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Britain’s two biggest cancer charities have become embroiled in a public
row with the Medical Research Council over trials of a drug to prevent breast
cancer. Last week the MRC withdrew its support for the proposed trial because
of concern about the toxic effects of the drug, tamoxifen, in animals. The
next day the other bodies funding the trial, the Imperial Cancer Research
Fund and the Cancer Research Campaign, announced their intention to go ahead
with the trial alone.

‘I am very surprised and concerned at the MRC’s response,’ said Jack
Cuzick of the ICRF in a statement issued jointly by the charities. ‘They
have overridden judgments of the cancer charities, the Committee on Safety
of Medicines, the Food and Drug Administration in America, the manufacturers
and government ministers, who have approved it.’

The row is a major embarrassment to both sides and to the government.
‘The government is giving mixed messages in that one of its agencies is
saying yes and no,’ said Cuzick. The public difference of opinion could
also give ammunition to animal rights activists. ‘We are going to be in
a situation where the animal rights people are going to be saying to us
‘You ignore animal data when you choose to’,’ said a spokeswoman for the
ICRF.

At the centre of the dispute are experiments showing that the drug causes
liver tumours in rats at doses ‘equivalent’ to those used to treat people
(This Week, 29 February). The CSM and the FDA are aware of these data and
have approved the trial because the drug appears to be relatively safe in
large numbers of women with breast cancer. The MRC appears to have attached
greater importance than other authorities to the animal experiments. It
said last week it would support the trial only if it were restricted to
women at extremely high risk. This would effectively make the trial impossible,
as there are not enough women in this category.

John Patterson, medical director at ICI, the drug’s manufacturer, says
that the doctors proposing the trial have known about the data for years.
‘But to the MRC, as far as I know, it is all new, because this is not an
area in which they have been active.’

The doctors and the charities are furious about the MRC’s decision.
‘What irritates me greatly is that they are claiming the moral high ground,’
says Gordon McVie, scientific director at the CRC. ‘They are implying that
the charities didn’t do a risk assessment, which is blatant nonsense.’

Meanwhile, the charities’ statement has also provoked some irritation.
ICI is unhappy with the wording of the statement. ‘We did not approve in
any formal sense, and do not approve, studies by independent scientific
groups such as this one,’ said Patterson. The company agreed to supply the
drug because the CSM had approved it, which amounted to ‘tacit rather than
explicit’ approval, he said.

The Department of Health said this week that it did not have a view
on the trial.