Siltuximab, a Novel Anti-Interleukin-6 Monoclonal Antibody, for Castleman's Disease
ABSTRACT Interleukin-6 (IL-6) has emerged as a key factor in the pathogenesis of the atypical lymphoproliferative disorder Castleman's disease (CD). Siltuximab is a new anti-IL-6, chimeric monoclonal antibody with potential therapeutic benefit in patients with CD.
We report interim results from an open-label, dose-finding, seven-cohort, phase I study in which patients with symptomatic, multicentric or unresectable, unicentric CD received siltuximab at 1-, 2-, or 3-week intervals. The main efficacy end point of clinical benefit response (CBR) was defined as a composite of clinical and laboratory measures relevant to the management of CD. In addition, radiologic response was independently assessed by using modified Cheson criteria.
Eighteen (78%) of 23 patients (95% CI, 56% to 93%) achieved CBR, and 12 patients (52%) demonstrated objective tumor response. All 11 patients (95% CI, 72% to 100%) treated with the highest dose of 12 mg/kg achieved CBR, and eight patients (73%) achieved objective tumor response. Overall objective-response duration ranged from 44 to > or = 889 days, and one patient had complete response for > or = 318 days. Hemoglobin increased markedly in 19 patients (median increase, 2.1 g/dL; range, 0.2 to 4.7 g/dL) in the absence of transfusion or erythropoiesis-stimulating agents. No dose-limiting toxicity was reported, and only three patients had grade 3 or higher adverse events after a median exposure of 331 days (range, 1 to 1,148 days).
These interim results strongly suggest that siltuximab is an effective treatment with favorable safety for the management of CD. An additional study is planned to fully evaluate safety and efficacy at the recommended dose of 12 mg/kg every 3 weeks.
SourceAvailable from: PubMed Central[Show abstract] [Hide abstract]
ABSTRACT: Multicentric Castleman's disease is a rare lymphoproliferative disorder whose hallmark is atypical lymph node hyperplasia. Symptoms can include fever, splenomegaly, and abnormal blood cell counts. High levels of interleukin 6 (IL-6) are observed frequently in this disorder and are believed to drive the disease. Recently, therapies that target interleukin-6 or its receptor have been shown to be effective in Castleman's disease. We report the case of a 76-year-old Caucasian man with aggressive biopsy-proven Castleman's disease who experienced pulmonary and lymph node involvement, as well as fever and weight loss. He was treated with siltuximab, a chimeric anti-interleukin-6 antibody. After 5 months, fluorodeoxyglucose positron emission tomography computed tomography scans showed marked improvement in his lungs, but worsening mediastinal disease, consistent with a mixed response. Biopsy of the mediastinal disease revealed lymphoplasmacytic infiltrate with non-caseating, ill-defined granulomas and scarring consistent with sarcoidosis. Prednisone 50mg by mouth daily was started, which was tapered to 2.0-5.0mg daily. Siltuximab was continued. A subsequent fluorodeoxyglucose positron emission tomography computed tomography scan showed near-complete resolution of lung and mediastinal disease, now ongoing for 3.5+ years without serious adverse events. Lymphomas have previously been reported to coexist with sarcoidosis, albeit rarely, but there has been only a single previous case of this type with Castleman's disease. Of importance, early recognition of the presence of sarcoidosis in our patient prevented discontinuation of siltuximab therapy due to "progression." Our experience may also have broader implications in that it suggests that etiology of "mixed responses" should be confirmed by performing biopsies on the progressive tumor.Journal of Medical Case Reports 12/2015; 9(1):517. DOI:10.1186/s13256-015-0517-8
[Show abstract] [Hide abstract]
ABSTRACT: Siltuximab is a monoclonal antibody that binds to interleukin (IL)-6 with high affinity and specificity; C-reactive protein (CRP) is an acute-phase protein induced by IL-6. CRP suppression is an indirect measurement of IL-6 activity. Here, modeling and simulation of the pharmacokinetic (PK)/pharmacodynamic (PD) relationship between siltuximab and CRP were used to support dose selection for multicentric Castleman's disease (CD). PK/PD modeling was applied to explore the relationship between siltuximab PK and CRP suppression following intravenous siltuximab infusion in 47 patients with B cell non-Hodgkin's lymphoma (n = 17), multiple myeloma (n = 13), or CD (n = 17). Siltuximab was administered as 2.8, 5.5, or 11 mg/kg q2wks, 11 mg/kg q3wks, or 5.5 mg/kg weekly. Simulations of studied or hypothetical siltuximab dosage regimens (15 mg/kg q4wks) were also performed to evaluate maintenance of CRP suppression below the cutoff value of 1 mg/L. A two-compartment PK model and an inhibitory indirect response PD model adequately described the serum siltuximab and CRP concentration-time profiles simultaneously. PD parameter estimates were physiologically plausible. For all disease types, simulations showed that 11 mg/kg q3wks or 15 mg/kg q4wks would reduce serum CRP to below 1 mg/L after the second dose and throughout the treatment period. PK/PD modeling was used to select doses for further development of siltuximab in multicentric CD. The dosing recommendation was also supported by the observed efficacy dose-response relationship. CRP suppression in the subsequent randomized multicentric CD study was in agreement with the modeling predictions.Cancer Chemotherapy and Pharmacology 03/2015; 75(5). DOI:10.1007/s00280-015-2720-0 · 2.57 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Multicentric Castleman's disease (MCD) is a rare lymphoproliferative disorder driven by dysregulated interleukin-6 production. MCD has a poor prognosis, and treatment is generally noncurative and aimed at symptom relief. Siltuximab is a novel, monoclonal interleukin-6 antibody recently shown to be effective in a registration clinical trial. MCD symptoms, such as fatigue, pain, and weakness, are most appropriately quantified using patient-reported outcome (PRO) measures. We assessed the effect of siltuximab on patient perception of symptoms, functional status, and wellbeing using PRO instruments. We analyzed results of a randomized, double-blind trial comparing siltuximab 11 mg/kg every 3 weeks with placebo to treat MCD. Subjects (N = 79) completed the recently developed MCD-Symptom Scale (MCD-SS), the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) scale, and the Short Form (SF)-36 at predetermined time points throughout the treatment period. Scores were compared at baseline and over time between the treatment arms and PRO instruments. At baseline, the mean number of symptoms reported was 9.2 (standard deviation 3.76) out of 16 total, as measured by the MCD-SS. Fatigue was a key symptom across all PRO instruments. Siltuximab-treated subjects reported early improvements in symptoms compared with subjects in the placebo arm on both the MCD-SS and FACIT-Fatigue scale. Statistically significant improvements in five SF-36 domains were observed in siltuximab-treated patients, namely role physical, role emotional, vitality, bodily pain, and mental health. Patients with MCD commonly report impairments in functioning, wellbeing, and fatigue at baseline. Siltuximab-treated patients reported significant improvements in these outcomes after treatment.The patient 03/2015; 8(2). DOI:10.1007/s40271-015-0120-5 · 1.96 Impact Factor