A month after Pfizer and Janssen’s Alzheimer’s drug bapineuzumab failed in a late-stage study, a new trial has found it may benefit a sub-group of patients.

New Phase III data for the drug - known as ‘bapi’ - at a medical meeting in Sweden, show that the treatment reduced underlying markers of the disease in some patients, meaning it might work at an earlier stage.

The biomarker results show that bapi significantly reduced levels of the protein beta amyloid on the brain scans of patients - who had a certain gene mutation that increases their risk of Alzheimer’s - when compared with placebo.

The drug also significantly reduced the amount of a toxic form of the protein tau in spinal fluid, a sign of brain cell death, compared with patients who were given a placebo. However, MRI tests showed patients in the treatment and placebo groups had a similar loss of brain volume.

Bapineuzumab is an injectable monoclonal antibody that works by attacking the beta-amyloid protein, which is believed by some to play a key role in Alzheimer’s disease.

It is looking to be the first therapy to target the cause of Alzheimer’s, rather than just its symptoms.

Earlier this year the Pfizer and Janssen said that an intravenous form of bapineuzumab failed to significantly change cognitive and functional performance in patients with mild-to-moderate Alzheimer’s disease when compared to placebo.

The drugs pulled the drug in an IV form, but they do have an on-going study testing the treatment in an injectable form. But this new data could be a reprieve for the drug, which was once touted as a potential blockbuster for Pfizer and Janssen.

Professor Steve Salloway from Brown University told Bloomberg: “The disease begins 10 to 20 years before there are any symptoms, and now we are better at detecting some of those changes. We want to intervene as soon as possible to keep the brain healthy. Drugs like this that lower amyloid will probably have their greatest impact earlier on. We have to test that.”