The future of non-hormonal birth control: Antibodies can stop sperm in their tracks
Unwanted pregnancy can now be added to the list of preventions that antibodies may be fighting in the near future. For decades, really since the 1980s, engineered monoclonal antibodies have been knocking out invading germs — preventing everything from cancer to COVID. Sperm, which have some of the same properties as germs, may be next.
Not only is there an unmet need on the market for alternatives to hormonal contraceptives, the genesis for the original research was personal for the then 22-year-old scientist who led it. Her findings were used to launch a company that could, within the decade, bring a new kind of contraceptive to the marketplace.
The genesis
It’s Suruchi Shrestha’s research — published in Science Translational Medicine in August 2021 and conducted as part of her dissertation while she was a graduate student at the University of North Carolina at Chapel Hill — that could change the future of contraception for many women worldwide. According to a Guttmacher Institute report, in the U.S. alone, there were 46 million sexually active women of reproductive age (15–49) who did not want to get pregnant in 2018. With the overturning of Roe v. Wade this year, Shrestha’s research could, indeed, be life changing for millions of American women and their families.
Now a scientist with NextVivo, Shrestha is not directly involved in the development of the contraceptive that is based on her research. But, back in 2016 when she was going through her own problems with hormonal contraceptives, she “was very personally invested” in her research project, Shrestha says. She was coping with a long list of negative effects from an implanted hormonal IUD. According to the Mayo Clinic, those can include severe pelvic pain, headaches, acute acne, breast tenderness, irregular bleeding and mood swings. After a year, she had the IUD removed, but it took another full year before all the side effects finally subsided; she also watched her sister suffer the “same tribulations” after trying a hormonal IUD, she says.
For contraceptive use either daily or monthly, Shrestha says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
Shrestha unshelved antibody research that had been sitting idle for decades. It was in the late 80s that scientists in Japan first tried to develop anti-sperm antibodies for contraceptive use. But, 35 years ago, “Antibody production had not been streamlined as it is now, so antibodies were very expensive,” Shrestha explains. So, they shifted away from birth control, opting to focus on developing antibodies for vaccines.
Over the course of the last three decades, different teams of researchers have been working to make the antibody more effective, bringing the cost down, though it’s still expensive, according to Shrestha. For contraceptive use either daily or monthly, she says, “You want the antibody to be very potent and also cheap.” That was her goal when she launched her study.
The problem
The problem with contraceptives for women, Shrestha says, is that all but a few of them are hormone-based or have other negative side effects. In fact, some studies and reports show that millions of women risk unintended pregnancy because of medical contraindications with hormone-based contraceptives or to avoid the risks and side effects. While there are about a dozen contraceptive choices for women, there are two for men: the condom, considered 98% effective if used correctly, and vasectomy, 99% effective. Neither of these choices are hormone-based.
On the non-hormonal side for women, there is the diaphragm which is considered only 87 percent effective. It works better with the addition of spermicides — Nonoxynol-9, or N-9 — however, they are detergents; they not only kill the sperm, they also erode the vaginal epithelium. And, there’s the non-hormonal IUD which is 99% effective. However, the IUD needs to be inserted by a medical professional, and it has a number of negative side effects, including painful cramping at a higher frequency and extremely heavy or “abnormal” and unpredictable menstrual flows.
The hormonal version of the IUD, also considered 99% effective, is the one Shrestha used which caused her two years of pain. Of course, there’s the pill, which needs to be taken daily, and the birth control ring which is worn 24/7. Both cause side effects similar to the other hormonal contraceptives on the market. The ring is considered 93% effective mostly because of user error; the pill is considered 99% effective if taken correctly.
“That’s where we saw this opening or gap for women. We want a safe, non-hormonal contraceptive,” Shrestha says. Compounding the lack of good choices, is poor access to quality sex education and family planning information, according to the non-profit Urban Institute. A focus group survey suggested that the sex education women received “often lacked substance, leaving them feeling unprepared to make smart decisions about their sexual health and safety,” wrote the authors of the Urban Institute report. In fact, nearly half (45%, or 2.8 million) of the pregnancies that occur each year in the US are unintended, reports the Guttmacher Institute. Globally the numbers are similar. According to a new report by the United Nations, each year there are 121 million unintended pregnancies, worldwide.
