can be seriously considered as a significant modulator of inflammatory and immune processes. Once histamine is made available, it is capable of interacting in the local milieu with lymphocytes/macrophages or other cell types present at the site of the reaction and modulating immune and inflammatory events. Some of its pro-inflammatory effects include stimulating T effector cells to produce chemoattractant and migration-inhibitory lymphokines, thus recruiting other immunocompetent lymphocytes to the reaction site and retaining them there. Some of the anti-inflammatory events mediated by histamine include the activation of suppression cells following their interaction with macrophages and/or their products (IL-1), which leads to the production of HSF. The latter augments the production of prostaglandins by macrophages/monocytes. Histamine may modulate the function of cytotoxic T cells and natural killer cells directly, thereby reducing their ability to mediate damage to their target cells. Histamine inhibition of complement synthesis by macrophages may serve to limit the severity of the inflammatory response.

Mediators of immunity: lymphokines and monokines.

Publisher Summary This chapter discusses a broad array of lymphokines and monokines that have marked biological effects on a variety of cell types, including B and T lymphocytes, macrophages, and other cells. The migration inhibitory factors, the chemotactic factors, the mitogenic factors, the helper and suppressor factors, the lymphotoxins, and growth-promoting factors are discussed. Evidence is presented for single factors with multiple activities, a topic that has plagued investigators in this field. Cellular immune reactions are mediated by T lymphocytes, and the expression of these phenomena includes cutaneous delayed-type hypersensitivity, contact allergy, resistance to infection by facultative intracellular microorganisms, graft rejection, and tumor surveillance. These reactions result from complex interactions between T cells and B cells, T cells and other T cells, T cells and macrophages. Lymphokines are classified functionally according to their effects: inhibitory, stimulatory, or inflammatory. The chapter describes various soluble factors that are prime candidates for mediating various immunologic reactions, particularly those relating to cellular immunity. These factors can be produced by a variety of nonlymphoid sources. This implies a more general biologic role for lymphokines and monokines in host defense and other homeostatic mechanisms. The ability of cell types other than lymphocytes to produce lymphokine- and monokine-like factors provides a safeguard for the organism.

Characterization of the human blood lymphocytes that produce a histamine-induced suppressor factor (HSF)

Abstract The cells which elaborate a soluble suppressor factor in vitro in response to histamine (histamine-induced suppressor factor or HSF) were partially characterized in the present studies. Human blood T- and B-cell populations were purified by affinity chromatography with rabbit anti-human F(Ab′)2 and examined for their ability to make HSF. Highly purified populations of T cells, but not B cells, produced HSF in response to varying concentrations of histamine (10−4 to 10−4M). The HSF-producing cells were characterized further by means of affinity chromatography with columns containing conjugates of insolubilized histamine as well as by rosette formation with IgG (Tγ)- or IgM (Tμ)-coated ox red blood cells. These studies revealed the following: (a) Cells that synthesize HSF are retained on histamine (but not control) columns; (b) cells with histamine receptors comprise approximately 50% of the Tγ subpopulation but are not found in the Tμ subpopulation; (c) cells not retained by histamine columns have a reduced capacity to develop into suppressor cells following stimulation by concanavalin A or specific antigen (compared to unfractionated or control column passed cells). In addition, it was shown that cells synthesizing HSF predominantly express histamine type 2 receptors: (d)4-Methyl histamine (H2 agonist), but not 2-methyl histamine (H1 agonist), was capable of inducing HSF production; (e) cimetidine (H2 antagonist) inhibited HSF production but chlorpheniramine (H1 antagonist) did not. Taken together, these experiments suggest that T lymphocytes capable of expressing suppressor function following activation by histamine, specific antigen, concanavalin A, or perhaps through their Fc receptors may either be heterogeneous within the same subpopulation or more likely be the same cell with the complement of receptors described above.

The effect of immunotherapy on humoral and cellular responses in ragweed hayfever.

The effect of specific immunotherapy on several in vitro responses to ragweed antigen E has been evaluated in 17 atopic patients with ragweed hayfever. The methods employed were leukocyte histamine release, measurement of specific IgE anti-ragweed antibody and specific IgG anti-ragweed antibody, lymphocyte proliferation, and the production of two lymphocyte mediators (migration inhibitory factor and mitogenic factor). The duration of treatment and symptom improvement were also recorded for comparison. Immunotherapy was associated with a decrease in leukocyte sensitivity for histamine release to ragweed antigen E in a majority of the patients. In addition, there was a significant decrease in IgE anti-ragweed antibody and a significant increase in IgG anti-ragweed antibody. Immunotherapy also resulted in a significant decrease in lymphocyte responsiveness to ragweed antigen E as measured by proliferation and the production of mediators. Symptomatic improvement was best correlated with the presence of IgG anti-ragweed antibody responses. The production of this antibody was also associated with a decrease in lymphocyte responsiveness. The results of this study indicate that specific immunotherapy in ragweed-sensitive patients induces alterations in immunologic reactivity to ragweed antigen in vitro. This response is antigen specific, includes elements of both humoral and cellular immunity, and may account for the clinical improvement that is often observed in patients who undergo this form of therapy.

In Vitro Evidence for Cellular Hypersensitivity to Glomerular-Basement-Membrane Antigens in Human Glomerulonephritis

Abstract The macrophage inhibition assay was used to study in vitro the reactivity of human blood lymphocytes to a soluble preparation of glomerular-basement-membrane antigen. Twenty-one patients w...

The Guillain-Barré syndrome and multiple sclerosis. In vitro cellular responses to nervous-tissue antigens.

Abstract Blood lymphocytes from 83 subjects were evaluated for the presence of cellular hypersensitivity to peripheral and central-nervous-tissue antigens by means of the in vitro production of macrophage migration inhibitory factor (MIF). In the group of 25 patients with peripheral neuropathies, only lymphocytes from patients with the Guillain-Barre syndrome produced MIF in response to peripheral-nerve antigen. Lymphocytes from five of 15 patients with multiple sclerosis produced MIF when incubated with central-nerve antigen. An unexpected finding was that MIF was produced in response to central-nervous-tissue antigen by lymphocytes from six of nine patients who had had cerebrovascular accidents. Although these results further demonstrate that cellular hypersensitivity to components of nervous tissue is present in some neurologic diseases, the data from studies in patients with cerebrovascular accidents suggest that cellular hypersensitivity can be present as a result of nervous-tissue damage.