Five years after its initial investment in Maverick Therapeutics Inc., Takeda Pharmaceutical Co. Ltd. is exercising its option to buy the privately held company for a pre-negotiated up-front payment plus development and regulatory milestones of up to $525 million.

Costs include Maverick’s debt and the $23 million equity stake Takeda placed in Maverick when the two began their 2017 collaboration. The original deal included developing T-cell engager treatments and the right to buy Maverick after five years had passed.

That five-year ride with Takeda has been a strong one, Maverick’s CEO, Jim Scibetta, told BioWorld.

“We’ve had a close relationship with Takeda from the beginning, they’ve been a fantastic partner and we’ve had clear boundaries,” he added.

Once the acquisition closes, Maverick’s employees will be part of Takeda’s R&D organization.

James Scibetta, CEO, Maverick

The Maverick platform, COBRA, a bispecific T-cell engaging platform, targets a range of solid tumors and is designed to hold toxicities at bay in normal tissues. The therapies engineered by the platform are protein based to activate T-cell-mediated killing only in the tumor.

The entire idea behind the company’s founding was T-cell engagers, Scibetta said. It is a proven modality in terms of efficacy, and Brisbane, Calif.-based Maverick didn’t repurpose anything to get where it is today, Scibetta said.

"We believe that T-cell engagement is the next generation of antibody therapeutic for cancer," Maverick co-founder Jeanmarie Guenot told BioWorld when the original deal was cut. Many companies have since followed the T-cell path.

Bringing Maverick into the Takeda fold means acquiring lead candidate TAK-186 (formerly MVC-101), which is in a phase I/II study for treating EGFR-expressing solid tumors. The T-cell-engaging molecule from Maverick’s platform is conditionally active. The company reported data in August showing that the EGFR modulator reduced established solid tumors expressing EGFR in mice, while CD276 antigen/CD3 modulator MVC-280 (now TAK-280) degraded established solid tumors expressing B7H3 in mice. Half-life extended COBRAs were cleared more quickly after proteolytic activation, the company reported, with regression of established solid tumors dependent on tumor-mediated linker cleavage and COBRA activation.

TAK-280 is expected to enter the clinic for treating B7H3-expressing solid tumors. B7H3 is expressed on a range of solid tumor cancers, including prostate, renal, triple-negative breast, head and neck, ovarian and urothelial cancers.

Maverick was founded with initial financing from MPM Capital but it was a $125 million investment in Maverick by Takeda in early 2017 that got the new company up and moving. The money was both an equity investment and R&D funding that came with Takeda’s exclusive option to ultimately buy Maverick. The equity component was part of a series B round backed by Takeda, MPM's Bioventures 2014 fund and the UBS Oncology Impact Fund, managed by MPM.

T-cell engager platforms are a hot commodity. Amgen Inc. is buying South San Francisco-based Five Prime Therapeutics Inc. for $38 per share, or about $1.9 billion. Five Prime's lead asset, bemarituzumab, is a phase III-ready anti-fibroblast growth factor 2b receptor antibody being studied for treating gastric cancer that the company said will complement its own internal gastric cancer programs, which include AMG-199 and AMG-910, both antibodies from its bispecific T-cell engager platform.

Amunix Pharmaceuticals Inc., of South San Francisco, also in early March, brought in a $117 million series B to work on its masked, protease-activated immune-oncology prospects, optimized with its T-cell engager platform.