AIPAC: a Phase IIb study of eftilagimod alpha (IMP321 or LAG-3Ig) added to weekly paclitaxel in patients with metastatic breast cancer.

Eftilagimod alpha (IMP321), a soluble dimeric recombinant form of LAG-3, is a first-in-class antigen presenting cell activator under clinical development. By stimulating dendritic cells through MHC class II molecules, IMP321 was proven to induce sustained immune responses. Combining active immunotherapy with a standard cytotoxic chemotherapy regimen represents a promising novel strategy that might lead to therapeutic improvements in metastatic breast cancer. Here, we describe the rationale and design of AIPAC (NCT02614833), a double-blind, randomized, multicenter Phase IIb study evaluating IMP321 plus paclitaxel as a first-line chemotherapy compared with paclitaxel plus placebo in hormone receptor-positive metastatic breast cancer patients. The primary end point is progression-free survival and key secondary objectives include overall survival, safety, quality of life and objective response rate.

Cell Adhesion Molecule CD166 Drives Malignant Progression and Osteolytic Disease in Multiple Myeloma.

Multiple myeloma is incurable once osteolytic lesions have seeded at skeletal sites, but factors mediating this deadly pathogenic advance remain poorly understood. Here, we report evidence of a major role for the cell adhesion molecule CD166, which we discovered to be highly expressed in multiple myeloma cell lines and primary bone marrow cells from patients. CD166+ multiple myeloma cells homed more efficiently than CD166- cells to the bone marrow of engrafted immunodeficient NSG mice. CD166 silencing in multiple myeloma cells enabled longer survival, a smaller tumor burden, and less osteolytic lesions, as compared with mice bearing control cells. CD166 deficiency in multiple myeloma cell lines or CD138+ bone marrow cells from multiple myeloma patients compromised their ability to induce bone resorption in an ex vivo organ culture system. Furthermore, CD166 deficiency in multiple myeloma cells also reduced the formation of osteolytic disease in vivo after intratibial engraftment. Mechanistic investigation revealed that CD166 expression in multiple myeloma cells inhibited osteoblastogenesis of bone marrow-derived osteoblast progenitors by suppressing Runx2 gene expression. Conversely, CD166 expression in multiple myeloma cells promoted osteoclastogenesis by activating TRAF6-dependent signaling pathways in osteoclast progenitors. Overall, our results define CD166 as a pivotal director in multiple myeloma cell homing to the bone marrow and multiple myeloma progression, rationalizing its further study as a candidate therapeutic target for multiple myeloma treatment. Cancer Res; 76(23); 6901-10. ©2016 AACR.

Implantation of CD133+ stem cells in patients undergoing coronary bypass surgery: IMPACT-CABG pilot trial.

BACKGROUND: The Implantation of Autologous CD133(+) Stem Cells in Patients Undergoing CABG (IMPACT-CABG) trial is investigating the feasibility, safety, and efficacy of intramyocardial injections of autologous CD133(+) stem cells during coronary artery bypass grafting (CABG) in patients with chronic ischemic cardiomyopathy. We are reporting the results of the first 5 open-label patients. METHODS: Bone marrow was harvested from iliac crests and stem cells were isolated using the CliniMACS CD133(+) Reagent System (Miltenyi Biotec, GmbH, Bergisch Gladbach, Germany). Patients received CABG, followed by CD133(+) cellular injection in the revascularized hypokinetic myocardium. RESULTS: Five males New York Heart Association (NYHA) class III patients aged 64 ± 10 years were treated. Immunomagnetic cell processing allowed an average of 100 ± 48-fold enrichment in CD133(+) cells, with 92 ± 11% recovery after selection. Mean number of CD133(+) cells injected was 8.4 ± 1.2 million. There were no protocol-related complications during the 18-month follow-up and all patients improved to NYHA class I. Six-month echocardiography showed no significant improvement in left ventricular ejection fraction (34 ± 2% at baseline vs 38 ± 12%: P = 0.50). However, cardiac magnetic resonance showed that systolic wall thickening increased from 15.0 ± 10.5% to 29.0 ± 22.1% (P = 0.01). In addition, mean segmental wall thickness also improved in comparison with baseline (10.7 ± 2.7% to 12.1 ± 4.8%; P < 0.01). CONCLUSIONS: This work represents the first Canadian experience with CD133(+) stem cells for the treatment of chronic ischemic cardiomyopathy. These results demonstrate the initial safety and feasibility of the IMPACT-CABG pilot trial. Subsequent patients are now being randomized to receive either CD133(+) stem cell or placebo.

