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April 1, 1998
Baxter Ceases Its Clinical Trials
For Blood Substitute HemAssist
By THOMAS M. BURTON
Staff Reporter of THE WALL STREET JOURNAL
Baxter International Inc. prematurely ended an advanced U.S. clinical trial
of its blood substitute for severely injured patients after the company found
a higher death rate among those given the product than those receiving
standard therapy.
The development was a major setback to Baxter, which is furthest along
of any company in conducting such clinical trials. The Deerfield, Ill.,
company has already finished building a $110 million facility in Neuchatel,
Switzerland, to manufacture the blood substitute.
While serious, the abrupt canceling of the study doesn't necessarily spell an
end to Baxter's product, called HemAssist. That is because Baxter already
has two other clinical studies under way for HemAssist and said it hasn't
encountered any safety problems in either.
The company has enrolled 100 or more patients in each of those studies,
one dealing with trauma patients in Europe, the other with surgical patients
in the U.S. Tom Schmitz, general manager of Baxter's
hemoglobin-therapeutics division, said no safety concerns have emerged in
either of those studies and that the company intends to proceed with
developing HemAssist.
Seeking Answers
The results in the U.S. trauma study left doctors at Baxter and in hospital
trauma sections wondering about an explanation. Baxter didn't disclose the
number of excess deaths in the HemAssist group, but said about 50
patients received HemAssist and 50 others received standard treatment
for traumatic injuries like gunshots, knife wounds and car accidents. The
company ended the study after an independent safety committee advised it
of the increased deaths in the HemAssist group, and said there was less
than a 5% likelihood that this was due to chance alone.
Baxter's product comes from outdated, donated human blood.
Hemoglobin, the oxygen-carrying component of blood, is chemically
altered to produce HemAssist. The idea of such blood substitutes is that
they can act like human blood, but not carry the risk of infection and the
need for time-consuming typing and cross-matching normally associated
with donated blood.
In New York Stock Exchange composite trading Tuesday, Baxter shares
closed at $55.125, down $1.625.
It has been known for some time that HemAssist and the artificial blood
products made by several competitors have an unwanted side effect called
"vasoconstriction" -- a narrowing of blood vessels that increases blood
pressure. However, Mr. Schmitz said this tendency doesn't appear related
to the deaths in the trauma study. Some doctors actually consider the
effect an advantage, since the severely injured patients in the study had
suffered blood loss and their blood pressure had fallen. Mr. Schmitz said
Baxter is studying the medical records of patients to seek an explanation
for the increased mortality.
Problems in Creating Trials
David Gens, a surgeon at the University of Maryland's Shock-Trauma
Center in Baltimore and a participant in the research, said the study's
cancellation may simply illustrate how hard it is to construct a clinical trial
with severely injured patients.
"The problem is, we would like the patients to be homogeneous, but
trauma patients aren't," he said. "I personally believe HemAssist acts as a
strong drug, and that it works." He speculated it is possible, for example,
that too many patients with especially severe head injuries from car
accidents or other blunt trauma might have been inadvertently assigned to
HemAssist therapy, as opposed to being put into the control group.
John Barrett, director of the trauma service at Cook County Hospital in
Chicago, said he was extremely surprised by the unexpectedly high death
rate. "Baxter already did the safety trials, and the safety trials went fine," he
said.
Baxter and several other major players continue to pursue work toward
producing blood substitutes, believing there may ultimately be a
multibillion-dollar market for the products both for trauma and surgical
patients. Baxter said it still believes it is on track for possible marketing
approval for HemAssist in late 1999 or 2000, either in Europe or the U.S. |
