Dexamethasone for DME shows stronger results compared with sham group

Take-home message: In this article Dr Anat Lowenstein explains that the benefits of treatment with a dexamethasone intravitreal implant for DME were observed across a variety of demographic characteristics.

By Vanessa Caceres, Reviewed by Dr Anat Lowenstein

The benefits of treatment with a dexamethasone intravitreal implant (Ozurdex, Allergan, Irvine, CA, USA) for diabetic macular edema (DME) were found in a variety of subgroups. These groups were defined by demographics, diabetes status, diabetes and DME duration, prior treatment, and severity of diabetes, according to Dr Anat Lowenstein, Sourasky Medical Center, Tel Aviv, Israel.

Study details

Dr Lowenstein presented the results of a subgroup analysis of the MEAD trial, focused on 3-year results with the dexamethasone implant 0.7 and 0.35 mg in 1,048 patients with DME.

The trial met its primary efficacy endpoint of improvement in best-corrected visual acuity (BCVA) stronger than that of the sham-controlled group and had a safety profile consistent with previous reports, according to study authors.¹

Dr Lowenstein described a typical patient from the trial. The patient was a 65-year-old with severe diabetic retinopathy in both eyes. Despite focal laser therapy and three bevacizumab injections, the patient still had severe DME. The patient was treated with the dexamethasone implant, responded nicely for 4 to 5 months, and then had another recurrence. The patient developed a cataract and was treated for it after the third use of the implant. 

“At the last follow-up, with the seventh injection, the patient had good anatomic results,” Dr Lowenstein said.

Dr Lowenstein also described the various parameters under which the implant performed better than the sham-controlled group, including mean change in BCVA from baseline at 3 years, a BCVA improvement of 15 letters or more at 3 years, the time that it took to reach an improvement of 15 letters or more and the mean average change from baseline in ocular coherence tomography retinal thickness at the centre subfield. The numbers were clinically higher in patients in the 0.35mg group as well as the 0.7mg group. 

Subgroup analysis

The improvements with the implant also spanned a variety of demographic characteristics.

“The higher percentage of at least three lines of improvement was seen with the dexamethasone implant across sex, age, and ethnic group,” reported Dr Lowenstein.

Although statistics seemed to show a strikingly high result in patients under the age of 45, that was likely because of a smaller sample size. When analysing vision improvement based on diabetes and DME characteristics, there was a higher percentage of at least three lines of improvement with the implant versus the sham across diabetes duration (measured as fewer than or greater than 15 years), HbA1C (less than or greater than 8%), and duration of DME (broken down into year-long increments and then 3 years or longer).

“There was a trend toward an increased benefit from dexamethasone in patients with a shorter duration of disease and better control,” Dr Lowenstein explained. “However, the sample size is small.”

When analysing patients’ prior treatments, those receiving the implant once again saw a benefit regardless of the previous type of therapy or the type of DME they had, she said. There was also a higher percentage of 15-letter improvement or greater in patients receiving the implant regardless of their baseline ocular BCVA or retinal thickness.

“The differential efficacy here is likely caused by the ceiling effect and less thick retinas at baseline, with less room for improvement possible,” Dr Lowenstein added.

Study researchers also analysed the benefit of the implant in phakic versus pseudophakic eyes. Although they observed a treatment benefit consistent at all time points in pseudophakic eyes, this was not initially seen in the phakic eyes. “When we looked at patients who underwent cataract surgery, they eventually did gain the same acuity benefits as pseudophakic patients,” she said.

Finally, researchers analysed how effective the implant was in patients based on the severity of their diabetic retinopathy. “In patients with diabetic retinopathy graded as severe NPDR or worse, the implant was significantly more effective than sham in all visual acuity and retinal thickness parameters,” concluded Dr Lowenstein.

References

• Boyer DS et al., Ophthalmology. 2014;121:1904-1914.

Dr Anat Lowenstein

e: anatl@tlvmc.gov.il

Dr Lowenstein works at Tel Aviv Sourasky Medical Center, Tel Aviv, Israel. 

This article was adapted from Dr. Lowenstein’s presentation during Retina Subspecialty Day at the 2014 meeting of the American Academy of Ophthalmology.