Results of a phase I study to evaluate the feasibility, safety, and biological effects of intravenous administration of wild-type reovirus with docetaxel to patients with advanced malignancies
e13524 Background: Reovirus has minimal pathogenicity in humans but selectively replicates in cells with activated Ras. Wild- type reovirus serotype 3 Dearing strain (Reolysin) has selective antitumor activity in vitro, in murine models, and after systemic delivery in humans in phase 1 trials. Synergistic tumour kill has been observed combining reovirus with taxanes in a range of cancer cell lines and in vivo. Methods: Patients were treated in an open-label, dose-escalating, phase I trial and received 3- weekly 75mg/m2 docetaxel i.v. and reovirus i.v. (day 1–5 of first week inclusive). Reovirus was administered at a starting dose of 3x109 tissue culture infectious dose (TCID50) and then increased to 1 x 1010 and 3 x 1010 TCID50. Primary endpoints were to determine the maximum tolerated dose (MTD), dose limiting toxicity (DLT) and to recommend a dose and schedule for future investigation. Secondary endpoints were to evaluate pharmacokinetics, neutralizing antibody development, cell- mediated immune response and anti-tumour activity. Results: 17 patients were treated (15 males, median age 60 years). No MTD has been reached. DLT's observed were G4 neutropenia (and a recurrent perianal abcess) and G3 rise in AST. Other toxicities observed were fatigue, hypotension and neutropenic sepsis. At present, 5 patients remain on treatment. We have observed 2 partial responses (breast and gastric carcinoma) and 10 patients had stable disease as best response. Conclusions: Reovirus is well tolerated when administered in combination with intravenous docetaxel, with predictable toxicity observed. The recommended dose has been defined at 3x1010 TCID50 and phase II studies are planned. Objective radiological evidence of anticancer activity for this combination has been observed. [Table: see text]