A fully-virulent retargeted oncolytic HSV armed with IL-12 elicits local immunity and vaccine therapy towards distant tumors.

Oncolytic herpes simplex viruses (oHSVs) showed efficacy in clinical trials and practice. Most of them gain cancer-specificity from deletions/mutations in genes that counteract the host response, and grow selectively in cancer cells defective in anti-viral response. Because of the deletions/mutations, they are frequently attenuated or over-attenuated. We developed next-generation oHSVs, which carry no deletion/mutation, gain cancer-specificity from specific retargeting to tumor cell receptors-e.g. HER2 (human epidermal growth factor receptor 2)-hence are fully-virulent in the targeted cancer cells. The type of immunotherapy they elicit was not predictable, since non-attenuated HSVs induce and then dampen the innate response, whereas deleted/attenuated viruses fail to contrast it, and since the retargeted oHSVs replicate efficiently in tumor cells, but spare other cells in the tumor. We report on the first efficacy study of HER2-retargeted, fully-virulent oHSVs in immunocompetent mice. Their safety profile was very high. Both the unarmed R-LM113 and the IL-12-armed R-115 inhibited the growth of the primary HER2-Lewis lung carcinoma-1 (HER2-LLC1) tumor, R-115 being constantly more efficacious. All the mice that did not die because of the primary treated tumors, were protected from the growth of contralateral untreated tumors. The long-term survivors were protected from a second contralateral tumor, providing additional evidence for an abscopal immunotherapeutic effect. Analysis of the local response highlighted that particularly R-115 unleashed the immunosuppressive tumor microenvironment, i.e. induced immunomodulatory cytokines, including IFNγ, T-bet which promoted Th1 polarization. Some of the tumor infiltrating cells, e.g. CD4+, CD335+ cells were increased in the tumors of all responders mice, irrespective of which virus was employed, whereas CD8+, Foxp3+, CD141+ were increased and CD11b+ cells were decreased preferentially in R-115-treated mice. The durable response included a breakage of tolerance towards both HER2 and the wt tumor cells, and underscored a systemic immunotherapeutic vaccine response.

Pharmacokinetics of buprenorphine following constant rate infusion for postoperative analgesia in dogs undergoing ovariectomy.

OBJECTIVE: To investigate the pharmacokinetics of buprenorphine and its main active metabolite, norbuprenorphine, after administration of an intravenous loading dose followed by constant rate infusion (CRI) in dogs. STUDY DESIGN: Prospective, clinical study. ANIMALS: A total of seven healthy dogs undergoing elective ovariectomy. METHODS: Buprenorphine was administered as a loading dose (intravenous bolus of 15 µg kg-1) followed by CRI (2.5 µg kg-1 hour-1 for 6 hours). Moreover, intraoperative analgesia was supplemented by an intramuscular carprofen (4 mg kg-1) injection, administered prior to surgery, and by lidocaine, administrated through subcutaneous infiltration and through a splash on the ovarian vascular pedicle during surgery. Pain and sedation were scored for all animals throughout the 24-hour study period and rescue analgesia was administered when a visual analogue scale score was > 40 mm. Blood samples were collected from a jugular catheter at regular intervals, and plasma concentrations of buprenorphine and norbuprenorphine were determined by a validated liquid chromatography-tandem mass spectrometry method. RESULTS: Buprenorphine showed a two-compartment kinetic profile. Maximum concentration was 23.92 ± 8.64 ng mL-1 at 1 minute (maximum time); elimination half-life was 41.87 ± 17.35 minutes; area under the curve was 486.68 ± 125.66 minutes ng-1 mL-1; clearance was 33.61 ± 13.01 mL minute-1 kg-1, and volume of distribution at steady state was 1.77 ± 0.50 L kg-1. In no case was rescue analgesia required. Norbuprenorphine resulted below the lower limit of quantification in almost all samples. CONCLUSIONS AND CLINICAL RELEVANCE: The results suggest that a buprenorphine CRI can be a useful tool for providing analgesia in postoperative patients, considering its minor side effects and the advantages of a CRI compared to frequent boluses. The negligible contribution of norbuprenorphine to the therapeutic effect was confirmed.