Bespoke therapy

A probe that can show whether specific chemotherapy will be effective on an individual's cancer treatment could save the lives of patients and millions of pounds for the NHS, its developers claim.

was the brainchild of a scientist whose wife died of cancer despite undergoing chemotherapy that ultimately proved ineffective. He approached colleagues to help develop bespoke cancer treatments that are determined by the chemosensitivity of individual patient tumours.

According to Jim Bristow, Oncoprobe's chairman, the key to the device's success is that the measurement of responsiveness of individual cancer cells is carried out passively. 'We don't do anything to the cells, just take them from the body and put them into the sensor to be measured.'

Other methods involve growing a culture of cells, which can introduce changes in their characteristics as they adapt to environmental changes through each 'passage', or cycle of mitotic division; the number of cells per thousand actively dividing at a particular time.

'We take the patient's tissue and separate the cancer cells, immediately placing them on the probe, so no passages take place. The whole assay occurs before any transformation takes place. We're getting very close to an

situation,' said Bristow.

The method does not require passing a current over the cells or intruding within the cell wall, both of which could affect responses.

The probe's core technology is an electrochemical measurement indicative of a cell's response towards chemotherapy.

Drugs companies typically carry out empirical research into new chemotherapy treatments on a large population, allowing them to say the treatment will be effective for a percentage of people with that type of cancer. But they cannot say whether it would suit an individual.

'When doctors decide on a chemotherapy course, they do so based on empirical experience and the particular indications of the patient. It's very difficult for them to be absolutely correct.'

Oncoprobe's process uses fresh cancer cells taken directly from the patient and measures the effect of a target treatment on them. 'We isolate the cancer cells and keep them viable, measuring their responses,' said Bristow. 'We put in the drugs the doctor is proposing, and within 48 hours we're given a response and a report detailing how the cells reacted to those drugs. That helps the doctor choose the optimal chemotherapy course for that particular patient.'

The probe reads the open circuit potential between the surface of the cell and the surface of the sensor. The area between them is known as the environment. The equipment reads the difference between that environment and the sensor. That measurement is translated into a signal, which can be viewed as a graph, which moves in relation to the cell's behaviour.

'When the chemotherapy agent kills a cell, the signal reverts to the control, giving you a gradient which shows how fast the cell died,' said Bristow.

Oncoprobe has been successfully tested on animals, where it predicted tumour suppression by drug therapy in rats. The company is now undertaking a clinical study with renal cancer patients at the

, Manchester, where it will be trialled in parallel with existing courses to see if the tests match the actual effectiveness. but it will not affect the choice of treatment.

'We hope to have a very clear finished piece of research in maybe six to nine months,' said Bristow. 'On the basis of that, we would then start to offer a service to renal patients. We then plan a study on bowel cancer in the US with the University of Tennessee.'

The company then plans to start using Oncoprobe commercially and will go on to test its effectiveness in breast cancer treatment.

Oncoprobe was awarded a £128,000 Department of Health grant to develop the prototype four years ago, and received a DTI grant to carry out noise analysis on the signal.

As well as being of direct benefit to patients, Oncoprobe could also save the NHS money. 'With the correct treatment identified, you don't waste money, time or ill effects on the patient by giving them drugs that aren't going to work,' said Bristow.

'It also means that if an expensive and a lower-cost drug prove equally effective, you have the opportunity to save money. The target cost for the assay would be insignificant compared with the savings across the cancer chemotherapy population, so there's a good cost-benefit model as well as a treatment model.'

Estimates on annual UK chemotherapy spend vary, but are around £500m-£700m. 'A 20 per cent saving on those costs is very significant,' said Bristow. 'Hopefully it can be put into hip replacements or more hospital beds.'

Oncoprobe worked with medical electrochemical equipment manufacturer Uniscan to develop a working model for the trial phase, and the DTI's Sensor Knowledge Transfer Network helped bring the two companies together.