iCo Therapeutics has reported top-line results from a Phase II clinical trial of iCo-007 in patients with diabetic macular edema (DME).
The results are related to the eight month visual acuity (VA) primary endpoint for subjects enrolled in the Phase II iDEAL study, carried out in collaboration with JDRF, assessing the efficacy and safety after repeated injections of iCo-007 in DME patients.
The company said that statistical methods employed included both last observation carry forward (LOCF) and multiple imputation (MI) analyses given the departure of patients from the trial before their eight month visit.
Using both statistical methods, mean changes in VA measures in all four groups at both month four and month eight were negative.
Using the LOCF method, mean change in VA at eight months was about minus 11 letters (350µg monotherapy), minus 21 letters (700µg monotherapy), minus 14 letters (350µg + laser arm) and minus 14 letters (350µg + Lucentis).
Some patients in each group did show improvements in mean change in VA.
At eight months using the LOCF analysis, about 20% of patients in the 350µg monotherapy arm gained five letters or greater of vision versus 13% in the 700µg monotherapy arm, 12% in the 350µg + laser arm and 11% in the 350µg + Lucentis arm.
According to the company, at four months, patients gaining five letters or more for the 350µg, 700µg, 350µg + laser and 350µg + Lucentis arms were around 24%, 18%, 21% and 30% respectively.
When using LOCF method it was observed that at month eight, there was an inverse statistically significant difference in mean VA change from baseline between 350µg monotherapy and 700µg monotherapy arms, as there was greater loss of VA in the 700µg monotherapy cohort.
The company said that there was no statistically significant difference in mean VA between the 350µg monotherapy and either 350µg + laser or 350µg + Lucentis arms.
When utilising MI analysis there was no statistically significant difference observed between 350µg monotherapy and each of the 700µg monotherapy, 350µg + laser and 350µg + Lucentis arms.
At eight months, 64% of patients experienced a 15 letter or greater loss of vision in the 700µg monotherapy arm, compared with 33% in the 350 µg monotherapy arm, 33% in the 350µg + laser arm, and 41% in the 350µg + Lucentis arm.
While at four months the corresponding numbers were 29%, 9%, 9%, and 14% respectively.
iCo Therapeutics president and CEO Andrew Rae said: "Further data analysis at 12 months, including secondary endpoints, will be necessary to better understand the viability of iCo-007 in DME."
"There were patients that responded to treatment and others that didn’t respond. Central retinal thickness and sub group analyses represent just a few examples of outstanding data sets that are required to give clarity to the VA data we have generated at eight months.
"No clear conclusions can be reached at this time though it appears the patient population represents a difficult to treat population overall and therefore analysis of factors such as patient resistance to drugs like Lucentis and patient history of cataracts and progression in the study need to be thoroughly analysed."
The iDEAL trial, which includes 187 randomised patients of 18 years and older, explores whether varying combinations and concentrations of iCo-007, alone or in combination, are effective in improving visual acuity in persons with DME.