The science
The early work on antibodies as a contraceptive had been inspired by women with infertility. It turns out that 9 to 12 percent of women who are treated for infertility have antibodies that develop naturally and work against sperm. Shrestha was encouraged that the antibodies were specific to the target — sperm — and therefore “very safe to use in women.” She aimed to make the antibodies more stable, more effective and less expensive so they could be more easily manufactured.
Since antibodies tend to stick to things that you tell them to stick to, the idea was, basically, to engineer antibodies to stick to sperm so they would stop swimming. Shrestha and her colleagues took the binding arm of an antibody that they’d isolated from an infertile woman. Then, targeting a unique surface antigen present on human sperm, they engineered a panel of antibodies with as many as six to 10 binding arms — “almost like tongs with prongs on the tongs, that bind the sperm,” explains Shrestha. “We decided to add those grabbers on top of it, behind it. So it went from having two prongs to almost 10. And the whole goal was to have so many arms binding the sperm that it clumps it” into a “dollop,” explains Shrestha, who earned a patent on her research.
Suruchi Shrestha works in the lab with a colleague. In 2016, her research on antibodies for birth control was inspired by her own experience with side effects from an implanted hormonal IUD.
UNC - Chapel Hill
The sperm stays right where it met the antibody, never reaching the egg for fertilization. Eventually, and naturally, “Our vaginal system will just flush it out,” Shrestha explains.
“She showed in her early studies that [she] definitely got the sperm immotile, so they didn't move. And that was a really promising start,” says Jasmine Edelstein, a scientist with an expertise in antibody engineering who was not involved in this research. Shrestha’s team at UNC reproduced the effect in the sheep, notes Edelstein, who works at the startup Be Biopharma. In fact, Shrestha’s anti-sperm antibodies that caused the sperm to agglutinate, or clump together, were 99.9% effective when delivered topically to the sheep’s reproductive tracts.
The future
Going forward, Shrestha thinks the ideal approach would be delivering the antibodies through a vaginal ring. “We want to use it at the source of the spark,” Shrestha says, as opposed to less direct methods, such as taking a pill. The ring would dissolve after one month, she explains, “and then you get another one.”
Engineered to have a long shelf life, the anti-sperm antibody ring could be purchased without a prescription, and women could insert it themselves, without a doctor. “That's our hope, so that it is accessible,” Shrestha says. “Anybody can just go and grab it and not worry about pregnancy or unintended pregnancy.”
Her patented research has been licensed by several biotech companies for clinical trials. A number of Shrestha’s co-authors, including her lab advisor, Sam Lai, have launched a company, Mucommune, to continue developing the contraceptives based on these antibodies.
And, results from a small clinical trial run by researchers at Boston University Chobanian & Avedisian School of Medicine show that a dissolvable vaginal film with antibodies was safe when tested on healthy women of reproductive age. That same group of researchers earlier this year received a $7.2 million grant from the National Institute of Health for further research on monoclonal antibody-based contraceptives, which have also been shown to block transmission of viruses, like HIV.
“As the costs come down, this becomes a more realistic option potentially for women,” says Edelstein. “The impact could be tremendous.”
These Sisters May Change the Way You Think About Dying
For five weeks, Anita Freeman watched her sister writhe in pain. The colon cancer diagnosed four years earlier became metastatic.
"I still wouldn't wish that ending on my worst enemy."
At this tormenting juncture, her 66-year-old sister, Elizabeth Martin, wanted to die comfortably in her sleep. But doctors wouldn't help fulfill that final wish.
"It haunts me," Freeman, 74, who lives in Long Beach, California, says in recalling the prolonged agony. Her sister "was breaking out of the house and running in her pajamas down the sidewalk, screaming, 'Help me. Help me.' She just went into a total panic."
