The Promise of Pills That Know When You Swallow Them
Dr. Sara Browne, an associate professor of clinical medicine at the University of California, San Diego, is a specialist in infectious diseases and, less formally, "a global health person." She often travels to southern Africa to meet with colleagues working on the twin epidemics of HIV and tuberculosis.
"This technology, in my opinion, is an absolute slam dunk for tuberculosis."
Lately she has asked them to name the most pressing things she can help with as a researcher based in a wealthier country. "Over and over and over again," she says, "the only thing they wanted to know is whether their patients are taking the drugs."
Tuberculosis is one of world's deadliest diseases; every year there are 10 million new infections and more than a million deaths. When a patient with tuberculosis is prescribed medicine to combat the disease, adherence to the regimen is important not just for the individual's health, but also for the health of the community. Poor adherence can lead to lengthier and more costly treatment and, perhaps more importantly, to drug-resistant strains of the disease -- an increasing global threat.
Browne is testing a new method to help healthcare workers track their patients' adherence with greater precision—close to exact precision even. They're called digital pills, and they involve a patient swallowing medicine as they normally would, only the capsule contains a sensor that—when it contacts stomach acid—transmits a signal to a small device worn on or near the body. That device in turn sends a signal to the patient's phone or tablet and into a cloud-based database. The fact that the pill has been swallowed has therefore been recorded almost in real time, and notice is available to whoever has access to the database.
"This technology, in my opinion, is an absolute slam dunk for tuberculosis," Browne says. TB is much more prevalent in poorer regions of the world—in Sub-Saharan Africa, for example—than in richer places like the U.S., where Browne's studies thus far have taken place. But when someone is diagnosed in the U.S., because of the risk to others if it spreads, they will likely have to deal with "directly observed therapy" to ensure that they take their medicines correctly.
DOT, as it's called, requires the patient to meet with a healthcare worker several days a week, or every day, so that the medicine intake can be observed in person -- an expensive and time-consuming process. Still, the Centers for Disease Control and Prevention website says (emphasis theirs), "DOT should be used for ALL patients with TB disease, including children and adolescents. There is no way to accurately predict whether a patient will adhere to treatment without this assistance."
Digital pills can help with both the cost and time involved, and potentially improve adherence in places where DOT is impossibly expensive. With the sensors, you can monitor a patient's adherence without a healthcare worker physically being in the room. Patients can live their normal lives and if they miss a pill, they can receive a reminder by text or a phone call from the clinic or hospital. "They can get on with their lives," said Browne. "They don't need the healthcare system to interrupt them."
A 56-year-old patient who participated in one of Browne's studies when he was undergoing TB treatment says that before he started taking the digital pills, he would go to the clinic at least once every day, except weekends. Once he switched to digital pills, he could go to work and spend time with his wife and children instead of fighting traffic every day to get to the clinic. He just had to wear a small patch on his abdomen, which would send the signal to a tablet provided by Browne's team. When he returned from work, he could see the results—that he'd taken the pill—in a database accessed via the tablet. (He could also see his heart rate and respiratory rate.) "I could do my daily activities without interference," he said.
Dr. Peter Chai, a medical toxicologist and emergency medicine physician at Brigham and Women's Hospital in Boston, is studying digital pills in a slightly different context, to help fight the country's opioid overdose crisis. Doctors like Chai prescribe pain medicine, he says, but then immediately put the onus on the patient to decide when to take it. This lack of guidance can lead to abuse and addiction. Patients are often told to take the meds "as needed." Chai and his colleagues wondered, "What does that mean to patients? And are people taking more than they actually need? Because pain is such a subjective experience."
The patients "liked the fact that somebody was watching them."
They wanted to see what "take as needed" actually led to, so they designed a study with patients who had broken a bone and come to the hospital's emergency department to get it fixed. Those who were prescribed oxycodone—a pharmaceutical opioid for pain relief—got enough digital pills to last one week. They were supposed to take the pills as needed, or as many as three pills per day. When the pills were ingested, the sensor sent a signal to a card worn on a lanyard around the neck.
Chai and his colleagues were able to see exactly when the patients took the pills and how many, and to detect patterns of ingestion more precisely than ever before. They talked to the patients after the seven days were up, and Chai said most were happy to be taking digital pills. The patients saw it as a layer of protection from afar. "They liked the fact that somebody was watching them," Chai said.
