Proven clinical efficacy in patients with iMCD
The efficacy of SYLVANT® (siltuximab) has been proven in the only randomized clinical trial conducted in patients with idiopathic multicentric Castleman disease (iMCD).1
All patients received BSC, which included management of effusions; use of antipyretic, antipruritic, antihistamine, and pain drugs; management of infections and transfusions; and standard management of infusion-related reactions, as specified in institutional guidelines.
The median progression-free survival (PFS) was 14.5 months (95% CI, 13.6-upper bound not reached) for patients on placebo, but was not reached for patients on SYLVANT.2
Baseline interleukin-6 levels were not associated with durable tumor and symptomatic response or best tumor response.1 This study was conducted before the diagnostic criteria for iMCD were established.1,3
Safety and efficacy of SYLVANT®: Largest randomized phase 2 clinical study in iMCD to date
Primary End Point
-
Percentage of patients who achieved a durable tumor and symptomatic
response
Durable response defined as tumor and symptomatic response that persisted for a minimum of 18 weeks without treatment failure
Key Secondary End Points
- Tumor response rate: percentage of participants who achieved CR + PR
- Median time to treatment failureb
- ≥1.5 g/dL increase in hemoglobin
Additional Analysis
- Reduction in CRP levels
Study was conducted before the diagnostic criteria for iMCD were established1,3
Response to SYLVANT was significantly greater when minor criteria were met3,b
Diagnostic criteria for iMCD were established after the pivotal clinical trial. An additional efficacy analysis was performed by retrospectively applying the minor criteria to the siltuximab-treated patients from the pivotal clinical trial.1,3
(P = .0003)
Using Fisher’s exact test, those who met at least 2 minor criteria were significantly more likely to respond to SYLVANT than those who did not meet 2 minor criteria (P = .0003).3
bMinor Criteria include anemia, thrombocytopenia, constitutional symptoms, and ascites.3
Response rate was greater in the subset of patients who met the current criteria for iMCD (≥2 minor criteria)3
Patients who met 0 minor criteria (n=16) did not show response to SYLVANT and would not be eligible for siltuximab under current diagnostic guidelines3
Patients who were anemic showed a significant increase in hemoglobin1
Secondary end point analysis:
© Elsevier Inc. van Rhee et al. Lancet Oncol. 2014;15:966-974. Reprinted with permission.
of anemic patients (n=19/31)c achieved a >1.5 g/dL increase with SYLVANT (P = .0002)1
of anemic patients (n=13/31)c achieved normalized hemoglobin with SYLVANT1
cMean baseline hemoglobin level (g/dL) in all patients in the siltuximab arm was 11.8 (6.5-17.0).1
References: 1. van Rhee F, Wong RS, Munshi N, et al. Siltuximab for multicentric Castleman's disease: a randomised, double-blind, placebo-controlled trial. Lancet Oncol. 2014;15(9):966-974. 2. van Rhee F, Rosenthal AL, Kanhai K, et al. Siltuximab is associated with improved progression-free survival in idiopathic multicentric Castleman disease. Blood Adv. Published ahead of print July 6, 2022. doi:10.1182/bloodadvances.2022007112 3. Fajgenbaum DC, Uldrick TS, Bagg A, et al. International, evidence-based consensus diagnostic criteria for HHV-8-negative/idiopathic multicentric Castleman disease. Blood. 2017;129(12):1646-1657.