Tamarkin thought he would spend the day sharing the good news that CytImmune’s lead product, Aurimune, which is designed to treat cancer, would enter clinical trials this week, with support of the National Cancer Institute in Bethesda. The company had just raised $5 million in private funding to support the trials.
But then the U.S. Food and Drug Administration had some last-minute questions and Tamarkin was at the office, answering the queries.
He said he understands the agency’s caution: Aurimune is a nanotech product and the FDA is adjusting its drug approval process for such products.
Perhaps Tamarkin is also patient because, if Aurimune is approved, its market size ‘‘would be extraordinarily significant, billions of dollars,” he said. In the United States alone, there are close to 1 million new patients a year, he said.
‘‘There is a bit of challenge yet to this whole thing,” Tamarkin explained. ‘‘We are there with the agency, helping them assess risk to the patient. I think the challenge for FDA and then the challenge for us is that [Aurimune] is simply not just drug in water, that this is a product that has multiple components to it. And each of the components serves a different function.”
Aurimune uses CytImmune’s patented method of attaching drugs to a molecule of colloidal gold to carry the drugs safely — in animals, so far — through the bloodstream. It is ‘‘a unique, injectable method,” according to Donald P. Malinowski, CytImmune’s product manager.
Colloidal gold has been on the drug market for 70 years for rheumatoid arthritis, giving CytImmune a distinct market advantage, Malinowski said.
‘‘The business plan is that there are companies with proven drugs going off patent,” he said. ‘‘We can deliver them with our method [and] get that same therapeutic effect.”
The FDA has its hands full with nanomedicines, said Hamid Ghandehari, director of the Center for Nanomedicine and Cellular Delivery at the University of Maryland, Baltimore.
‘‘That is an evolving situation. Right now the FDA feels that they do not have enough expertise to regulate us because the moment you put a drug into a particle, then it becomes a different beast,” Ghandehari said. ‘‘Once you put a very small molecule drug on a nanoparticle then its distribution in the body might change. FDA wants to know how much you can release into the system and how much of that reaches the target.”
Calls to the FDA’s drug division were not returned. But the agency’s Web master has been busy posting its nanodrug approval policies:
‘‘In the development of nanotechnology medical products, will it be possible to develop characterization protocols for classes of materials such that, once one, or a few, members of the class have been characterized, no additional testing will be required to justify the use of similar members of the class in medical products? FDA has not taken a position on this issue ...
‘‘Most sponsors would like to know their regulatory pathway as early in the product development process as possible, and FDA strives to do just that.”
Tamarkin said CytImmune has answered the FDA’s questions and expects to start Aurimune trials ‘‘any time now.” CytImmune’s second nanoproduct, AuriTol, is a new version of Taxol for treatment of breast cancer.