Studies presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) by Par Pharmacueticals., showed that PAR-101 was potentially efficacious in treating clostridum difficile-associated diarrhoea (CDAD).

According to Centers for Disease Control and Prevention, CDAD has been a cause of some mortality and significant morbidity in hospitalised patients. More recent and less commonly encountered strains of CDAD are exhibiting significantly higher rates of mortality and have been less responsive to current treatments, such as metronidazole.

According to Sherwood L. Gorbach,Tufts University School of Medicine, "New strains of CDAD have emerged which are not responding to certain commonly used antibacterials. PAR-101 may provide healthcare professionals with a new tool to treat this potentially deadly bacterial illness. CDAD is highly contagious and has recurrence rates ranging from 20% to 25% after existing therapies. It is important that healthcare professionals have additional agents to treat this illness."

According to a Par release, the phase 1B study was a randomised, double-blind, multiple-dose, placebo-controlled study to evaluate pharmacokinetics, tolerance, and safety of PAR-101 in healthy volunteers. Oral doses of PAR-101 150 mg, 300 mg, and 450 mg were administered once-daily for 10 days. PAR-101 was well tolerated by all subjects at all doses; no adverse events were considered to be drug related. The absorption of PAR-101 was minimal, with the majority of drug being eliminated in the faeces.

In the proof-principle phase 2A study, PAR-101 was evaluated in 45 CDAD patients in order to select an appropriate dose for subsequent trials. Subjects were randomised to receive 50 mg, 100 mg, or 200 mg of treatment every twelve hours followed by clinical evaluation.

The clinical evaluation included relief of symptoms of CDAD, time to resolution of diarrhoea, and clinical recurrence. Plasma and faecal samples were collected to investigate the relationship among dose, concentration, and excretion of PAR-101 in CDAD patients. PAR-101 was well tolerated by all subjects at all doses

"PAR-101 has the potential to address an emerging health problem for both patients in hospitals and patients living in healthcare related environments. We are looking forward to the development of PAR-101 for this marketplace," said John MacPhee, president, branded products division, Par Pharmaceutical Companies, Inc.

C. difficile-associated diarrhoea (CDAD), a potentially deadly bacterial illness, is the most common cause of nosocomial diarrhoea in developed countries.

PAR-101 is a narrow-spectrum antibiotic that is highly selective for C. difficile, thus preserving gut microbial ecology, an important consideration for the treatment of CDAD.

Par Pharmaceutical Companies Inc develops, manufactures and markets generic drugs and innovative branded pharmaceuticals for specialty markets.