Lean Body Mass Improves in Sylvant Treated Multicentric Castleman's Disease Patients

At the 2014 American Society Clinical Oncology  (ASCO) Annual Meeting,  Sawyer et al presented data looking at lean body mass (LBM) outcomes in patients with multicentric Castleman’s disease who received Sylvant (siltuximab) or placebo in a randomized, double-blind, placebo-controlled study.  

As Dr Michael Sawyer, Associate Professor, Medical Oncology at University of Alberta explains in this exclusive interview,  Interleukin-6 (IL-6) plays a pivotal role in multicentric Castleman’s disease  and has a major role in cachexia (loss of weight, muscle atrophy, fatigue, weakness) which is common in patients with cancer and multicentric Castleman’s disease. Sylvant is an IL-6 antagonist and recently approved for multicentric Castleman’s disease (in patients who are human immunodeficiency virus (HIV) negative and human herpesvirus-8 (HHV-8) negative).

Based on those observations, LBM was measured in the patients receiving either Sylvant or placebo in the pivotal phase 3 trial.

Patients with confirmed symptomatic multicentric Castleman’s disease were randomized 2:1 to Sylvant (11 mg/kg; n = 53) or placebo (n = 26) IV q3wk. Abdominal CT scans suitable for body composition analysis were available for 57 (37 on Sylvant, 20 on placebo) of the 79 subjects.

As Dr Sawyer explains in this video, mean maximal gain in LBM in the Sylvant patients was 2.4 kg compared to 1.1 kg in the placebo patients (P = 0.04). Further, at 9 weeks, 50% of Sylvant patients had gained 1 kg of LBM while at no point did 50% of placebo patients gain 1 kg.

Castleman's disease is not a cancer but is a lymphoproliferative disorder involving an overgrowth (proliferation) of lymphatic cells. Castleman's disease affects the lymph nodes and may require treatment with surgery, chemotherapy and/or radiation therapy. Castleman's disease is also referred to as giant lymph node hyperplasia, or angiofollicular lymph node hyperplasia.

Sylvant is an IL-6 antagonist and recently approved for treating patients with multicentric Castleman’s disease who are HIV negative and HHV-8 negative. Sylvant was not studied in patients with multicentric Castleman’s disease who are HIV positive or HHV-8 positive because Sylvant did not bind to virally produced IL-6 in a nonclinical study.

Sawyer MB, Casper C, Munshi NC, et al. Effect of siltuximab on lean body mass (LBM) in multicentric Castleman’s disease (MCD) patients (pts). J Clin Oncol 32:5s, 2014 (suppl; abstr 8576)
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