Threshold Pharmaceuticals has reported preliminary data from a Phase I/II study of TH-302, in combination with Bevacizumab, in patients with recurrent glioblastoma.

TH-302 is a hypoxia-targeted drug designed to be activated under tumour hypoxic conditions.

According to the preliminary results, a median time to progression (worsening of disease) of 128 days, compared with a median time to progression of 89.5 days, was observed in six patients who were taking single-agent bevacizumab prior to study enrolment.

The Institute for Drug Development at the Cancer Therapy and Research Center in San Antonio, clinical investigator and the study principal investigator Dr Andrew Brenner said the early data from a small number of patients provides the first insight into the potential combination of TH-302 with bevacizumab for treating patients with recurrent glioblastoma.

"Safe and effective treatment options for this particularly aggressive cancer are urgently needed, and we look forward to further evaluation of TH-302 as dose escalation in this study continues," Brenner said.

Preclinical data suggest that antiangiogenic agents may increase tumour hypoxia, which supports the rationale for combining TH-302 with bevacizumab in treating glioblastoma.

No dose limiting toxicity has been reported to date in the study, which is enrolling patients with recurrent glioblastoma whose disease has progressed following initial treatment with bevacizumab and who are scheduled for debulking craniotomy.

Grade 3 or 4 adverse events were not observed with 240mg/m2 TH-302 while one Grade 3 adverse event (skin ulceration) and no Grade 4 adverse events have been observed so far in the second cohort at 340mg/m2 TH-302.

Threshold CEO Barry Selick said; "We believe TH-302 has the potential to be complementary to targeted cancer therapies, and we will continue to evaluate its safety and efficacy in combination with a variety of antiangiogenic agents in different tumor types."