- The stock price of Monopar Therapeutics Inc (NASDAQ: MNPR) increased by over 3% pre-market. This is why it happened.
The stock price of Monopar Therapeutics Inc (NASDAQ: MNPR) increased by over 3% pre-market. Investors are responding positively to Monopar Therapeutics Inc. (Nasdaq: MNPR) and NorthStar Medical Radioisotopes, LLC, announcing the filing of a provisional patent with the U.S. Patent and Trademark Office (USPTO) titled “Bio-Targeted Radiopharmaceutical Compositions Containing Ac-225 and Methods of Preparation.”
Radiopharmaceutical therapy has been a promising approach to treat cancer and other diseases using radioactive metals bound with proteins/antibodies to target and kill cells. And Actinium-225 (Ac-225) is emerging as a radioactive isotope of choice for radiopharmaceuticals due to favorable properties such as its long half-life, high potency, and induction of localized cell death.
This provisional patent relates to the unexpected observation by Monopar and NorthStar that using the metal binding agent 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid (PCTA) to attach Ac-225 to antibodies resulted in nearly 100% binding of Ac-225 to the PCTA-antibody conjugates. And if validated through further evaluation, it could potentially improve efficacy and safety and enhance manufacturing efficiency of Actinium-based radiopharmaceuticals.
Based on Monopar and NorthStar’s work so far, PCTA-antibody conjugates appear to bind Ac-225 and its daughter ions such as Bi-213 with high affinity. And this could be important in the situation of transportation delays resulting in Ac-225 decaying during transport.
“Actinium is quickly becoming a premier radioisotope in cancer-targeting therapies, but its potential is limited due to its price and scarcity,” said James Harvey, PhD, Chief Scientific Officer of NorthStar, in a statement. “Enabling radiopharmaceutical manufacturers and drug developers to maximize the binding efficiency of Ac-225, and thereby reduce the quantity of Ac-225 required for purchase and use, would permit this promising class of drugs to reach its full potential.”
When compared to DOTA (the standard binding agent for attaching Ac-225 to an antibody), PCTA-antibody conjugates displayed a significantly higher affinity to Ac-225. And this high affinity binding may decrease the amount of Ac-225 and its daughter ions that detach from the antibody, which could potentially increase efficacy and reduce off-target toxicity and enable higher dosing. Plus Monopar and NorthStar plan to explore both internal development and out-licensing opportunities of this promising approach in Actinium-based radiopharmaceuticals.
“Binding Actinium to antibodies using PCTA instead of DOTA has displayed unexpected and unique properties including substantially tighter binding of Ac-225 and a much higher incorporation into the PCTA-antibody conjugate,” added Andrew Mazar, PhD, Chief Scientific Officer of Monopar. “This technology could have broad applicability to the manufacturing of numerous radio-immuno-conjugates and may also extend to other proteins.”
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