For its part, Merck notes that its BACE inhibitor recently demonstrated a reduction in cerebral spinal fluid, or CSF, a biomarker, in a Phase I study.

FORBES: Merck Makes A 'Speculative' Step Into Alzheimer's

Eli Lilly , meanwhile, is touting data from its two amyloid drugs, including a pill drug that dramatically lowers levels of amyloid in the cerebral spinal fluid.

FORBES: Alzheimer's Drug Showdown

Eli Lilly (nyse: LLY - news - people ), meanwhile, is touting data from its two amyloid drugs, including a pill drug that dramatically lowers levels of amyloid in the cerebral spinal fluid.

FORBES: Alzheimer's Drug Showdown

Giffords had hydrocephalus after she was shot, a condition where an excess of cerebral-spinal fluid puts pressure on the brain.

CNN: Doctors: Giffords faces a long, rocky road to recovery