Monopar and
NorthStar Announce Patent Filing on
Promising
Radiopharmaceutical Discovery
Potential
to significantly improve the yield of Actinium-based
radiopharmaceuticals
WILMETTE, Ill. and BELOIT, Wis., May
24,
2021 – Monopar Therapeutics Inc. (Nasdaq:
MNPR) and NorthStar Medical Radioisotopes, LLC, today
announced 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 is a promising
approach to treat cancer and other diseases using radioactive
metals bound with proteins/antibodies to target and kill cells.
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. 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 to date, PCTA-antibody conjugates appear to
bind Ac-225 and its daughter ions such as Bi-213 with high
affinity. This could be important in the situation of
transportation delays resulting in Ac-225 decaying during
transport. Furthermore, 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.
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. Monopar and NorthStar plan to explore both
internal development and out-licensing opportunities of this
promising approach in Actinium-based
radiopharmaceuticals.
“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.
“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.”
“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,” said 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.”
About Monopar Therapeutics Inc.
Monopar
Therapeutics is a clinical-stage biopharmaceutical company focused
on developing proprietary therapeutics designed to extend life or
improve the quality of life for cancer patients. Monopar’s
pipeline consists of Validive® for
the prevention of chemoradiotherapy-induced severe oral mucositis
in oropharyngeal cancer patients; camsirubicin for the treatment of
advanced soft tissue sarcoma; and a preclinical stage uPAR targeted
antibody MNPR-101 for advanced cancers and severe COVID-19. For
more information, visit: www.monopartx.com.
About NorthStar Medical Radioisotopes, LLC
NorthStar Medical Radioisotopes is a global
innovator in the production and distribution of radioisotopes used
for medical imaging and therapeutic purposes. NorthStar is a
company committed to providing the United States with reliable and
environmentally friendly radioisotope supply solutions to meet the
needs of patients and to advance clinical research. The
Company’s first product is the RadioGenix® System
(technetium Tc 99m generator), an innovative and flexible platform
technology initially approved by the U.S. Food and Drug
Administration in February 2018. For more information,
visit: www.northstarnm.com.
Forward-Looking Statements
Statements contained in this press release
regarding matters that are not historical facts are
“forward-looking statements” within the meaning of the
Private Securities Litigation Reform Act of 1995. The words
“may,” “will,” “could,”
“would,” “should,” “expect,”
“plan,” “anticipate,” “intend,”
“believe,” “estimate,”
“predict,” “project,”
“potential,” “continue,”
“target” and similar expressions are intended to
identify forward-looking statements, although not all
forward-looking statements contain these identifying words.
Examples of these forward-looking statements include: that radiopharmaceutical therapy is a
promising approach to treat cancer and other diseases using
radioactive metals bound with proteins/antibodies to target and
kill cells; that binding Ac-225 to PCTA-antibody conjugates could
potentially improve efficacy and safety and enhance manufacturing
efficiency of Actinium-based radiopharmaceuticals; that 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; that Monopar and NorthStar plan to explore both internal
development and out-licensing opportunities of this promising
approach in Actinium-based radiopharmaceuticals; that by reducing
the quantity of Ac-225 required for purchase and use would permit
this promising class of drugs to reach its full potential; and that
this technology could have broad applicability to numerous
radio-immuno-conjugates and may also extend to other proteins. The
forward-looking statements involve risks and uncertainties
including, but not limited to: whether the provisional patent will
result in an issued patent; whether preliminary observations and
findings to date will be validated by further evaluation; whether
this technology will improve efficacy and safety and enhance
manufacturing efficiency of Actinium-based radiopharmaceuticals, if
at all; whether this technology could potentially reduce off-target
toxicity and enable higher dosing of antibody conjugates; Monopar
and NorthStar not successfully internally developing or
out-licensing this technology; the lack of any clinical activities
to date with respect to Ac-225 bound to antibodies using PCTA; the
requirement for additional capital to complete preclinical and
clinical development, and if successful, commercialization; the
success and prevalence of the use of Ac-225 in radiopharmaceutical
therapies; not being able to ensure volumes of this radioisotope
can be manufactured and scaled up to meet potential demand;
uncertainties about levels of demand if and when a treatment is
available for commercialization and the significant general risks
and uncertainties surrounding the research, development, regulatory
approval and commercialization of therapeutics. Actual results may
differ materially from those expressed or implied by such
forward-looking statements. Monopar and NorthStar are not making
any express or implied claims that these Ac-225 based
radiopharmaceuticals have the ability to eliminate or mitigate
cancers, severe COVID-19, or other diseases at this time. Risks
are described more fully in
Monopar’s filings with the Securities and Exchange
Commission. All forward-looking statements contained in this press
release speak only as of the date on which they were made. Monopar
and NorthStar undertake no obligation to update such statements to
reflect events that occur or circumstances that exist after the
date on which they were made. Any forward-looking statements
contained in this press release represent Monopar’s and
NorthStar’s views only as of the date hereof and should not
be relied upon as representing its views as of any subsequent
date.
CONTACTS:
For Monopar Therapeutics Inc.:
Investor
Relations:
Kim R.
Tsuchimoto
Chief
Financial Officer
kimtsu@monopartx.com
For NorthStar Medical Radioisotopes, LLC
Investor
Relations:
Paul
Estrem
Senior Vice
President and Chief Financial Officer
pestrem@northstarnm.com
Corporate:
Lisa
Holst
Vice
President Sales and Marketing
678-471-9027
lholst@northstarnm.com
Media:
Priscilla
Harlan
781-799-7917
pharlan@shiningrockllc.com