Immune activation and a 9-year ongoing complete remission following CD40 antibody therapy and metastasectomy in a patient with metastatic melanoma

Abstract

Direct immune activation via agonistic mAbs is a potentially complementary approach to therapeutic blockade of inhibitory immune receptors in cancer. Here, we provide genetic analysis of the immunologic consequences associated with the use of an agonistic CD40 mAb in a patient with metastatic melanoma who responded, underwent a single metastasectomy, and then achieved a complete remission ongoing for more than 9 years after starting therapy. Tumor microenvironment after immunotherapy was associated with proinflammatory modulations and emergence of a de novo T-cell repertoire as detected by next-generation sequencing of T-cell receptors (TCR) in the tumor and blood. The de novo T-cell repertoire identified in the posttreatment metastasectomy sample was also present-and in some cases expanded-in the circulation years after completion of therapy. Comprehensive study of this "exceptional responder" highlights the emerging potential of direct immune agonists in the next wave of cancer immunotherapies and a potential role for TCR deep sequencing in cancer immune assessment.

Conflict of interest statement

Disclosure of Potential Conflicts of Interest

Robert Vonderheide receives research funding from Pfizer and Roche. Cindy Desmarais owns stock in and is an employee of Adaptive Biotechnologies.

©2014 American Association for Cancer Research.

Figures

Figure 1. Imaging response following treatment with CP-870,893

Panels A-F represent serial axial CT images of two anatomical regions with tumor involvement. Panels A and D are baseline images; Panels B and E, after 10 infusions of CP-870,893; Panels C and F, after an additional 5 years of clinical follow-up. Images correspond to the timeline in Panel G, as indicated. Red circle indicates a left iliopsoas mass and blue circle indicates a lesion detected in the left anterior thigh that had fluorodeoxyglucose (FDG) uptake (not shown) and that was resected after CP-870,893 treatment. Panel G demonstrates the size of the patient's melanoma lesions over the 9-year course of treatment with CP-870,893, metastasectomy, and clinical observation (arrows within blue panel indicate CP-870,893 infusions).

Figure 2. Changes in the tumor microenvironment after treatment with CP-870,893

Panels A and F show hematoxylin and eosin staining of pre-treatment and post-treatment tumor specimens, respectively. Panels B-E and K-O show immunohistochemical analyses of pre-treatment specimens, and panels G-J and P-T show corresponding post-treatment specimens. All images are magnified by a factor of 20 unless otherwise noted. Panel U, Map shows relative gene expression in the tumor prior to and following treatment with CP-870,893 for leukocyte subsets, cytokines/chemokines, leukocyte activation markers, microenvironment markers and melanoma-associated antigens.

Figure 3. Identification and tracking of tumor-infiltrating lymphocytes by TCRβ deep-sequencing

For each unique T-cell clone detected in the pre-treatment and post-treatment tumor specimens, Panel A displays the percentage of each clone among total T cells as a function of rank, starting with the most common clones at the left of the axis. Inset shows this pattern for the top 1% of clones in each sample. Each symbol represents a unique clone. Panel B demonstrates the top first, second, and third percentage of the most frequent clones as a function of the total percentage of T cells in each sample. Top quartile (TQ) clones are the subset of the most frequent unique clones that together comprise 25% of total T cells. Panel C demonstrates the number of TQ clones in each sample and the overlaps in the two samples. Panel D indicates as a percentage the distribution of all TQ clones in either Pre-treatment, Post-treatment or in both samples. Panel E shows the five patterns of change in blood frequency of TQ clones in the post-treatment sample that can be identified by serially tracking with TCRβ deep-sequencing. Five exemplary clones are shown, one for each pattern. Panel F demonstrates the percentage of TQ post-treatment clones that fall into each pattern, shown for all clones in the post-treatment sample as well as clones that could be identified as CD8+ or CD4+ by TCR deep-sequencing of purified subsets.