Lorus Therapeutics allowed Canadian patent to protect anticancer drugs

Lorus Therapeutics today announced that its wholly owned subsidiary, GeneSense Technologies Inc., has been allowed a patent by the Canadian Patent Office entitled "Antitumor Antisense Sequences Directed Against R1 and R2 Components of Ribonucleotide Reductase." The patent protects Lorus' antisense molecules that target R1 and R2, including its lead anticancer drugs in the clinic, GTI-2401 and GTI-2501.

GTI-2040 is currently the subject of a Clinical Trials Agreement with the United States National Cancer Institute (NCI) under which GTI-2040 is being tested in combination with chemotherapy in five different clinical trials. These include studies of GTI 2040 in breast, lung, colon, acute myeloid leukemia and a variety of solid tumors.

Promising phase II interim clinical data arising from GTI-2040 in combination therapy for the treatment of renal cell carcinoma has provided evidence of disease stabilizations, tumor reductions and a favourable safety profile at the recommended phase II dose. Patients in the clinical study had previously failed or were ineligible for standard therapies, and were representative of a population with very poor prognostic outcome.

GTI-2501 is a novel antisense drug which has shown a favorable safety profile in preclinical studies, and in a phase I clinical trial. The drug is in a phase II clinical trial in combination with docetaxel for the treatment of hormone refractory prostate cancer. Initial testing has demonstrated strong antitumor activity in preclinical studies in prostate cancer and a variety of other tumor types.

In addition to this Canadian patent allowance, GTI-2040 and GTI-2501 have been protected by patents issued by the United States, Singapore, Australian and New Zealand Patent Offices. Patent applications for these antisense drugs have also been filed in numerous other international jurisdictions.

"Lorus Therapeutics is focused on developing anticancer drugs which complement the efficacy of more toxic chemotherapies without adding significant additional toxicity," said Dr. Jim Wright, CEO of Lorus Therapeutics. "We were pleased with the safety profile previously seen with GTI-2040 alone, and its positive clinical results to date in combination treatment for kidney cancer."

Added Dr. Wright: "This Canadian patent allowance contributes to our strong global intellectual property portfolio, an important part of our strategy for the creation of value within Lorus."

GTI-2040 is an antisense oligonucleotide complementary to the R2 component of ribonucleotide reductase, an activity that is essential for DNA synthesis. R2 is frequently over-expressed in cancer cells, and has been shown to cooperate with a variety of oncogenes to increase the tumorigenic and malignant potential of cancer cells. GTI-2501 is designed to exert its activity by specific downregulation of the R1 component of ribonucleotide reductase, a component essential for DNA replication and tumor cell proliferation.