The field of xenotransplantation has made dramatic scientific progress this year, with a number of technological advances that promise to drive development past the roadblocks to human clinical trials.

The obstacles have included the hyperacute rejection that occurs within minutes of xenotransplantation; a second event called acute humoral (vascular) rejection; worries about transmission of animal viruses (zoonoses) to humans; and the challenges of cloning pigs suited for organ donation.

In particular, the success of pig cloning has prompted Novartis Pharma AG (NVS; SWX:NOVN) to form a joint venture with BioTransplant Inc. (BTRN) to compile and direct a critical mass of technology toward commercialization.

NVS (Basel, Switzerland), which will own two-thirds of the joint venture, plans to fold its Imutran Ltd. transplant subsidiary into the yet unnamed company and will provide $30 million in funding over the next three years. BTRN will contribute its xenotransplantation technology, allowing it to remain internally focused on allotransplantation.

"It will take a collaborative effort to bring xenotransplantation to fruition," said Julia Greenstein, CSO of the new venture. "BioTransplant has been working together with Novartis for eight years. Novartis has transgenic pigs and immunosuppression technology, and BioTransplant has tolerance induction."

Another key player in the collaborative approach is Infigen Inc. (Deforest, Wis.), known for cloning "Gene" the calf, which is supplying cloning technology.

Although it is not a part of the joint venture, Infigen already has partnered with Imutran to develop a nuclear transfer protocol for reproducibly producing cloned pigs (see BioCentury, Oct. 2). According to Infigen CEO Michael Bishop, the next step is to clone genetically modified, regular size pigs and then transfer the technology to mini-pigs more suited for human transplant (see "The Need for Organs", A4).

Other important breakthroughs this year include a report from PPL Therapeutics plc (LSE:PTH, Roslin, U.K.), which in March announced the birth of five piglets cloned using nuclear transfer with adult cells (see BioCentury, March 20). That report was followed by an announcement from the National Institute of Animal Industry in Japan that it also had cloned a pig (see BioCentury, Aug. 21).

Finally, in August, BTRN said it had created a line of inbred miniature swine that do not contain replication-competent porcine endogenous retrovirus (PERV) (see BioCentury, Sept. 5).


The advances in pig cloning also have led a number of researchers to believe that the hyperacute rejection problem may be solved.