Two independent research studies suggest the beleaguered pharmaceutical firm may have Alzheimer's cure.

Fortunes may finally have turned for Elan, the troubled Irish pharmaceutical company, and its Alzheimer's disease vaccination product. Two independent research groups have shown its vaccine does work and also suggest ways to make it safer.

Elan and pharmaceutical partner Wyeth halted a trial of the vaccine earlier this year after some patients developed serious brain inflammation. This reversal, coupled with questions about accounting practices in Elan post Enron, combined to send its shares plummeting.

Elan shares have collapsed from a high of $65 to a current value of $1.26. This forced an extensive retrenchment as the firm shed staff and valuable product lines to keep itself afloat. Elan closed its Trinity College research base with the loss of 60 scientific jobs, and another 60 staff jobs were lost at its Athlone manufacturing plant, which still employs 700. Twenty more staff have left the company's headquarters in Dublin, where 80 are now employed.

While Elan still faces legal action in the US over its accounting practices, the research studies, published this morning in the journal, Nature Medicine, renew hopes that it may be sitting on a cure for Alzheimer's disease.

"We would definitely look upon these as encouraging," said Dr Ivan Lieberburg, Elan's San Francisco-based chief scientific and medical officer. It was too soon, however, to expect a share value resurgence on the back of these findings, he said.

Alzheimer's is an incurable brain disorder causing progressive loss of memory and serious disturbance to thought processes. Typically patients cannot recognise family or friends and need constant care and attention. A large proportion of all patients with age-related dementia actually have Alzheimer's.

The company developed a vaccine meant to attack the root cause of Alzheimer's, the build-up in the brain of a protein substance called beta-amyloid, and tested it on mice. Not only did the vaccine destroy the beta-amyloid, it also seemed to reverse the loss of brain function in test animals.

The vaccine successfully passed Phase I human safety trials, but the larger international Phase II trial involving 375 patients was halted abruptly when 17 of the 300 people receiving the active vaccine developed serious brain inflammation. All recovered safely but the apparent failure represented a serious blow to Elan's hopes for a hugely valuable Alzheimer's treatment.

The two independent research studies into the vaccine, one involving patients that participated in the Elan trial, now renew hopes that the vaccine can be made to work. Prof Robert Nitsch and colleagues at the University of Zürich studied samples taken from trial patients, some whom had become ill and others who had not.

The vaccine had succeeded in causing the patients' immune systems to produce antibodies against beta-amyloid. Equally important, these antibodies only attacked the beta-amyloid target and not similar but essential substances also found in the brain cells.

"The high degree of specificity of the antibodies observed in our present study together with the absence of unwanted cross-reactions with normal brain cells argue in favour of the vaccination against beta-amyloid," Prof Nitsch told The Irish Times.

In the second study, researchers at the University of Toronto and the University of Konstanz, Germany, took a closer look at the vaccine in mice. They found that while Elan initially used a large 42-part vaccine in the mouse and human trial, a much smaller four- to 10-part vaccine was big enough to produce the same beneficial effects in the mice.

This much smaller vaccine element raised the mouse antibodies against beta-amyloid "without eliciting an inflammatory response" according to lead author Prof JoAnne McLaurin.

"It is a smaller portion of the original than what was originally used," she said. This also raised the possibility that researchers could "make a mimic of the antibody" directly, and avoid using the vaccine at all.

"That is encouraging but it still doesn't explain why those 17 patients became ill," Dr Lieberburg said.

"One would have to assume the antibodies were not the source of the inflammation. Our view is perhaps in those patients who developed inflammation it was a non-necessary part of the \."

While the findings were supportive of Elan's view, any new vaccine form would have to go through whole new safety checks.

"Obviously people are waiting for us to go back to the FDA [US Food and Drug Administration]," he added. The firm expected to do this with a smaller vaccine from next year.