Religion Clause, the blog of Professor Howard M. Friedman, published an article revealing the existence of a letter from the OIC to the Chairman of the Ad Hoc Committee for the Elaboration of Complementary Standards. The letter was issued coincident with the introduction of the current draft of the Defamation of Religions resolution in the Third Committee. It is an attempt to reinforce the supposed necessity of protecting Islam from criticism.
The blog post also reported the existence of a U.S. Commission on International Religious Freedom publication: The Dangerous Idea of Protecting Religions from "Defamation": A Threat to Universal Human Rights Standards.
There is a clear contrast between the OIC's letter and the USCIRF's report. Reading both of them will help you to understand the necessity of defeating the Defamation resolution in the General Assembly.