New ovarian cancer drug: caution please!


Dispensing medicines for a clinical trial (Jan Chlebik for the ICR)

I’m not so sure how wise it is to report the results of a Phase 1 clinical trial as a ‘breakthrough’ as in “Researchers have hailed the biggest breakthrough in advanced ovarian cancer for a decade after a new treatment was found to dramatically shrink tumours.” (Independent 3 June,2017). Really? A Phase 1 trial of 15 women, of whom seven saw their tumours shrink is a breakthrough? That’s less than 50%! A better figure is that that 10 of these 15 women had the particular molecular target for the drug of whom seven saw their tumours shrink.

The Mirror even had a case study of a trial participant. “She is now considered to have stabilised the disease.” However the same woman is having radiotherapy on a tumour in her back.  That looks to me as though the disease has now progressed.

With such small numbers any statistician would exercise caution in interpreting these reports. Are these results replicable on a larger scale? How long does it take before the disease progresses again? That is what Phase 2 and 3 will be about. Phase 1 drug trials are about testing for side effects, not efficacy.

I looked at what the researchers actually said. The report on the website of the Institute of Cancer Research (one of the partners in the research) says, “Ovarian cancer drug delivers ‘very promising’ results in early trial.” The ensuing article never mentions the word ‘breakthrough’ and nothing about the biggest breakthrough for a decade.

So where did the media get this headline? I found a quote from the study leader Dr Udai Banerji in the Mirror, “This is a completely new mechanism and should add upward of 6 months to patients’ lives with minimal side effects in extremely late phase ovarian cancer. This is much more than anything achieved in the last 10 years.” I don’t know if these were the actual words Dr Banerji used but he could be talking about any of those effects (the 6 months, the side effects, the late stage), not a blanket endorsement of this particular drug.

A much more guarded report from the Guardian doesn’t use the word ‘breakthrough’ but says the researchers “believe the drug could hold promise for women whose ovarian cancer has stopped responding to traditional treatment.” And other experts also exercise caution in interpreting the results. The drug only prolongs life, perhaps by as little as six months. Once the drug is stopped the tumours will continue to grow. At this stage – my own stage – the drug will do nothing for overall survival.  It’s just a delaying tactic.

Michel Coleman, professor of epidemiology and vital statistics at the London School of Tropical Medicine points this out in the Guardian article. “One should be cautious about interpreting this results as a breakthrough for ovarian cancer patients until data on longer-term outcomes are available.”

I don’t know how the report about this drug hit the mainstream media on Saturday – perhaps from the briefing on the Institute of Cancer Research’s website,  posted when the results were reported at the American Society of Clinical Oncology. But I do think the way it’s been reported is misleading – giving false hope to many women (and in particular to their much more optimistic friends) in the last stage of this dreadful disease.


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