Finally, a post-acute care center offered pentobarbital, a sedative that induced a state of unconsciousness, but only after an empathetic palliative care doctor called and insisted on ending the inhumane suffering. "We even had to fight the owners of the facility to get them to agree to the recommendations," Freeman says, describing it as "the only option we had at that time; I still wouldn't wish that ending on my worst enemy."
Her sister died a week later, in 2014. That was two years before California's medical aid-in-dying law took effect, making doctors less reliant on palliative sedation to peacefully end unbearable suffering for terminally ill patients. Now, Freeman volunteers for Compassion & Choices, a national grassroots organization based in Portland, Oregon, that advocates for expanding end-of-life options.
Palliative sedation involves medicating a terminally ill patient into lowered awareness or unconsciousness in order to relieve otherwise intractable suffering at the end of life. It is not intended to cause death, which occurs due to the patient's underlying disease.
In contrast, euthanasia involves directly and deliberately ending a patient's life. Euthanasia is legal only in Canada and some European countries and requires a health care professional to administer the medication. In the United States, laws in seven states and Washington, D.C. give terminally ill patients the option to obtain prescription medication they can take to die peacefully in their sleep, but they must be able to self-adminster it.
Recently, palliative sedation has been gaining more acceptance among medical professionals as an occasional means to relieve suffering, even if it may advance the time of death, as some clinicians believe. However, studies have found no evidence of this claim. Many doctors and bioethicists emphasize that intent is what distinguishes palliative sedation from euthanasia. Others disagree. It's common for controversy to swirl around when and how to apply this practice.
Elizabeth Martin with her sister Anita Freeman in happier times, before metastatic cancer caused her tremendous suffering at the end of her life.
(Courtesy Anita Freeman)
"Intent is everything in ethics. The rigor and protocols we have around palliative sedation therapy also speaks to it being an intervention directed to ease refractory distress," says Martha Twaddle, medical director of palliative medicine and supportive care at Northwestern University's Lake Forest Hospital in Lake Forest, Illinois.
Palliative sedation should be considered only when pain, shortness of breath, and other unbearable symptoms don't respond to conventional treatments. Left to his or her own devices, a patient in this predicament could become restless, Twaddle says, noting that "agitated delirium is a horrible symptom for a family to witness."
At other times, "we don't want to be too quick to sedate," particularly in cases of purely "existential distress"—when a patient experiences anticipatory grief around "saying goodbye" to loved ones, she explains. "We want to be sure we're applying the right therapy for the problem."
Encouraging patients to reconcile with their kin may help them find inner peace. Nonmedical interventions worth exploring include quieting the environment and adjusting lighting to simulate day and night, Twaddle says.
Music-thanatology also can have a calming effect. It is live, prescriptive music, mainly employing the harp or voice, tailored to the patient's physiological needs by tuning into vital signs such as heart rate, respiration, and temperature, according to the Music-Thanatology Association International.
"When we integrated this therapeutic modality in 2003, our need for using palliative sedation therapy dropped 75 percent and has remained low ever since," Twaddle observes. "We have this as part of our care for treating refractory symptoms."
"If palliative sedation is being employed properly with the right patient, it should not hasten death."
Ethical concerns surrounding euthanasia often revolve around the term "terminal sedation," which "can entail a physician deciding that the patient is a lost cause—incurable medically and in substantial pain that cannot adequately be relieved," says John Kilner, professor and director of the bioethics programs at Trinity International University in Deerfield, Illinois.
By halting sedation at reasonable intervals, the care team can determine whether significant untreatable pain persists. Periodic discontinuation serves as "evidence that the physician is still working to restore the patient rather than merely to usher the patient painlessly into death," Kilner explains. "Indeed, sometimes after a period of unconsciousness, with the body relieved of unceasing pain, the body can recover enough to make the pain treatable."
The medications for palliative sedation "are tried and true sedatives that we've had for a long time, for many years, so they're predictable," says Joe Rotella, chief medical officer at the American Academy of Hospice and Palliative Medicine.
