A wonder drug, perhaps, but one with caveats. Most of those in the artificial-blood world, like Steven A. Gould, the CEO of Northfield Laboratories in Evanston, Illinois, have hedged their bets on the more common hemoglobin-based substitutes. Northfield's PolyHeme, for instance, has recently completed its last clinical trial; the company is now compiling its data for the FDA to review.
"The benefit of hemoglobin-based oxygen carriers is that oxygen is loaded onto them when we're breathing room air," Gould says. That is, hemoglobin-based substitutes work just like our own blood. To get the full effect from Oxycyte, on the other hand, a patient breathes in 50 to 100 percent oxygen four hours before receiving it and for 12 hours after it's infused (air contains 21 percent oxygen). "That's a logistical limitation," Gould says, "and in general, it's preferable not to breathe supplemental oxygen if it can be avoided."
Most of today's ambulances carry oxygen on board, as do military rescue helicopters, so the problem isn't getting a tank of air to the patient. It's the risk of inhaling supplemental oxygen for too long. Scientists know that pure oxygen increases the number of free radicals in our bloodstream, which can damage tissues and membranes, but the long-term severity of that damage is unknown. Spiess believes that Oxycyte could still work at even lower levels of oxygen, or even with room air, but he hasn't yet been able to test out either of those scenarios on humans.
And there are other, undeniable side effects. In past PFC studies, patients were found to experience a transient swelling of the liver as it absorbed the oily molecules of the PFC; some patients demonstrated a decrease in platelet count, which can hinder the blood's ability to clot; and some suffered short-term flu-like effects. Spiess has a quick response to concerns like these: "If you've been hit in the head or you've been shot or you're having a stroke, you don't sweat the flu-like symptoms." All drugs have some measure of toxicity, Spiess says. It's simply a case of the good outweighing the bad.
Although the sample size is far too small to be statistically definitive, it seems that VCURES's brain-injury trial may be an example of just that. By August, the hospital had enrolled all of the eight patients it needed to complete the Phase II study. Even at the best trauma centers in the world, the mortality rate for TBI victims is one in three. Of the eight patients Spiess and Bullock treated with Oxycyte, only one died. The recovery process for the surviving patients has been unusually smooth.
Extraordinarily so, in Bess-Lyn's case. After regaining consciousness two weeks after the accident, she recovered movement in her paralyzed right side and was ultimately deemed well enough to leave rehab a week earlier than predicted. She is expected to make a full recovery. Meanwhile, Spiess and Bullock are busy designing a larger trial that will bring their oxygen therapy to emergency rooms across the country-perhaps as soon as next year.
Nicole Davis is a journalist based in Brooklyn.single page
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