Has the Roman Catholic Church ever issued an official response to the accusations of the Reformers?

There are many responses being made such as Colloquy at Regernsburg in 1541, Joint Declaration on the Doctrine of Justification in 1994, and lately together with Evangelicals in Evangelicals and Catholics Together in 1994. The main purpose of this response is to bridge an ecumenical reconciliation between Catholic and Protestant groups. Council of Trent is the official Catholic position but it can't be read in isolation apart from Vatican I, Vatican II, and recent ecumenical dialogues.

The fundamental issue that still dividing Protestant groups and Catholic is the doctrine of Justification. For Protestant groups, justification and sanctification must be distinguished without being separated. While Catholic without confusing faith and works maintain that the two are united. This differences is similar to that which lead into Formula of Union between St. Cyril and John of Antioch, where the two were reconciled over one nature vs two natures Christology. Similarly the issue about the relationship between imputative alien righteousness and transformative acts of the Holy Spirit in believers' life are not that different. Reconciliation is not impossible, we're still on a journey from conflict to communion.

The closest thing you'll find is the Council of Trent, the catechism which resulted from it and the structural reforms shortly thereafter. But, for the most part, those addressed what were considered abuses within the Church and not the criticisms of the reformers.

To be honest, it is relatively normal for breakaway groups to indulge in fairly vehement polemic against the Catholic Church (a practice which dates back to the Gnostics in the second century). Often the Church's official response is to simply clarify the points of doctrine which were in dispute and move on.

Catholic Professor Geoffrey Saint-Clair, from Catholic Dossier Magazine (September/October 2001), writes:

Success or failure often depends on leadership—what leaders do or fail to do. When it comes to the Reformation, the lion’s share of the blame rests squarely with the hierarchy, including the papacy. Or at least so said Pope Adrian VI, who in 1523 sent his legate to confess the following before the German princes gathered in Nuremberg:

“We freely acknowledge that God has allowed this chastis*m*nt to come upon His Church because of the sins of men and especially because of the sins of priests and prelates . . . We know well that for many years much that must be regarded with horror has come to pass in this Holy See: abuses in spiritual matters, transgressions against the Commandments; indeed, that everything has been gravely perverted” (quoted in K. Adam, One and Holy, p. 97).

Medieval papal scandals, including the so-called Babylonian Captivity of the Church and the Great Western Schism, in which there were first two, then three, claimants to the papal office, brought derision upon the papacy, as did scandalous living and nepotism. Furthermore, the popes themselves failed to reform the Church, even when they were in a position to do so. And when the Reformation eventually broke out, the papacy failed to understand the challenge to the Church and failed to act quickly to address the problems that gave rise to it. At the same time, when the Church finally did get around to reform, the papacy helped lead the way.

The only response I know of it the counter-reformation amount the Catholics : http://en.wikipedia.org/wiki/Counter-Reformation.

period of Catholic revival beginning with the Council of Trent (1545–1563) and ending at the close of the Thirty Years' War, 1648 which is sometimes considered a response to the Protestant Reformation. The Counter-Reformation was a comprehensive effort, composed of four major elements:

1. Ecclesiastical or structural reconfiguration
2. Religious orders
3. Spiritual movements
4. Political dimensions