SGX Pharmaceuticals, Inc., a biotechnology company, has discontinued the phase II/III clinical trial of Troxatyl as a third-line treatment for patients suffering from acute myelogenous leukaemia (AML), based upon the recommendation of the study's independent data and safety monitoring board (DSMB).

The DSMB found that the study response rates were unlikely to provide evidence of a treatment benefit as a third-line treatment for patients with AML. The recommendation to discontinue the clinical trial was not made due to safety concerns.

"The response rates observed to date in our phase II/III trial of Troxatyl are not at a level that we believe would support a New Drug Application as a third-line treatment for AML and we feel it is appropriate to follow the recommendation of the DSMB to discontinue this trial," said Mike Grey, president and chief executive officer of SGX Pharmaceuticals. "Although we are disappointed with the results of Troxatyl in this very difficult to treat third-line AML population, Troxatyl has produced interesting clinical results in other indications and we remain optimistic for its potential in these other indications. We will now analyze data from all patients treated thus far in the Phase II/III trial and will be taking a careful look at the range of opportunities to determine an appropriate development path for Troxatyl."

Grey added, "We remain enthusiastic about our pipeline and our proprietary drug discovery platform, FAST. We expect to identify a development candidate later this year, with a targeted IND filing in the first half of 2007, in our BCR-ABL inhibitor programme in collaboration with Novartis for the treatment of drug resistant chronic myelogenous leukaemia, which is our most advanced program developed using our FAST drug discovery platform."

The phase II/III trial was designed to establish the safety and effectiveness of Troxatyl in patients with relapsed or refractory AML. Patients targeted in this study are those who are in a second relapse with duration of second response less than six months, or who were refractory to two previous courses of induction chemotherapy. A DSMB was instituted prior to the study's commencement to periodically review safety and efficacy data and make recommendations about study conduct. The study was designed to demonstrate a meaningful improvement over the historical data from the M.D. Anderson Cancer Center database which documented a complete response rate of 4.7 percent in this patient subgroup. The observed response rates in the Phase II/III trial to date did not show a meaningful improvement over the response rates in the M.D. Anderson Cancer Center historical database. There currently are no approved therapies for treating third-line adult AML patients and the historical median survival time is approximately two months.