The decision to suspend the trial is viewed as highly questionable, raising disturbing questions about the role that marketing
played--especially in light of the fact that
Zytiga's patent is due to expire in 2017.
A dust storm is being kicked up following the announcement at the annual
meeting of the American Society of Clinical Oncology of the early
suspension of Johnson
& Johnson's drug trial testing its prostate cancer drug,
aribraterone (Zytiga).
The trial was suspended by J & J's Data Safety Monitoring Board
(DSMB), a committee that operates in secret. The DSMB determined that
the data showed that the drug reduced the spread of prostate cancer by
57%, and that the results hinted, but didn’t prove, that Zytiga was
extending the
men’s lives by a startling 33%.
But the decision to suspend the trial is viewed as highly questionable, raising disturbing questions about the role that marketing
played--especially in light of the fact that
Zytiga's patent is due to expire in 2017.
Could marketing considerations have been the determining factor leading
to the suspension of the trial, thereby promoting its (unproven)
superiority?
Wall Street analysts wasted no time in trumpeting the news to their
clients as a positive for J & J and a negative for its rival
Dendreon.
The Zytiga trial enrolled 1,088 men around the world who had prostate cancer
that had spread, but who hadn’t yet turned to chemotherapy. The
patients, at 151 clinical sites in 12 countries, had no visible symptoms
or only mild symptoms of their disease. They were randomly assigned to
get Zytiga or a placebo.
Forbes science reporter, Matthew Herper, notes: "lately DSMBs have
been deciding to stop trials early an awful lot, causing some
statisticians to worry that they are too eager to deliver early
results. Stopped-early studies proved the benefits of Viread for
preventing HIV infection, Afinitor in breast cancer, Viread for
preventing HIV infection, Crestor for preventing heart attacks and
strokes, Revlimid for use in multiple myeloma after a stem cell
transplant, Sutent in treating the rare form of pancreatic cancer
that afflicted Steve
Jobs, and studies of Lotrel and Norvasc, both blood pressure
drugs, just to name a few."
He further informs us that DSMBs "are often recruited by companies
themselves, [and] are making decisions “driven by marketing
considerations” and the desire to get drugs to market faster and not
their obligation to society."
DSMBs were established as independent monitors of clinical trial data in
real
time--data to which they alone are (presumably) privy. DSMBs were
introduced as a safeguard to protect the safety of human subjects
while maintaining the integrity of the blinded study. DSMBs are empowered to suspend a study for ethical
reasons--when the evidence
demonstrates unambiguously that one treatment is overwhelmingly superior
for survival to the other.
As with pretty much every aspect of clinical trials, the
integrity of the entire process is muddied by those with high
financial stakes in the endeavor. Those stake holders control the
protocol design and time
frame, the selection of the research centers and the investigating
scientists, the number and selection of patients, the data and data
monitoring boards. Absolutely nothing is left to
impartial evaluation or oversight. Indeed, "Michael Meyers, the
J&J executive in charge of Zytiga, said that the
DSMB makes only recommendations, and that the sponsor – the company –
makes final decisions."
Likewise, GlaxoSmithKline and Merck were intimately involved in the
deliberations of their DSMBs involving the diabetes drug Avandia (GSK) and the
cholesterol drug Vytorin (Merck).
To paraphrase a Mae West quip in response to an admirer who exclaimed,
"Goodness, what beautiful diamonds..." to which Mae West famously
responded:
"Goodness had
nothing to do with it."
Ethics had nothing to do with these suspensions.
Vera Sharav
FORBES
New Cancer Data Shine Spotlight On The Secret Committees That Make Medicine's Toughest Decisions
Matthew Herper
On Saturday, a researcher from the University of California, San Francisco,
stood in front of a crowd of doctors at the year’s biggest cancer
conference and presented stunning results from a company-funded study of
a new Johnson & Johnson
drug, Zytiga. The study tested the pill, already approved for men who
have received chemotherapy for prostate cancer, in those with an earlier
stage of the disease. It slowed the spread of their cancer by 57%. Even
more tantalizingly, the results hinted, but didn’t prove, that Zytiga
was extending the men’s lives by a startling 33%.
Immediately after the data were presented, statistician Susan Halabi from Duke University
took the stage to discuss the study – a job she’d been given by the
American Society of Clinical Oncology, which runs the conference. She
raised real concerns about how confident doctors could be about Zytiga’s
benefit. The Zytiga clinical trial had been stopped too early, she
said, and that meant that right now it might be giving an impression
that the drug is more effective than it actually is. It would also make
it difficult to prove Zytiga extended these men’s lives once and for
all. In an interview, she said that the decision to give placebo
patients the drug “sacrificed” the trial. “This decision,” she said, “is
irreversible.”
~~~~~~~~~~
XCONOMY
J&J Prostate Cancer Trial Shouldn’t Have Been Stopped Early
Pieter Droppert
.....
Why did the Data Monitoring Committee (DMC) recommend unblinding the study based on an interim analysis?
That was the question that Susan
Halabi, associate professor of biostatistics and bioinformatics at Duke
University, sought to answer in her excellent discussion of Ryan’s
presentation. Given the complexity of the statistical issues in
question, and the difficulties of questioning the decision to end the
study early, Halabi gave a very fair review of the issues.
The COU-AA-302 trial had several
planned interim analyses, with clearly defined criteria that would show,
based on how much study data was available, whether the drug was
effective or not.
Halabi presented the COU-AA-302
overall survival data in the context of the O’Brien-Fleming boundary,
that graphically represents a curve, one side of which the drug is
judged to be “ineffective,” the other side “effective.” Based on this
analysis, abiraterone was “ineffective.” But as Halabi went on to say,
it was extremely close to the boundary. In that case, why would the
independent data monitoring committee (DMC) choose to unblind the study
at the time it did the analysis, rather than wait a little longer until
statistical significance might be reached?
The judgment of the DMC has to be
questioned. The decision to unblind the study means that the “interim”
data presented by Ryan is effectively the final data for the randomized
trial. Unblinding a study introduces biases, which essentially turns
a well-controlled randomized study into an observational one. As Halabi
noted in her presentation, the “follow-up data will be biased due to
confounding,” —which means other factors besides abiraterone could be
influencing whether patients live longer in one group or another. By
halting the study early, patients in the placebo group are now being
switched over to abiraterone, which makes the comparison between the
drug group and the placebo group less clear. Statistically, the
COU-AA-302 data only shows a “trend to overall survival,” said Halabi.
The DMC’s decision to terminate the
trial early has led to the trial’s failure to show a statistically
significant survival advantage. Would it have required long to wait to
show overall survival? Probably not. The interim analysis that Ryan
presented was based on 43 percent of the expected overall survival
events (333 deaths of trial subjects). This took place in the fourth
quarter of 2011. The next interim analysis was planned for the second
quarter of 2012 based on the expectation that 425 deaths (55 percent of
the expected death events) would have occurred. Halabi told me after her
presentation that it was highly likely this interim analysis would have
crossed the O’Brien-Fleming boundary, and shown a statistically
significant overall survival advantage for abiraterone in
chemotherapy-naïve patients.
.........
The early interim analysis of the COU-AA-302 trial is an opportunity
missed to show an unequivocal survival advantage for abiraterone in the
pre-chemo setting. The study failed to show overall survival and no
matter what the positive PR spin is put on the data, it is unlikely that
the study will ever show statistically significant overall survival for
abiraterone. On some level this must be regarded as a failure of drug
development. Ending studies in this way does a disservice both to
medicine and the men who participated in the trial.
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