Both doctors, Browne and Chai, are in early stages of studies with patients taking pre-exposure prophylaxis, medicines that can protect people with a high-risk of contracting HIV, such as injectable drug users. Without good adherence, patients leave themselves open to getting the virus. If a patient is supposed to take a pill at 2 p.m. but the digital pill sensor isn't triggered, the healthcare provider can have an automatic message sent as a reminder. Or a reminder to one of the patient's friends or loved ones.
"Like Swallowing Your Phone"?
Deven Desai, an associate professor of law and ethics at Georgia Tech, says that digital pills sound like a great idea for helping with patient adherence, a big issue that self-reporting doesn't fully solve. He likes the idea of a physician you trust having better information about whether you're taking your medication on time. "On the surface that's just cool," he says. "That's a good thing." But Desai, who formerly worked as academic research counsel at Google, said that some of the same questions that have come up in recent years with social media and the Internet in general also apply to digital pills.
"Think of it like your phone, but you swallowed it," he says. "At first it could be great, simple, very much about the user—in this case, the patient—and the data is going between you and your doctor and the medical people it ought to be going to. Wonderful. But over time, phones change. They become 'smarter.'" And when phones and other technologies become smarter, he says, the companies behind them tend to expand the type of data they collect, because they can. Desai says it will be crucial that prescribers be completely transparent about who is getting the patients' data and for what purpose.
"We're putting stuff in our body in good faith with our medical providers, and what if it turned out later that all of a sudden someone was data mining or putting in location trackers and we never knew about that?" Desai asks. "What science has to realize is if they don't start thinking about this, what could be a wonderful technology will get killed."
Leigh Turner, an associate professor at the University of Minnesota's Center for Bioethics, agrees with Desai that digital pills have great promise, and also that there are clear reasons to be concerned about their use. Turner compared the pills to credit cards and social media, in that the data from them can potentially be stolen or leaked. One question he would want answered before the pills were normalized: "What kind of protective measures are in place to make sure that personal information isn't spilling out and being acquired by others or used by others in unexpected and unwanted ways?"
If digital pills catch on, some experts worry that they may one day not be a voluntary technology.
Turner also wonders who will have access to the pills themselves. Only those who can afford both the medicine plus the smartphones that are currently required for their use? Or will people from all economic classes have access? If digital pills catch on, he also worries they may one day not be a voluntary technology.
"When it comes to digital pills, it's not something that's really being foisted on individuals. It's more something that people can be informed of and can choose to take or not to take," he says. "But down the road, I can imagine a scenario where we move away from purely voluntary agreements to it becoming more of an expectation."
He says it's easy to picture a scenario in which insurance companies demand that patient medicinal intake data be tracked and collected or else. Refuse to have your adherence tracked and you risk higher rates or even overall coverage. Maybe patients who don't take the digital pills suffer dire consequences financially or medically. "Maybe it becomes beneficial as much to health insurers and payers as it is to individual patients," Turner says.
In November 2017, the FDA approved the first-ever digital pill that includes a sensor, a drug called Abilify MyCite, made by Otsuka Pharmaceutical Company. The drug, which is yet to be released, is used to treat schizophrenia, bipolar disorder, and depression. With a built-in sensor developed by Proteus Digital Health, patients can give their doctors permission to see when exactly they are taking, or not taking, their meds. For patients with mental illness, the ability to help them stick to their prescribed regime can be life-saving.
But Turner wonders if Abilify is the best drug to be a forerunner for digital pills. Some people with schizophrenia might be suffering from paranoia, and perhaps giving them a pill developed by a large corporation that sends data from their body to be tracked by other people might not be the best idea. It could in fact exacerbate their sense of paranoia.
The Bottom Line: Protect the Data
We all have relatives who have pillboxes with separate compartments for each day of the week, or who carry pillboxes that beep when it's time to take the meds. But that's not always good enough for people with dementia, mental illness, drug addiction, or other life situations that make it difficult to remember to take their pills. Digital pills can play an important role in helping these people.
"The absolute principle here is that the data has to belong to the patient."
The one time the patient from Browne's study forgot to take his pills, he got a beeping reminder from his tablet that he'd missed a dose. "Taking a medication on a daily basis, sometimes we just forget, right?" he admits. "With our very accelerated lives nowadays, it helps us to remember that we have to take the medications. So patients are able to be on top of their own treatment."
