Tuesday May 23 3:51 PM ET | | Cancer Drugs Show
Danger and Hope | | By DANIEL Q. HANEY, AP Medical Editor |
| NEW ORLEANS (AP) - Drugs designed to stop tumors by |
cutting off their blood supply have shown modest benefit in |
tests against three kinds of cancer, but have also raised |
concerns about possible dangerous side effects. | |
Angiogenesis inhibitors, as these drugs are called, are among |
the most closely watched new developments in cancer | research.
In animal studies, they sometimes dramatically | reverse cancer, and
hopes are high they will do something | similar in people. | |
Several reports on mid-size studies of these medicines were |
reported at this week's annual cancer conference sponsored | by
the American Society of Clinical Oncology. Together, | experts say,
these studies offer proof that the concept is | sound: Attacking
tumors' ability to sprout blood vessels clearly | inhibits cancer
growth, even in terminally ill patients who have | tried all of the
standard cancer drugs. | |
However, these studies also show that |
these drugs can have a variety of |
unwanted side effects, some of which |
are fatal. | |
``These are drugs in every sense of the | word,'' said Dr. George
Sledge of Indiana University. ``They | have activity, and they have
toxicity.'' | | On Tuesday, doctors reported studies on drugs
developed by | Genentech and Sugen that are designed to block tumors'
use | of vascular endothelial growth factor, or VEGF. This
substance | is a key fuel that allows the cancer to grow new blood
vessels | and repair old ones. Without a new blood supply, cancers |
never get bigger than a pinhead. | | As is usual at this
stage of testing, the drugs were given only to | people with spreading,
incurable tumors, sometimes alone, | sometimes in combination with
standard chemotherapy | medicines. | | Doctors say that
while no one was clearly cured, the | anti-VEGF compounds did seem to
slow the tumors' spread, at | least for a few months. | |
``We have three common solid tumors - breast, colon and lung |
cancer - and this drug shows some evidence of clinical benefit |
in all three, the most common cancers we deal with. That's the |
real significance,'' said Dr. Russell DeVore of Vanderbilt |
University, referring to new results with the Genentech drug. | |
However, DeVore's study, conducted on 99 terminally ill lung |
cancer patients, also shows the drugs' potential hazards. Six |
patients developed sudden, catastrophic bleeding in their |
tumors, killing four of them. | | ``We were taken by
surprise. This was not an expected side | effect,'' DeVore said. |
| However, Dr. Nicholas J. Vogelzang of the University of |
Chicago called this bleeding ``very exciting,'' despite its |
unfortunate consequences, since it suggests the treatment truly |
does appear to disrupt the tumor's ability to maintain a blood |
supply. |
