Fort Washington-based Vitae Pharmaceuticals and German drugmaker Boehringer Ingelheim are partnering to develop enzyme-inhibiting drugs with the potential to slow or even halt progression of Alzheimer's disease.

The two companies will work together to develop drugs that block an enzyme called beta secretase, or BACE, involved in producing the amyloid-beta plaques that accumulate in the brains of Alzheimer's patients. Amyloid-beta peptide is a major part of those plaques, and is thought to be the key culprit in the development of Alzheimer's, a chronic neurodegenerative disorder that causes progressive memory loss.

According to the companies, lab studies in mice have shown that deleting a related gene called BACE1 prevents formation of the peptide in brain cells and also prevents related memory problems in the mice.

Therapies now available for Alzheimer's can improve symptoms, but do not alter its progression.

Vitae chief Executive Jeffrey Hatfield said in a statement that the partnership will add substantial expertise and specialized resources to his company's 16-month-old research program on BACE and continues its focus on partnering versus seeking money from capital markets.

Vitae will get $42 million in upfront cash and research funding, plus an equity investment from Boehringer of Ingelheim, Germany, the world's 15th-largest drug maker by sales. Vitae could receive another $200 million for reaching clinical and regulatory goals, as well as additional milestone payments and royalties on any future product sales.

Alzheimer's disease, the most common form of dementia in adults, affects an estimated 4.5 million Americans and more than 30 million people worldwide, with prevalence expected to double over the next 20 years as the global population ages.

Sales of Alzheimer's drugs, which hit approximately $5 billion last year, are expected to surpass $14 billion by 2015, according to the companies.