CC-122 Expands Activated and Memory CD4 and CD8 T Cells In Vivo and Induces T Cell Activation Ex Vivo in Subjects with Relapsed or Refractory Diffuse Large B Cell Lymphoma and Multiple Myeloma

Background: CC-122 is a first in class PPM^TM pleiotropic pathway modifier compound with multiple biological activities including potent anti-proliferative activity against B lineage cells, anti-angiogenic activity and immunomodulatory effects. CC-122 binds cereblon, and promotes ubiquitination of lymphoid transcription factors Ikaros and Aiolos, leading to their subsequent degradation resulting in activation of T cells. The immunological properties of CC-122 including effects on T cell subset number in vivo and T cell cytokine production ex vivo was explored in subjects with advanced aggressive non-Hodgkin Lymphoma (NHL) and Multiple Myeloma (MM) enrolled in a Phase 1b trial (NCT01421524) at 3 mg QD and 4 and 5 mg 5/7 days dosed in 28 day cycles until disease progression.

Methods: As of June 25, 2015, 76 total DLBCL and MM subjects were enrolled in the expansion phase of the study. Assessments for T cell subset numbers were performed at screening (baseline), cycle 1 day 15 (C1D15), cycle 1 day 22, cycle 2 day 15 and cycle 2 day 22 by flow cytometric immunophenotyping of fresh whole blood. Ex vivo whole blood T cell activation as measured by IL-2, IL-6, IFNg and GM-CSF cytokine production was performed using the anti-CD3 TruCulture Assay. Changes from baseline were evaluated using the t test with p<0.05 considered significant.

Results: T cell subsets which were significantly changed are shown in italics in Table 1. In MM subjects (n=19-21) and DLBCL subjects (n=30-31), CC-122 treatment significantly expanded several T cell activator and memory T cell subsets while decreasing naïve T cells. A single dose of CC-122 on C1D1 activated T cells as measured in an ex vivo T cell activation assay in MM subjects (n=6-13) and DLBCL subjects (n=5-12) (Table 2). In addition, we evaluated potential correlations of clinical outcome with baseline biomarker and biomarker changes upon CC-122 treatment.

Conclusions: CC-122 significantly increases the proportion of several cytotoxic and helper T cells subsets while decreasing naïve T cells in both DLBCL and MM subjects. CC-122 also significantly activates T cells ex vivo as measured by cytokine production. These results indicate that CC-122 is a potent modulator of T cell numbers and activation and this may serve as rationale for combinations with other immunotherapies.