Sir

We wish to clarify your News report (Nature 404, 319–320, 2000) about transgenic mice patents. The Mayo Clinic conducts research to improve patient care and to benefit society. We believe this is best accomplished by freely and openly sharing our ideas and research tools with all academic researchers and by interacting closely with the commercial sector. For not-for-profit institutions such as Mayo, interaction with the commercial sector has two benefits. It is generally the only practical way to translate scientific ideas and research tools into improved diagnosis and therapy for the public; and it provides additional resources through licensing and sponsored research agreements.

Karen Hsiao Ashe deserves enormous credit, not only for her development of the Tg2576 mouse model of Alzheimer's disease but also for her decision to distribute this mouse promptly and freely to academic researchers. Mayo has covered the cost of breeding and genotyping Tg2576 mice that are free of specific pathogens. As pointed out in your News report, many mice have been distributed to academic researchers. Recipients were asked only to pay a nominal fee, primarily to defray the shipping charge. Despite the lawsuit, we will continue to support Hsiao Ashe in distributing Tg2576 mice to academic researchers.

The material transfer agreement (MTA) under which Tg2576 was distributed initially to academic researchers did not contain a ‘reach-through’ provision enabling Mayo to receive automatically a specified percentage of revenues generated by new scientific developments involving Tg2576. Rather, this MTA contained a provision that, if any intellectual property was developed using Tg2576, Mayo would be given an opportunity to purchase rights to this through a negotiated agreement with mutually acceptable terms. Although we continue to welcome the opportunity to license new developments involving Tg2576, this provision has been eliminated from our current MTA, and we are allowing academic centres that signed the initial MTA to transfer to the current MTA.

In distributing Tg2576, it was important to involve the commercial sector, as it is best positioned to develop novel therapies. To achieve maximum therapeutic impact, we wanted to license the mouse to any interested company.

Mayo performed considerable due diligence with respect to licensing Tg2576. We trust that the many companies to whom we gave a licence performed their own due diligence. None of us expected to be sued. We regret the hardship that some academic researchers have suffered because of Elan's decision to subpoena and depose them.

It is essential that we defend ourselves successfully if Elan continues to pursue this lawsuit. We are confident that we can do so. We would prefer, however, to resolve this matter amicably, outside the courtroom.