Amy Bitterman, who teaches at Rutgers Law School in Newark, gets enormous pleasure from her three mixed-breed rescue cats, Spike, Dee, and Lucy. To manage her chronically stuffy nose, three times a week she takes Allegra D, which combines the antihistamine fexofenadine with the decongestant pseudoephedrine. Amy's dog allergy is rougher--so severe that when her sister launched a business, Pet Care By Susan, from their home in Edison, New Jersey, they knew Susan would have to move elsewhere before she could board dogs. Amy has tried to visit their brother, who owns a Labrador Retriever, taking Allegra D beforehand. But she began sneezing, and then developed watery eyes and phlegm in her chest.
"It gets harder and harder to breathe," she says.
Animal lovers have long dreamed of "hypo-allergenic" cats and dogs. Although to date, there is no such thing, biotechnology is beginning to provide solutions for cat-lovers. Cats are a simpler challenge than dogs. Dog allergies involve as many as seven proteins. But up to 95 percent of people who have cat allergies--estimated at 10 to 30 percent of the population in North America and Europe--react to one protein, Fel d1. Interestingly, cats don't seem to need Fel d1. There are cats who don't produce much Fel d1 and have no known health problems.
The current technologies fight Fel d1 in ingenious ways. Nestle Purina reached the market first with a cat food, Pro Plan LiveClear, launched in the U.S. a year and a half ago. It contains Fel d1 antibodies from eggs that in effect neutralize the protein. HypoCat, a vaccine for cats, induces them to create neutralizing antibodies to their own Fel d1. It may be available in the United States by 2024, says Gary Jennings, chief executive officer of Saiba Animal Health, a University of Zurich spin-off. Another approach, using the gene-editing tool CRISPR to create a medication that would splice out Fel d1 genes in particular tissues, is the furthest from fruition.
"Our goal was to ensure that whatever we do has no negative impact on the cat."
Customer demand is high. "We already have a steady stream of allergic cat owners contacting us desperate to have access to the vaccine or participate in the testing program," Jennings said. "There is a major unmet medical need."
More than a third of Americans own a cat (while half own a dog), and pet ownership is rising. With more Americans living alone, pets may be just the right amount of company. But the number of Americans with asthma increases every year. Of that group, some 20 to 30 percent have pet allergies that could trigger a possibly deadly attack. It is not clear how many pets end up in shelters because their owners could no longer manage allergies. Instead, allergists commonly report that their patients won't give up a beloved companion.
No one can completely avoid Fel d1, which clings to clothing and lands everywhere cat-owners go, even in schools and new homes never occupied by cats. Myths among cat-lovers may lead them to underestimate their own level of risk. Short hair doesn't help: the length of cat hair doesn't affect the production of Fel d1. Bathing your cat will likely upset it and accomplish little. Washing cuts the amount on its skin and fur only for two days. In one study, researchers measured the Fel d1 in the ambient air in a small chamber occupied by a cat—and then washed the cat. Three hours later, with the cat in the chamber again, the measurable Fel d1 in the air was lower. But this benefit was gone after 24 hours.
For years, the best option has been shots for people that prompt protective antibodies. Bitterman received dog and cat allergy injections twice a week as a child. However, these treatments require up to 100 injections over three to five years, and, as in her case, the effect may be partial or wear off. Even if you do opt for shots, treating the cat also makes sense, since you could protect more than one allergic member of your household and any allergic visitors as well.
An Allergy-Neutralizing Diet
Cats produce much of their Fel d1 in their saliva, which then spreads it to their fur when they groom, observed Nestle Purina immunologist Ebenezer Satyaraj. He realized that this made saliva—and therefore a cat's mouth--an unusually effective site for change. Hens exposed to Fel d1 produce their own antibodies, which survive in their eggs. The team coated LiveClear food with a powder form of these eggs; once in a cat's mouth, the chicken antibody binds to the Fel d1 in the cat's saliva, neutralizing it.
The results are partial: In a study with 105 cats, the level of active Fel d1 in their fur had dropped on average by 47 percent after ten weeks eating LiveClear. Cats that produced more Fel d1 at baseline had a more robust response, with a drop of up to 71 percent. A safety study found no effects on cats after six months on the diet. "Our goal was to ensure that whatever we do has no negative impact on the cat," Satyaraj said. Might a dogfood that minimizes dog allergens be on the way? "There is some early work," he said.
