The dog's blog no. 18 Does the legal decision about a sight-saving drug have implications for the veterinary cascade?

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This blog is named after Moscow, Veterinary Prescriber's rescue hound.

While sitting at my desk one day, I looked up at the window, and saw that the straight lines of the venetian blinds were looking a bit wobbly – but only when I looked with my right eye. I dismissed it, thinking maybe it was some form of migraine. When it was still there the next day, I phoned my optician who told me to get to an eye hospital promptly. It transpired that I had maculopathy – fluid that had leaked from newly-formed blood vessels at the back of my eye had caused the central part of the retina to bulge and was the reason for the distorted vision. This is what happens in a condition called ‘wet’ age-related macular degeneration (AMD). Except in my case it was not due to advanced age, but extreme short-sightedness. 

Maculopathy is a serious sight-threatening condition. It is also frightening. As the condition progressed over the next few days, the sight in my right eye deteriorated so that eventually I could not see the face of a person standing before me. This is the loss of central vision that people with macular degeneration experience. Click here see what that looks like. Fortunately, for people with the ‘wet’ or neovascular type of macular degeneration there is an effective treatment. Sadly, for the ‘dry’, more common type, there is none. 

The treatment, which is needed promptly, involves injection of a type of drug called a vascular endothelial growth factor (VEGF) antagonist. These drugs are monoclonal antibodies that interact with a receptor involved in the creation of new blood vessels. They are used in the treatment of cancers, halting the development of a tumour’s blood supply. There are two such drugs licensed for treating ‘wet’ AMD: ranibizumab (brand name Lucentis) and aflibercept (Eyelea). A similar drug, bevacizumab (brand name Avastin), which is authorised for the treatment of bowel cancer, has also been shown in clinical trials (including one funded by the NHS) to be as effective and safe as ranibizumab in 'wet' AMD, but the drug is not authorised for this use.

Here’s the problem: there is ten-fold difference in price between the licensed drugs and bevacizumab (Royal Courts of Justice 2018). When I had my treatment, 6 years ago, I was offered bevacizumab. I was also offered ranibizumab, but only if I agreed to take part in a clinical trial. I accepted treatment with bevacizumab, which involved having a single injection directly into my eye. My sight gradually returned over the following weeks, and has been fine ever since. 

As AMD is a fairly common condition in older people, the cost to the NHS of using the more expensive option runs into £millions. And so it is not surprising that many NHS organisations have chosen to offer patients the option of treatment with bevacizumab. This off-label use of the drug was recently challenged, through a judicial review, by the pharmaceutical companies that market the licensed drugs. The outcome was that the judge ruled against the companies, so allowing the NHS to offer patients treatment with the unlicensed drug.

Some have wondered if this decision has implications for veterinary cascade prescribing. This is unlikely. The cascade allows vets to prescribe unlicensed medicines or use licensed medicines off-label, in particular to avoid causing unacceptable suffering, but cost is not normally considered adequate justification. In the case of bevacizumab, the issue concerned a potential enormous cost to the public purse, and concerned a drug with a strong evidence base supporting its use.

Interestingly, one of the conclusions of the judgement was that “the EMA [regulatory authority] does not have exclusive competence to determine whether Avastin is clinically effective and safe for opththalmic use”. This is an important point, because it is up to companies to apply for changes to the licensed indications. If they do not want to for any reason (e.g. not wanting to alter a product’s market niche or unwilling to sponsor the trials needed to support an application) the result is that there may not be a licensed product that reflects the current evidence. In such circumstances it must surely be justifiably in an animal’s best interest to prescribe an off-licence or off-label treatment. 

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Reference

Royal Courts of Justice. Approved judgement, 21 September 2018