ImmunoGen Inc. sold its residual rights to receive royalty payments on commercial sales of breast cancer drug Kadcyla to the pension plan for municipal employees in Ontario, for $65 million.

The sale to the Ontario Municipal Employees Retirement System, or OMERS, is related to the residual interest held by ImmunoGen from a prior transaction with Immunity Royalty Holdings LP.

In 2015, the biotechnology company announced a $200 million non-dilutive royalty transaction through which it sold the right to receive 100% of the royalty revenue on Kadcyla commercial sales to an undisclosed threshold amount, subject to certain conditions. ImmunoGen would receive 85% of the royalty revenue, and the original purchaser would receive 15% for the remaining term of the royalty once the threshold was met.

Following the sale, OMERS now owns 100% of ImmunoGen's rights to receive Kadcyla royalties. Waltham, Mass.-based ImmunoGen also stated that it has terminated the 2015 agreement with Immunity Royalty Holdings.

MTS Health Partners LP acted as exclusive financial adviser to ImmunoGen and Mintz Levin Cohn Ferris Glovsky and Popeo PC acted as special transactional counsel to ImmunoGen.

Genentech, a part of Roche Holding AG, developed Kadcyla using technology licensed from ImmunoGen under a 2000 agreement established between the companies. The agreement entitled ImmunoGen to receive royalties ranging from 3% to 5% on Kadcyla sales in countries where ImmunoGen holds valid patents covering Kadcyla, and 2% in countries without relevant ImmunoGen patents.