Image courtesy of Boylston Properties

The initial tenant of a speculative Watertown lab development is more than doubling its space after recently reporting progress on its drug development pipeline.

C4 Therapeutics leased an additional 66,052 square feet at 490 Arsenal Way, the LINX life science complex, bringing its total occupancy up to 111,611 square feet.

C4 Therapeutics was the first tenant to commit to the LINX life science development at 490 Arsenal St. by Boylston Properties, leasing 45,000 square feet of office and lab space in 2017 and relocating from Mass Innovation Labs in Kendall Square. Clarion Partners acquired the 185,000-square-foot facility after it was 100 percent leased in 2018 for $158 million.

The amended lease brings C4 Therapeutics’ total payments over the 120-month term to $104.8 million, according to an SEC filing.

A clinical-stage biopharma firm, C4 Therapeutics is developing drug candidates for multiple myeloma and non-Hodgkin’s lymphomas.

In 2020, C4 Therapeutics raised $210 million in an initial public offering. The company reported a net loss of $83.9 million for the year ending Dec. 31 on revenues of $45.8 million.