Some patients prefer to keep their eyes open and remain conscious to answer by name, while others tell their doctors in advance that they want to be more heavily sedated while receiving medications to manage pain and other symptoms. "We adjust the dosage until the patient is sleeping at a desired level of sedation," Rotella says.
Sedation is an intrinsic side effect of most medications prescribed to control severe symptoms in terminally ill patients. In general, most people die in a sleepy state, except for instances of sudden, dramatic death resulting from a major heart attack or stroke, says Ryan R. Nash, a palliative medicine physician and director of The Ohio State University Center for Bioethics in Columbus.
"Using those medications to treat pain or shortness of breath is not palliative sedation," Nash says. In addition, providing supplemental nutrition and hydration in situations where death is imminent—with a prognosis limited to hours or days—generally doesn't help prolong life. "If palliative sedation is being employed properly with the right patient," he adds, "it should not hasten death."
Nonetheless, hospice nurses sometimes feel morally distressed over carrying out palliative sedation. Implementing protocols at health systems would help guide them and alleviate some of their concerns, says Gregg VandeKieft, medical director for palliative care at Providence St. Joseph Health's Southwest Washington Region in Olympia, Washington. "It creates guardrails by sort of standardizing and normalizing things," he says.
"Our goal is to restore our patient. It's never to take their life."
The concept of proportionality weighs heavily in the process of palliative sedation. But sometimes substantial doses are necessary. For instance, an opioid-tolerant patient recently needed an unusually large amount of medication to control symptoms. She was in a state of illness-induced confusion and pain, says David E. Smith, a palliative medicine physician at Baptist Health Supportive Care in Little Rock, Arkansas.
Still, "we are parsimonious in what we do. We only use as much therapeutic force as necessary to achieve our goals," Smith says. "Our goal is to restore our patient. It's never to take their life."
Steven Pinker: Data Shows That Life Today Is Better Than Ever
The government shutdown. A volatile stock market. Climate change.
It's so easy to get discouraged by the latest headlines, argues Steven Pinker, that we lose sight of the bigger picture: life today is actually improving.
"To appreciate the world, we've got to look at numbers and trends."
Pinker, a cognitive psychologist from Harvard, says in his book "Enlightenment Now" that we're living at the greatest moment of progress in history, thanks to reason, science, and humanism. But today, he says, these ideals are under-appreciated, and we ignore them at our peril.
So he set out to provide a vigorous moral defense of the values of the Enlightenment by examining the evidence for their effectiveness. Across a range of categories from happiness and health to peace and safety, Pinker examines the data and reassures readers that this is a pretty great time to be alive. As we kick off the new year, he's hopeful that our embrace of science and reason will lead to an even more prosperous future. But political and cultural hurdles must still be overcome before the heroic story of human progress can continue to unfold.
Pinker spoke with our Editor-in-Chief Kira Peikoff in advance of the book's paperback release, which hits stores next Tuesday. This interview has been edited and condensed for clarity.
One anecdote you describe in the book was particularly striking: how the public reacted when the polio vaccine was announced. People took the day off work to celebrate, they smiled at each other in the streets, they offered to throw parades. Today, it's hard to imagine such prevalent enthusiasm for a new advance. How can we bring back a culture of respect and gratitude for science?
That's such a good question. And I wish I knew the answer. My contribution is just to remind people of how much progress we've made. It's easy to ignore if your view of the world comes from headlines, but there are some built-in biases in journalism that we have to counteract. Most things that happen all of a sudden are bad things: wars break out, terrorists attack, rampage shootings occur, whereas a lot of the things that make us better off creep up by stealth. But we have to become better aware of them.
It's unlikely that we're going to have replications of the great Salk event, which happened on a particular day, but I think we have to take lessons from cognitive science, from the work of people like Daniel Kahneman and Amos Tversky, showing how misled we can be by images and narratives and that to appreciate the world, we've got to look at numbers and trends.
The cover of "Enlightenment Now," which comes out in paperback next week.
You mention that the President's Bioethics Council under Bush was appointed to deal with "the looming threat of biomedical advances." Do you think that professional bioethicists are more of a hindrance than a help when it comes to creating truly enlightened science policy?