Browne is convinced that digital pills can help people in developing countries with high rates of TB and HIV, though like Turner and Desai she cautions that patients' data must be protected. "I think it can be a tremendous technology for patient empowerment and I also think if properly used it can help the medical system to support patients that need it," she said. "But the absolute principle here is that the data has to belong to the patient."
Jamie Rettinger was still in his thirties when he first noticed a tiny streak of brown running through the thumbnail of his right hand. It slowly grew wider and the skin underneath began to deteriorate before he went to a local dermatologist in 2013. The doctor thought it was a wart and tried scooping it out, treating the affected area for three years before finally removing the nail bed and sending it off to a pathology lab for analysis.
"I have some bad news for you; what we removed was a five-millimeter melanoma, a cancerous tumor that often spreads," Jamie recalls being told on his return visit. "I'd never heard of cancer coming through a thumbnail," he says. None of his doctors had ever mentioned it either. "I just thought I was being treated for a wart." But nothing was healing and it continued to bleed.
A few months later a surgeon amputated the top half of his thumb. Lymph node biopsy tested negative for spread of the cancer and when the bandages finally came off, Jamie thought his medical issues were resolved.
Melanoma is the deadliest form of skin cancer. About 85,000 people are diagnosed with it each year in the U.S. and more than 8,000 die of the cancer when it spreads to other parts of the body, according to the Centers for Disease Control and Prevention (CDC).
There are two peaks in diagnosis of melanoma; one is in younger women ages 30-40 and often is tied to past use of tanning beds; the second is older men 60+ and is related to outdoor activity from farming to sports. Light-skinned people have a twenty-times greater risk of melanoma than do people with dark skin.
"When I graduated from medical school, in 2005, melanoma was a death sentence" --Diwakar Davar.
Jamie had a follow up PET scan about six months after his surgery. A suspicious spot on his lung led to a biopsy that came back positive for melanoma. The cancer had spread. Treatment with a monoclonal antibody (nivolumab/Opdivo®) didn't prove effective and he was referred to the UPMC Hillman Cancer Center in Pittsburgh, a four-hour drive from his home in western Ohio.
An alternative monoclonal antibody treatment brought on such bad side effects, diarrhea as often as 15 times a day, that it took more than a week of hospitalization to stabilize his condition. The only options left were experimental approaches in clinical trials.
Early research
"When I graduated from medical school, in 2005, melanoma was a death sentence" with a cure rate in the single digits, says Diwakar Davar, 39, an oncologist at UPMC Hillman Cancer Center who specializes in skin cancer. That began to change in 2010 with introduction of the first immunotherapies, monoclonal antibodies, to treat cancer. The antibodies attach to PD-1, a receptor on the surface of T cells of the immune system and on cancer cells. Antibody treatment boosted the melanoma cure rate to about 30 percent. The search was on to understand why some people responded to these drugs and others did not.
At the same time, there was a growing understanding of the role that bacteria in the gut, the gut microbiome, plays in helping to train and maintain the function of the body's various immune cells. Perhaps the bacteria also plays a role in shaping the immune response to cancer therapy.
One clue came from genetically identical mice. Animals ordered from different suppliers sometimes responded differently to the experiments being performed. That difference was traced to different compositions of their gut microbiome; transferring the microbiome from one animal to another in a process known as fecal transplant (FMT) could change their responses to disease or treatment.
When researchers looked at humans, they found that the patients who responded well to immunotherapies had a gut microbiome that looked like healthy normal folks, but patients who didn't respond had missing or reduced strains of bacteria.
Davar and his team knew that FMT had a very successful cure rate in treating the gut dysbiosis of Clostridioides difficile, a persistant intestinal infection, and they wondered if a fecal transplant from a patient who had responded well to cancer immunotherapy treatment might improve the cure rate of patients who did not originally respond to immunotherapies for melanoma.
The ABCDE of melanoma detection
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Clinical trial
"It was pretty weird, I was totally blasted away. Who had thought of this?" Jamie first thought when the hypothesis was explained to him. But Davar's explanation that the procedure might restore some of the beneficial bacterial his gut was lacking, convinced him to try. He quickly signed on in October 2018 to be the first person in the clinical trial.
