Lucentis, Avastin, and the role of licensing
Two drugs for treating age-related macular degeneration (AMD), a disease that can lead to important loss of vision, have recently been much in the news. The drugs are Lucentis (generic name ranibizumab), which is expensive and is licensed for the treatment of AMD, and Avastin (generic name bevacizumab), which is much cheaper, but not licensed for the treatment of AMD.
Both drugs are inhibitors of vascular endothelial growth factor A. In other words, they have the same mechanism of action. The are, in fact, similar in many ways. It might be reasonable to expect that they would have similar clinical efficacy, and indeed that seems to be true. One large randomised trial, the CATT study, found similar efficacy for Lucentis and Avastin after both 1 year and 2 years of follow up. Another randomised trial has recently reported its results at a conference, and although the results are not yet published, press reports suggest that it also found similar efficacy.
It does, however, appear that Avastin may be less safe than Lucentis. The CATT study found that 40% of Avastin-treated patients had serious adverse events in the first year of treatment, compared with 32% of Lucentis-treated patients. That difference was statistically significant. Whether that justifies the higher price tag for Lucentis is an interesting question.
But I think the really interesting question here is this: who gets to decide? What should happen in theory is that both drugs would be licensed for the treatment of AMD. An economic evaluation could then be done by a body such as NICE to determine which is the more cost effective treatment.
However, Avastin is not licensed for AMD, and NICE has therefore not assessed its cost effectiveness.
So, in the absence of that assessment, individual primary care trusts (PCTs) within the NHS have decided for themselves that Avastin represents better value for money. Novartis, the makes of Lucentis, are challenging this in the courts, arguing that it undermines the regulatory process if individual PCTs can simply bypass it if they prefer to fund an unlicensed drug.
I don't think this is a smart move on the part of Novartis. It presents an open goal for those in the media arguing that the pharmaceutical industry is only interested in profits. However, I do have some sympathy with them, as there is an important debate to be had here.
We have to ask what is the role of the regulatory environment for medicines if NHS PCTs can simply ignore it if they don't like it.
I think there are really only 2 ways you could argue this. Either you accept that the regulatory process must be followed, in which case the PCTs are obviously in the wrong. Alternatively, you could argue that it's perfectly clear that Avastin represents better value for money, given how much cheaper it is, in which case we have to conclude that the regulatory process is not doing what it needs to do.
I do think there are some serious questions to be asked about whether the regulatory environment is serving the best interests of patients. If we have a regulatory system, then it sets a really bad precedent to ignore it. But asking questions about whether the system is working or whether it needs to be urgently changed is perfectly legitimate.
On a scientific level, Lucentis and Avastin being 'similar in many ways' is arguably a bit of an understatement. They are derived from the same 'parent' anti VEGF-A mouse monoclonal antibody. Avastin is a humanized antibody, so basically the antigen-binding region (the bit that recognises and binds to VEGF-A) is like the original mouse antibody, but the rest of the antibody structure is like a human antibody. Lucentis is a 'cut-down' antibody fragment, being mainly just the 'antigen-binding fragment' (aka Fab) . Though it probably also has some other slight changes to the antigen-binding site relative to Avastin (it is often described as a 'high-affinity Fab fragment', they are more than just similar, at least as I would look at it.
One interesting question is at what stage Genentech, the original developer of both drugs, chose not to pursue Avastin for wet AMD, but rather to develop the customised Fab fragment 'relative' (Lucentis) targeted at this application. The two agents were actually both developed by the same team led by Dr Napoleone Ferrara, as I have read it.
Dr Aust,
There is a wee bit more to this than the above. The Fc portion present on Avastin is missing on Lucentis. The FcR binds Fc and ACTIVELY transports it out of the eye and into the systemic circulation. This is where the differences in serious systemic AEs come from.
Avastin was simply never designed to be injected into an eye - Lucentis was.
OK, so the stats bear out equivalent efficacy, but the SAE data don't bear out equivalent safety. Furthermore, the compounding technique used for Avastin in both of the studies in the press this week was different to that used in clinical practice. In clinical practice we have seen cases of endophthalmitis that can be traced to the compounding pharmacy. So those are the clinical facts.
The other valuable service that is available with Lucentis and not with Avastin is a comprehensive pharmacovigilance programme. When you add all this together, the features gap widens and the cost gap narrows.