A Brigham and Women’s doctor is using tiny drones to target cancer
Drones are increasingly being used in innovative ways—from responding to train derailments to documenting fall foliage.
They’ve even made it into the fight against cancer—though on a much, muchsmaller scale.
Dr. Wilfred Ngwa, a medical physicist in radiation oncology at Brigham and Women’s Hospital, is working to apply drone technology to cancer treatment.
Ngwa and his colleagues have developed tiny drones designed to target and kill cancer cells that have spread in the body. Their research project won the hospital’s BRIght Future’s Prize in October.
“It’s really about curing cancer,” Ngwa said of the project, which combines radiotherapy, immunotherapy, and microscopic nanotechnology.
Worldwide in 2012, 8.2 million people died of cancer and 14.1 new cases were diagnosed, according to the Centers for Disease Control and Prevention. By 2025, the agency expects 19.3 million cases will be diagnosed each year.
Currently, surgery, chemotherapy, and radiation therapy are the most common treatments for cancer. Chemotherapy, or chemo, uses drugs that may slow or prevent the cancer from spreading by killing cancer cells, while radiotherapy uses high-energy radiation to damage or kill cancer cells. Surgery and radiotherapy often target cancer in a particular part of the body, while chemotherapy is used to treat cancer that has spread.
But new ways of approaching the disease—like with targeted therapies orimmunotherapy, which uses the body’s immune system (namely the white blood cells) to kill cancer cells either by stimulating the patient’s immune response or providing manmade immune components to the patient—are continually emerging.
Working in radiotherapy, Ngwa said all the research in his field has focused on maximizing the damage to the cancer in a patient, while minimizing the damage to healthy tissue. Currently, rice-sized biomaterials are implanted in patients receiving radiotherapy to track tumors and guide treatment with cancers like pancreatic, lung, or prostate.
Ngwa wants to make the rice-sized implants “smarter,” so that they’d become more like tiny programmable robots, or “drones,” that can carry medicine directly in the patient.
With his project, which he began working on last year, the drones are implanted into the tumors carrying immunotherapy medicine and microscopic nanoparticles that can amplify the effect of radiation therapy on cancer cells locally.
“Once they are implanted, as is currently done in the clinic,” Ngwa said. “They can be programmed to release these microscopic nanoparticles and the immunotherapy medicine so that they can work together with the radiation to train your white blood cells to fight cancer more effectively.”
After the cancer cells begin to die, he said the immunotherapy medicine acts as a “homing beacon,” calling in the patient’s white blood cells, which are then trained to kill the cancer cells and able to patrol the rest of the body, fighting cancer cells that have spread.
Cancer, as Ngwa explained it, is basically a rogue cell the body has no control over killing, so the cell keeps multiplying, while camouflaging itself so the body’s immune system, its white blood cells, don’t recognize the cancer as bad cells.
But with immunotherapy, Ngwa said you can “take the hoodie” off the hiding cancer cells.
“If you can train your white blood cells to recognize the cancer for what it is, then they can attack the cancer,” he said. “They can kill the cancer cells the way that they fight the flu when you get the flu vaccine, essentially.”
The best time to bring in the white blood cells with the immunotherapy is when the cancer cells have been damaged by the radiotherapy, Ngwa said.
“At this point they take off their hoodies because they are bleeding,” he said of the cancer cells. “So then the white blood cells can recognize the cancer for what it is, and, therefore, your body can fight the cancer itself.”
Together, the radiotherapy and immunotherapy serve a one-two punch, he said.
Currently, 50 percent of patients get radiotherapy at some point in their cancer treatment, usually for localized disease. He said using the tiny drones to deliver radiotherapy directly would transform the treatment because it would allow patients to get it after the cancer has spread. It would also minimize toxicity and damage to the healthy tissue from radiation since the treatment is amplified locally by the microscopic nanoparticles.
But Ngwa said the main innovation to the current practice would be applying smart technology in order to allow the rice-sized particles to be programmed for certain actions once they are implanted in a patient.
“We call them drones basically because they’re robotic, in the sense that you can program them,” he said.
The “drones” are made of FDA-approved, biodegradable polymers. The medicine is loaded onto them, and they are programmed to trigger the release of the treatment on the desired schedule. Once they’ve been implanted into a patient and have released the therapy, they biodegrade.
“That’s why they’re smart,” said Ngwa. “You program when they release the medicine. So that will be compatible to radiotherapy schedules and be more effective.”
The great thing, he said, is that since the new technology is very similar to a current practice, there will not be any additional inconvenience to patience.
“It’s just a superior upgrade to what is currently being done,” Ngwa said. “Now these tiny implants, the rice-sized materials, are going to be much smarter and then they can deliver directly, locally, to the cancer cells these immunotherapy medicines which can work to train the white blood cells.”
The use of the drones, the medicines they deliver directly, and the involvement of the body’s natural defenses would also improve the quality of life for patients because they would not have to deal with the toxicities of other treatments like chemotherapy, he said.
In addition to improving quality of life for patients, Ngwa believes the devices would also help prevent cancer recurrence.
“That is one of the biggest burdens for cancer patients,” he said.
“Every time they come in yearly for their checkups, there’s always the fear that the scan will find cancer. But if you train your white blood cells to recognize the cancer, then basically you get this immunity against any recurrence. So those two factors are really huge—increasing the survival and quality of life and also preventing cancer recurrence.”
Depending on funding, Ngwa and his team are planning to do human clinical trials in late 2016. The project won $100,000 when it was voted by members of the public from 96 countries as the winner of the BRIght Futures Prize.
Ngwa said the project went through two levels of scientific review before it was put out to the public.
“By itself, it’s really symbolic,” he said of winning the prize.
“Because the clinical trials are going to cost millions of dollars. Butthe prize is really huge because it gives an endorsement.”
It shows there is interest in pushing the work forward, Ngwa said.