CHICAGO (CBS) — Cardinal Francis George, the retired head of the Catholic Archdiocese of Chicago, has been dropped from an experimental cancer drug trial, after it proved ineffective in treating the cancer in his right kidney.

While the experimental anitbody drug the cardinal has been taking since August did not reduce or contain the cancer in his right kidney, it also has not spread to other vital organs, according to spokeswoman Colleen Dolan.

“Recent scans showed that this experimental drug has not been effective in his case, but the physicians and others who are overseeing this trial assured him that the information that they had gathered during his course of treatment will be of benefit to others,” Dolan said in an email.

George will meet with his doctors at Loyola University Medical Center next month to address side effects of his cancer.

“He is at peace, but he counts on everyone’s prayers that he might be of service to the Lord and His Church in the time left to him,” Dolan said. “Cardinal George would like to thank all those who have been praying for him, and asks them to continue to do so. You and those you love are remembered in his prayers as well. Cardinal George wishes you a blessed New Year.”

The cardinal revealed his third bout with cancer in March. In 2006, he was diagnosed with bladder cancer, and had his bladder and prostate removed. Cancer returned in 2012, when he underwent chemotherapy after the disease spread to his kidney and liver.

George has said he expects cancer to likely be the cause of his death.

He retired as head of the Catholic church in Chicago in November, and was succeeded by Archbishop Blase Cupich.