The Niche

Correspondence: Response to article on spinal cord study

This letter, from Francisco Silva, President of DaVinci Biosciences, responds to a Nature Reports Stem Cells article on one of his research papers as well as subsequent correspondence.

In response to PrimeGen Biotech’s letter to NRSC, I would like to make it clear that my comments regarding PrimeGen Biotech’s position on publishing were in no way meant to imply that their strategy was wrong. Cell based therapeutics is a very challenging and competitive industry, developing a technology in the laboratory and translating it into human application is very difficult. During my tenure as Executive VP of Research and Development at PrimeGen Biotech, my primary responsibilities were to identify and develop new technology which is demonstrated by PrimeGen Biotech’s intellectual property portfolio with seven patent applications.

With PrimeGen Biotech’s revamping of their R&D management as per Dr. Izadyar, I look forward to seeing them in clinical application next year. After all, “Our goals are ambitious—we believe with this therapy, we can be in clinic in 2010,” said PrimeGen president John Sundsmo in an interview. [Editor’s note: Fari Izadyar emailed on June 6 to say that John Sundsmo left PrimeGen during the revamp.]

I would like to thank Dr Schwartz for his remarks. At the time of entering our clinical study for spinal cord injury (SCI), we understood that it would have been ideal to include a control group, but being that this was a safety and feasibility study, the safety of the patients came first.

To include a control sham group in this study would be to subject SCI patients to possible adverse events which may be unethical. I would like to point out a review of the guidelines for the conduct of clinical trials for spinal cord injury, developed by the International Campaign for Cures of Spinal Cord Injury Paralysis (ICCP) Panel . “The choice of an appropriately matched control group, and the ability to perform double-blinded analysis, is not always a straightforward issue in SCI. For example, there is little doubt regarding the inclusion of a control group when the substance under investigation is an orally administered drug with a relatively safe adverse event profile. In this case, a placebo control arm is simple to include in the study, and double blinding can be implemented. However, when the study requires open surgical manipulation, then the use of a sham surgery ‘control’ group may subject a patient to risk of adverse events caused by the sham procedure itself. SCI patients may be medically unstable, concurrently infected, or at high risk of suffering postoperative complications such as pneumonia or other infection. Sham surgical procedures could also lead to autonomic dysreflexia. These risks are not trivial, and are particularly notable after acute SCI.” Spinal Cord. 2007 Mar;45(3):222-31. Once again I reiterate that this was a safety and feasibility study and we obtained useful information that has allowed our clinical program to continue, we look forward to advancing this candidate therapy for SCI to include a more controlled study as demanded by clinical studies that have advanced beyond safety and feasibility.

Francisco Silva


DaVinci Biosciences


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