Inexpensive drug to stop sight loss shown to be
effective
Friday, June 11,
2010
An inexpensive, but unlicensed drug to help prevent severe sight
loss in older people has been shown to be safe and effective, finds
a study published on bmj.com today.
Bevacizumab (Avastin) is licensed as a treatment for bowel cancer,
but it is widely used "off label" as a considerably cheaper
alternative to the approved drug ranibizumab (Lucentis) to prevent
wet age related macular degeneration (AMD) and several large trials
comparing the two drugs are now underway.
Although ranibizumab was not included in this study (it was not
licensed for use when the trial began) the researchers support its
immediate implementation. In the majority of countries in the
world, where either no treatment or inferior therapies are
available to patients with wet AMD, the appropriate use of
bevacizumab, a highly cost effective intervention, would have an
immediate impact in reducing incident blindness from this
condition, they say.
Wet AMD is the leading cause of visual loss in people over the age
of 50 in Europe and North America. Visual loss is a result of
progressive loss of light sensitive cells at the back of the eye
due to damage from abnormal, leaking blood vessels. Sufferers do
not go blind, but find it virtually impossible to read, drive, or
do tasks requiring fine, sharp, central vision.
In 2006, researchers based at three UK eye centres, set out to test
whether bevacizumab is an effective and safe treatment for wet AMD
compared with standard NHS care available at the time.
A total of 131 patients aged at least 50 years with wet AMD were
randomised to either bevacizumab injections at six week intervals
or standard care (one of three different treatments available on
the NHS at the start of the study). Visual acuity was measured at
the start of the study (baseline) and then monitored over one year
(54 weeks).
At one year, 32% of patients in the bevacizumab group gained 15 or
more letters from baseline visual acuity compared with 3% in the
standard care group.
In addition, the proportion of patients who lost fewer than 15
letters of visual acuity from baseline was significantly greater
among those receiving bevacizumab treatment (91%) compared with 67%
in the standard care group.
Average visual acuity increased by seven letters in the bevacizumab
group with a median of seven injections compared with a decrease of
9.7 letters in the standard care group, and the initial improvement
at week 18 was sustained to week 54.
Bevacizumab treatment was associated with a low rate of serious
adverse events.
These results show that bevacizumab injections given at six weekly
intervals for wet AMD is superior to the standard care available at
the start of the trial, say the authors. This trial provides
level-one evidence for the use of bevacizumab injections for the
treatment of wet AMD, they conclude.
In an accompanying editorial, Professor Usha Chakravarthy from the
Royal Victoria Hospital in Belfast says that, although this trial
fills a gap in the evidence base and shows robustly that
bevacizumab is better than previously employed treatments, it does
not tell us whether the drug is as effective as ranibizumab. And
she warns that "the off label use of bevacizumab should not be
encouraged until the large randomised trials comparing it with
ranibizumab report their findings."
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Thanks to BMJ-British Medical Journal for this article.