Virulizin

The purpose of this study was to determine the efficacy of intracavitary cisplatin against local regrowth and metastasis after resection of a murine mammary carcinoma and the ability of a biologic response modifier (Virulizin) to enhance chemotherapy. C3H-HeJ mice were injected with Gollin-B tumor cells. Once growth reached 8 mm, tumors underwent marginal resection and the mice were assigned randomly to intraperitoneal (i.p.) cisplatin, Virulizin, a controlled release cisplatin-impregnated sponge (OPLA-Pt), a combination of treatments or no treatment and were evaluated for local regrowth, metastasis, and toxicity at 14 or 60 days after surgery. A possible beneficial interaction was seen between OPLA-Pt and Virulizin at 14 days. All cisplatin groups had significant advantages over controls in all variables measured with OPLA-Pt displaying significant advantages over i.p. cisplatin in local recurrence rate, tumor score, survival time, and delay in regrowth at 60 days. No toxicity related to either cisplatin or Virulizin was observed.

Virulizin, a biological response modifier, is a mixture of proteins and peptides that have been extracted from bovine reticuloendothelial tissue that activates macrophages. It is being developed by Lorus Therapeutics (formerly Imutec Pharma) for the treatment of various cancers and had completed phase II clinical trials in Canada for the treatment of pancreatic cancer and advanced malignant melanoma. The commencement of phase III clinical trials in Canada, for the treatment of pancreatic cancer, was delayed due to quality control problems with batches of virulizin and all clinical trials of virulizin were suspended as Lorus underwent a major restructuring programme. However, phase I/II clinical trials are now underway again in Canada in HIV-positive patients with Kaposi's sarcoma and for the treatment of pancreatic cancer. A phase I/II clinical trial is also underway in patients with pancreatic cancer in the USA. Lorus announced in June 2000 that it had completed a meta analysis of three phase I/II studies of virulizin that showed the drug increased survival and improved quality of life for pancreatic cancer patients. Based on these positive results, Lorus initiated a phase III trial to be conducted at 40 sites in North America in November 2001. The study aims to enrol 350 patients with advanced pancreatic cancer and will test the effectiveness of virulizin as first- and second-line treatment of pancreatic cancer. The study will compare virulizin + gemcitabine with gemcitabine alone as first-line therapy, while second-line treatment will involve patients who have failed to respond to gemcitabine. Some of these patients will receive virulizin + fluorouracil while another group will receive only fluorouracil. The study is scheduled to complete in 2004 or early 2005. Virulizin received orphan drug status for this indication from the US FDA in February 2001. Lorus received fast track designation from the FDA in June 2002 for virulizin for the treatment of pancreatic cancer. Virulizin is registered for the treatment of malignant melanoma in Mexico and is due to be launched there in 2002. Lorus has entered into an exclusive 7-year distribution agreement with Faulding Canada Inc., giving Faulding (now part of Mayne Group) the right to market and sell virulizin in Mexico for the treatment of melanoma. Lorus will receive royalties from sales of the product and will be responsible for its manufacture. In April 2002, Mayne exercised its option to acquire the distribution rights for virulizin in Brazil. Lorus Therapeutics has signed a collaborative agreement with NaPro BioTherapeutics, USA, to study the efficacy of virulizin in combination with paclitaxel for the treatment of lung adenocarcinoma. Lorus is conducting preclinical studies of virulizin in human breast cancer, lung, ovarian and prostate cancer, and has reported successful activity of the agent in these indications. Lorus was awarded a patent by the US Patent and Trademark Office to protect the only known process used to create virulizin. This patent, in conjunction with the patents issued in Australia, South Africa, New Zealand, Korea and Singapore, broadens and strengthens the protection of Lorus' intellectual property rights regarding the process, composition and use of virulizin.