Profibrotic potential of prominin-1+ epithelial progenitor cells in pulmonary fibrosis.

BACKGROUND: In idiopathic pulmonary fibrosis loss of alveolar epithelium induces inflammation of the pulmonary tissue followed by accumulation of pathogenic myofibroblasts leading eventually to respiratory failures. In animal models inflammatory and resident cells have been demonstrated to contribute to pulmonary fibrosis. Regenerative potential of pulmonary and extra-pulmonary stem and progenitor cells raised the hope for successful treatment option against pulmonary fibrosis. Herein, we addressed the contribution of lung microenvironment and prominin-1(+) bone marrow-derived epithelial progenitor cells in the mouse model of bleomycin-induced experimental pulmonary fibrosis. METHODS: Prominin-1(+) bone marrow-derived epithelial progenitors were expanded from adult mouse lungs and differentiated in vitro by cytokines and growth factors. Pulmonary fibrosis was induced in C57Bl/6 mice by intratracheal instillation of bleomycin. Prominin-1(+) progenitors were administered intratracheally at different time points after bleomycin challenge. Green fluorescence protein-expressing cells were used for cell tracking. Cell phenotypes were characterized by immunohistochemistry, flow cytometry and quantitative reverse transcription-polymerase chain reaction. RESULTS: Prominin-1(+) cells expanded from healthy lung represent common progenitors of alveolar type II epithelial cells, myofibroblasts, and macrophages. Administration of prominin-1(+) cells 2 hours after bleomycin instillation protects from pulmonary fibrosis, and some of progenitors differentiate into alveolar type II epithelial cells. In contrast, prominin-1(+) cells administered at day 7 or 14 lose their protective effects and differentiate into myofibroblasts and macrophages. Bleomycin challenge enhances accumulation of bone marrow-derived prominin-1(+) cells within inflamed lung. In contrast to prominin-1(+) cells from healthy lung, prominin-1(+) precursors isolated from inflamed organ lack regenerative properties but acquire myofibroblast and macrophage phenotypes. CONCLUSION: The microenvironment of inflamed lung impairs the regenerative capacity of bone marrow-derived prominin-1(+) progenitors and promotes their differentiation into pathogenic phenotypes.

First-line chemoimmunotherapy in metastatic breast carcinoma: combination of paclitaxel and IMP321 (LAG-3Ig) enhances immune responses and antitumor activity.

BACKGROUND: IMP321 is a recombinant soluble LAG-3Ig fusion protein that binds to MHC class II with high avidity and mediates APC and then antigen-experienced memory CD8+ T cell activation. We report clinical and biological results of a phase I/II in patients with metastatic breast carcinoma (MBC) receiving first-line paclitaxel weekly, 3 weeks out of 4. METHODS: MBC patients were administered one dose of IMP321 s.c. every two weeks for a total of 24 weeks (12 injections). The repeated single doses were administered the day after chemotherapy at D2 and D16 of the 28-day cycles of paclitaxel (80 mg/m2 at D1, D8 and D15, for 6 cycles). Blood samples were taken 13 days after the sixth and the twelfth IMP321 injections to determine sustained APC, NK and memory CD8 T cell responses. RESULTS: Thirty MBC patients received IMP321 in three cohorts (doses: 0.25, 1.25 and 6.25 mg). IMP321 induced both a sustained increase in the number and activation of APC (monocytes and dendritic cells) and an increase in the percentage of NK and long-lived cytotoxic effector-memory CD8 T cells. Clinical benefit was observed for 90% of patients with only 3 progressors at 6 months. Also, the objective tumor response rate of 50% compared favorably to the 25% rate reported in the historical control group. CONCLUSIONS: The absence of toxicity and the demonstration of activity strongly support the future development of this agent for clinical use in combined first-line regimens. TRIAL REGISTRATION: ClinicalTrials.gov NCT00349934.

