Dyne Therapeutics, Inc. (Nasdaq: DYN) has amended its senior secured term loan facility with Hercules Capital, Inc. (NYSE: HTGC), expanding total borrowing capacity to up to $400 million, according to a press release from the company.

Under the terms of the amendment, $50 million was funded at closing. An additional $50 million tranche may be drawn at Dyne's option upon achievement of certain milestones, and a final tranche of up to $75 million may be funded at Hercules Capital's discretion upon Dyne's request.

Including the $50 million funded at closing, Dyne has borrowed an aggregate of $200 million across three tranches under the facility and retains access to up to $200 million in potential future funding.

Dyne said the expanded facility is intended to support the advancement of two drug candidates: zeleciment rostudirsen (z-rostudirsen, also known as DYNE-251) for exon 51 Duchenne muscular dystrophy, and zeleciment basivarsen (z-basivarsen, also known as DYNE-101) for myotonic dystrophy type 1.

"This additional access to capital enhances our financial flexibility as we prepare for two potential U.S. launches in the next two years," said Erick Lucera, chief financial officer of Dyne Therapeutics.