RECENT NOTEWORTHY STUDIES TO STIMULATE DISCUSSION AND DEBATE
■ New treat-and-extend data. Controversy persists over optimal dosing schedules for ranibizumab (Lucentis, Genentech, South San Francisco, CA) in wet AMD. A new study offers more evidence for the safety and efficacy of treat-and-extend.
Forty-five treatment-naïve patients were enrolled. They received a loading dose of three monthly injections, followed by the treat-and-extend protocol, adding or subtracting two weeks to the interval between injections depending on the presence of exudative disease.
At 12 months of follow-up, only 5% of the patients >3 lines of vision, with 74% losing none and 25% gaining ≥3 lines. The mean improvement was 1.3 lines (~7 ETDRS letters). Also, central retinal thickness improved by a mean of 65 μm. Subjects received approximately eight injections on average.
Although head-to-head studies of treat-and-extend vs monthly dosing are needed to confirm the findings of this study, the authors state the treat-and-extend protocol is safe and effective.
Toalster N, Russell M, Ng P. A 12-month prospective trial of inject and extend regiment for ranibizumab treatment of age-related macular degeneration. Retina. 2013;33:1351-1358.
■ Chemoreduction in retinoblastoma. A new report from the German Retinoblastoma Reference Center indicates that chemoreduction with cyclophosphamide, with or without focal treatment, could control the progression of retinoblastoma (Figure) and prevent enucleation.
Over 10 years, 56 eyes received six cycles of chemo and were followed for a mean of 101 months. Primary chemo was successful in 42 eyes, requiring neither enucleation nor external-beam radiation. Only age at diagnosis was correlated with relapse.
In addition, one-third of the relapsed eyes were salvaged without enucleation or external-beam radiation, the latter of which has shown correlations with secondary cancer development. Cyclophosphamide allowed for safe reduction of carboplatin, the most potentially harmful agent.
Künkele A, Jurklies C, Wieland R, et al. Chemoreduction improves eye retention in patients with retinoblastoma: a report from the German Retinoblastoma Reference Centre. Br J Ophthalmol. 2013 July 7. [Epub ahead of print]
Figure. Mostly calcified retinoblastoma following chemoreduction and consolidation (top). Time-domain OCT demonstrates disorganization and irregularity of the inner retinal layers and posterior shadowing from calcification (bottom).
CREDIT: HINDAWI PUBLISHING CORP.
■ Bevacizumab in DME. To determine factors in response to treatment with bevacizumab (Avastin, Genentech) for DME, ophthalmologists conducted a retrospective review of responses in fellow eyes.
The authors reviewed the charts of 28 patients with bilateral DME who received bilateral treatment with bevacizumab. They tracked changes in VA and in central subfield thickness.
The authors found that the percentage change in the previously treated eye could explain 21% of the reduction in central subfield thickness. Further, preinjection thickness predicted 14% of treatment response in the same eye. Lens status, changes in VA and age were not statistically significant factors.
The authors suggested that in patients in whom both eyes receive treatment for DME, but not synchronously, the response of the first eye can be helpful in predicting post-treatment thickness in the fellow eye and continued response in the same eye.
Karth PA, Chang A, Wirotsko W. Paired responses to intravitreal bevacizumab in diabetic macular edema: predictors of response in the fellow eye. Graefes Arch Clin Exp Ophthalmol. 2013 July 20. [Epub ahead of print]
■ Macular detachment with optic disk pit. Gas tamponade can be effective in treating macular detachment with optic disk pit, according to a recent study conducted in Japan.
Surgeons performed intravitreal gas injections on eight patients with unilateral macular detachments associated with optic disk pits. Each patient received 0.3 mL sulfur hexafluoride gas without an anterior-chamber tap and was positioned face down for five days.
After a mean number of 1.8 injections, four of the eight patients experienced reattachment, and the mean VA post-treatment was 20/20. No cases of recurrence arose in patients with reattachment over 94 months of follow-up.
Although the mechanism of optic disk pit remains unknown, the authors are confident in stating that gas tamponade is an effective alternative treatment for macular detachment. They caution surgeons to bear in mind the long (up to one year) period necessary to achieve perfect vision. RP
Akiyama H, Shimoda Y, Fukuchi M, et al. Intravitreal gas injection without vitrectomy for macular detachment associated with optic disk pit. Retina. 2013 Jul 18. [Epub ahead of print]
Retinal Physician, Volume: 10 , Issue: September 2013, page(s): 18