Cell carriage, delivery, and selective replication of an oncolytic virus in tumor in patients.

Oncolytic viruses, which preferentially lyse cancer cells and stimulate an antitumor immune response, represent a promising approach to the treatment of cancer. However, how they evade the antiviral immune response and their selective delivery to, and replication in, tumor over normal tissue has not been investigated in humans. Here, we treated patients with a single cycle of intravenous reovirus before planned surgery to resect colorectal cancer metastases in the liver. Tracking the viral genome in the circulation showed that reovirus could be detected in plasma and blood mononuclear, granulocyte, and platelet cell compartments after infusion. Despite the presence of neutralizing antibodies before viral infusion in all patients, replication-competent reovirus that retained cytotoxicity was recovered from blood cells but not plasma, suggesting that transport by cells could protect virus for potential delivery to tumors. Analysis of surgical specimens demonstrated greater, preferential expression of reovirus protein in malignant cells compared to either tumor stroma or surrounding normal liver tissue. There was evidence of viral factories within tumor, and recovery of replicating virus from tumor (but not normal liver) was achieved in all four patients from whom fresh tissue was available. Hence, reovirus could be protected from neutralizing antibodies after systemic administration by immune cell carriage, which delivered reovirus to tumor. These findings suggest new preclinical and clinical scheduling and treatment combination strategies to enhance in vivo immune evasion and effective intravenous delivery of oncolytic viruses to patients in vivo.

Severe sequence-specific toxicity when capecitabine is given after Fluorouracil and leucovorin.

PURPOSE: Options for single-agent fluoropyrimidine adjuvant therapy after bowel cancer resection include intravenous fluorouracil with leucovorin (FU/LV) or oral capecitabine. These treatments have similar efficacy but differ in convenience and toxicity. We therefore wished to compare their overall acceptability to patients. PATIENTS AND METHODS: Patients scheduled for adjuvant single-agent fluoropyrimidine therapy were randomly assigned to receive once-weekly FU/LV (425 mg/m(2) FU, 45 mg LV) for 6 weeks, followed by two 3-week cycles of capecitabine (1,250 mg/m(2) twice daily, days 1 through 14), or the same treatments but in reverse order. After 12 weeks, the patients were asked which treatment they preferred, and received the preferred treatment for an additional 12 weeks. The primary end point was patient preference. RESULTS: After 40 of the planned 74 patients had been randomly assigned, real-time adverse event monitoring led to early trial closure because of excess sequence-specific toxicity. Eleven of 14 patients (79%) receiving capecitabine as their second treatment experienced grade >/= 3 toxicity. This compared with five of 18 patients (28%) receiving capecitabine as the first treatment, and no patients receiving FU/LV as the first treatment (zero of 16) or the second treatment (zero of 12). Similar imbalances were seen in the proportion of patients requiring interruption of treatment. CONCLUSION: In chemotherapy-naïve patients, capecitabine produced more toxicity than FU/LV, but at levels in line with previously reported data. However, treatment with capecitabine after FU/LV caused markedly increased toxicity, indicating a sequence-specific interaction. The mechanism has not been determined, but interaction with intracellularly retained folate after FU/LV therapy is a possibility. Oncologists need to be aware of this risk if considering crossing patients over from FU/LV to capecitabine-based regimens.