Safety and efficacy assessment of two new leprosy skin test antigens: randomized double blind clinical study.

BACKGROUND: New tools are required for the diagnosis of pre-symptomatic leprosy towards further reduction of disease burden and its associated reactions. To address this need, two new skin test antigens were developed to assess safety and efficacy in human trials. METHODS: A Phase I safety trial was first conducted in a non-endemic region for leprosy (U.S.A.). Healthy non-exposed subjects (n = 10) received three titrated doses (2.5 µg, 1.0 µg and 0.1 µg) of MLSA-LAM (n = 5) or MLCwA (n = 5) and control antigens [Rees MLSA (1.0 µg) and saline]. A randomized double blind Phase II safety and efficacy trial followed in an endemic region for leprosy (Nepal), but involved only the 1.0 µg (high dose) and 0.1 µg (low dose) of each antigen; Tuberculin PPD served as a control antigen. This Phase II safety and efficacy trial consisted of three Stages: Stage A and B studies were an expansion of Phase I involving 10 and 90 subjects respectively, and Stage C was then conducted in two parts (high dose and low dose), each enrolling 80 participants: 20 borderline lepromatous/lepromatous (BL/LL) leprosy patients, 20 borderline tuberculoid/tuberculoid (BT/TT) leprosy patients, 20 household contacts of leprosy patients (HC), and 20 tuberculosis (TB) patients. The primary outcome measure for the skin test was delayed type hypersensitivity induration. FINDINGS: In the small Phase I safety trial, reactions were primarily against the 2.5 µg dose of both antigens and Rees control antigen, which were then excluded from subsequent studies. In the Phase II, Stage A/B ramped-up safety study, 26% of subjects (13 of 50) showed induration against the high dose of each antigen, and 4% (2 of 50) reacted to the low dose of MLSA-LAM. Phase II, Stage C safety and initial efficacy trial showed that both antigens at the low dose exhibited low sensitivity at 20% and 25% in BT/TT leprosy patients, but high specificity at 100% and 95% compared to TB patients. The high dose of both antigens showed lower specificity (70% and 60%) and sensitivity (10% and 15%). BL/LL leprosy patients were anergic to the leprosy antigens. INTERPRETATION: MLSA-LAM and MLCwA at both high (1.0 µg) and low (0.1 µg) doses were found to be safe for use in humans without known exposure to leprosy and in target populations. At a sensitivity rate of 20-25% these antigens are not suitable as a skin test for the detection of the early stages of leprosy infection; however, the degree of specificity is impressive given the presence of cross-reactive antigens in these complex native M. leprae preparations. TRIAL REGISTRATION: ClinicalTrials.gov NCT01920750 (Phase I), NCT00128193 (Phase II).

A comparison of the change in clinical severity scale score and a retrospective physician assessment of neurological outcome in individuals with leprosy associated nerve function impairment after treatment with corticosteroids.

OBJECTIVES: To determine whether the measured change in score of a validated clinical severity scale reflected physician assessed improvement in individuals who had received corticosteroid therapy for leprosy associated nerve damage. DESIGN: Patients with nerve function impairment who participated in a randomised controlled trial of corticosteroids were classified into two groups using a retrospectively determined physician assessment of improvement. One group consisted of patients who had recovered or improved the other of patients who were unchanged or had deteriorated. The change in the clinical severity scale scores of these two groups was compared. RESULTS: The change in the clinical severity scale scores of the 34 eligible individuals in the two groups were significantly different (P = 0.003). Individuals in the group who recovered or improved had a greater change in severity score than those whose nerve function was unchanged or deteriorated. CONCLUSION: The scale for measuring the severity of leprosy Type 1 reactions (T1Rs) and/or nerve function impairment reflects the clinical improvement of individuals with leprosy associated nerve damage.

A phase two randomised controlled double blind trial of high dose intravenous methylprednisolone and oral prednisolone versus intravenous normal saline and oral prednisolone in individuals with leprosy type 1 reactions and/or nerve function impairment.

BACKGROUND: Leprosy Type 1 reactions are a major cause of nerve damage and the preventable disability that results. Type 1 reactions are treated with oral corticosteroids and there are few data to support the optimal dose and duration of treatment. Type 1 reactions have a Th1 immune profile: cells in cutaneous and neural lesions expressing interferon-γ and interleukin-12. Methylprednisolone has been used in other Th1 mediated diseases such as rheumatoid arthritis in an attempt to switch off the immune response and so we investigated the efficacy of three days of high dose (1 g) intravenous methylprednisolone at the start of prednisolone therapy in leprosy Type 1 reactions and nerve function impairment. RESULTS: Forty-two individuals were randomised to receive methylprednisolone followed by oral prednisolone (n = 20) or oral prednisolone alone (n = 22). There were no significant differences in the rate of adverse events or clinical improvement at the completion of the study. However individuals treated with methylprednisolone were less likely than those treated with prednisolone alone to experience deterioration in sensory function between day 29 and day 113 of the study. The study also demonstrated that 50% of individuals with Type 1 reactions and/or nerve function impairment required additional prednisolone despite treatment with 16 weeks of corticosteroids. CONCLUSIONS: The study lends further support to the use of more prolonged courses of corticosteroid to treat Type 1 reactions and the investigation of risk factors for the recurrence of Type 1 reaction and nerve function impairment during and after a corticosteroid treatment. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN31894035.

Effective treatment of erythema nodosum leprosum with thalidomide is associated with immune stimulation.

The immunomodulatory drug thalidomide is the treatment of choice for erythema nodosum leprosum (ENL), an inflammatory cutaneous and systemic complication of multibacillary leprosy. To elucidate the mechanism of action of thalidomide in this syndrome, we prospectively investigated 20 patients with ENL who were treated with thalidomide for 21 days. All patients responded to treatment, with the majority of them having complete resolution of cutaneous lesions within 7 days. This response was associated with a marked but transient increase in ex vivo mitogen-induced expression of interleukin (IL)-2 and interferon- gamma by CD4(+) and CD8(+) T cells that was observed on treatment day 7, but these returned to pretreatment levels by day 21. Plasma tumor necrosis factor- alpha levels were not high at baseline, and they increased modestly during treatment. Plasma levels of IL-12 increased steadily during thalidomide treatment. Hence, the therapeutic effect of thalidomide in ENL appears to be associated with transient immune stimulation, which suggests that the drug may promote an active immunoregulatory response.

Clinical outcomes in a randomized controlled study comparing azathioprine and prednisolone versus prednisolone alone in the treatment of severe leprosy type 1 reactions in Nepal.

The ILEP nerve function impairment and reaction research programme (INFIR 2) was a group of clinical trials conducted to identify second-line treatments for severe leprosy type 1 reactions (T1R). This paper presents the clinical results of one of these trials in which azathioprine was used in combination with short-course prednisolone to ascertain if the combination was effective in controlling the symptoms and signs of reaction. Forty patients were alternately assigned to a 12-week treatment with either AP (12 weeks azathioprine at 3mg/kg/d plus 8 week reducing course prednisolone starting at 40mg/d) or P (12-week reducing course prednisolone starting at 40mg/d). Evaluation included serial quantitative clinical assessments. The overall frequency of side effects was similar in both groups. Results show that there was no difference in clinical outcome in the AP and P groups and a similar number of patients in each group required extra prednisolone for worsening clinical features. We conclude that a 12-week course of azathioprine at 3mg/kg/day plus an 8 week reducing course of prednisolone starting at 40mg/d is as effective as a 12 week reducing course of prednisolone starting at 40mg/d and that the combination therapy is well-tolerated in severe leprosy T1R patients.