hematopoietic progenitor cells from human blood into iPS cells using Cellular Dynamics’ previously patented episomal reprogramming method. That method involves introducing episomal vectors, or circular pieces of DNA, into an adult cell, which revert it to stem cell form before the vectors depart the cell. That’s an improvement over the original viral reprogramming method that involves inserting four genes into the adult cell’s DNA, Cellular Dynamics says. There are concerns over the potential side effects of that infusion of foreign DNA into the cell’s genome, including errors that could cause tumors.
The other two patents cover the production of iPS cells from freshly collected and banked blood samples. (For the hardcore scientists and patent attorneys out there, the exact U.S. patent numbers are 8,691,574, 8,741,648, and 8,765,470.)
Greely says the patent covering episomal reprogramming of cells from blood samples is likely the most important of the three. “But for it to turn out to be important, first, iPSCs have to turn out to be really important,” he says. “I think we expect they will, but nobody knows for sure.”
And since the first two patents cover one type of cell, there’s always the risk that a competitor will come up with a different method that achieves the same result without violating the patent, Greely says.
“Even if the cell type has some advantages over using other cell types, the market power is limited. If you charge too much, somebody else could make iPSCs from skin cells or some other cell type that doesn’t infringe their patent,” Greely says. “[The blood sourcing is] only really important if their route is powerfully the best. And there are lots of different routes.”
