The company has been speaking to advisers as it prepares to explore options that may include a sale or partnership, the report said. Ireland, Dublin-based Prothena could attract interest from larger drugmakers if it decides to go ahead, according to the report. Prothena said it does not comment on market speculation, when contacted by Reuters.

The Bloomberg report said the deliberations are in early stage and Prothena could opt to remain independent for longer, especially if the data from its Alzheimer's trial is negative.