Since 2013, the research group has tested more than 1,000 ready-made drugs on nematode worms, human cells in a dish and mice.
Two were shown to prevent both a form of dementia and prion disease by stopping brain cells dying.
Prof Mallucci told the BBC News website: "Both were very highly protective and prevented memory deficits, paralysis and dysfunction of brain cells."
The best known drug of the pair is trazodone, which is already taken by patients with depression.
The other, DBM, is being tested in cancer patients.
Prof Mallucci said: "It's time for clinical trials to see if there's similar effects in people and put our money where our mouth is.
"We're very unlikely to cure them completely, but if you arrest the progression you change Alzheimer's disease into something completely different so it becomes liveable with."
But, although trazodone is a current medication, she added: "As a professional, a doctor and a scientists, I must advise people to wait for the results."