Good safety results for Prana

Source: Prana Biotechnology

Melbourne's Prana Biotechnology has announced promising results from its Phase IIa study of its lead drug PBT2 in patients with early Alzheimer's disease.

PBT2 is Prana's lead metal protein attenuating compound (MPAC) for Alzheimer's patients.

The trial results showed that PBT2 demonstrated safety and tolerability and reduced amyloid beta, or Abeta 42, the protein that is the main constituent of the amyloid plaques found in Alzheimer's brains.

The compound also improved executive function performance in select cognitive tests.

"This is a very exciting and important milestone for the company, particularly because PBT2, a drug known to inhibit the toxic oligomers of Abeta that cause the functional damage in Alzheimer's disease, was able to show such a clear effect in a short trial," Geoffrey Kempler, Prana's chairman and CEO, said.

In the double blind multi-centre clinical trial, 78 patients in Sweden and Australia were randomised to receive either a placebo, PBT2 50mg or PBT2 250mg capsule once per day for 12 weeks.

Analysis of the trial data demonstrated that the safety and tolerability profile of PBT2 at both doses was indistinguishable from that of placebo. There were no study withdrawals related to adverse events. There was no serious adverse event (SAE) in any PBT2 treated patient.

The study also demonstrated the impact of PBT2 on reducing Abeta 42 in the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord, considered a key biomarker for Alzheimer's.

Specifically, PBT2 at the 250mg dose showed a highly significant reduction in CSF Abeta 42 compared to placebo (p=0.006). The effect of PBT2 was dose related (p=0.02).

Professor Jeffrey Cummings, head of Prana's research and development advisory board and director of the Easton Centre for Alzheimer's Disease at the University of California Los Angeles, said PBT2 had hit what the company considered to be the critical target for Alzheimer's disease, as evidenced by the significant reduction in Abeta 42.

Encouraging signs of cognitive improvement, as measured by the Neuropsychological Test Battery (NTB), were also observed.

Statistically significant improvement was evident in two of the four executive function NTB tests: the Category Fluency Test (p=0.028) and the Trail Making Test part B (p=0.005), both after 12 weeks of treatment at the 250mg dose compared to placebo.

PBT2, in this study of early disease progression, had no effect on ADAS-cog, a test of cognition not designed to measure executive function changes. The NTB is a test of cognition that is more sensitive to the changes in executive function that are seen in the early stage of Alzheimer's disease.

"The impact of this drug on executive function is very encouraging as this is likely to predict an improvement in the day to day functioning in the lives of people with Alzheimer's Disease," Cummings said.

"The ability to plan and execute everyday activities, even more so than memory, offers great practical and clinical benefit to patients."

These results build on earlier observations using PBT2 in transgenic mouse models of Alzheimer's Disease, where PBT2: reduced toxic oligomers of Abeta, reversed the Abeta-induced loss of neurotransmission and improved cognition.

Prana now plans to further progress PBT2 into larger and longer clinical trials to investigate its potential as a disease modifying drug.

"We are very hopeful that PBT2 will continue to perform as well as it has in this trial and progress through the development pathway, eventually to bring true benefit to patients with Alzheimer's disease," Kempler said.