CAP-100: First-in-class antibody for CCR7+ hematological malignancies.

e19008 Background: CCR7 is highly expressed in many hematological malignancies including CLL, several B-cell non-Hodgkin lymphomas (NHL), and various T-cell neoplasias with nodal involvement. Upon engagement by its ligands (CCL19 and CCL21), CCR7 controls trafficking of cells to locations where these chemokines are expressed, such as the lymph node (LN) and central nervous system. In these protective microenvironments CCR7 ligands contribute to tumor cell survival and proliferation. Indeed, both high CCR7 surface expression levels and high migratory responses to CCR7 ligands correlate with LN involvement, adverse prognostic factors, and shorter patient survival. Thus, strategies targeting CCR7 could provide a novel therapeutic approach for CCR7+ hematological malignancies. Methods: We have generated CAP-100, the first humanized immunoglobulin G1 (IgG1) monoclonal antibody (mAb) that specifically binds to human CCR7 and neutralizes ligand-mediated signaling from both CCL19 and CCL21, and evaluated the antibody in various in-vitro and in-vivo preclinical models. Results: CAP-100 effectively inhibited in vitro migration of primary patient samples of CLL, B-cell NHLs and T-cell neoplasias such as T-PLL or T-ALL. Furthermore, in in vivo pre-clinical studies, CAP-100 was shown to inhibit entry of CCR7-expressing cells to LNs. CAP-100 also abrogated survival elicited by CCR7 in CLL, and showed potent cell killing activity against CLL or CCR7+ T-lymphomas cells. This Fc-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) clearly outperformed anti-CD20 or anti-CD52 standard-of-care antibodies in B-NHL and T-lymphomas respectively. In all cases, ADCC and migration inhibition were both independent of prognostic markers for high risk disease. Finally, when given as monotherapy in disseminated B-NHL and CLL xenograft tumors in SCID mice, CAP-100 exhibited tumor growth inhibition and extended survival significantly. Conclusions: Our results demonstrate that CAP-100, the first-in-class anti-CCR7 mAb, is a potent antagonist with biological activity in several CCR7+ hematological malignancies, including relapsed/refractory disease. Moreover, these results highlight the relevance of the CCR7-CCL19/CCL21 pathway as a therapeutic target in these diseases. CAP-100’s unique propensity to block migration of tumor cells to the LN, in combination with its potent cell killing activity provides the biological rationale for use of CAP-100, either as monotherapy or in combination with novel agents. Clinical trials in CLL and CCR7-expressing NHL will be initiated soon.

Cutaneous extranodal NK/T-cell lymphoma: a clinicopathologic study of 5 patients with array-based comparative genomic hybridization

Extranodal natural killer/T-cell (ENK/T) lymphoma is a rare neoplasm, subcategorized into ENK/T-nasal (ENK/T-N) and ENK/T-nasal type (ENK/T-NT) lymphomas. ENK/T-NT lymphoma with initial presentation in the skin is known as primary cutaneous ENK/T-NT (PC-ENK/T-NT) lymphoma. The aim of this study was to investigate pathogenesis, genomic alterations, and prognosis of cutaneous ENK/T lymphomas to provide further insights into clinicopathologic features and genetic mechanism of lymphomagenesis. A retrospective case study of 5 white patients affected by ENK/T lymphoma (4 PC-ENK/T-NT and 1 ENK/T-N with cutaneous involvement) was performed. Most of the cases presented with multiple nodules and ulcerations localized on the extremities. A considerable percentage had disease in advanced stage with a 12-month survival rate of 40%. Genomic alterations were detected by array-based comparative genomic hybridization that showed gains of 1q, 7q and loss of 17p in the cases of PC-ENK/T-NT lymphomas and gain of 7q and loss of 9p, 12p, 12q in the case of ENK/T-N lymphoma. In conclusion, ENK/T lymphoma is a very aggressive entity, and, in our cases, the exclusively cutaneous presentation was not associated with a better prognosis. The results of our array comparative genomic hybridization analysis could be useful to better define the different ENK/T lymphoma subgroups with cutaneous involvement.

Aberrant V(D)J recombination is not required for rapid development of H2ax/p53-deficient thymic lymphomas with clonal translocations

Histone H2AX is required to maintain genomic stability in cells and to suppress malignant transformation of lymphocytes in mice. H2ax−/−p53−/− mice succumb predominantly to immature αβ T-cell lymphomas with translocations, deletions, and genomic amplifications that do not involve T-cell receptor (TCR). In addition, H2ax−/−p53−/− mice also develop at lower frequencies B and T lymphomas with antigen receptor locus translocations. V(D)J recombination is initiated through the programmed induction of DNA double-strand breaks (DSBs) by the RAG1/RAG2 endonuclease. Because promiscuous RAG1/RAG2 cutting outside of antigen receptor loci can promote genomic instability, H2ax−/−p53−/− T-lineage lymphomas might arise, at least in part, through erroneous V(D)J recombination. Here, we show that H2ax−/−p53−/−Rag2−/− mice exhibit a similar genetic predisposition as do H2ax−/−p53−/− mice to thymic lymphoma with translocations, deletions, and amplifications. We also found that H2ax−/−p53−/−Rag2−/− mice often develop thymic lymphomas with loss or deletion of the p53+ locus. Our data show that aberrant V(D)J recombination is not required for rapid onset of H2ax/p53-deficient thymic lymphomas with genomic instability and that H2ax deficiency predisposes p53−/−Rag2−/− thymocytes to transformation associated with p53 inactivation. Thus, H2AX is essential for suppressing the transformation of developing thymocytes arising from the aberrant repair of spontaneous DSBs.