New Hope for Alzheimer's Disease
by Gail Dutton for Genetic Engineering & Biotechnology News:
Optimism Fostered by More Than 150 Firms Working in Space and Countless Approaches.
The global market value of Alzheimer's disease (AD) therapeutics could soar to the $8 billion range once therapeutics are approved that actually change the course of the disease. The current therapeutic market is valued at $3 to $4 billion, shared among drugs that temporarily delay disease progression or address the symptoms but do not alter the underlying disease, according to Ian Sanderson, senior analyst, Cowen & Company.Progress to a cure for AD has been hampered by the lack of information about the biology of the disease, he points out. “Only recently have scientists confirmed that amyloid plaques are associated with the disease, and they still debate whether they are causative or symptomatic.”More than 150 companies are working in the Alzheimer's space, including approximately 15 multinationals and 30 generics companies. Of those, “More than 100 companies have drugs in the pipeline,” according to Aiswariya Chidambaram, senior research analyst for life sciences, healthcare—Europe, at Frost & Sullivan.“More than 50 percent of the drug candidates are in the preclinical phase of development, with just two promising candidates in Phase III trials,” Chidambaram says. There are at least a dozen different approaches, but “drug developers are focusing upon beta-amyloid plaque inhibitors and amyloid synthesis inhibitors.”In Sanderson’s view, “Right now, the most highly anticipated program is at Janssen (which acquired Elan’s AD program in 2009) and Pfizer.” The joint Janssen/Pfizer project fast-tracks bapineuzumab, a monoclonal antibody (mAb) to target and clear ß-amyloid. This vaccine is the first new drug aimed at slowing or even halting AD progression. Fourteen trials are under way, involving 10,000 patients. The first of those trials is expected to report data in August.After Janssen paid Elan $1.5 billion for co-marketing rights in 2010, “Phase II results were mixed, but showed clear evidence of biological activity. Researchers hope a larger study may achieve statistically significant results,” Sanderson says. Compared to placebo, bapineuzumab slowed cognitive decline over 18 months and “could be the first disease-modifying agent to show success.”He predicts the drug will be most effective on the earliest-stage AD patients. In addition to its work with Janssen, Pfizer also has three other therapies in Phase I, one in Phase II, and one in Phase III trials.Last March, the USPTO granted a patent for Antisenilin, developed by Intellect Neurosciences. This therapy is similar to bapineuzumab, but targets either end of ß-amyloid. It is in Phase III trials.Baxter has a Phase III program under way for Gammagard, a naturally occurring plasma-derived immunoglobulin for moderate-stage AD patients. The trial runs until February 2013. Phase II results suggest Gammagard may positively affect brain atrophy and cognition. The compound already is approved for immunodeficiency diseases.AstraZeneca has a nicogenic receptor agonist that upregulates the neurotransmitter acetylcholine to help the remaining neurons function more effectively. The company is also working on another approach with Astex Pharmaceuticals.Roche has three AD compounds in Phase II studies, including the fully human mAb gantenerumab to neutralize ß-amyloid; a humanized mAb that binds to ß-amyloid; and the small molecule inhibitor of monoamine oxidase-B (MAO-B) to halt neuronal damage. Still in Phase I studies, Roche also has a small molecule inhibitor of beta-secretase (BACE), a key enzyme in the production of amyloid-beta peptides.Others developing AD treatments include TransTech Pharma, Memory Pharmaceuticals, and Sanofi-Aventis. Most of the therapeutics in development bind to soluble ß-amyloid in the periphery blood rather than attempting to cross the blood brain barrier, Sanderson points out.
Elderly Rat ModelCharles River Labs is expanding the research options with its elderly Fischer rat model, which is believed to provide a more comprehensive picture of aging than models in which AD is induced in young rats. This enables researchers to gain a more wholistic view of AD, beyond the accumulation of plaque. Consequently, because these rats are allowed to age and develop natural cognitive impairments, results are considered more representative than other models of human aging. In contrast, Sanderson says, “Standard animal models haven’t worked well. It’s possible they had a different genetic predisposition.”Source: https://www.genengnews.com/magazine/186/new-hope-for-alzheimers-disease/Picture: There are at least a dozen different approaches to new Alzheimer's disease treatments, but beta-amyloid plaque inhibitors and amyloid synthesis inhibitors currently top the list. [GordonGrand/Fotolia]