This is a year when vaccines changed the lives of billions. Saiba's vaccine, HypoCat, delivers recombinant Fel d1 and the coat from a plant virus (the Cucumber mosaic virus) without any vital genetic information. The viral coat serves as a carrier. A cat would need shots once or twice a year to produce antibodies that neutralize Fel d1.
HypoCat works much like any vaccine, with the twist that the enemy is the cat's own protein. Is that safe? Saiba's team has followed 70 cats treated with the vaccine over two years and they remain healthy. Again the active Fel d1 doesn't disappear but diminishes. The team asked 10 people with cat allergies to report on their symptoms when they pet their vaccinated cats. Eight of them could pet their cat for nearly a half hour before their symptoms began, compared with an average of 17 minutes before the vaccine.
Jennings hopes to develop a HypoDog shot with a similar approach. However, the goal would be to target four or five proteins in one vaccine, and that increases the risk of hurting the dog. In the meantime, allergic dog-lovers considering an expensive breeder dog might think again: Independent research does not support the idea that any breed of dog produces less dander in the home. In fact, one well-designed study found that Spanish water dogs, Airedales, poodles and Labradoodles--breeds touted as hypo-allergenic--had significantly more of the most common allergen on their coat than an ordinary Lab and the control group.
One day you might be able to bring your cat to the vet once a year for an injection that would modify specific tissues so they wouldn't produce Fel d1.
Nicole Brackett, a postdoctoral scientist at Viriginia-based Indoor Biotechnologies, which specializes in manufacturing biologics for allergy and asthma, most recently has used CRISPR to identify Fel d1 genetic sequences in cells from 50 domestic cats and 24 exotic ones. She learned that the sequences vary substantially from one cat to the next. This discovery, she says, backs up the observations that Fel d1 doesn't have a vital purpose.
The next step will be a CRISPR knockout of the relevant genes in cells from feline salivary glands, a prime source of Fel d1. Although the company is considering using CRISPR to edit the genes in a cat embryo and possibly produce a Fel d1-free cat, designer cats won't be its ultimate product. Instead, the company aims to produce injections that could treat any cat.
Reducing pet allergens at home could have a compound benefit, Indoor Biotechnologies founder Martin Chapman, an immunologist, notes: "When you dampen down the response to one allergen, you could also dampen it down to multiple allergens." As allergies become more common around the world, that's especially good news.
A decade ago, Elizabeth Summers' options for birth control suddenly narrowed. Doctors diagnosed her with Factor V Leiden, a rare genetic disorder, after discovering blood clots in her lungs. The condition increases the risk of clotting, so physicians told Summers to stay away from the pill and other hormone-laden contraceptives. "Modern medicine has generally failed to provide me with an effective and convenient option," she says.
But new birth control options are emerging for women like Summers. These alternatives promise to provide more choices to women who can't ingest hormones or don't want to suffer their unpleasant side effects.
These new products have their own pros and cons. Still, doctors are welcoming new contraceptives following a long drought in innovation. "It's been a long time since we've had something new in the world of contraception," says Heather Irobunda, an obstetrician and gynecologist at NYC Health and Hospitals.
On social media, Irobunda often fields questions about one of these new options, a lubricating gel called Phexxi. San Diego-based Evofem, the company behind Phexxi, has been advertising the product on Hulu and Instagram after the gel was approved by the Food and Drug Administration in May 2020. The company's trendy ads target women who feel like condoms diminish the mood, but who also don't want to mess with an IUD or hormones.
Here's how it works: Phexxi is inserted via a tampon-like device up to an hour before sex. The gel regulates vaginal pH — essentially, the acidity levels — in a range that's inhospitable to sperm. It sounds a lot like spermicide, which is also placed in the vagina prior to sex to prevent pregnancy. But spermicide can damage the vagina's cell walls, which can increase the risk of contracting sexually transmitted diseases.
"Not only is innovation needed, but women want a non-hormonal option."
Phexxi isn't without side effects either. The most common one is vaginal burning, according to a late-stage trial. It's also possible to develop a urinary tract infection while using the product. That same study found that during typical use, Phexxi is about 86 percent effective at preventing pregnancy. The efficacy rate is comparable to condoms but lower than birth control pills (91 percent) and significantly lower than an IUD (99 percent).
