Favorable disease responses included complete responses in 35% of the 23 patients and significant cytoreduction of leukemic blasts in two others. As a further favourable outcome, these two patients and five of the patients who had complete responses were able to progress to a successful transplant, a desired outcome of successful salvage therapy. Notably, the study population included unfavourable patients with at least one adverse prognostic characteristic.
The clinical study also measured intracellular uptake of LOR-2040 in the bone marrow leukemic cells, and identified significant accumulation of the drug in the bone marrow blast cells and suggested preferential uptake of the drug by CD34+ cells, an important malignant bone marrow cell population.
The authors concluded that LOR-2040 in combination with high dose cytarabine is feasible, is active against its target R2, and "holds promise in younger patients with refractory or relapsed AML". The tolerability profile of this combination regimen was assessed as similar to that expected from high dose cytarabine alone.
"This successful clinical study has provided a detailed supporting rationale for our ongoing development program with LOR-2040 in AML", said Dr Aiping Young, Lorus' President and CEO. "This study supports Lorus' view that a highly specific targeted therapy approach can achieve efficacy with minimal impact on toxicity".
A Phase II program with LOR-2040 in this combination is presently ongoing to extend and confirm these findings in patients with refractory or relapsed AML.
LOR-2040 (formerly GTI-2040) is an antisense drug that specifically
targets the R2 component of ribonucleotide reductase, which is required for
DNA synthesis and cell proliferation. Through downregulation of R2,
LOR-2040 has demonstrated strong antitumor and antimetastatic act
|SOURCE Lorus Therapeutics Inc.|
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