Synthetic drugs vs. animal extracts

Some thyroid patients, diabetics insist natural medications work better

August 11, 2006|By CHRIS EMERY | CHRIS EMERY,SUN REPORTER

For much of the 20th century, the drugs used to treat diabetes and thyroid disease were extracted from animals - mostly cows and pigs.

That started to change in the 1960s, when scientists began to mass produce synthetic thyroid hormone in the lab. The change accelerated in the 1980s, when insulin became the first synthetic drug manufactured through genetic engineering.

But not everyone considers the shift to synthetics a sign of progress. Of the millions of people who rely on hormone therapies, several thousand still insist that traditional, animal-derived drugs work better and are safer than the newer synthetic versions.

"I can only take the insulins that come from a pig," said Joi Shaivitz, 47, of Owings Mills, who claims synthetic insulins aren't effective for managing her diabetes and that they once caused her to go into a coma.

Likewise, some people with thyroid disease insist thyroid extracts derived from the glands of pigs work best. The steroidal hormone estrogen is also made synthetically now, and some patients shun it, too.

Many are organizing in an attempt to keep animal-based versions of their drugs on the market - at a price they can afford.

Most doctors, on the other hand, say newer, synthetic drugs are superior to the older versions. For them, a patient's insistence upon animal-derived drugs can be a source of frustration.

"The vast majority of patients use the synthetic forms, but the people who use the animal extracts are extremely attached to them," said Dr. Gregory Brent, a professor at David Geffen School of Medicine at the University of California, Los Angeles.

Drugs such as insulin, thyroid hormone, testosterone and estrogen were originally obtained by extracting them from the organs of animals. In 1922, Canadian Frederick G. Banting was the first recorded doctor to administer insulin to a diabetic patient. The 14-year-old patient suffered a severe allergic reaction, but later responded well to better-purified extracts, which helped regulate his blood sugar, since the molecular structure of animal insulin is nearly identical to the human variety.

Following Banting's discovery, pharmaceutical makers refined techniques for purifying animal insulin and marketed it to the masses. The drug greatly increased the life expectancy of diabetics, who often died in childhood before insulin was available.

Still, impurities in the animal extracts provoked occasional allergic reactions and caused some patients to develop resistance to the drugs.

"Early on, you never knew what you were going to get for sure in a bottle of insulin," said Brent Hoadley, 63, a diabetic from Lamont, Fla., who still uses the animal version. "But over time the beef and pork insulins became quite pure."

In the mid-1980s, Eli Lilly and Co. produced the first synthetic human insulin, Humulin, using genetically modified bacteria. Scientists spliced human genes that coded for the hormones into the DNA of E. coli bacteria. The modified bacteria were then cultured in large numbers to produce the human hormone.

Match to humans

Most experts agree that the synthetic insulins work better because they are purer and an exact match to human insulin. In recent years, genetic engineers have even developed "designer" insulins, with slightly varied chemical structures to make them more efficient at regulating blood sugar.

"When you look at that kind of space-age technology and compare it to an 80-year-old therapy, you can see why the market has changed," said Scott MacGregor, a spokesman for Eli Lilly.

Lilly was the last company to produce the animal insulins in North America, but announced last summer it would stop production and focus on its synthetic insulins.

"We estimated that there were fewer than 2,000 patients still using pork insulin," said MacGregor. "This is driven by what's going on in the market and what physicians see as the best therapy."

About 6.5 million diabetics in the United States rely on insulin, according to the American Diabetes Association.

When U.S. stocks of pork insulin ran out this spring, Shaivitz acquired a permit from the FDA and began importing the pork insulin from Europe, where it is still sold.

"I was running out and was frantic," said Shaivitz, who is unemployed and uninsured. A neighbor donated money to help her import enough animal insulin to last several months, she said.

Hoadley said his insurance company is covering the cost of importing his animal insulin. He tried switching to synthetic insulin several times in the 1980s but was unimpressed. "It just didn't work very well," he said.

A similar shift has occurred in the production of thyroid hormone, which is taken orally by patients whose thyroid glands are underactive or have been removed.

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