Enhanced permeability of the tumor vasculature allows macromolecules to enter the tumor interstitial space, while the suppressed lymphatic filtration allows them to stay there. This phenomenon - EPR has been the basis of nanotechnology platforms to deliver drugs to tumors. However, progress in developing effective drugs using this approach has been hampered by heterogeneity of EPR effect in different tumors and limited experimental data from patients on effectiveness of this mechanism as related to enhanced drug accumulation. This report summarizes the workshop discussions on key issues of the EPR effect and major gaps that need to be addressed to effectively advance nanoparticle-based drug delivery.

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Background:Serum interleukin (IL)-6 levels correlate with disease outcomes in renal cell carcinoma (RCC) patients. Siltuximab, a chimeric, murine-human mAb against IL-6, was evaluated in a three-part phase I/II study in patients with progressive metastatic RCC.Methods:In part 1, 11 patients received 1, 3, 6, or 12 mg kg–1 at weeks 1, 4 and q2w × 2 thereafter; in part 2, 37 patients randomly received 3 or 6 mg kg–1 q3w × 4; in part 3, 20 low-risk patients received 6 mg kg–1 q2w × 6. Modified WHO response criteria were assessed at weeks 7, 11, the 6-week follow-up, and when clinically indicated.Results:Siltuximab was well tolerated overall, with no maximum tolerated dose or immune response observed. In all, 5 out of 11, 17 out of 37, and 9 out of 20 patients in parts 1, 2, and 3, respectively, received extended treatment beyond 4–6 initial infusions. In part 2, stable disease (SD) (⩾11weeks) or better was achieved by 11 out of 17 (65%) 3 mg kg–1 treated patients (one partial response (PR) ∼8 months, 10 SD) and 10 out of 20 (50%) 6 mg kg–1 treated patients (10 SD). In part 3, documented complete or PR was not observed, but 13 out of 20 (65%) patients achieved SD.Conclusion:Siltuximab stabilised disease in >50% of progressive metastatic RCC patients. One PR was observed. Given the favourable safety profile of siltuximab and poor correlation of tumour shrinkage with clinical benefit demonstrated for other non-cytotoxic therapies, further evaluation of dose-escalation strategies and/or combination therapy may be considered for patients with RCC.

Integrins are heterodimeric cell adhesion receptors that mediate intercellular communication through cell-extracellular matrix interactions and cell-cell interactions. Integrins have been demonstrated to play a direct role in cancer progression, specifically in tumor cell survival, tumor angiogenesis, and metastasis. Therefore, agents targeted against integrin function have potential as effective anticancer therapies. Numerous anti-integrin agents, including monoclonal antibodies and small-molecule inhibitors, are in clinical development for the treatment of solid and hematologic tumors. This review focuses on the role of alpha(v) integrins in cancer progression, the current status of integrin-targeted agents in development, and strategies for the clinical development of anti-integrin therapies.

Purpose: Interleukin-6 (IL-6) induces tumor growth, invasion, metastasis, and angiogenesis. Siltuximab (CNTO 328) is a chimeric, murine-human monoclonal antibody that specifically binds human IL-6 with high affinity. C-reactive protein (CRP) can be a pharmacodynamic (PD) marker of IL-6 bioactivity. Reductions in CRP may correlate with clinical activity and IL-6 bioactivity.Experimental Design: Starting-dose selection for this study was based on a previous siltuximab study in multiple myeloma patients. Pharmacokinetic (PK)/PD modeling explored the relationship between siltuximab PK and CRP suppression following i.v. siltuximab infusion in a three-part phase I/II study in 68 metastatic renal cell carcinoma patients. Modeling results were then used to simulate and determine which siltuximab dosage regimens would maintain CRP suppression below the lower limit of quantification (4 mg/L). Siltuximab was given at 1, 3, 6, or 12 mg/kg at weeks 1 and 4 and then every 2 weeks for 2 cycles in part 1; at 3 or 6 mg/kg every 3 weeks for 4 cycles in part 2; and at 6 mg/kg every 2 weeks for 6 cycles in part 3.Results: A two-compartment PK model adequately described the serum siltuximab concentration-time data. An inhibitory indirect response PD model examined the relationship between siltuximab concentrations and CRP suppression. PD parameter estimates seemed reliable and physiologically relevant. Simulations showed that 6 mg/kg siltuximab every 2 weeks or 9 mg/kg every 3 weeks would reduce serum CRP to below 4 mg/L.Conclusions: Using a stepwise design, PK/PD modeling was used to select the dose levels in this study. Furthermore, PK/PD modeling results were used to help select doses to be used in future siltuximab clinical development. Clin Cancer Res; 16(5); 1652-61. ©2010 AACR.

in association with the Biotherapy Development Association Abstract Purpose: A fully human monoclonal antibody to anti^a v integrins (CNTO 95) has been shown to inhibit angiogenesis and tumor growth in preclinical studies. We assessed the safety and pharmacokinetics of CNTO 95 in patients with advanced refractory solid tumors. Experimental Design: In this phase I trial, CNTO 95 (0.1, 0.3, 1.0, 3.0, and 10.0 mg/kg) was infused on days 0, 28, 35, and 42, and clinical assessments, dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and [18 F]-2-fluorodeoxyglucose positron emission tomography (FDG-PET) were done. Patients achieving stable disease or better were eligible for extended dosing every 3 weeks for up to 12 months. Results: Among the 24 enrolled patients, CNTO 95 was associated with one episode of grade III and four episodes of grade II infusion-related fever (all responded to acetaminophen). Of the six patients who received extended dosing, one patient (10.0 mg/kg), with cutaneous angiosarcoma, had a 9-month partial response. Pre-and post-treatment lesion biopsies confirmed tumor cell a v integrin expression, as well as CNTO 95 penetration of the tumor and localization to tumor cells in association with reduced bcl-2 expression. A lesion in one patient (10.0 mg/kg) with stable ovarian carcinosarcoma was no longer detectable by FDG-PET by day 49. Exposure to CNTO 95 seemed to increase in a greater-than-dose-proportional manner; dose-dependent mean halflife ranged from 0.26 to 6.7 days. Conclusions: CNTO 95 was generally well tolerated. Six patients received extended therapy, including one patient with a prolonged response. Biopsy data confirmed tumor localization and pharmacodynamic activity.

Infliximab treatment was safe and well tolerated in patients with advanced cancer. There was evidence of biological activity with baseline TNF-alpha and CCL2 being correlated with infliximab response.