Sondel, Paul M.

Abstract Myeloma remains a virtually incurable malignancy. The inevitable evolution of multidrug-resistant clones and widespread clonal heterogeneity limit the potential of traditional and novel therapies to eliminate minimal residual disease (MRD), a reliable harbinger of relapse. Here, we show potent anti-myeloma activity of macrophage-activating immunotherapy (αCD40+CpG) that resulted in prolongation of progression-free survival (PFS) and overall survival (OS) in an immunocompetent, preclinically validated, transplant-based model of multidrug-resistant, relapsed/refractory myeloma (t-Vκ*MYC). αCD40+CpG was effective in vivo in the absence of cytolytic natural killer, T, or B cells and resulted in expansion of M1-polarized (cytolytic/tumoricidal) macrophages in the bone marrow. Moreover, we show that concurrent loss/inhibition of Tpl2 kinase (Cot, Map3k8), a MAP3K that is recruited to activated CD40 complex and regulates macrophage activation/cytokine production, potentiated direct, ex vivo anti-myeloma tumoricidal activity of αCD40+CpG–activated macrophages, promoted production of antitumor cytokine IL12 in vitro and in vivo, and synergized with αCD40+CpG to further prolong PFS and OS in vivo. Our results support the combination of αCD40-based macrophage activation and TPL2 inhibition for myeloma immunotherapy. We propose that αCD40-mediated activation of innate antitumor immunity may be a promising approach to control/eradicate MRD following cytoreduction with traditional or novel anti-myeloma therapies. Cancer Immunol Res; 3(8); 881–90. ©2015 AACR.

AbstractPurpose: To determine the response rate to oral capsular fenretinide in children with recurrent or biopsy proven refractory high-risk neuroblastoma.Experimental Design: Patients received 7 days of fenretinide: 2,475 mg/m2/d divided TID (<18 years) or 1,800 mg/m2/d divided BID (≥18 years) every 21 days for a maximum of 30 courses. Patients with stable or responding disease after course 30 could request additional compassionate courses. Best response by course 8 was evaluated in stratum 1 (measurable disease on CT/MRI ± bone marrow and/or MIBG avid sites) and stratum 2 (bone marrow and/or MIBG avid sites only).Results: Sixty-two eligible patients, median age 5 years (range 0.6–19.9), were treated in stratum 1 (n = 38) and stratum 2 (n = 24). One partial response (PR) was seen in stratum 2 (n = 24 evaluable). No responses were seen in stratum 1 (n = 35 evaluable). Prolonged stable disease (SD) was seen in 7 patients in stratum 1 and 6 patients in stratum 2 for 4 to 45+ (median 15) courses. Median time to progression was 40 days (range 17–506) for stratum 1 and 48 days (range 17–892) for stratum 2. Mean 4-HPR steady-state trough plasma concentrations were 7.25 μmol/L (coefficient of variation 40–56%) at day 7 course 1. Toxicities were mild and reversible.Conclusions: Although neither stratum met protocol criteria for efficacy, 1 PR + 13 prolonged SD occurred in 14/59 (24%) of evaluable patients. Low bioavailability may have limited fenretinide activity. Novel fenretinide formulations with improved bioavailability are currently in pediatric phase I studies. Clin Cancer Res; 17(21); 6858–66. ©2011 AACR.