— How do people currently get phage therapy in the US?
Open up nearly any phage-related article, and the first paragraph will probably tell you that phage treatments have been going on for decades in Eastern Europe. But maybe your ears perked up when you heard that patients are now getting phage treatments in the USA, too.
How long has this been going on?
It’s pretty new. In 2016, Steffanie Strathdee and her team at UCSD were the first to get approval from the FDA to use phages on an experimental, emergency, last-resort basis in the US (we wrote about this in our first issue). This was to treat Tom Patterson.
How is this legal?
If a physician has a patient with a serious, multi-drug resistant infection that does not respond to antibiotics, they can get approval to use phages by filing an emergency investigational new drug (eIND) application (also known as Single Patient Expanded Access) with the FDA. Approval can be granted very quickly, and 99% of requests are approved. The eIND only applies to that specific patient, so a doctor has to apply separately for each new patient. Since Tom’s phage treatment in 2016, several other patients have been treated in this way.
Where do the phages come from?
The process of finding and preparing phages for patients in immediate need is actually a much bigger hurdle than securing FDA approval. As well, approval cannot even be granted until phages are found and someone has agreed to produce them for the patient in question.
In the US, two companies are participating in this process on an ongoing basis: Ampliphi and Adaptive Phage Therapeutics (APT). After receiving the patient’s isolate, they test the isolate for phage susceptibility, then propagate and purify the phages that work to kill the patient’s specific strain. Then, the phages are administered to the patient by the patient’s medical team.
The Center for Innovative Phage Applications and Therapeutics (IPATH) at UCSD in San Diego, which involves a team of physicians well-versed in phage therapy, has been involved in the treatment of at least 6 patients in this manner. APT has been involved in the treatment of at least 7 patients in this manner, and Ampliphi has treated patients this way as well.
Sometimes, physicians partner with academic groups to find and prepare phages to treat patients. For instance, the lab of Dr. Ry Young at Texas A&M was heavily involved in preparing phages for Tom Patterson’s case, as was the lab of Dr. Forest Rohwer at SDSU. At Yale, Dr. Benjamin Chan led a successful effort to treat a patient with an infected heart valve with a Pseudomonas aeruginosa phage in his collection.
An uphill battle
It’s very resource-intensive to round up and purify enough of the right phages for a patient. These days, the companies and labs that provide phages for emergency treatments are at or near capacity, and can’t take on all patients who qualify for phage treatments. If that weren’t enough, sometimes a patient is infected with a strain that no one’s phages will kill.
To help surmount some of these obstacles, sometimes a phage crowdsourcing effort will begin. Tune in next week for details on how this process works!
Thanks for reading!