Update 2 p.m. ET: 90 minutes after the IOM report's public release, NIH director Francis Collins announced that "I have considered the report carefully and have decided to accept the IOM committee recommendations." The report recommended the NIH establish an independent oversight committee to evaluate each study, limiting biomedical experiments only to what is absolutely necessary and ensuring that all research is ethically conducted. No new research funding will be granted until the recommendations are in place.

Human ingenuity and compassion have prevailed in an Institute of Medicine declaration that invasive medical experiments on chimpanzees are largely unnecessary.

Though the report's suggestions are not legally binding, the Institute is widely respected. Its judgments often shape government and academic policy. According to the report, experiments that inflict physical and mental harm to humanity's closest living relatives are justified only when absolutely indispensable, and when no other alternatives exist.

Thanks to improvements in drug design, research techniques and experimental methods, alternatives do exist. Of 436 federally owned research chimps and 501 kept in private laboratories, only a few might be considered important to medical progress – and perhaps not for long.

"While the chimpanzee has been a valuable animal model in past research, most current use of chimpanzees for biomedical research is unnecessary," conclude the 12 members of the Committee on The Use of Chimpanzees in Biomedical and Behavioral Research. They describe a "decreasing need for chimpanzee studies due to the emergence of non-chimpanzee models and technologies."

Said John Pippin of the Physicians Committee for Responsible Medicine, an animal advocacy group, "the IOM report paves the way for the end of invasive chimpanzee research in the United States."

The report, commissioned in January after the National Institutes of Health tried to return 209 retired chimpanzees to research duty, is based on almost seven months of deliberation, including reviews of hundreds of studies and testimony from dozens of experts.

Housed at the Alamogordo Primate Facility in New Mexico, the chimps had been rescued in 2001 from the Coulston Foundation, a private laboratory infamous for cruelty and negligence to animals. Many had lived for decades in captivity, subjected to forced infections and surgeries, separated from families, and held in isolation. Now, after earning the closest thing to freedom they'd ever get, they'd be sent back.

Medical research on chimps has long been opposed by animal advocates, but the Alamogordo colony's plight also resonated in the consciences of non-activist citizens and many scientists. Faced with public outrage and Congressional pressure, the NIH agreed to postpone the move until an Institute of Medicine committee evaluated chimpanzee research, which hadn't been nationally debated since the early 1990s, when chimps were thought important for insights into HIV.

Much had changed since, including our fundamental understanding of chimps. Cognitive and behavioral research formally described deep capacities for thought and feeling: Chimps experience happiness and grief, are both self-aware and empathic, and have culture and the rudiments of morality. On the spectrum of personhood, they're not far from people.

In the medical world, scientists discouraged by the practical, financial and ethical challenges of chimp testing found ways to avoid it. Several pharmaceutical companies, including GlaxoSmithKline, renounced experimentation on chimps and other great apes. Only hepatitis C – a virus that, apart from infecting humans, only infects chimps – remained a highly active area of chimpanzee medical experimentation. Subjecting them to procedures that would traumatize people, and do traumatize chimps, no longer seemed essential for medical progress.

Some researchers, especially those who already experimented with chimpanzees and studied hepatitis C, still argued that chimps were necessary. But they didn't convince the Institute of Medicine's committee.

"If you boil the report down, there was no area of biomedical research for which chimps are currently used that they're necessary for," said Kathleen Conlee, animal research director with the Humane Society.

In June, chimpanzee advocates were joined by the high-profile journal Nature in criticizing the NIH's original request that the Institute of Medicine consider only the scientific aspects of chimpanzee research, and ignore the ethical. In the final report, ethics are paramount: For medical research to be justified, "the knowledge gained must be necessary to advance the public’s health," and "there must be no other research model by which the knowledge could be obtained," including ethical studies on humans.

On the battleground subject of hepatitis C, the IOM found that – as Wired.com reported in November – chimps have limited uses. What researchers needed to learn from them has been learned. Chimps are not necessary to develop and test new drugs, and improved tests of human tissue and genetically engineered cells have rendered chimps superfluous in basic research on virus behavior and infection dynamics. To test drug safety, so-called microdosing trials, in which people are monitored after receiving minute doses of new drugs, have proved more informative than tests on chimps.

"The committee finds that chimpanzees are not necessary for HCV antiviral drug discovery and development and does not foresee the future necessity of the chimpanzee model in this area," they wrote.

On the importance of chimps for developing vaccines that protect against hepatitis C infection, the committee split. A case can be made for chimp use: Vaccines are harder than drugs to develop, requiring demonstrations of protection in living systems. Vaccinating a chimp, then intentionally trying to infect it, is impossible in humans and allows for close, controlled monitoring. However, chimps don't always respond to hepatitis C like humans do, and statistically powerful sample sizes are difficult to obtain. It's also possible to test experimental vaccine safety in other animals before testing effectiveness in people.

"The committee was evenly split and unable to reach consensus on the necessity of the chimpanzee model, and on whether or how much the chimpanzee model would accelerate or improve prophylactic HCV vaccine development," they wrote.

