Research that was once focused on unlocking the secrets to prolonging life may now hold the key to halting or curbing two often-fatal blood disorders affecting bone marrow cells and clotting.
Two papers published online Wednesday in the New England Journal of Medicine show promising results in the treatment of two rare blood disorders using an experimental therapy developed by Menlo Park, Calif., biopharmaceutical firm Geron Corp.
Geron's drug Imetelstat was the result of two decades of research involving telomeres, described as the caps on each strand of DNA that protect chromosomes from deteriorating. When a cell splits, the telomere's length is shortened, a process that continues until the telomere becomes too short to continue protecting the chromosomes, causing the cell to die.
The length of human telomeres is a key to aging. Longer telomeres are associated with longer life and less risk of developing chronic conditions often associated with old age such as cancer, diabetes and dementia. Telomeres are protected by an enzyme called telomerase, and it is believed that aging can be slowed and some of its effects halted by activating telomerase when it has stopped working.
Telomerase activity distinguishes normal cells from cancerous cells. Cell division is limited within normally aging cells, but high telomerase activity causes cell division within tumor cells to continue indefinitely. Researchers have long sought ways to limit cell division within cancer cells by targeting and stopping their telomerase activity, causing them to age and die.
One of the newly published studies found Imetelstat, a drug developed to target telomerase activity, caused partial or complete remission in seven of 33 patients diagnosed with myelofibrosis, a rare bone marrow disorder that disrupts the body's normal blood cell production.
The second new study found the same drug decreased blood platelet levels in all 18 study patients with essential thrombocythemia, a disorder in which the body overproduces blood platelets, increasing the risk of blood clots.
Geron CEO Dr. John Scarlett said in an e-mail that the data "provide compelling evidence that use of a telomerase inhibitor, such as Imetelstat, may result in groundbreaking changes in how we approach the future treatment of hematologic myeloid malignancies."
Although well-known for its embryonic stem-cell research, Geron left that business in 2011 to concentrate on cancer therapies, citing a scarcity of stem-cell funding.
The company received partial clearance from the U.S. Food and Drug Administration to continue testing of Imetelstat last November after regulators had put a full clinical hold on the drug because its prolonged use was found to carry liver damage risks.
The partial green light for further clinical study was enough for pharmaceutical giant Johnson & Johnson to step in and form an agreement with Geron that provided $35 million upfront with the promise of up to $900 million more if Imetelstat completes development and receives FDA approval.
Although still in its early stages, the science around telomerase has sparked the growth of a number of companies that provide telomere testing to purportedly give people a sense of their "biological age."