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Lucentis looks sharp but short in macular edema

Genentech's Lucentis for diabetic macular edema shows promise, physicians say; duration of effect may be short, however

* Lucentis looking promising; physicians say it could be coupled with laser treatment to up the standard of care for macular edema

* Duration of effect appears short, could be an issue for long-term usage

* Split usage of Lucentis and off-label Avastin possible for this market, similar to current usage for wet AMD, physicians speculate

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Genentech’s Lucentis for diabetic macular edema shows promise as a treatment, and could be a strong contender in combination therapy with the current standard of care, physicians say. However, the duration of effect is looking to be relatively short.
Genentech is currently recruiting for its Phase III macular edema trial in diabetes mellitus.
In macular edema, blood vessels in the retina, the thin layer of tissue in the back of eye, become leaky and the retina swells. The macula, the center part of the retina, which is responsible for fine vision may also swell, causing vision loss.
The current standard of care for the disorder is focal/grid laser coagulation therapy, according to physicians interviewed by this news service.
Dr Abdhish Bhavsar, a retina specialist at the University of Minnesota, said Lucentis was exciting as a combination therapy option with focal laser treatment – the current standard of care – and together held the most promise for efficacy in diabetic macular edema.
He said it is important to note, however, that Lucentis is a short-acting agent and it's not clear that the clinical effects will last more than a few weeks or months. While strong short-term gains were very possible with this medication, the efficacy could discontinue, unless dosing was done long term.
“The data we have seen from the early diabetic macular edema studies is that if you follow the macular edema and visual acuity, they’re relatively similar to the dosing patterns,” Bhavsar explained. He said that when a dose is given, the edema goes down and vision improves, but when the dosing stops, visual acuity can decrease again.
He added that a long-term effect without continued dosing may not be possible with Lucentis, therefore a combination with a laser treatment would have value.
Dr Kourous Rezaei, an ophthalmologist at Illinois Retina Associates, said that anti-VEGF treatment is successful in a large number of diabetic macular edema patients. He also agreed with Bhavsar that Lucentis in combination with laser treatment looked to be a strong possibility in the future.
He noted, however, that with anti-VEGF treatments he thought that one was unlikely to get an immediate response, and that a few injections would be needed in order to achieve the desired results. He also agreed with Bhavsar that the effects did not stay long after the medication wore off and dosing needed to be fairly frequent.
Dr Nick Holderman Professor and associate dean for clinical education, chief of medical services, University Eye Institute at the University of Houston, agreed that the half-life of Lucentis is rather short. He speculated that dosing could need to occur as frequently as once or twice a month, though he did note the efficacy possibilities of Lucentis were exciting. He thought a combination with laser therapy would bring out the best of both treatments, leading to a halt in macular edema progression via lasers, with Lucentis then raising visual acuity.
Dr Andreas Lauer, a retina and vitreous disease specialist at Oregon Health and Sciences University, said he was very excited about the possibilities of Lucentis as a treatment for macular edema. He explained that vascular endothelial growth factors (VEGF) make blood vessels leaky and that Lucentis is capable of eradicating this by blocking VEGF. The low toxicities in comparison to steroid treatments also made this a very attractive potential option, Lauer noted.
Dr Robert Frank, professor of ophthalmology at the Kresge Eye Institute at the Wayne State School of Medicine, said this was an upcoming treatment for diabetic macular edema that looked to be the most promising in terms of efficacy and safety. He added that he had much higher hopes for Lucentis than for steroid treatments currently available for macular edema.

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Frank noted, however, that macular edema appears to be a very complex condition and there is more to the disease perhaps than physicians currently understand, and a single drug compound may not hold all the answers.
Lucentis is currently approved for the treatment of wet age-related macular degeneration. Genentech’s Avastin is currently used off-label in this indication, due both to its efficacy and cost effectiveness. Physicians interviewed by this news service acknowledged the possibility of the drug's use in macular edema.
Experts say that there will be 1.5 million cases of diabetic macular edema in the United States by 2010.
Calls placed to Genentech seeking comment were not returned.

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