I do. I think that there are some problems in the culture of bioethics. And of course, I would not argue against that the concept of bioethics. Obviously, we have to do biomedical research and applications conscientiously and ethically. But the field called Bioethics tends to specialize in exotic thought experiments that tend to imagine the worst possible things that can happen, and often mire research in red tape that results in a net decrease in human welfare, whereas the goal of bioethics should be to enhance human welfare.
In an op-ed that I published in the Boston Globe a few years ago, I said, deliberately provocatively, that the main moral imperative of bioethics is to get out of the way since there's so much suffering that humans endure from degenerative diseases, from cancer, from heart disease and stroke. The potential for increasing happiness and well-being from biomedical research is just stupendous. So before we start to drag out Brave New World for the umpteenth time, or compare every advance in genetics to the Nazis, we should remember the costs of people dying prematurely from postponing advances in biomedical research.
Later in the book, you mention how much more efficient the production of food has become due to high-tech agriculture. But so many people today are leery of advances in the food industry, like GMOs. And we will have to feed 10 billion people in 2050. Are you concerned about how we will meet that challenge?
Yes, I think anyone has to be, and all the more reason we should be clear about what is simultaneously best for humans and for the planet, which is to grow as much food on this planet as possible. That ideal of density -- the less farmland the better -- runs up against the ideal of the organic farming and natural farming, which use lots of land. So genetically modified organisms and precision agriculture of the kind that is sometimes associated with Israel -- putting every last drop of water to use, delivering it when it's needed, using the minimum amount of fertilizer -- all of these technologically driven developments are going to be necessary to meet that need.
"The potential for increasing happiness and well-being from biomedical research is just stupendous."
You also mention "sustainability" as this big buzz word that you say is based on a flawed assumption that we will run out of resources rather than pivot to ingenious alternatives. What's the most important thing we can do as a culture to encourage innovation?
It has to be an ideal. We have restore it as what we need to encourage, to glorify in order to meet the needs of humanity. Governments have to play a role because lots of innovation is just too risky with benefits that are too widely diffuse for private companies and individuals to pursue. International cooperation has to play a role. And also, we need to change our environmental philosophy from a reflexive rejection of technology to an acknowledgement that it will be technology that is our best hope for staving off environmental problems.
And yet innovation and technology today are so often viewed fearfully by the public -- just look at AI and gene editing. If we need science and technology to solve our biggest challenges, how do we overcome this disconnect?
Part of it is simply making the argument that is challenging the ideology and untested assumptions behind traditional Greenism. Also, on the part of the promoters of technology themselves, it's crucial to make it not just clear, but to make it a reality that technology is going to be deployed to enhance human welfare.
That of course means an acknowledgement of the possible harms and limitations of technology. The fact that the first widely used genetically modified crop was soybeans that were resistant to herbicides, to Roundup -- that was at the very least a public relations disaster for genetically modified organisms. As opposed to say, highlighting crops that require less insecticide, less chemical fertilizers, less water level. The poster children for technology should really be cases that quite obviously benefit humanity.
"One of the surprises from 'Enlightenment Now' was how much moral progress depends on economic progress."
Finally, what is one emerging innovation that you're excited about for 2019?
I would say 4th generation nuclear power. Small modular reactors. Because everything depends on energy. For poor countries to get rich, they are going to have to consume far more energy than they do now and if they do it via fossil fuels, especially coal, that could spell disaster. Zero-carbon energy will allow poor countries to get richer -- and rich countries to stay rich without catastrophic environmental damage.
One of the surprises from "Enlightenment Now" was how much moral progress depends on economic progress. Rich countries not only allow the citizens to have cool gadgets, but all kinds of good things happen when a country gets rich, like Norway, Netherlands, Switzerland. Countries that are richer on average are more democratic, are less likely that to fight wars, are more feminist, are more environmentally conscientious, are smarter -- that is, they have a greater increase in IQ. So anything that makes a country get richer, and that's going to include a bunch of energy, is going to make humanity better off.
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.