More than 100 drugs have been approved to treat cancer, but predicting which ones will help a particular patient is an inexact science at best.
A new device developed at the Massachusetts Institute of Technology (MIT) may change that. The implantable device, about the size of a grain of rice, can carry small doses of up to 30 different drugs. After implanting it in a tumor and letting the drugs diffuse into the tissue, researchers can measure how effectively each one kills the patient’s cancer cells.
Such a device could eliminate much of the guesswork now involved in choosing cancer treatments, said Oliver Jonas, a postdoctoral researcher at MIT’s Koch Institute for Integrative Cancer Research and lead author of a paper describing the device in Science Translational Medicine.
“You can use it to test a patient for a range of available drugs and pick the one that works best,” Jonas said.
Putting the Lab in the Patient
Most of the commonly used cancer drugs work by damaging DNA or otherwise interfering with cell function. Scientists have recently developed more targeted drugs designed to kill tumor cells that carry a specific genetic mutation. However, it is usually difficult to predict whether a particular drug will be effective in an individual patient.
In some cases, doctors extract tumor cells, grow them in a lab dish, and treat them with different drugs to see which ones are most effective. However, this process removes the cells from their natural environment, which can play an important role in how a tumor responds to drug treatment, Jonas said.
“The approach that we thought would be good to try is to essentially put the lab into the patient,” he said. “It’s safe, and you can do all of your sensitivity testing in the native microenvironment.”
The MIT device is made from a stiff, crystalline polymer and can be implanted in a patient’s tumor using a biopsy needle. After implantation, drugs seep 200 to 300 microns (about 1/64 in.) into the tumor but do not overlap with each other. Any type of drug can go into the device’s reservoir, and the researchers can formulate the drugs so that the doses that reach the cancer cells are similar to what a patient would receive if the drug were given by typical delivery methods such as intravenous injection.
After one day of drug exposure, the implant is removed, along with a small sample of the tumor tissue surrounding it, and the researchers analyze the drug’s effects by slicing up the tissue sample and staining it with antibodies that can detect markers of cell death or proliferation.
“This device could help us identify the best chemotherapy agents and combinations for every tumor prior to starting systemic administration of chemotherapy, as opposed to making choices based on population-based statistics. This has been a long-standing pursuit of the oncology community and an important step toward our goal of developing precision-based cancer therapy,” said José Baselga, MD, PhD, chief medical officer at Memorial Sloan Kettering Cancer Center and an author of the paper.
Possibilities for the Future
The researchers are now working on ways to make the device easier to read while it is still inside the patient to allow faster results. They are also planning to launch a clinical trial in breast cancer patients in 2016.
Another possible application for the device is guiding the development and testing of new cancer drugs. In a small trial with human patients, researchers could create and test several different variants of a promising drug compound all at once, then choose the most effective one to carry on to a larger clinical trial.
This article was adapted from information provided by the Koch Institute.
