This is mind-blowing. Consider: The last edition of John Calvin's Institutes was published in 1560, four years before his death. Thomas Aquinas stopped working on Summa Theologica when he died in 1274, almost 300 years prior. Thomas Aquinas died in Italy, while John Calvin was born in France and died in Switzerland: two countries that share a border with Italy. How could it take 300 years for a seminal work like this to travel a few hundred miles?
I'm not sure that we can easily attribute this to negligence on the part of Calvin, as he clearly valued interacting with (and often criticizing) his intellectual forebears, as seen in his frequent references to church fathers and the Scholastics (the "schoolmen").
What is the evidence that Calvin read or did not read Summa Theologica? And if he never read it, what prevented him from doing so?