Threshold reports positive results from Phase I study of tumor drug

The clinical trial was designed with an initial accelerated titration design followed by a standard dose escalation schema. The trial has completed the accelerated titration design component and has enrolled the eighth dosing cohort.

The weekly dose has been escalated from the initial dose of 7.5mg/m2 to 670mg/m2. None of the 20 patients enrolled to date has experienced any dose limiting toxicities (DLT). Importantly, one patient with refractory small cell lung cancer metastatic to the liver had a partial response at their initial response assessment with a greater than 45% reduction in target lesion diameters.

The patient, who has received two cycles of TH-302 at 480mg/m2, is being followed by Recist criteria. Additionally, this patient experienced a marked improvement in liver function tests. Other anti-tumor activity observed include one patient with non-small cell lung cancer with tumor shrinkage lasting over six months.

The company also reported on in vivo translational studies designed to select effective combinations of TH-302 and standard chemotherapies in order to complement the activity and tolerance of chemotherapy.

In preclinical models, TH-302 demonstrated single agent activity; however, combination therapy was associated with higher complete response rates, longer survival and greater tumor growth inhibition in multiple preclinical models utilizing various tumor types and tumor implantation methods.

The results from the preclinical studies facilitated the planning of the next clinical trial of TH-302, a multiple-arm, Phase I/II clinical trial of TH-302 in combination with docetaxel, in combination with gemcitabine, and in combination with pemetrexed. The company plans to commence this trial in the third quarter of 2008.