1790s

1790s

1800s

1800s

1810s

1810s

1820s

1820s

1830s

1830s

1840s

1840s

1850s

1850s

1860s

1860s

1870s

1870s

1880s

1880s

1890s

1890s

1900s

1900s

1910s

1910s

1920s

1920s

1930s

1930s

1940s

1940s

1950s

1950s

1960s

1960s

1970s

1970s

1980s

1980s

1990s

1990s

2000s

2000s

2010s

2010s

Timelines: 1994

Prev : Next Thrombopoietin

Technical breakthrough, no medical payoff


Researchers at Zymogenetics, Inc., of Seattle, and Molecumetics, Inc., of Bellvue, Washington, work together to clone the platelet-replenishing cytokine, thrombopoietin. Scientists at Genentech and three other groups soon report that they have duplicated the feat independently. Thrombopoietin (TPO) had proven an elusive target for cloners. So difficult was the purification of the protein from plasma that some researchers doubted its existence.

Once the gene for the protein is cloned, a race ensues, with Zymogenetics and Genentech leading the field, to develop a pharmaceutical product that will help patients recover platelet counts after rounds of chemotherapy that suppress bone marrow function.

None of the horses ever finds a finish line. Perversely, clinical trials show that recombinant TPO frequently inhibits platelet production. Patients often develop antibodies against the drug that cross-react with natural TPO. This worsens rather than improves their conditions. Despite the scientific and technological accomplishments of finding and manipulating the protein, the experts concede defeat to the complexities of biology – the battle is lost and the research programs abandoned.

You have clicked on a link that will take you to another website. Click here to continue and leave the Life Sciences Foundation website.
Close