Dose Escalation Trial of Dalotuzumab (MK-0646) in Advanced Solid Tumors and Multiple Myeloma (MK-0646-001)

Toxicity was graded and recorded according to National Cancer Institute (NCI) Common Toxicity Criteria for Adverse Events version 3.0 (CTCAE 3.0). A DLT was defined as any Grade 3 or 4 toxicity. A Grade 3 toxicity was defined as severe or medically significant but not immediately life-threatening OR hospitalization or prolongation of hospitalization indicated OR disabling OR limiting self care activities of daily living. A Grade 4 toxicity was defined as: life-threatening consequences OR urgent intervention indicated. Participants were monitored for the occurrence of DLTs during the first 3 weeks of dosing with dalotuzumab.

Terminal half-life is defined as the time it takes for the blood plasma concentration of a substance to halve (plasma half-life). Blood samples for measurement of serum levels of dalotuzumab were obtained at: pre-dose; pre-end infusion; 0.5, 5, 10, 24, 30 (Q1W only), 48, 96, 168 (Q2W/Q3W only), 336 (Q3W only) hours post infusion. For infusions >1 hour in duration, an additional sample was obtained at the mid-point of the infusion. Data presented are for the harmonic mean t1/2 for dalotuzumab.

AUC0-∞ represents the total drug exposure over time. Blood samples for measurement of serum levels of dalotuzumab were obtained at: Predose; pre-end infusion; 0.5, 5, 10, 24, 30 (Q1W only), 48, 96, 168 (Q2W/Q3W only), 336 (Q3W only) hours post-infusion. For infusions >1 hour in duration, an additional sample was obtained at the mid-point of the infusion.

Clearance is defined as the volume of serum from which study drug was completely removed per unit of time. Blood samples for measurement of serum levels of dalotuzumab were obtained at: pre-dose; pre-end infusion; 0.5, 5, 10, 24, 30 (Q1W only), 48, 96, 168 (Q2W/Q3W only), 336 (Q3W only) hours post infusion. For infusions >1 hour in duration, an additional sample was obtained at the mid-point of the infusion.

The lowest (trough) concentration of dalotuzumab prior to the next dose of dalotuzumab was measured.

IGF-1R expression was measured in pre- and post-dose skin biopsy samples using an immunohistochemistry (IHC) assay as a function of time and dose. Results were expressed as an IGF-1R membrane H-score which could range from 0 to 300; with a score of 0 representing the absence of IGF-1R expression and an H-score of 300 representing maximum IGF-1R expression. Changes in IGF-1R expression levels from Baseline are summarized for all participants for whom these paired data were available. A post-dose decrease in IGF-1R membrane H-score was an indication of target engagement by dalotuzumab. A larger decrease in H-score correlated with a greater target engagement.

IGF-1R expression was measured in pre- and post-dose tumor biopsy samples using an IHC assay as a function of time and dose. Results were expressed as an IGF-1R membrane H-score which could range from 0 to 300; with a score of 0 representing the absence of IGF-1R expression and an H-score of 300 representing maximum IGF-1R expression. Changes in IGF-1R expression levels from Baseline are summarized for all participants for whom these paired data were available. A post-dose decrease in IGF-1R membrane H-score was an indication of target engagement by dalotuzumab. A larger decrease in H-score correlated with a greater target engagement.

It is thought that the formation of HAHAs may block efficacy by prematurely clearing dalotuzumab and limit the possibility of future dalotuzumab therapy. Blood samples for the measurement of serum levels of HAHAs were obtained prior to treatment with dalotuzumab, and pre-dose Week 2 (Q1W), pre-dose Week 3 (Q2W), pre-dose Week 4 (QW3), pre-dose Week 5 (Q1W/Q2W), pre-dose Week 7 (Q2W/Q3W), pre-dose Week 9 (Q2W), pre-dose Week 10 (QW3) and pre-dose every 4 subsequent weeks and end of treatment (post-study: 4 weeks after last dose of study drug).

Tumor responses were measured by using Response Evaluation Criteria in Solid Tumors (RECIST) criteria in participants with solid tumors and using European Group for Blood and Marrow Transplantation (EBMT) criteria in participants with multiple myeloma. RECIST criteria for CR: Disappearance of all target lesions. RECIST criteria for PR: ≥30% decrease in the sum of diameters of target lesions. EBMT criteria for CR: Disappearance of the original mAb protein from the blood and urine AND <5% plasma cells in the bone marrow AND no increase in the size or number of lytic bone lesions AND disappearance of soft tissue plasmacytomas AND normal serum calcium levels. EMBT criteria for PR: ≥50% reduction in the serum mAb protein level AND if a urine M-component is present, a reduction in 24-hour urinary light chain excretion by either ≥90% or to <200 mg AND ≥50% reduction in the size of soft tissue plasmacytomas AND no increase in size or number of lytic bone lesions.