Manufacturing & Logistics

Isotope Supply

Perspective uses isotopes of lead (Pb) for the imaging and treatment of cancers. Lead is one of the few elements with matched isotopes for imaging and therapy.

Pb-212 is Plentiful, Storable, Scalable & Suitable for Distribution Logistics

Perspective Therapeutics chose Pb-212 as a therapeutic isotope for its potent alpha-emitting properties. The alpha particles released by Pb-212 are highly energetic over a short range, causing significant damage to the DNA of cancer cells while minimizing harm to surrounding healthy tissue. Pb-212’s half-life of 10.6 hours is ideal for therapeutic applications, providing enough time for the radiopharmaceutical to reach and bind to tumor cells while reducing prolonged radiation exposure to the patient.

In comparison with other commonly used isotopes, Pb-212 has several therapeutic advantages.

Pb-212 is the only naturally occurring therapeutic radioisotope currently in use and is a daughter radioisotope found within the thorium-228 decay chain (Th-228). Th-228 is available in large quantities due to its production as a by-product in mining and industrial processes, and with a half-life of nearly 2 years it is possible to stockpile in sufficient quantities to produce hundreds of thousands of doses per year.

Th-228 decays into radium-224 (Ra-224), which has a half-life of 3.7 days and can be loaded into a generator from which Pb-212 can be eluted. Perspective Therapeutics has secured a long-term supply contract with the Department of Energy for the supply of Th-228 and pioneered the chemical separation process to purify Pb-212 from Ra-224 and Th-228. Perspective’s proprietary generator system allows for Pb-212 to be produced on demand at manufacturing centers. Commercially scaled generators using this chemical purification system are in development to support the manufacturing of 100,000+ doses per year.

Pb-212 Isotope Generator

Enables a nimble supply of therapeutic radioisotope

Perspective Therapeutics has developed a proprietary Pb-212 isotope generator, VMT-𝛼-GEN, to ensure supply of fresh Pb-212 for on-demand radiopharmaceutical manufacturing. This system takes advantage of the following:

Abundant Radium-224 feedstock from nuclear and mining waste material
Auto-regenerates overnight with ≃1 week shelf life to ensure supply for daily manufacturing
Small footprint allows for benchtop use and simple logistics – the size of a coffee thermos
Perspective Therapeutics has a long-term supply contract with the National Isotope Development Center of the U.S. Department of Energy Isotope Program

Isotope Generator

Isotope generator

Pb-203 – a Chemically-matched SPECT Imaging Isotope for Pb-212

Pb-203 is a SPECT imaging isotope that emits gamma rays and is commercially available through production at medical cyclotron facilities. One of the primary benefits of using Pb-203 as a SPECT imaging agent is its longer half-life of about 52 hours. This extended half-life allows for longer transport distances and prolonged usage periods, which is particularly advantageous for situations with limited access to imaging facilities or when multiple imaging studies are required over an extended timeframe, such as dosimetric and pharmacokinetic/biodistribution studies.

Perspective is investigating Pb-203 in First-in-Human imaging studies to de-risk its novel therapeutic agents. The imaging is done with radiopharmaceuticals identical to the therapeutic molecule to determine tumor target expression, potential off-target distribution and clearance kinetics. Based on this imaging, physicians can determine patient eligibility as well as where the alpha-particle emitting Pb-212 will deposit its energy. This theranostic approach, integrating diagnosis and treatment using the same molecular targets, is used in Perspective’s clinical programs.

Tumors visible within 1 hour indicates rapid binding to SSTR2 target
High intensity above background implies excellent therapeutic window
Unbound drug in bladder within 1 hour for excretion
Low renal retention due to neutral charge on proprietary Pb-specific chelator