Evaluation of the QTc prolongation potential of a monoclonal antibody, siltuximab, in patients with monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, or low-volume multiple myeloma.

Abstract

PURPOSE:

A phase 1 study evaluated the QTc prolongation potential of siltuximab, a chimeric, anti-interleukin-6 mAb, in patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or low-volume MM.

METHODS:

Patients with baseline QTcF and QTcB ≤ 500 ms, QRS < 100 ms, PR < 200 ms and no significant cardiac disease received siltuximab 15 mg/kg q3w, the highest dosage used in clinical studies, for 4 cycles. Twelve-lead ECGs obtained at multiple time points pre- and post-infusion at cycles 1 and 4 were evaluated by central cardiology laboratory. No effect on QTc interval was concluded if the upper limit of least square (LS) mean 90 % CI for QTc change from baseline at each time point was <20 ms.

RESULTS:

An effect on QTc prolongation was ruled out, as the upper bound of 90 % CI was <10 ms at each time point in 27 evaluable patients (13 MGUS, 13 SMM, 1 low-volume MM) with no differences between disease types. Maximum mean QTc increase from baseline occurred 3 h after cycle 1 infusion (QTcF = 3.2 [LS mean 90 % CI -0.01, 6.45] ms; QTcB = 2.7 [-0.69, 6.14] ms). At all other time points, mean QTcF and QTcB increase from baseline was ≤1.5 ms and upper bound 90 % CI was ≤5.1 ms. Twenty patients had mostly low-grade AEs, including nausea, fatigue (20 % each); thrombocytopenia, headache (each 13 %); dyspnea, leukopenia, neutropenia, paresthesia, abnormal hepatic function, URTI (each 10 %). Three MGUS patients achieved 50 % M-protein reduction. There was no association between siltuximab pharmacokinetics and QTc interval.

CONCLUSIONS:

Siltuximab did not affect the QTc interval. Overall safety was similar to other single-agent siltuximab studies.

• Authors: Sheeba K Thomas, Alexander Suvorov, Lucien Noens, Oleg Rukavitsin, Joseph Fay, Ka Lung Wu, Todd M Zimmerman, Helgi van de Velde, Rajesh Bandekar, Thomas A Puchalski, Ming Qi, Clarissa Uhlar, Olga S Samoylova
• Journal: Cancer chemotherapy and pharmacology (Cancer Chemother Pharmacol) Vol. 73 Issue 1 Pg. 35-42 (Jan 2014) ISSN: 1432-0843 [Electronic] Germany
• PMID: 24149943 (Publication Type: Clinical Trial, Phase I, Journal Article, Multicenter Study)

Chemical References

• Antibodies, Monoclonal
• siltuximab

Topics

• Adult
• Aged
• Antibodies, Monoclonal (adverse effects, pharmacokinetics)
• Electrocardiography (drug effects)
• Humans
• Middle Aged
• Monoclonal Gammopathy of Undetermined Significance (drug therapy)
• Multiple Myeloma (drug therapy)