Intarcia Therapeutics, a Boston-based company looking to revolutionize treatment for Type 2 diabetes, on Thursday will announce that it has raised $215 million in new venture capital funding.

Intarcia also said that it expects a “larger second close” with additional investors in Q4, and that it’s between one and two months away from submitting its new drug application (NDA) to U.S. regulators for its lead product — a “GLP-1” that is continuously delivered for six months via a tiny pump inserted just below the skin. Once the NDA is filed, the biotech company also will receive the final $100 million milestone payment from a $300 million synthetic royalty deal signed last year.

Fortune spoke exclusively with Intarcia CEO Kurt Graves, and learned some additional information.

Valuation: The new equity investment (Series EE) has a $3.5 billion pre-money valuation. That’s a significant boost from the $1.5 billion pre-money Intarcia received on its $200 million Series DD round in early 2014. But wait, says rhetorical reader, I thought Intarcia was valued at $5.5 billion? That figure was tied to the aforementioned royalty deal, signed in mid-2015. Per terms of the royalty arrangement, the investors will be entitled to 1.5% of Intarcia’s lead candidate sales (once it’s on the market), but the investors also have an option to return the royalty in exchange for equity at the $5.5 billion (post-money) figure.

History: Intarcia actually was founded in 1997, and initially focused on a cancer treatment that failed in Phase 3 clinical trials. It was recapitalized in 2006 and, in 2010, former Novartis executive Graves took the helm and refocused the company around diabetes.

Who did the deal? Baillie Gifford, a British mutual fund firm that recently has become active in pre-IPO investing, led the new investment. Other new backers include The Pritzker Organization and Luxin (China), while returning shareholders included Baupost, Fidelity Investments, Foresite Capital and RA Capital Management. Morgan Stanley served as placement agent.

Up next: Graves says that the subsequent close should bring the round total to between $500 million and $600 million (excluding the milestone payment), which would mean that it has around $1 billion of cash in the bank (at the high end). “We’re deep into conversations about the second tranche, and I wouldn’t be talking about it unless I thought we’d get it,” he adds.

That should bring the company through at least the first year of commercialization, with no additional equity financing expected until a possible IPO at the end of 2018. Unlike most VC-backed biotech companies, Intarcia is trying to maximize value by having its lead candidate in market before going public.