Phexxi – which comes in a pack of 12 – represents a tiny but growing part of the birth control market. Pharmacies dispensed more than 14,800 packs from April through June this year, a 65 percent increase over the previous quarter, according to data from Evofem.
"We've been able to demonstrate that not only is innovation needed, but women want a non-hormonal option," says Saundra Pelletier, Evofem's CEO.
Beyond contraception, the company is carrying out late-stage tests to gauge Phexxi's effectiveness at preventing the sexually transmitted infections chlamydia and gonorrhea.
Phexxi is inserted via a tampon-like device up to an hour before sex.
A New Pill
The first birth control pill arrived in 1960, combining the hormones estrogen and progestin to stop sperm from joining with an egg, giving women control over their fertility. Subsequent formulations sought to ease side effects, by way of lower amounts of estrogen. But some women still experience headaches and nausea – or more serious complications like blood clots. On social media, women recently noted that birth control pills are much more likely to cause blood clots than Johnson & Johnson's COVID-19 vaccine that was briefly paused to evaluate the risk of clots in women under age 50. What will it take, they wondered, for safer birth control?
Mithra Pharmaceuticals of Belgium sought to create a gentler pill. In April, the FDA approved Mithra's Nextstellis, which includes a naturally occurring estrogen, the first new estrogen in the U.S. in 50 years. Nextstellis selectively acts on tissues lining the uterus, while other birth control pills have a broader target.
A Phase 3 trial showed a 98 percent efficacy rate. Andrew London, an obstetrician and gynecologist, who practices at several Maryland hospitals, says the results are in line with some other birth control pills. But, he added, early studies indicate that Nextstellis has a lower risk of blood clotting, along with other potential benefits, which additional clinical testing must confirm.
"It's not going to be worse than any other pill. We're hoping it's going to be significantly better," says London.
The estrogen in Nexstellis, called estetrol, was skipped over by the pharmaceutical industry after its discovery in the 1960s. Estetrol circulates between the mother and fetus during pregnancy. Decades later, researchers took a new look, after figuring out how to synthesize estetrol in a lab, as well as produce estetrol from plants.
"That allowed us to really start to investigate the properties and do all this stuff you have to do for any new drug," says Michele Gordon, vice president of marketing in women's health at Mayne Pharma, which licensed Nextstellis.
Bonnie Douglas, who followed the development of Nextstellis as part of a search for better birth control, recently switched to the product. "So far, it's much more tolerable," says Douglas. Previously, the Midwesterner was so desperate to find a contraceptive with fewer side effects that she turned to an online pharmacy to obtain a different birth control pill that had been approved in Canada but not in the U.S.
Even if a contraceptive lands FDA approval, access poses a barrier. Getting insurers to cover new contraceptives can be difficult. For the uninsured, state and federal programs can help, and companies should keep prices in a reasonable range, while offering assistance programs. So says Kelly Blanchard, president of the nonprofit Ibis Reproductive Health. "For innovation to have impact, you want to reach as many folks as possible," she says.
In addition, companies developing new contraceptives have struggled to attract venture capital. That's changing, though.
In 2015, Sabrina Johnson founded DARÉ Bioscience around the idea of women's health. She estimated the company would be fully funded in six months, based on her track record in biotech and the demand for novel products.
But it's been difficult to get male investors interested in backing new contraceptives. It took Johnson two and a half years to raise the needed funds, via a reverse merger that took the company public. "There was so much education that was necessary," Johnson says, adding: "The landscape has changed considerably."
Johnson says she would like to think DARÉ had something to do with the shift, along with companies like Organon, a spinout of pharma company Merck that's focused on reproductive health. In surveying the fertility landscape, DARÉ saw limited non-hormonal options. On-demand options – like condoms – can detract from the moment. Copper IUDs must be inserted by a doctor and removed if a woman wants to return to fertility, and this method can have onerous side effects.
So, DARÉ created Ovaprene, a hormone-free device that's designed to be inserted into the vagina monthly by the user. The mesh product acts as a barrier, while releasing a chemical that immobilizes sperm. In an early study, the company reported that Ovaprene prevented almost all sperm from entering the cervical canal. The results, DARÉ believes, indicate high efficacy.
A late-stage study, slated to kick off next year, will be the true judge. Should Ovaprene eventually win regulatory approval, drug giant Bayer will handle commercializing the device.