Another area of arguable chimpanzee medical utility is in so-called monoclonal antibodies, or proteins engineered to attack specific sites on cells. When these were originally designed, researchers looked for sites common to both chimpanzee and human cells, making chimp testing important. Since then, researchers have found sites shared by human and mouse cells. Mice are far easier to use than chimps.

"There may be a limited number of monoclonal antibodies already in the developmental pipeline that may require the continued use of chimpanzees," wrote the committee, but "development of future monoclonal antibody therapies will not require the chimpanzee."

A few chimp studies involve respiratory tract infections, but the committee said abandoning these lines of research won't slow progress.

"At this point it is very difficult to defend the large-scale approach to medical chimpanzee research," said Brian Hare, a Duke University evolutionary anthropologist who studies chimp behavior. "The large-scale medical labs were intended to study dozens of diseases that were otherwise intractable without chimpanzee research. The intention was never to have hundreds of chimpanzees in six different government labs to maybe, possibly, hopefully develop a vaccine for a single disease. Especially when the committee clearly recognized real research alternatives that are way cheaper and likely more effective."

The Institute of Medicine committee did, however, leave the door open to the sort of research that Hare performs: non-invasive, voluntary, and conducted with chimps who live in almost-natural conditions. The committee also approved comparative genomics research, in which scientists try to learn genetic principles from similarities and differences between humans and chimps.

"One should not do any research on chimpanzees that one could not do in humans, realizing that conditions for ethical management are necessarily a bit different," said Ajit Varki, a University of California, San Diego glycobiologist who studies the molecular differences between human and chimpanzee cells.

The committee stopped short of calling for an end to invasive research, but recommended extremely rigorous review of all ongoing and proposed studies. Per the committee's own examples, much present research probably wouldn't pass that review. (On a cautionary note, anthropologist Mary Lee Jensvold of the Chimpanzee and Human Communication Institute at Central Washington University warned that the committee's calls for chimps to be housed in "ethologically appropriate" environments needed clarification. "Is a natural environment … a cage with dirt of the floor?" she said in an email. Depending on how guidelines are interpreted, studies in which chimps voluntarily submit to distress-causing procedures might also be permitted. "This report is open to interpretation," she said.)

The NIH isn't bound by the report's recommendations, but they do provide a scientific justification to cease what's become a highly visible blot on the agency's reputation. The National Center for Research Resources, the NIH division tasked with managing chimp research, allowed 137 chimpanzees to be bred in direct violation of government rules at the New Iberia Research Center in Louisiana. When pressed, they justified their mismanagement by appealing to legalistic loopholes.

After publicly saying it would wait for the IOM report, the NCRR in September quietly approved a grant proposal to finish the Alamogordo move and put those chimps back into research. While the NCRR said grant approval didn't necessarily guarantee full funding, their plan made no mention of the controversy or the IOM report, and was only made public by Freedom of Information Act requests.

With the NIH thinking of abolishing the NCRR to make budgetary room for a translational science department, and Congress considering the Great Ape Protection and Cost Savings Act – which would move all federally owned chimps into sanctuaries – fundamental change seems possible. And if the United States, the only country apart from Gabon to permit invasive research on chimps, were to end federal support, private research would likely fade.

"We now have reached the point at which NIH should take a bold stance," said ethologist Frans de Waal of Emory University, one of the world's foremost chimpanzee cognition experts and a board member of Chimp Haven, the largest U.S. chimpanzee sanctuary. "If not now, when?"

De Waal said his comments reflected his own opinions, not those of the Yerkes National Primate Research Center where he works – and which, for the record, stopped invasive research years ago, and only performs "studies we would not mind doing on human volunteers," he said.

Said de Waal, "It is time to follow in the footsteps of other developed nations, and put a halt to invasive research on our closest relatives."

Update 12/16: Some ethicists and animal advocates said the IOM report is fundamentally flawed. "It is a clear advance in the clarification and examination of the major issues about necessity," read a statement issued by Georgetown Institute's Kennedy Institute of Ethics, but "the report is superficial in its treatment of the most critical issues in the literature on the use of chimpanzees in research, namely the moral justification of chimpanzee research. Necessity, after all, did not generate the current controversy; that framing is an NIH-filtered reading of the issues. The moral permissibility and moral justification underlies every issue about necessity."

"The report repeatedly states how close chimpanzees are to humans in anatomical structure, in cognitive structure, and even in moral capacity to act altruistically," they continue. "Given that a chimpanzee is as close to a human being as this report correctly indicates a chimpanzee is, it is hard to understand why the same level of protections should not be provided to chimpanzees as are provided to humans. It is disappointing that the report never addresses this central issue."

Lori Marino, an Emory University neurobiologist, reinforced the Kennedy Institute's critique. "The task of the project was to consider only the scientific merit of continued use of chimpanzees," she said. "But it is just as objectionable to do that in the case of using chimpanzees as it is for humans."

Image: Infant chimpanzee at the Walter Zoo in Gossau, Switzerland. (Tambako the Jaguar/Flickr)