Diffusion Pharmaceuticals Inc. announced positive effects from its second Oxygenation Trial, the Altitude Trial. Under hypoxic conditions, cells become starved for oxygen and they transition to anaerobic metabolism, increasing lactic acid production and resulting in a decreased pH and increased total lactate levels within the blood. In the Altitude Trial, following exercise under hypoxic conditions, an increase in pH and a decrease in lactate were observed in the study subjects treated with the highest dose of TSC (2.5 mg/kg), both at the end of the exercise period and at 10 minutes post-exercise.

These data suggest the 2.5 mg/kg dose of TSC decreased blood acidity (i.e., lactic acid accumulation) and enhanced metabolic recovery at 10 minutes after completion of exercise under the stressful conditions of simulated high altitude and exercise. These positive changes observed in blood markers of oxygen utilization results in the Altitude Trial suggest TSC may enhance oxygen availability at the cellular level. Specific results include the following: Positive effects on lactate and pH were observed with the TSC 2.5 mg/kg dose at the end of the exercise period versus the baseline measurement.

The effects on pH were significantly different (p<0.1) when compared to placebo. A “carry-over” effect was observed in subjects who received TSC in the first treatment (“ascent”) of the day versus those who received placebo first and TSC for the second ascent. The change in pH from baseline to last study measurement was also significantly lower (p<0.05) when placebo was administered for the first ascent of the day.

The 2.5 mg/kg dose appeared to have a positive effect on post-exercise recovery based on comparison of the measurements for pH, lactate, oxygen saturation (SpO2) and other markers at 10 minutes post-exercise versus last exercise measurements. There were no observed changes among subject's intra-day maximal oxygen consumption tests or in subject's partial pressure of arterial blood oxygen. TSC was safe and well-tolerated at all doses tested in the study with no serious adverse events reported.

The Altitude Trial was a double-blind, randomized, placebo-controlled crossover dose exploration study designed to investigate TSC's effects on oxygen enhancement using an experimental model to induce hypoxia in study participants. The primary endpoints measured in this study were maximal oxygen consumption and partial pressure of arterial blood oxygen in normal healthy volunteers subjected to incremental levels of physical exertion while exposed to hypoxic and hypobaric conditions at a simulated altitude of 15,000 feet above sea level. The secondary endpoints were to assess the effect of TSC on SpO2 and lactate.

A total of 30 healthy volunteers were enrolled in the trial with each subject serving as their own control by completing the experiment twice in a random, blinded order in the same day with a 3-hour rest and wash out period between experimental intervals. During one ascent, study subjects received intravenous (IV) placebo administration and the other ascent the same subject received a single IV dose of TSC at one of three dose levels (0.5 mg/kg, 1.5 mg/kg, or 2.5 mg/kg).