A phase I pharmacokinetic and biological correlative study of IMP321, a novel MHC class II agonist, in patients with advanced renal cell carcinoma.

PURPOSE: To evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of IMP321, a recombinant soluble LAG-3Ig fusion protein which agonizes MHC class II-driven dendritic cell activation. EXPERIMENTAL DESIGN: Patients with advanced renal cell carcinoma were treated with escalating doses of IMP321 s.c. Blood samples were assayed to determine plasma pharmacokinetic parameters, detect human anti-IMP321 antibody formation, and determine long-lived CD8 T cell responses. RESULTS: Twenty-one advanced renal cell carcinoma patients received 119 injections of IMP321 at doses ranging from 0.050 to 30 mg/injection s.c. biweekly for 6 injections. No clinically significant adverse events were observed. Good systemic exposure to the product was obtained following s.c. injections of doses above 6 mg. IMP321 induced both sustained CD8 T-cell activation and an increase in the percentage of long-lived effector-memory CD8 T cells in all patients at doses above 6 mg. Tumor growth was reduced and progression-free survival was better in those patients receiving higher doses (>6 mg) of IMP321: 7 of 8 evaluable patients treated at the higher doses experienced stable disease at 3 months compared with only 3 of 11 in the lower dose group (P = 0.015). CONCLUSION: The absence of toxicity and the demonstration of activity at doses above 6 mg warrant further disease-directed studies of IMP321 in combined regimens (e.g., chemoimmunotherapy).

IMP321 (sLAG-3) safety and T cell response potentiation using an influenza vaccine as a model antigen: a single-blind phase I study.

sLAG-3 (IMP321), a natural high affinity ligand for MHC class II, was tested for safety, tolerability and its ability to increase Th-1-type T cell responses to a commercial trivalent split influenza vaccine (Agrippal) in a phase I single-blinded, randomized, controlled clinical trial. Twenty healthy volunteers were first injected with increasing doses of IMP321 alone (safety for first-in-man use). Then 40 volunteers were recruited into 4 consecutive cohorts of 10 subjects, who were randomly assigned to receive the flu vaccine plus 3, 10, 30 or 100 microg IMP321 or the flu vaccine plus saline control. All vaccine formulations were found to be generally well tolerated with similar frequency and intensity of adverse reaction in groups receiving IMP321 as in controls. Post-vaccination humoral immune responses, as determined 29 and 57 days later by assay of hemagglutinin inhibition activity were similar for both IMP321 and control groups. In contrast, the addition of 10, 30 or 100 microg IMP321 to the flu vaccine resulted in higher levels of Th1-type (IFN-gamma, TNF-alpha or IL-2) flu-specific CD4 T cells in PBMC recovered at D29 and D57 and tested in a short-term ex vivo restimulation assay (6-colour FACS analysis after intra-cellular staining of cytokines). In summary, IMP321 as an adjuvant to a model antigen (Agrippal) was well-tolerated and may enhance T cell response vaccine immunogenicity.

Enhanced immune response to DNA-based HPV16L1 vaccination by costimulatory molecule B7-2.

We have investigated whether co-injection of DNA encoding the costimulatory molecule B7-2 augments immune response to the major capsid protein L1 of the high-risk human papillomavirus type 16 (HPV16L1). While immunoglobulin G (IgG) specific to HPV16L1 was detected in sera from mice injected intramuscularly with pcDNA-L1 that encodes HPV16L1, a significantly increased level of IgG was found in sera from mice immunised with pcDNA-L1 in conjunction with pLXHDmB7-2 DNA. Levels of IgG in the anti-sera were correlated with the inhibitory activity of the murine erythrocyte hemagglutination caused by the virus-like particles (VLP) and the binding of VLP to HeLa cells. Moreover, splenic cells isolated from mice co-injected with pLXHDmB7-2 had stronger proliferation and more IFN-gamma producing T cells (CD4(+) and CD8(+)) when stimulated with HPV16 VLP compared with cells from mice that had received pcDNA-L1 alone and mice of the control groups. Furthermore, in footpad swelling test, mice co-immunised with pLXHDmB7-2 had greater skin thickness over those immunised with pcDNA-L1 alone or control mice. We conclude that co-injection of DNA encoding B7-2 can enhance both humoral and cellular immune responses elicited by DNA-based vaccination against HPV16 infection in mice.