Fecal donations go through the same safety procedures of screening for and inactivating diseases that are used in processing blood donations to make them safe for transfusion. The procedure itself uses a standard hollow colonoscope designed to screen for colon cancer and remove polyps. The transplant is inserted through the center of the flexible tube.
Most patients are sedated for procedures that use a colonoscope but Jamie doesn't respond to those drugs: "You can't knock me out. I was watching them on the TV going up my own butt. It was kind of unreal at that point," he says. "There were about twelve people in there watching because no one had seen this done before."
A test two weeks after the procedure showed that the FMT had engrafted and the once-missing bacteria were thriving in his gut. More importantly, his body was responding to another monoclonal antibody (pembrolizumab/Keytruda®) and signs of melanoma began to shrink. Every three months he made the four-hour drive from home to Pittsburgh for six rounds of treatment with the antibody drug.
"We were very, very lucky that the first patient had a great response," says Davar. "It allowed us to believe that even though we failed with the next six, we were on the right track. We just needed to tweak the [fecal] cocktail a little better" and enroll patients in the study who had less aggressive tumor growth and were likely to live long enough to complete the extensive rounds of therapy. Six of 15 patients responded positively in the pilot clinical trial that was published in the journal Science.
Davar believes they are beginning to understand the biological mechanisms of why some patients initially do not respond to immunotherapy but later can with a FMT. It is tied to the background level of inflammation produced by the interaction between the microbiome and the immune system. That paper is not yet published.
Surviving cancer
It has been almost a year since the last in his series of cancer treatments and Jamie has no measurable disease. He is cautiously optimistic that his cancer is not simply in remission but is gone for good. "I'm still scared every time I get my scans, because you don't know whether it is going to come back or not. And to realize that it is something that is totally out of my control."
"It was hard for me to regain trust" after being misdiagnosed and mistreated by several doctors he says. But his experience at Hillman helped to restore that trust "because they were interested in me, not just fixing the problem."
He is grateful for the support provided by family and friends over the last eight years. After a pause and a sigh, the ruggedly built 47-year-old says, "If everyone else was dead in my family, I probably wouldn't have been able to do it."
"I never hesitated to ask a question and I never hesitated to get a second opinion." But Jamie acknowledges the experience has made him more aware of the need for regular preventive medical care and a primary care physician. That person might have caught his melanoma at an earlier stage when it was easier to treat.
Davar continues to work on clinical studies to optimize this treatment approach. Perhaps down the road, screening the microbiome will be standard for melanoma and other cancers prior to using immunotherapies, and the FMT will be as simple as swallowing a handful of freeze-dried capsules off the shelf rather than through a colonoscopy. Earlier this year, the Food and Drug Administration approved the first oral fecal microbiota product for C. difficile, hopefully paving the way for more.
An older version of this hit article was first published on May 18, 2021
All organisms have the capacity to repair or regenerate tissue damage. None can do it better than salamanders or newts, which can regenerate an entire severed limb.
That feat has amazed and delighted man from the dawn of time and led to endless attempts to understand how it happens – and whether we can control it for our own purposes. An exciting new clue toward that understanding has come from a surprising source: research on the decline of cells, called cellular senescence.
Senescence is the last stage in the life of a cell. Whereas some cells simply break up or wither and die off, others transition into a zombie-like state where they can no longer divide. In this liminal phase, the cell still pumps out many different molecules that can affect its neighbors and cause low grade inflammation. Senescence is associated with many of the declining biological functions that characterize aging, such as inflammation and genomic instability.
Oddly enough, newts are one of the few species that do not accumulate senescent cells as they age, according to research over several years by Maximina Yun. A research group leader at the Center for Regenerative Therapies Dresden and the Max Planck Institute of Molecular and Cell Biology and Genetics, in Dresden, Germany, Yun discovered that senescent cells were induced at some stages of regeneration of the salamander limb, “and then, as the regeneration progresses, they disappeared, they were eliminated by the immune system,” she says. “They were present at particular times and then they disappeared.”
Senescent cells added to the edges of the wound helped the healthy muscle cells to “dedifferentiate,” essentially turning back the developmental clock of those cells into more primitive states.
