Potential New Treatment for Hypothyroidism Hailed as a "Sort of 'Holy Grail'"
“This is very exciting from the clinical perspective, because it’s different from any other formulation of LT3 currently available.” – Dr. Elizabeth McAninch
(Chicago, IL) -- A new “metal-coordinated” drug-delivery technology potentially could be used to supplement the standard therapy for hypothyroidism, which affects nearly 10 million Americans, and many more patients worldwide, according to results of a study published in the journal Thyroid this month.
Researchers at Rush University Medical Center have been pursuing an improved treatment for the minority of hypothyroid patients who don’t respond well to the standard therapy. Now, their investigations into the way thyroid hormones given in tablets are absorbed and metabolized by the body suggest that a metal-coordinated molecule could prove to be a more effective therapy for all hypothyroid patients, according to Dr. Antonio Bianco. He is a professor of medicine at the University of Chicago who was formerly a researcher and clinician at Rush, where the work detailed in the Thyroid paper was completed.
Disease, environmental toxins, medical treatments such as radiation, and genetics all can cause hypothyroidism. Symptoms include fatigue, weight gain, lack of energy, depression, cold intolerance and muscle aches.
The new drug, poly-zinc-liothyronine (PZL), worked well in laboratory studies, Bianco said. Safety tests in animals and clinical trials in humans must still be conducted, and funding must be obtained to support that work. If all goes well, though, PZL could be offered to patients in only a few years, according to Bianco.
“We know enough about thyroid physiology in rats and humans that we feel confident that this drug is ready for prime time” in terms of working as well in humans as it has in the lab, he said.
About 10 to 15 percent of hypothyroidism patients respond poorly to standard treatment
The standard treatment for hypothyroidism is levothyroxine (L-T4), a synthetic version of the thyroid hormone thyroxine (T4), which in a healthy person is secreted by the thyroid gland. However, about 10 to 15 percent of L-T4-treated patients continue to have symptoms of the condition when treated, including weight gain, fatigue, lethargy, mood fluctuations, and problems with memory.
This medical mystery has led physicians to try a combination therapy of L-T4, plus liothyronine (L-T3), the synthetic form of the more active thyroid hormone triiodothyronine (T3). However, when L-T3 is given in conventional tablet form, it’s absorbed very rapidly, causing spikes in serum blood levels that may result in heart palpitations, tightness in the chest, sweating and anxiety.
In the study, researchers successfully treated laboratory rats that had been made hypothyroid with a capsule containing PZL, a pharmaceutical compound that is made of zinc bound to three L-T3 molecules. This metal-coordinated drug is packaged in a capsule specially coated to allow it to travel intact through the stomach to the duodenum (the first part of the small intestine). There, the zinc facilitates the slow release of L-T3 for sustained absorption into the blood stream …
Click here to continue reading.