Thursday, June 11, 2009

Stem cell flap over US 7,217,565?

Back in April 2009, IPBiz noted an anti-patent diatribe which appeared on californiastemcellreport. [ ]

The initial californiastemcellreport post noted:

[John M. Simpson] reported that Philip Schwartz, head of the Resource, said his organization's efforts to promote research with human neural stem cells has been effectively blocked by patents held by Stem Cells Inc ["SCI"].

The patent issue had been widely circulated: Simpson's piece was the result of a notice by Schwartz to about 2,700 persons, mostly academics, about the patent issue. Simpson sent out a note to about 75 journalists nationwide about his item.

There was a recent comment on that post:

It should also be pointed out that the isolation methods which SCI has published differs significantly from that published by Schwartz. The Schwartz method basically amounts to disassociating brain tissue and out growing cells, while the Uchinda/Weissman method, to which i assume anonymous 1 is referring, uses "cell surface markers" to isolate a subpopulation enriched for progenitors.

In fact i just searched the patent office. There is only one patent assigned to STI for neural stem cell isolation and it is exactly as i suspected: see patent #7,217,565.
Or just search for Irving Weissman patents.

If Dr. Schwartz has not isolated his NSCs using the cell surface markers, then STI has no claim.

However, if Schwartz did use the cell surface markers found in the Weissman patent then they should be required to acquire a license to distribute the NSCs for academic investigators.

So my understanding is that Schwartz is NOT using the trick covered by the Weissman patent and that STI is basically using the implied threat of legal action to prevent distribution of cells not covered under their patent. If true, neat trick - but doing it to a Children's Hospital is bad form, even for STI.

I am someone who was denied a request to receive NSCs from CHOC and prevented from collaborating with Dr. Schwartz. I've now obtained cells from a european collaborator (who will remain anonymous but who also did NOT use the Weissman method).

IPBiz notes the first claim of US 7,217,565 states:

A method of producing a population enriched for human central nervous system stem cells (CNS-SC), which can initiate neurospheres (NS-IC), comprising:
a) contacting neural or neural derived cells with monoclonal antibody 8G1;
b) selecting said neural or neural-derived cells that bind to monoclonal antibody 8G1; and
c) removing said bound cells wherein the remaining cells in the population are enriched for human CNS-SC, the method further comprising the steps of further enriching a population for CNS-SC by
d) contacting the remaining cells with a second monoclonal antibody selected from the group consisting of AC133 and 5E12, and
e) selecting those cells that bind to said second monoclonal antibody to produce a population enriched for CNS-SC.

Claim 9 states:

A method for producing a population enriched for human central nervous system stem cells (CNS-SC) which can initiate neurospheres (NS-IC) comprising eliminating from a population of neural or neural-derived cells those cells that are CD24.sup.+, the method further comprising the step of further enriching the population for CNS-SC by selecting from the remaining population of neural or neural-derived cells for cells that bind to monoclonal antibody AC133.

The summary states:

This invention provides methods for identifying, isolating, and enriching for human non-hematopoietic progenitor and stem cells, and particularly central nervous system (CNS) neural stem cells which can initiate neurospheres (NS-IC) and progenitor cells. The invention also provides for enriched populations containing CNS neural stem cells that can initiate neurospheres, and progenitor cells. A "neurosphere initiating cell (NS-IC)" is a cell that can initiate long-term neurosphere culture. A "neurosphere", in turn, is an aggregate or cluster of cells which includes neural stem cells and primitive progenitors. The identification, culture, growth, and use of neurospheres is disclosed in Weiss et al., U.S. Pat. No. 5,750,376 and Weiss et al., U.S. Pat. No. 5,851,832, both incorporated herein by reference. While the term "NS-IC" is defined by the ability or capacity of that cell to form a neurosphere, these cells may be appropriately grown in adherent culture (see, for example, Johe, U.S. Pat. No. 5,753,506, incorporated herein by reference), and it should be noted that the methods and populations described herein are not to be limited to suspension cultures of NS-IC. An NS-IC is nestin.sup.+ and has the capability to differentiate, under appropriate differentiating conditions, to neurons, astrocytes, and oligodendrocytes.


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