Luigi Manenti

Phase I Pharmacokinetic and Pharmacodynamic Dose-Escalation Study of RG7160 (GA201), the First Glycoengineered Monoclonal Antibody Against the Epidermal Growth Factor Receptor, in Patients With Advanced Solid Tumors

PURPOSE We conducted a phase I dose-escalation study to characterize the safety, efficacy, pharmacokinetic (PK), and pharmacodynamic properties of RG7160 (GA201), a humanized and glycoengineered immunoglobulin G(1) anti-epidermal growth factor receptor (EGFR) monoclonal antibody with enhanced antibody-dependent cell-mediated cytotoxicity. PATIENTS AND METHODS Seventy-five patients with advanced EGFR-positive solid tumors received RG7160 (50 to 1,400 mg) administered every week, every 2 weeks, or every 3 weeks. Dose escalation followed a three-plus-three trial design. RESULTS No maximum-tolerated dose was reached for any dosing schedule. Common adverse events (AEs) included rash (80% of patients), infusion-related reactions (77%), and hypomagnesemia (56%). Grades 3 and 4 AEs were rash (grade 3, 25%), infusion-related reaction (grade 3, 7%; grade 4, 1%), paronychia (grade 3, 3%), and hypomagnesemia (grade 3, 1%; grade 4, 1%). RG7160 exposure increased greater than proportionally over the 50- to 400-mg dose range (with greater than proportional decline in clearance) and approximately dose proportionally above 400 mg (where clearance plateaued). A marked reduction in circulating natural killer cells and increased infiltration of immune effector cells into skin rash were seen. Clinical efficacy included one complete response and two partial responses in patients with colorectal cancer (including one with KRAS mutation) and disease stabilization in 27 patients. CONCLUSION RG7160 had an acceptable safety profile with manageable AEs and demonstrated promising efficacy in this heavily pretreated patient cohort. On the basis of modeling of available PK parameters, the RG7160 dose selected for part two of this study is 1,400 mg on days 1 and 8 followed by 1,400 mg every 2 weeks.

An HSP90-mimic peptide revealed by fingerprinting the pool of antibodies from ovarian cancer patients.

To gain insight into the mechanisms of molecular recognition and humoral immune response in ovarian cancer, we used fingerprinting, a phage display-based combinatorial selection to isolate peptide ligands to tumor-related antibodies present in ascites from patients with advanced disease. First, we have isolated a consensus motif (sequence CVPELGHEC) in 86% of the peptides screened; this enriched motif was selected from a total of 108–109 unique random sequences present in the library. Next, we identified the heat-shock protein 90 kDa (HSP90) as the native antigen mimicked by the motif. Finally, we evaluated the expression of HSP90 and the presence of antibodies against the HSP90-mimic peptide in a large panel of ovarian cancer patients and controls. In tissue microarrays, we show that the expression of HSP90 is ubiquitous. However, the corresponding humoral immune response against HSP90 is restricted to a subset of patients with stage IV disease. Together, these results show that screening humoral response can identify tumor antigens that may serve as molecular targets in ovarian cancer. Recognition of such relevant proteins in the immunobiology of malignant tumors may lead to the development of therapies.

Open-label, multicentre expansion cohort to evaluate imgatuzumab in pre-treated patients with KRAS-mutant advanced colorectal carcinoma.

