29 agosto 2012

The Alzheimer's pipeline: What's next? .

Alzheimer's is a devastating disease: Victims lose their memories, personalities, sense of time, and grip on reality as friends and families watch their loved ones slowly lose their identities, and eventually their lives.

The disease afflicts an estimated 5.4 million people in the U.S., where the memory-robbing illness is the 6th-leading killer of Americans, according to Alzheimer's Association. The association estimates that more than $200 billion will be spent between drugmakers and patients for research, medication and caregivers this year.

The efforts and research dollars of the medical industry have given us more failure than success and left more questions than answers. Research suggests that three cups of caffeinated coffee a day, reading, and crossword puzzles may prevent or slow Alzheimer's disease, but scientists have yet to agree on a cause, let alone a cure.

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Grifols Immunoglobulin

Baxter International ($BAX) and Barcelona, Spain-based Grifols developed Gammagard liquid, an intravenous immunoglobulin (IVIG) lasting two weeks to three months, to treat immune deficiency disorders. IVIG contains various antibodies, including polyvalent, immunoglobulin antibody G (IgG) and extracted plasma. Originally developed for immunodeficient patients without antibody capabilities, the drug could contribute to beta amyloid clearance from the brain by suppressing harmful inflammation and mitigating the toxicity of the plaque.

In a Phase II clinical trial of 16 patients, Gammagard effectively shut down the progression of Alzheimer's with the optimal dosage. Patients who received a placebo or did not receive the optimal dosage continued to decline.

So far, this seems to be the most promising medication in the Alzheimer's pipeline, consistently stalling the progression of the disease for four years in a small clinical trial. Baxter's goal for the medication is to maintain high levels of functionality during the early stages of the disease. Though few patients are better than no patients, Phase III data are due in the first half next year and that, as tradition demonstrates, is where prospective Alzheimer's medications go to die.

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Solanezumab was one of two drugs able to hurdle the risk of the field altogether and make the cut. Despite the fact that the Phase II trial was oddly halted at 12 weeks, ostensibly to move the drug into Phase III as fast as possible, looking beyond the fact that there was no cognitive improvement reported in the truncated trial. Solanezumab data showed that it did not cause harm and, in Alzheimer's, a good safety profile helps to get a drug over the Phase II hurdle.

Or it was at the time. Analysts have been lambasting Lilly now for the mid-stage rush. And another big failure will undermine the company's credibility in R&D. Due to the lackluster data released Friday, Lilly is running the drug for a second round. Solanezumab failed both primary endpoints of its Phase III study, but showed marginal slowing of cognitive decline in a follow-up analysis. CEO John Lechleiter seems determined to push this drug ahead, and encouraged by even the mildest of data.

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Failures

AN-1792--The first Alzheimer's vaccine to reach trials was designed to help patients develop antibodies against beta amyloid, the chief component in plaque, and mobilize participants' immune systems as opposed to using continuous medication. Though the "Alzheimer's vaccine" had an effective and profound effect on the brain, researchers learned in autopsy results that it was the cause of brain inflammation resembling meningoencephalitis.

Bapineuzumab--Elan, Pfizer and J&J's laboratory-produced beta amyloid antibody aimed at decreasing plaque levels in the brain. Recently, it failed to outperform a placebo in two of four Phase III trials, prompting J&J and Pfizer to scuttle the late-stage program early this month.

Dimebon--Though early data suggested that Dimebon improved communication between neurons, Phase II and III studies were unable to confirm any progress. Even though Medivation and Pfizer's drug showed no improvement in Alzheimer's, it has recently returned to animal studies in a rush of optimism. Whether scientists plan to renew clinical development efforts or not, the 2010 study was an abject failure.

Rosiglitazone--It was originally developed as a diabetes medication that increases a cell's sensitivity to insulin. Researchers predicted a potential treatment for Alzheimer's due to links between the disease and Type II diabetes and pushed the drug into clinical trials, but it failed to provide any cognitive improvement.

Semagacestat--Lilly's gamma-secretase inhibitor hurt patients more than helped them by producing more beta amyloid and speeding up Alzheimer's disease.

Tarenflurbil--The drug was developed to change the behavior of gamma-secretase, but it failed to improve patients' memory and/or ability to perform daily activities in trials.

Tramiprosate--This modified form of an amino acid may prevent beta-amyloid aggregation but provided inconclusive data. It is currently being sold on the market as a medical food.

Scientists are still on the hunt, using every trick in the preclinical development book from homegrown neurons to radiation to find potential answers to Alzheimer's. As some pharma companies continue to dig for late-stage gold, the focus is shifting away from treatment back to prevention. Late-stage is becoming too late.

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