On October 15, 2021, Molecular Templates Inc. received notice from Vertex Pharmaceuticals Incorporated (Vertex") that Vertex has decided to terminate the Company's Master Collaboration Agreement by and between the Company and Vertex, dated November 18, 2019 (the Collaboration Agreement"), a research collaboration which the Company and Vertex entered into focused on developing conditioning agents for applications outside of oncology. The termination of the Collaboration Agreement will be effective on October 29, 2021. In this collaboration, the Company was developing engineered toxin bodies for myeloablation, an indication separate from the Company's core focus on cancer therapeutics.

Pursuant to the terms of the Collaboration Agreement, Vertex paid the Company an upfront payment of $38.0 million, which included proceeds from a concurrent equity investment. In addition to the upfront payments, under the Collaboration Agreement, the Company had the opportunity to receive an additional $22.5 million through the exercise by Vertex of the options to license engineered toxin body products or to add an additional target. The Company also had the opportunity, for each target under the Collaboration Agreement, to receive up to an additional $180.0 million in milestone payments upon the achievement of certain development and regulatory milestone events and up to an additional $70.0 million in milestone payments upon the achievement of certain sales milestone events.

The Company also had the opportunity to receive, subject to certain reductions, tiered mid-single digit royalties as percentages of calendar year net sales, if any, on any licensed product under the Collaboration Agreement.