This is an open-label, two-stage, Phase 2 study to investigate the safety, tolerability, and efficacy of administering increased siltuximab doses to patients with iMCD who progressed with elevated and rising serum C reactive protein (CRP) levels after prior treatment with siltuximab 11 mg/kg every 3 weeks (q3w) without unacceptable toxicity, and is primarily designed to leverage opportunities for intrapatient dose escalation with available clinical, nonclinical, and PK justification as a means to restore or enable disease control.~Enrolling in Stage 1a and Stage 1b of this study in parallel will be up to 6 patients each with siltuximab-relapsed or refractory IL-6-driven iMCD and TAFRO-iMCD patients, respectively, who will undergo intrapatient dose escalation of siltuximab beginning with 22 mg/kg q3w, then possibly dose escalating to 33 mg/kg q3w then 44 mg/kg q3w if clinically indicated in the absence of DLT. The justifications for escalating siltuximab doses up to 44 mg/kg q3w will be based on intrapatient dose escalation and DLT assessments as described below.
Phase 2 study to investigate the safety, tolerability, and efficacy of administering increased siltuximab doses to patients with iMCD