Purpose: To assess the safety, efficacy, and immunomodulatory effects of CC-4047 (Actimid; Celgene, San Diego, CA) in patients with relapsed or refractory myeloma.
Patients and methods: Twenty-four relapsed or refractory patients were treated with a dose-escalating regimen of oral CC-4047. Clinical responses and adverse effects were identified, and peripheral T-cell subsets, serum cytokines, and proangiogenic factors were evaluated.
Results: CC-4047 was tolerated with no serious nonhematologic adverse events. All patients were eligible for analysis. Toxicity criteria during the initial 4 weeks of study were used to define the maximum-tolerated dose (MTD). During this period, one patient withdrew with a deep vein thrombosis (DVT) probably caused by an undiagnosed primary melanoma with lymphadenopathy in the groin, one patient withdrew because of progressive disease (PD), and three patients discontinued with neutropenia. Nineteen of 24 patients continued on treatment beyond 4 weeks to PD or development of a serious adverse event. Three further patients developed a DVT at 4, 9, and 11 months. Treatment resulted in a greater than 25% reduction in paraprotein in 67% of patients, 13 patients (54%) experienced a greater than 50% reduction in paraprotein, and four (17%) of 24 patients entered complete remission. The MTD was 2 mg/d. All patients showed increased CD45RO expression on CD4(+) and CD8(+) cells, with a concomitant decrease in CD45RA(+) cells. CC-4047 treatment was associated with significantly increased serum interleukin (IL)-2 receptor and IL-12 levels, which is consistent with activation of T cells and monocytes and macrophages.
Conclusion: This study demonstrates the safety and efficacy of CC-4047. The MTD of CC-4047 orally was 2 mg/d. This is the first report demonstrating in vivo T-cell costimulation by this class of compound, supporting a potential role for CC-4047 as an immunostimulatory adjuvant treatment.