AIDS Treatment News Issue #228, August 4, 1995
It appears that this workshop (see FDA Workshop on Clinical
Trial Design, September 6-7 -- Registration by Aug. 18) has
been requested to address profoundly wrong issues. It is
being asked to design trials to meet the requirements of the
accelerated approval regulations. Worse, the official
announcement of the workshop includes the statement, "In HIV,
the clinical endpoints that have been considered meaningful
are survival and disease progression as manifested by the
development of AIDS-defining opportunistic infections." As we
will show below, this statement reflects the fundamental
error which has made AIDS clinical trials unproductive. If it
becomes the focus or agenda of the workshop, then nothing
valuable will emerge.
We believe that the real reason confirmatory trials are
proving so difficult is that the kind of confirmatory trials
which are now being designed and run should not be done at
all. The accelerated approval regulations, when Kessler
introduced them several years ago, were a tremendous advance
over what existed before. We and many others have strongly
supported them. But now it is time to move on. We may not
even need to change the accelerated approval regulations --
let alone abandon them. But we do need to interpret them in a
way which is productive for today. We need confirmatory trial
designs which are rational and cost-effective in the light of
current knowledge.
Today -- even though it has not yet been officially "proven"
in a formal, academic sense -- there is in fact an ever-
growing, unmistakable if not overwhelming practical sense
that modern surrogate markers do mean something. In case
after case, when viral load goes down, good things happen
clinically -- for example, symptoms of many different kinds
go away, and HIV infected mothers with low viral load do not
transmit the virus to their babies. Long-term survivors are
usually people who have low viral load naturally. Researchers
may not have prospectively "proven" that patients who
maintain a viral load under 10,000 copies due to drug
treatment live longer than if they let their viral load stay
at 500,000 or a million, but the reason for the lack of such
proof is that no one has done the study. Who would volunteer
to be left with the high viral load until something happened
to them? And even if volunteers could be found, it would take
some time to complete such a trial, because it would take
time for enough people to develop AIDS-defining infections or
die. We do not have that time. But quite a number of bright
people are now designing just this kind of study -- the
stylish "strategy" trial -- with the expectation of finishing
it before "confirmatory" trials, as currently understood, are
allowed to go away.
What needs to be done now is to break the irrational mind-
set, which started early in the AIDS epidemic and has
continued as if on autopilot ever since, that clinical proof
of a drug (that is, proving that the drug really helps
patients, not just improves blood tests) requires clinical
endpoints (understood as death or AIDS-defining opportunistic
infections). In other words, instead of starting with mostly
healthy people and waiting until they get AIDS-defining
illnesses or die, start with people who are clinically ill,
and whose symptoms are easily measurable and not intolerable,
and see if the antiviral treatment in question can get them
better -- can make their symptoms go away. This is clinical
proof of drug efficacy -- proof that the drug does help real
patients, not just blood-test numbers. And at the same time,
this kind of trial uses the easily measured symptoms as a
"marker" for more profound activity of the drug.
Admittedly this kind of trial would not prove survival
benefit. We can afford to do without this proof because, as
time moves on: (1) we are becoming more confident that the
survival benefit is in fact there, even though it would be
very difficult and ethically questionable to prove it for
sure; (2) the cost of trying to prove survival is continually
increasing, and the feasibility of doing so is becoming less,
as patients have more treatment options open to them; (3) if
we are wrong about survival benefit -- if a particular
treatment lowers viral load, and raises CD4 count, and also
makes clinical symptoms go away, and yet does not affect
survival -- doctors would soon recognize this incongruity,
and such a very surprising finding would provide invaluable
leads in pathogenesis research; and (4) the drugs could be
justified even in the unlikely case that they did not prolong
survival, as they would have been formally proven to improve
quality of life.
The one truly bad consequence of the unlikely possibility of
being wrong about survival benefit (when viral load, CD4, and
disappearance of clinical symptoms all do show treatment
benefit) is that thousands of patients may choose a treatment
which turns out not to keep them alive longer, when otherwise
they might have chosen one which did help keep them alive.
But this worst possible scenario is no worse, and may be less
bad, in the system we are proposing than in what exists now.
For in the current system, where confirmatory trials have to
prove survival (or AIDS progression) benefit, the drug is
already approved; thousands of people are using it before its
failure to improve lifespan is known. In our proposed system,
the long, slow survival-type confirmatory trial is replaced
by a rapid, symptom-reduction confirmatory trial. Since this
trial takes weeks instead of years, doctors get the symptom-
reduction information almost immediately. If a treatment
makes people healthier in every measurable way, including
clinical symptom reduction, but still they die as fast with
the drug as without, then physicians will probably realize
that something is wrong, due to the unexpected deaths, and
shift to other treatments, even before any survival trial
results could be ready.
The kind of confirmatory trial we propose -- seeing if an
antiviral treatment relieves existing AIDS-related symptoms,
instead of seeing if it delays progression to AIDS or death
-- not only can be done in weeks instead of years, but also
needs a few dozen or fewer volunteers, not hundreds. And this
kind of trial can ethically use a placebo control --
scientifically the best control -- provided that the symptoms
are tolerable, and that the volunteers freely choose to risk
enduring them for a few additional weeks, in order to
contribute to science. No one we have talked to, including
some hard-line skeptics, has been able to find any
fundamental problem with this approach to confirmatory
trials. But still the trials do not happen, the idea does not
translate into reality, into a far better system for doing
confirmatory studies, because inertia is strong and no
institutional machinery exists to oppose it.
If it really is so easy, why wasn't this done years ago? We
do not know. Perhaps the wrong ways of doing things were
enshrined by necessity early in the epidemic, and then became
a religion for many.
This writer will probably attend the September 6-8 meetings.
We are reluctant, fearing yet another waste of time, because
for years we have addressed meeting after meeting with little
result -- little or no input into the ongoing national
conversation about clinical trial design, about AIDS
research, about why AIDS research has been unproductive,
about how it could be made to work better. People are set in
their ways. Ongoing political battles, often addressing
obsolete issues, have a long history, and the combatants are
now dug in.
If you might also attend the meetings, or send a statement,
and will help me to get the above message heard, let me hear
from you.
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