Development of dendritic-cell based prostate cancer vaccine.

Available treatments for metastatic prostate cancer have failed to demonstrate significant curative potential. Current efforts are now directed towards developments of novel strategies for the treatment of metastatic prostate cancer. Cancer immunotherapeutic strategies utilize patient immune system components to kill cancer cells. This review discusses progress in active specific immunotherapeutic approaches as potential alternative methods in the treatment of metastatic prostate cancer. One of the newest advances in cancer immunotherapy is the use of dendritic cells as the vehicle to deliver cancer antigens for an effective in vivo T cell activation. The development of dendritic cell-based prostate cancer vaccine, as well as results of several clinical trials in prostate cancer involving the administration of peptide-pulsed autologous dendritic cell pulsed are discussed.

A safety and pharmacokinetic study of intravenous natalizumab in patients with MS.

A phase 1, randomized, placebo-controlled, five-level dose escalation safety and tolerability and pharmacokinetic study of a single IV dose of natalizumab was performed. Doses of 0.03 to 3.0 mg/kg natalizumab or placebo were studied in 28 stable relapsing-remitting or secondary-progressive MS. All doses were safe and well tolerated in MS. Serum concentrations of natalizumab are detectable for 3 to 8 weeks after a single 1- or 3-mg/kg IV dose and justify controlled efficacy studies.

Treatment of active refractory rheumatoid arthritis with humanized monoclonal antibody CAMPATH-1H administered by daily subcutaneous injection.

OBJECTIVE: To investigate the dose tolerance and potential clinical activity of a humanized antilymphocyte monoclonal antibody, CAMPATH-1H (C1H), in patients with active, refractory rheumatoid arthritis (RA). METHODS: Thirty adult patients with active, refractory RA were treated in an open-label, 3-center, dose-escalation study of subcutaneously injected C1H. Six patients were assigned to each of 5 dosage groups (0.3, 1.0, 3.0, 10.0 or 30.0 mg/day), and received 10 daily injections of C1H over a 12-day period. RESULTS: Side effects occurred primarily during the first 1-2 days of dosing, and included mild fever, chills, nausea, vomiting, headache, and, in a minority of patients, hypotension. All patients developed some discomfort at the injection site. Self-limited infections occurred in 5 patients during the 6-month study period. Peripheral blood lymphocyte counts fell promptly after initial dosing and recovered slowly, usually over 2-3 months. Serum antibodies to C1H developed in 54% of patients following treatment. Clinical improvement was observed in 56% of patients, based on the composite Paulus criteria, with a median time-to-response of 22 days and a median response duration of 32 days. CONCLUSION: C1H is a lymphocyte-depleting antibody that exhibits biologic potency when administered subcutaneously to patients with refractory RA. Its use is associated with mild to moderate toxicity and short-term amelioration of disease activity.

Synovial tissue response to treatment with Campath-1H.

OBJECTIVE: Therapeutic trials in rheumatoid arthritis with the monoclonal antibody Campath-1H have demonstrated recurrent clinical synovitis in some patients, despite profound depletion of circulating lymphocytes. This study was undertaken to examine the cellular infiltrates in synovial tissue at a time of persistent peripheral lymphopenia. METHODS: Immunohistochemical staining of synovial tissue and peripheral blood lymphocyte phenotyping. RESULTS: Synovial tissues from 2 patients with recurrent synovitis after Campath-1H therapy contained significant T lymphocytic infiltrates at a time when circulating T lymphocytes were markedly depleted. CONCLUSION: These results demonstrate that peripheral blood analysis may not accurately reflect the synovial tissue response to monoclonal antibody therapy.