Troxacitabine: BCH 4556, SPD 758, Troxatyl

Troxacitabine [BCH 4556; SPD 758; Troxatyl] is a DNA synthesis inhibitor. This profile has been selected from R&D Insight, a pharmaceutical intelligence database produced by Adis International Ltd. It is a member of a novel class of nucleoside analogues discovered by BioChem Pharma and is the first example of a synthetic L-nucleoside analogue to have shown anticancer activity in animal models. On 11 May 2001, BioChem Pharma was acquired by, and integrated into, Shire Pharmaceuticals Group. In February 2002 Shire announced that it intended to pursue development of troxacitabine as a treatment for solid tumours. In addition, Shire indicated that it would pursue the drug's development for acute myeloid leukaemia. In March 1999, phase II trials were initiated to investigate the efficacy and tolerability of troxacitabine in a variety of solid tumours including pancreas, prostate, colorectal, renal and non-small cell lung cancers and melanoma. The trials were conducted throughout North America and were closed to patient accrual in 2000. Two phase I combination chemotherapy trials in solid tumours (one with cisplatin and another with paclitaxel) have been initiated. One of these trials is in patients with pancreatic cancer. A phase III trial in patients with pancreatic cancer is expected to begin during the second or third quarter of 2003. In addition, further clinical development was initiated in May 2000, in the form of a combination chemotherapy trial in patients with acute leukaemia. A phase II trial in patients with acute myeloid leukaemia (AML) and chronic myeloid leukaemia-blast phase (CML-BP) has reported that troxacitabine demonstrated significant activity in these cancers. However, Shire indicated that no further development for CML-BP will be conducted. The company indicated that it would focus future development in the haematological malignancy area on AML and has initiated an exploratory phase III trial of troxacitabine in previously untreated patients with poor prognosis AML. The study will compare troxacitabine in combination with either cytarabine or idarubicin, with a control drug regimen. The aim is to identify the most promising treatment regimens in a relatively small number of patients before commencing the larger pivotal trial. A pivotal phase III trial is expected to begin in the first half of 2003. In September 2002, Shire Pharmaceuticals forecast Troxatyl to reach peak sales of $US100-200 million, for the indications of pancreatic cancer and myeloid leukaemia.