AIM Imgatuzumab (GA201) is a novel anti-epidermal growth factor receptor (anti-EGFR) antibody glycoengineered for enhanced antibody-dependent cell-mediated cytotoxicity (ADCC). We investigated the efficacy of imgatuzumab in patients with EGFR-positive, KRAS-mutant advanced colorectal cancer. METHODS Patients received single-agent imgatuzumab (1400mg on day 1 and 8 followed by q2W) as third line therapy in an open-label, multicentre, non-randomised, expansion study. The primary end-point was tumour response. Pre- and on-treatment biopsies and blood samples were investigated for biomarkers related to imgatuzumabs believed mechanism of action (MoA). RESULTS 25 patients were treated and the best overall response was stable disease occurring in 40% of patients at 8weeks, 24% at 16weeks and 8% (two patients) at 32weeks. Median overall survival was 9.3months (95% confidence interval (CI): 5.1-12.3). Treatment-related rash, hypomagnesaemia and infusion-related reactions were the most common adverse events. Comparison of pre- and post-treatment biopsies revealed that the number of tumour-infiltrating immune cells increased notably after one cycle of therapy (median compound immune reactive score of 1491 versus 898 cells/mm(3) at baseline), whereas the number of peripheral natural killer cells decreased. A potential association between baseline tumour immune infiltration and clinical efficacy was seen. CONCLUSIONS These data may suggest that the MoA of imgatuzumab involves ADCC-related immune effects in the tumour and is not limited to simple receptor blockade.

Abstract LB-220: Translational research with RG7160 (GA201) leads to a phase II clinical study in combination with FOLFIRI in 2nd line metastatic colorectal cancer (mCRC)

GA201 is a novel dual-acting humanized, engineered IgG1 anti-EGFR mAb designed to enhance ADCC in combination with signaling inhibition. Superior efficacy was demonstrated versus cetuximab in orthotopic CRC xenograft models. Preclinical data indicated an increase in macrophages (4-5 fold) and NK cells (2-3 fold) infiltration in tumors treated with GA201 compared to cetuximab. In a phase I clinical study objective responses and long lasting disease stabilizations were observed. A marked reduction in circulating NK cells and an increased infiltration of immune cells into skin rash was seen. Preliminary evidence of the enhanced ADCC capacity of GA201 was investigated in 25 third line patients with KRAS-mutant mCRC. Best overall response was SD in 40% of patients and median OS was 9.4 months. Reduction in peripheral NK cells and regulatory T-cells was observed. Comparison of pre- and post-treatment tumour biopsies revealed that tumour-infiltrating immune cells, in particular CD68+ and CD3+ cells increased overall. EGFR-membrane staining in baseline tumour biopsies was markedly higher than in the corresponding archival tumour specimens (median H-score 52 vs 3, respectively), which might reflect technical, but most importantly, biological variability. Based on these results and the commitment to investigate the tumor immune infiltration profile as a potential predictive biomarker, a fresh tumor biopsy at baseline was mandated in the ongoing randomized phase II trial (GAIN-C). This compares GA201 plus irinotecan, infusional fluorouracil and leucovorin (FOLFIRI) with FOLFIRI alone in KRAS-mutant 2nd line mCRC patients and with cetuximab plus FOLFIRI in KRAS-wild type patients (n=160). Primary objective is PFS. The fresh tumor biopsy will be centrally analyzed for EGFR and KRAS. A comprehensive biomarker program was implemented to investigate potential predictive biomarkers, with an emphasis on the real time tumor immune-infiltration status. The safety run-in phase with 36 patients was completed. Most common treatment related AEs on GA201 arms vs cetuximab vs. chemotherapy included (≥ grade 3): rash (33 vs. 17 vs. 0%), IRR (10 vs. 0 vs. 0%), diarrhea (17 vs. 0 vs. 11%), fatigue/asthenia (0 vs. 17 vs. 0%), hypomagnesaemia (17 vs. 0 vs. 0%), stomatitis (17 vs. 0 vs. 0%) and vomiting/nausea (6 vs. 0 vs. 0%). So far, no patient discontinued due to EGFR-related skin toxicity. Immunological profiling is ongoing. Extensive research efforts, including a fresh tumor biopsy in second line mCRC patients, are taken to understand the immunological mechanism of action of GA201 and to select and test (ph. II) and validate (ph. III) potential predictive biomarkers. To guide personalized cancer immunotherapies there is a clear need for reliable biomarkers which would necessitate a tumor assessment directly prior to the therapy and immune monitoring throughout treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-220. doi:1538-7445.AM2012-LB-220