Diffusion Pharmaceuticals to start brain tumor clinical trial

July 27, 2022 - 4 minutes
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U.S. biopharma company Diffusion Pharmaceuticals Inc. is set to start a new phase 2 clinical trial.

Entitled “Open-Label, Dose-Escalation, Phase 2 Safety and Efficacy Study of TSC in Newly Diagnosed Glioblastoma (GBM) Patients when Administered with Standard of Care (“SOC”),” the company said the trial is a result of a collaboration with the United States Food and Drug Administration (FDA).

The trial will be designated Study 200-208. The company expects to initiate the trial by the end of 2022 and anticipates dosing the first patient in the trial in the first quarter of 2023.

GBM

GBM is an aggressive, deadly, and treatment-resistant type of malignant brain tumor, affecting approximately 13,000 newly diagnosed patients each year in the U.S. Few treatment options are available for patients with GBM, and none have extended life expectancy beyond a few months. According to the National Brain Tumor Society, the five-year survival rate for GBM is only 6.8 percent with an average survival time of eight months.

“Effective treatment of GBM remains a significant unmet need and we believe in the potential for TSC (trans sodium crocetinate) to enhance the effectiveness of standard of care therapy for GBM,” said Robert Cobuzzi, Jr., president and CEO of Diffusion. 

“These tumors are known to be hypoxic, which reduces the effectiveness of radio-, chemo-, and immunotherapeutic approaches and promotes tumor cell metastases. We have previously received Orphan Drug designation from the FDA for treatment of GBM with TSC in conjunction with radiotherapy. 

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“With the results of the TCOM and Altitude Trials, we now have better data on TSC dosing compared to the previous GBM trials, and we have used these data to design a unique trial that not only will allow us to evaluate the effects of TSC on key clinical outcomes such as survival, but the use of PET imaging also will enable us to obtain data on the direct effects of TSC on GBM tumor oxygenation well before clinical outcome data is typically available in clinical trials involving GBM patients.”

The study will include a dose-escalation phase to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of TSC at doses of 1.5 mg/kg, 2.0 mg/kg and 2.5 mg/kg administered in combination with concomitant standard of care radiotherapy (RT) plus temozolomide. 

An additional 17 subjects will be treated at the highest tolerable dose identified in the dose escalation phase. The primary objective of the study is to evaluate the safety and tolerability of TSC for the treatment of patients with newly diagnosed GBM when administered with SOC. Secondary objectives of the study are to evaluate progression-free survival at six months by magnetic resonance imaging and to evaluate overall survival at 12 months.

Study differences

Study 200-208 will vary in a variety of ways from the GBM trials conducted by Diffusion in the past.

The 1.5 mg/kg to 2.5 mg/kg doses of TSC to be administered in the study will be six- to 10-fold higher than the 0.25 mg/kg dose used in Diffusion’s prior GBM trials.

Also, TSC will be administered five days each week approximately 30-60 minutes prior to radiotherapy, as compared to the three days per week regimen in Diffusion’s prior GBM trials.

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The study trial will incorporate PET scans to directly evaluate the oxygen enhancing effects of TSC on tumor hypoxia using one of two radiotracers, 18F-FMISO or 18F-FAZA, with initial data readouts expected to be available within one year of the study’s initiation.

Motivation

“For patients with hypoxic tumor microenvironments such as glioblastoma, radiation can be less effective. Diffusion Pharmaceutical’s proposed phase 2 trial of Trans Sodium Crocetinate (TSC) for glioblastoma patients may help to overcome the relative resistance of the hypoxic tumor to ionizing radiation. Improvements in the clinical outcomes for high-grade glioma patients are critically needed,” said Jason Sheehan, neurosurgeon at University of Virginia School of Medicine.

“With Glioblastoma Awareness Day on July 20 serving as a stark reminder of the continued unmet need for this disease, our team is incredibly motivated to work with our clinical investigators to get this uniquely designed trial started to explore the potential of TSC to improve outcomes for patients suffering from this devastating diagnosis,” said Chris Galloway, chief medical officer of Diffusion.

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