Vertex announces plans for phase III trials of triple drug combinations

Feature -

As Vertex announces trials for new treatments that could benefit more than 90% of people with cystic fibrosis (CF) in the UK, Dr Belinda Cupid, Senior Impact Adviser at the Trust, takes a closer look.

***** Update - March 2019 *****

On 6 March 2019, Vertex Pharmaceuticals published a press release on the four-week results of their two clinical trials of triple combination of Symkevi (tezacaftor and ivacaftor) plus VX-445. The results were positive showing improvements in lung function. This is an early analysis ( sometimes called ‘interim’ analysis ) of the data collected in the study so far. The study is running for 24 weeks and the final results will be published once the study has been completed.

In one study people with CF over the age of 12 with two copies of the F508Delta mutation saw a 10% improvement in lung function after 28 days (four weeks), in those taking the ‘triple’ combination, in comparison to those taking Symkevi alone.

In the second study, people with CF over the age of 12 with one copy of the F508Delta mutation and one copy of a ‘minimal function’ mutation saw a 13.8% improvement in lung function over the same time period, in those receiving Symkevi plus VX-445 in comparison to those taking placebo.

More information on these results can be found on the Cystic Fibrosis Foundation website and on the website of Vertex Pharmaceuticals.

The interim results of the triple combination of Symkevi plus VX-659 were announced in November 2018. They also reported improvements in lung function after four weeks.

Vertex will decide which drug (either VX-445 or VX-659) to take forward for licencing when the full results of all of the studies are available in the autumn of 2019.

**** ****

This week the pharmaceutical company Vertex announced its plans for phase III trials for CF this year; drug combinations that will help approximately 90% of people with cystic fibrosis if trials are successful and NHS funding agreed.

The plans include testing a series of triple combinations of drugs in people with CF who carry different genetic mutations. Some trials will be looking at people with one copy of the F508del mutation and a ‘minimal function’ mutation and some with two copies of the F508del mutation.

The first trials to start will be with VX-659

In the first half of the year Vertex plans to conduct trials investigating ‘VX-659’ in combination with the compounds tezacaftor and ivacaftor. In the first trial they will be testing it in people with CF (who are 12 years old and over) with one copy of the F508del mutation and a minimal function mutation. In the second study they will be testing this triple combination in people with two copies of the F508del mutation.

Trials of VX-445 to come later in the year

Phase III studies to look at the beneficial effects of VX-445 in a triple combination will come later in the year. Again, VX-445 trials will be conducted in people with either one copy of F508del plus a minimal function mutation or those with two copies of F508del. They’ll be taking VX-445, and the compounds VX-561 and tezacaftor.

Details of these phase III trials, including when and where the studies will start, have yet to be announced.

Dr Aisling McMahon, Head of the Clinical Trials Accelerator Platform at the Cystic Fibrosis Trust, said: “This is exciting news for the CF community. For new medications to be made available, they also need to complete the clinical trials process, and it’s vital that people have the opportunity to participate in the UK.

"Our Trials Accelerator is working to increase these opportunities. We are encouraged by the number of pharmaceutical companies currently focussing on CF, which gives us great hope for the future."

If one or both of these treatments is licenced, there is no guarantee they will be made available on the NHS. Through the Stopping the Clock campaign, the Trust is lobbying to ensure that fair and sustainable deals are made between pharmaceutical companies and the NHS so that people with CF benefit from the best treatments as quickly as possible.

A potentiator and two correctors

Different drugs within the triple combination have different functions – either correctors or potentiators. The correctors will help correctly fold the CFTR protein (as mutations mean the protein can’t correctly fold itself), and the potentiators help open the channel in CFTR to allow chloride out.

So far, the triple combinations are one potentiatior (ivacaftor or VX-561) plus two correctors (tezacaftor plus either VX-445 or VX-659).

The plans announced this week are for phase III trials. If successful then the company will be in a position to apply for a licence to make the drugs more widely available.

Find out more about the stages of clinical trials.

Earlier studies

If you’ve been following the development of Vertex’s drugs over a period of time you’ll know that the drugs are referred to by a number until they’re given an easier to remember name like tezacaftor (formerly VX-661). Vertex currently has at least four ‘drugs with numbers’ in clinical trials.

Earlier results we told you about in July last year were using different Vertex drugs to those reported now. Vertex decides which combination of drugs might be most beneficial for people with CF depending on the effectiveness of the drugs, their safety profile and the effect on the quality of life of people with CF (as measured by a fully tested (‘validated’) questionnaire).

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