Other new forms of birth control in development are further out, and that's assuming they perform well in clinical trials. Among them: a once-a-month birth control pill, along with a male version of the birth control pill. The latter is often brought up among women who say it's high time that men take a more proactive role in birth control.
For Summers, her search for a safe and convenient birth control continues. She tried Phexxi, which caused irritation. Still, she's excited that a non-hormonal option now exists. "I'm sure it will work for others," she says.
Robert Thomas was a devoted runner, gym goer, and crew member on a sailing team in San Diego when, in his 40s, he noticed that his range of movement was becoming more limited.
He thought he was just getting older, but when he was hiking an uphill trail in Lake Tahoe, he kept tripping over rocks. "I'd never had this happen before," Robert says. "I knew something was wrong but didn't know what it was."
It wasn't until age 50 when he was diagnosed with Charcot-Marie-Tooth disease. The genetic disorder damages the peripheral nerves, which connect the brain and spinal cord to the rest of the body. This network of nerves is responsible for relaying information and signals about sensation, movement, and motor coordination. Over time, the disease causes debilitating muscle weakness and the loss of limb control.
Charcot-Marie-Tooth usually presents itself in childhood or in a person's teens, but in some patients, like Robert, onset can be later in life. Symptoms may include muscle cramping, tingling, or burning. Many patients also have high foot arches or hammer toes — toes that curl from the middle joint instead of pointing forward. Those affected often have difficulty walking and may lose sensation in their lower legs, feet, hands, or forearms. One of the most common rare diseases, it affects around 130,000 people in the United States and 2.8 million worldwide.
Like many people with Charcot-Marie-Tooth, or CMT, Robert wears corrective braces on his legs to help with walking. Now 61, he can't run or sail anymore because of the disease, but he still works out regularly and can hike occasionally. CMT also affects his grip, so he has to use special straps while doing some exercises.
For the past few years, Robert has been participating in a clinical trial for an investigational CMT drug. He takes the liquid formulation every morning and evening using an oral syringe. Scientists are following patients like Robert to learn if their symptoms stabilize or improve while on the drug. Dubbed PXT300, the drug was designed by French biopharmaceutical company Pharnext and is the farthest along in development for CMT. If approved, it would be the first drug for the disease.
Currently, there's no cure for CMT, only supportive treatments like pain medication. Some individuals receive physical and occupational therapy. A drug for CMT could be a game-changer for patients whose quality of life is severely affected by the disease.
CMT arises from mutations in genes that are responsible for creating and maintaining the myelin sheath — the insulating layer around nerves. Pharnext's drug is meant to treat patients with CMT1A, the most common form of the disease, which represents about half of CMT cases. Around 5% of those with CMT1A become severely disabled and end up in wheelchairs. People with CMT1A have an extra copy of the gene PMP22, which makes a protein that's needed to maintain the myelin sheath around peripheral nerves.
Typically, an individual inherits one copy of PMP22 from each parent. But a person with CMT1A receives a copy of PMP22 from one parent and two copies from a parent with the disease. This extra copy of the gene results in excess protein production, which damages the cells responsible for preserving and regenerating the myelin sheath, called Schwann cells.
The myelin sheath helps ensure that a signal from the brain gets carried to nerves in the muscles so that a part of the body can carry out a particular action or movement. This sheath is like the insulation on an electrical cord and the action is like a light bulb. If the insulation is fine, the light bulb turns on. But if the insulation is frayed, the light will flicker.
"The same happens to these patients," says David Horn Solomon, CEO of Pharnext. "The signal to their muscle is weak and flickers." Over time, their muscles become weaker and thinner.
The PMP22 gene has proven difficult to target with a drug because it's located in a protected space — the Schwann cells that make up the insulation around nerves. "There's not an easy way to tamp it down," Solomon says.
Another company, Acceleron Pharma of Cambridge, Massachusetts, was developing an injectable CMT drug meant to increase the strength of leg muscles. But the company halted development last year after the experimental drug failed in a mid-stage trial. While the drug led to a statistically significant increase in muscle volume, it didn't translate to improvements in muscle function or quality of life for trial participants.
Made by Design
Pharnext's drug, PXT3003, is a combination of three existing drugs — baclofen, a muscle relaxant; naltrexone, a drug that decreases the desire for alcohol and opioids; and sorbitol, a type of sugar alcohol.
