TerraPower's $450M Factory Tackles the Isotope Shortage Crippling Cancer Research

Bill Gates nuclear company is making a play for the radiopharmaceutical supply chain.

TerraPower Isotopes announced March 17 that it will invest $450 million to build a 250,000-square-foot actinium-225 manufacturing facility in the Bellwether District of Philadelphia — a redevelopment of the former Philadelphia Energy Solutions refinery site. The facility will produce Ac-225, a rare alpha-emitting radioisotope being used in an expanding class of targeted cancer therapies, and will create approximately 225 full-time jobs over three years, plus 500 construction positions. Isotope production is expected to launch in 2029.

The location decision was not casual. TerraPower Isotopes evaluated over 350 potential sites across the US, including 49 site visits in eight metropolitan areas, before settling on Philadelphia. The Bellwether District is a 1,300-acre redevelopment project transforming the old refinery into an advanced manufacturing and life sciences hub. Pennsylvania is contributing $10 million in direct incentives — $7 million through the PA SITES program and $3 million through the Pennsylvania First grant — and the company qualifies for additional tax benefits through a Keystone Opportunity Zone designation that runs through 2043.

The investment reflects a problem the radiopharmaceutical industry has been wrestling with for years: Ac-225 supply is severely constrained. The isotope is produced in vanishingly small quantities — primarily at Oak Ridge National Laboratory, which makes it as a byproduct of thorium processing — and demand is rising sharply as more Ac-225-based drugs enter clinical trials. Ac-225 is attractive because it delivers highly localized radiation to cancer cells while sparing surrounding tissue better than beta-emitting isotopes, making it well-suited for targeting micrometastases. Several biotech and pharma companies have Ac-225 programs in development for prostate cancer, neuroendocrine tumors, and other solid tumors. The supply bottleneck has been one of the fields limiting factors.

TerraPower Isotopes is a subsidiary of TerraPower, the nuclear science company founded by Bill Gates in 2008. The company is best known for its work on small modular nuclear reactors, but its isotopes division has been building capabilities specifically for medical applications. The Philadelphia facility will be its largest manufacturing investment to date and is designed to meet not just current demand but the anticipated growth from a pipeline of Ac-225-based drugs that are expected to reach patients in the 2030s.

The TerraPower announcement comes as the broader radiopharmaceutical market is attracting significant capital. RayzeBio, Novartis, and other companies have built or are building facilities dedicated to actinium-based drugs. The field is watching closely as several Ac-225-based drugs advance through clinical trials, with analysts expecting the isotope market to tighten further as those programs approach potential approvals. Novartis Pluvicto and Lutathera — both Lu-177 beta emitters — have driven much of the recent demand for lutetium-177, a different isotope used in a separate class of radiopharmaceuticals. Ac-225 demand, by contrast, comes from a growing pipeline of targeted alpha therapies in development at RayzeBio (acquired by Bristol Myers Squibb in 2024), Novartis, and other developers targeting neuroendocrine tumors and prostate cancer variants where alpha emission may offer advantages.

In a parallel manufacturing investment announced this week, Eli Lilly committed $126 million to expand its Seishin plant in Kobe, Japan, adding a new production line and warehouse by 2028 to supply the Japanese market with obesity medicines and other drugs. That announcement came from Lillys Japanese subsidiary and was reported by Nikkei Asia and FiercePharma. The Kobe expansion is separate from the TerraPower story but reflects the same pattern: major pharmaceutical companies are racing to lock in manufacturing capacity in key markets as GLP-1 and radiopharmaceutical demand accelerates.