Previous research on senescence in aging had suggested, logically enough, that applying those cells to the stump of a newly severed salamander limb would slow or even stop its regeneration. But Yun stood that idea on its head. She theorized that senescent cells might also play a role in newt limb regeneration, and she tested it by both adding and removing senescent cells from her animals. It turned out she was right, as the newt limbs grew back faster than normal when more senescent cells were included.
Senescent cells added to the edges of the wound helped the healthy muscle cells to “dedifferentiate,” essentially turning back the developmental clock of those cells into more primitive states, which could then be turned into progenitors, a cell type in between stem cells and specialized cells, needed to regrow the muscle tissue of the missing limb. “We think that this ability to dedifferentiate is intrinsically a big part of why salamanders can regenerate all these very complex structures, which other organisms cannot,” she explains.
Yun sees regeneration as a two part problem. First, the cells must be able to sense that their neighbors from the lost limb are not there anymore. Second, they need to be able to produce the intermediary progenitors for regeneration, , to form what is missing. “Molecularly, that must be encoded like a 3D map,” she says, otherwise the new tissue might grow back as a blob, or liver, or fin instead of a limb.
Wound healing
Another recent study, this time at the Mayo Clinic, provides evidence supporting the role of senescent cells in regeneration. Looking closely at molecules that send information between cells in the wound of a mouse, the researchers found that senescent cells appeared near the start of the healing process and then disappeared as healing progressed. In contrast, persistent senescent cells were the hallmark of a chronic wound that did not heal properly. The function and significance of senescence cells depended on both the timing and the context of their environment.
The paper suggests that senescent cells are not all the same. That has become clearer as researchers have been able to identify protein markers on the surface of some senescent cells. The patterns of these proteins differ for some senescent cells compared to others. In biology, such physical differences suggest functional differences, so it is becoming increasingly likely there are subsets of senescent cells with differing functions that have not yet been identified.
There are disagreements within the research community as to whether newts have acquired their regenerative capacity through a unique evolutionary change, or if other animals, including humans, retain this capacity buried somewhere in their genes.
Scientists initially thought that senescent cells couldn’t play a role in regeneration because they could no longer reproduce, says Anthony Atala, a practicing surgeon and bioengineer who leads the Wake Forest Institute for Regenerative Medicine in North Carolina. But Yun’s study points in the other direction. “What this paper shows clearly is that these cells have the potential to be involved in tissue regeneration [in newts]. The question becomes, will these cells be able to do the same in humans.”
As our knowledge of senescent cells increases, Atala thinks we need to embrace a new analogy to help understand them: humans in retirement. They “have acquired a lot of wisdom throughout their whole life and they can help younger people and mentor them to grow to their full potential. We're seeing the same thing with these cells,” he says. They are no longer putting energy into their own reproduction, but the signaling molecules they secrete “can help other cells around them to regenerate.”
There are disagreements within the research community as to whether newts have acquired their regenerative capacity through a unique evolutionary change, or if other animals, including humans, retain this capacity buried somewhere in their genes. If so, it seems that our genes are unable to express this ability, perhaps as part of a tradeoff in acquiring other traits. It is a fertile area of research.
Dedifferentiation is likely to become an important process in the field of regenerative medicine. One extreme example: a lab has been able to turn back the clock and reprogram adult male skin cells into female eggs, a potential milestone in reproductive health. It will be more difficult to control just how far back one wishes to go in the cell's dedifferentiation – part way or all the way back into a stem cell – and then direct it down a different developmental pathway. Yun is optimistic we can learn these tricks from newts.
Senolytics
A growing field of research is using drugs called senolytics to remove senescent cells and slow or even reverse disease of aging.
“Senolytics are great, but senolytics target different types of senescence,” Yun says. “If senescent cells have positive effects in the context of regeneration, of wound healing, then maybe at the beginning of the regeneration process, you may not want to take them out for a little while.”
“If you look at pretty much all biological systems, too little or too much of something can be bad, you have to be in that central zone” and at the proper time, says Atala. “That's true for proteins, sugars, and the drugs that you take. I think the same thing is true for these cells. Why would they be different?”
Our growing understanding that senescence is not a single thing but a variety of things likely means that effective senolytic drugs will not resemble a single sledge hammer but more a carefully manipulated scalpel where some types of senescent cells are removed while others are added. Combinations and timing could be crucial, meaning the difference between regenerating healthy tissue, a scar, or worse.