Cancer Therapy: Clinical A Phase I Study of the Combination of Intravenous Reovirus Type 3 Dearing and Gemcitabine in Patients with Advanced Cancer Martijn P. Lolkema 1 , Hendrik-Tobias Arkenau 1 , Kevin Harrington 2 , Patricia Roxburgh 3 , Rosemary Morrison 3 , Victoria Roulstone 2 , Katie Twigger 2 , Matt Coffey 4 , Karl Mettinger 4 , George Gill 4 , T.R. Jeffry Evans 3 , and Johann S. de Bono 1 Abstract Purpose: This study combined systemic administration of the oncolytic reovirus type 3 Dearing (reovirus) with chemotherapy in human subjects. We aimed to determine the safety and feasibility of combining reovirus administration with gemcitabine and to describe the effects of gemcitabine on the antireoviral immune response. Experimental Design: Patients received reovirus in various doses, initially we dosed for five consecutive days but this was poorly tolerated. We amended the protocol to administer a single dose and administered up to 3  10 10 TCID 50 . Toxicity was assessed by monitoring of clinical and laboratory measurements. We assessed antibody response by cytotoxicity neutralization assay. Results: Sixteen patients received 47 cycles of reovirus. The two initial patients and one patient in the final cohort experienced dose limiting toxicity (DLT). The DLTs consisted of two asymptomatic grade 3 liver enzyme rises and one asymptomatic grade 3 troponin I rise. Common toxicities consisted of known reovirus and gemcitabine associated side effects. Further analysis showed a potential interaction between reovirus and gemcitabine in causing liver enzyme rises. Grade 3 rises in liver enzymes were associated with concomitant aminocetophen use. Importantly, the duration of the liver enzyme rise was short and reversible. Neutralizing antibody responses to reovirus were attenuated both in time-to-occurrence and peak height of the response. Conclusions: Reovirus at the dose of 1  10 10 TCID 50 can be safely combined with full dose gemcitabine. Combination of reovirus with gemcitabine affects the neutralizing antibody response and this could impact both safety and efficacy of this treatment schedule. Clin Cancer Res; 17(3); 581–8. Ó2010 AACR. Introduction Reovirus type 3 Dearing (reovirus; REOLYSIN; Oncoly- tics Biotech Inc) is a wild-type member of the Reoviridae family and is nonpathogenic in humans. Infections are usually asymptomatic, however, reovirus infection of can- cer cells results in specific cytolysis. Activated signalling pathways downstream of KRAS or EGFR suppress the activity of double stranded RNA activated protein kinase (PKR), which normally inactivates viral replication (1,2). Therefore, reovirus is being tested as an anticancer therapy targeted at KRAS mutant tumors. Systemic administration of reovirus has been tested in human subjects in 2 phase I monotherapy trials. The first trial used a single infusion of 1  10 8 to 3  10 10 tissue culture infective dose (TCID) 50 every 4 weeks and the second trial tested treatment schedule infusing up to 3  10 10 TCID 50 5 consecutive days every 4 weeks (3,4). Neither study observed dose limiting toxicities (DLT). Commonly observed mild toxicities included fever, fatigue and head- ache. Dose escalation stopped at 3  10 10 TCID 50 because of limited quantities of reovirus available for clinical use at that time. Importantly, both studies showed evidence of viral replication in tumor tissue samples taken after treatment, indicating that systemic treatment with reovirus delivers the virus to the tumor site. The viral shedding after systemic delivery was minimal. The conclusion from these studies is that intravenous single agent reovirus administration is safe. This trial studied the combination of reovirus with gemcitabine. Exploration of combinations of reovirus with chemotherapy in clinical trials is an important step towards Authors' Affiliations: 1 Phase I Unit, Royal Marsden NHS Foundation Trust, Surrey & London, United Kingdom; 2 Cancer Research UK Targeted Therapy Laboratory, Centre for Cell and Molecular Biology, Chester Beatty Laboratories, Institute of Cancer Research, London, United Kingdom; 3 The Beatson Oncology Centre, Glasgow, United Kingdom; 4 Oncolytics Bio- tech Inc. Calgary, AB, Canada Note: Supplementary data for this article are available at Clinical Cancer Research Online (http://clinicalcancerres.aacrjournals.org/). Current address for Martijn P. Lolkema: Department Medical Oncology, University Medical Centre Utrecht, The Netherlands. Martijn P. Lolkema and Hendrik-Tobias Arkenau, equal contribution. Corresponding Author: Johann S. De-Bono, Section of Medicine, Insti- tute of Cancer Research, Royal Marsden Hospital, Drug Development Unit, Downs Road, Sutton, Surrey SM2 5PT, UK. E-mail: johann.De-Bono@icr.ac.uk. doi: 10.1158/1078-0432.CCR-10-2159 Ó2010 American Association for Cancer Research. Clinical Cancer Research www.aacrjournals.org 581 Cancer Research. on November 25, 2021. © 2011 American Association for clincancerres.aacrjournals.org Downloaded from Published OnlineFirst November 24, 2010; DOI: 10.1158/1078-0432.CCR-10-2159