Astex Therapeutics also confirmed that AT9283 was recently granted an Orphan Medicinal Product Designation by the European Commission for the same indication after a positive opinion from the European Medicines Agency (EMEA) Committee for Orphan Medicinal Products in October. Orphan drug legislation in Europe and the United States provides specific incentives for sponsors to develop products for rare diseases such as acute myeloid leukaemia (AML).

Astex is currently completing the enrolment of patients in a Phase I/IIa trial of AT9283 in patients with leukaemia at two clinical sites in the USA. The potential value of AT9283 in AML is supported by the observation that approximately one-third of the relapsed or refractory AML patients treated in this study have shown a reduction in bone marrow blasts and evidence of haematological improvement. This group of patients had either failed or were unsuitable for multiple lines of standard therapy.

Astex has also completed a Phase I study of AT9283 in patients with refractory solid tumours and is conducting a further Phase I study in patients with refractory solid tumours in partnership with the Clinical Trials Group of the National Cancer Institute of Canada. Further clinical studies are also currently underway and being planned with Cancer Research UK to investigate the use of AT9283 as a treatment for children and adolescents with solid tumours and leukaemias and with the National Cancer Institute of Canada as a treatment for patients with multiple myeloma.

If AT9283 is approved for the treatment of patients with AML in the USA or in Europe, orphan drug designation could provide Astex with potential market exclusivity for ten years in Europe and seven years in the USA. Orphan drug designation also enables Astex to seek scientific advice and guidance from the EMEA in optimizing the clinical development of AT9283. In addition, a drug candidate designated by the FDA and EMEA as an orphan drug product might qualify for subsidies on regulatory fees and tax incentives and might be eligible for research grant funding to assist in further clinical development.

Harren Jhoti, Chief Executive Officer of Astex Therapeutics, said, ‘The orphan drug designations for AT9283 underscore the high unmet medical need faced by patients with AML where only a minority of patients are currently cured of their disease. We are hopeful that we can build on the early evidence of clinical efficacy with AT9283 and translate this into new treatment opportunities for patients with AML.’