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| Paul Laikind |
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| Doug Melton, |
One might call it a California-Massachusetts stem cell
face-off. The tussle is over a stem cell cure of sorts for diabetes.
The players are Doug Melton of Harvard and Paul Laikind, CEO
of ViaCyte in San Diego.
Recently in separate forums, the men critiqued each other’s
approaches to diabetes.
Most recently it was Laikind three days ago on the blog,
ipscell.com, of UC Davis researcher Paul Knoepfler. Laikind was responding in a
Q&A carried by Knoepfler.
Knoepfler asked about
Melton’s comments in the MIT Technology Review last month. Melton was described in an article as being “worried”
that ViaCyte’s technology, now in a first stage clinical trial, would not work. The California stem cell agency has invested $55 million in the firm's approach.
Knoepfler continued,
“(Melton) raised concerns more specifically about the
Encaptra capsule, for example, functionally becoming fibrotic and mentioned
worries about your cells being immature and taking a long time to mature. Any
response on capsule and cells? He also has suggested that his beta cells will
be a better option.”
Laikind replied,
“Dr. Melton’s work on the beta cell is very interesting. As
to the cells, we made the choice to use the pancreatic progenitor cells. An
important consideration is that when you first put in cells, they are in a hypoxic
environment. Beta cells are sensitive to low oxygen levels, which can
negatively affect their survival and function. Beta cells typically exist in a
mature highly vascularized organ. The pancreatic progenitor cells that we use
undergo an organogenesis-like process, more similar to how they behave in
nature, and thus we believe they should be better able to handle low oxygen.
They also are believed to release angiogenic and other factors to promote
vascularization.
“In regards to the capsule, we do expect there to be a
foreign body reaction in patients after implantation, which will generate a
fibrotic capsule. In fact, we see a thin fibrotic capsule around the device in
mice. But in the mouse model this capsule around the device is very well vascularized.
The vasculature is right up against the device membrane on the outside,
allowing for oxygen and nutrient diffusion to the cells inside.”
Laikind said situation involving Melton and BetaLogic was “healthy competition.”
He continued,
“There’s room in this area for multiple efforts and we
aren’t especially concerned with competition. Yet we do feel we are ahead of
others and we have substantial intellectual property that they will need to
navigate (~50 patents issued in the United States, and a couple hundred pending
patent applications, including international). At ViaCyte we view the real competition
as the biology rather than with the efforts of others as we seek to cure this
devastating disease.”
Laikin had more to say about his firm’s product and Melton’s
comments. He also discussed ViaCyte’s clinical
trial, which now has four patients with a goal of 40. He said the initial
evaluation of efficacy could occur by late 2016. Within five years, he hopes to
see “success” with the product and “be moving to market.”
Responding to a question about “product placement,” Laikin
said the firm is currently inserting its tiny device in the lower back of
patients. Laikin said,
“The reason for that placement is that while the device can
withstand the impact of a 60 mph baseball (based on cadaver testing), a needle
could go right through it, so we want to put it where patients don’t typically
inject insulin.”
Concerning Melton’s views on ViaCyte, the Feb. 12 MIT
Technology Review piece said,
“Douglas Melton, a biologist at Harvard University who has
two children with type 1 diabetes, worries that the ViaCyte system may not
work. He thinks deposits of fibrotic, scarlike tissue will glom onto the
capsules, starving the cells inside of oxygen and blocking their ability to sense
sugar and release insulin. Melton also thinks it might take immature cells up
to three months to become fully functional. And many won’t become beta cells,
winding up as other types of pancreatic cells instead.
“Melton says the ‘inefficiency’ of the system means the
company ‘would need a device about the size of a DVD player’ to have enough
beta cells to effectively treat diabetes. ViaCyte says it thinks 300 million of
its cells, or about eight of its capsules, would be enough. (Each capsule holds
a volume of cells smaller than one M&M candy.) Last
October, Melton’s group announced it had managed to grow fully mature,
functional beta cells in the lab, a scientific first that took more than 10
years of trial-and-error research. Melton thinks implanting mature cells would
allow a bioartificial pancreas to start working right away.”