The company designed the drug using its artificial intelligence platform, which screened 20,000 existing drugs to predict combinations that could inhibit the PMP22 gene and thereby lower protein production. The AI system narrowed the search to several hundreds of combinations and Pharnext tested around 75 of them in the lab before landing on baclofen, naltrexone, and sorbitol. Individually, the drugs don't have much effect on the PMP22 gene. But combined, they work to lower how much protein the gene makes.
"How the drug inside the cell reduces expression isn't quite clear yet," says Florian Thomas, director of the Hereditary Neuropathy Center, and founding chair and professor in the department of neurology at Hackensack University Medical Center and Hackensack Meridian School of Medicine in New Jersey (no relation to Robert Thomas, the CMT patient). "By reducing the amount of protein being produced, we hopefully can stabilize the nerves."
In rodents genetically engineered to have the PMP22 gene, the drug reduced protein levels and delayed onset of muscle weakness when given to rats. In another animal study, the drug increased the size of the myelin sheath around nerves in rats.
"Like humans with CMT, one of the problems the animals have is they can't grip things, their grip strength is poor," Solomon says. But when treated with Pharnext's drug, "the grip strength of these animals improves dramatically even over 12 weeks."
Human trials look encouraging, too. But the company ran into a manufacturing issue during a late-stage trial. The drug requires refrigeration, and as a result of temperature changes, crystals formed inside vials containing the high dose of the drug. The study was a double-blind trial, meaning neither the trial participants nor investigators were supposed to know who received the high dose of the drug, who received the low dose, and who received a placebo. In these types of studies, the placebo and experimental drug should look the same so that investigators can't tell them apart. But because only the high dose contained crystals, not the low dose or placebo, regulators said the trial data could be biased.
Pharnext is now conducting a new randomized, double-blind trial to prove that its drug works. The study is recruiting individuals aged 16 through 65 years old with mild to moderate CMT. The company hopes to show that the drug can stop patients' symptoms from worsening, or in the best case scenario, possibly even improve them. The company doesn't think the drug will be able to help people with severe forms of the disease.
"In neurologic disease, you're looking for plasticity, where there's still the possibility of stabilization or reversal," Solomon says. Plasticity refers to the ability of the nervous system to change and adapt in response to stimuli.
Allison Moore, a CMT patient and founder and CEO of the Hereditary Neuropathy Foundation, has been following drug development for CMT since she founded the organization in 2001. She says many investigational drugs haven't moved forward because they've shown little success in animals. The fact that Pharnext's drug has made it to a late-stage human trial is promising, she says.
"It's really exciting," Moore says. "There's a chance that if you take the drug early before you're very severe, you'll end up not developing the disease to a level that's super disabling."
CMT has damaged Moore's peroneal nerve, a main nerve in the foot. As a result, she has foot drop, the inability to lift the front part of her foot, and needs to wear leg braces to help her walk. "The idea that you could take this early on and that it could stop progression, that's the hope that we have."
Thomas, the neurologist, says a drug doesn't have to be a cure to have a significant impact on patients. "If I have a CMT patient who's 50 years old, that patient will be more disabled by age 60," he says. "If I can treat that person with a drug, and that person is just as disabled at age 60 as they were at age 50, that's transformative in my mind."
While Robert Thomas says he hasn't noticed a dramatic improvement since he's been on the drug, he does think it's helping. Robert is now in an open-label study, which means he and his health provider are aware that he's receiving the drug.
When the COVID-19 pandemic hit, manufacturing and supply chain disruptions meant that Robert was without the trial drug for two months. When his medication ran out, his legs felt unstable again and walking was harder. "There was a clear distinction between being on and off that medication," he says.
Pharnext's current trial will take about a year and a half to complete. After that, the FDA will decide on whether to approve the drug for CMT patients.
As scientists learn more about the PMP22 gene and the more than 100 other genes that when mutated cause CMT, more precise treatments could be possible. For instance, scientists have used the gene-editing tool CRISPR to correct a CMT-causing mutation in human cells in the lab. The results were published August 16 in the journal Frontiers in Cell and Developmental Biology.
Pharnext is also interested in pursuing genetic treatments for CMT, but in the meantime, repurposed drugs may be the best shot at helping patients until more advanced treatments are available.