BioWorld International Correspondent

LONDON - IsoTis BV said it has carried out the world's first implants of autologous living bone tissue, in seven patients in Holland.

"We're pretty certain it's a world first," company spokesman Hans Herlots told BioWorld International. "Other people working with bone cells have just multiplied bone cells. We have taken precursor cells, cultured them and grown them on a scaffold of biomaterial."

The implants, carried out in December, involved four patients treated for revision hip surgery and three who received tissue-engineered bone implants for augmentation of the jaw. All seven have been discharged, and will be followed up for the trial over two years. Follow-up will involve assessing the development of the bone matrix.

"We expect to have enough data within six to nine months to say if we will start a large-scale multicenter trial," Herlots said. Because there are no immunological issues, IsoTis is expecting the technology to be a major advance in terms of clinical outcomes.

IsoTis, based in Bilthoven, the Netherlands, also expects to start two further feasibility trials in the second half of 2001, treating 40 patients for indications including osteolysis, various bone defects and spinal fusion.

Creating the IsoTis implants involves taking a bone marrow aspiration biopsy from the patient's pelvic or jaw bone. Osteoprogenitor cells from the marrow aspirate are cultured and subsequently seeded onto a biomaterial and stimulated to form osteoblasts (bone-forming cells). The osteoblasts in turn form bone matrix and ultimately turn into osteocytes.

It takes around four weeks from taking the biopsy to produce the bioimplants, covered with living bone. "We will try and speed this up, but it is not an issue because the operations are planned well in advance, and the biopsy is not very invasive," Herlots said.

Bone is the second most transplanted tissue after blood, with Datamonitor putting the current U.S. and European market at US$500 million. IsoTis President and CEO Clemens van Blitterswijk said, "The clinical application of cultured autologous bone tissue marks a major step for IsoTis in particular, and the tissue-engineering field in general."