• Three poster presentations from Perspective Therapeutics’ scientists and collaborators explore combinations of immunotherapy and targeted alpha-particle therapy in a malignant melanoma model, ²⁰³Pb manufacturing, and In Vivo Distribution of Recoiled ²¹³Bi from [²²⁵Ac]Ac-DOTATATE

RICHLAND, WASHINGTON & CORALVILLE, Iowa, May 24, 2023 (GLOBE NEWSWIRE) -- Perspective Therapeutics, Inc. (“Perspective” or “the Company”) (NYSE AMERICAN: CATX), a precision oncology company developing alpha-particle therapies and complementary diagnostic imaging agents and an innovator in seed brachytherapy treatment options for multiple cancers, today announced it will be presenting three posters at the 2023 International Symposium on Radiopharmaceutical Sciences (iSRS) Annual Meeting being held in Hawaii from May 22-26, 2023.

"We are thrilled to present our latest research on targeted alpha therapies at the Society of Radiopharmaceutical Sciences annual meeting. Our scientists and collaborators have made significant progress in this field, and we are excited to share our findings with the wider scientific community. We believe that targeted alpha therapies have the potential to revolutionize cancer treatment, and we are committed to advancing this promising new approach." said Thijs Spoor, Perspective Therapeutics’ Chief Executive Officer.

Michael Schultz, Perspective Therapeutics’ Chief Science Officer added, “I would like to thank our fabulous team of scientists and our collaborators for their relentless dedication to developing the best possible applications for our technology platform. This enables the best possible isotopes to be utilized to keep moving us toward the goal of improved cancer therapies. We are looking forward to discussing our findings with the global radiopharmaceutical science community at iSRS.”

Poster Presentation Summaries

Poster presentation #1: “Low-dose targeted alpha therapy induces strong anti-tumor effectiveness in combination with immune checkpoint inhibitors”

This poster shares the ongoing work by Perspective Therapeutics’ scientists and collaborators at the University of Wisconsin exploring the potential of targeted alpha therapies (TAT) in combination with established immune checkpoint inhibitor (ICI) therapies in preclinical melanoma models. The presented results confirm and extend the previously published preclinical work by the team, revealing long term curative responses from the combination of immunotherapies and TAT. In conclusion:

• When combined with dual ICIs, low doses of [²¹²Pb]VMT01 was more efficacious and resulted in complete tumor remission when compared with mid- and high-administered radioactivity doses. The immunostimulatory effects of TAT may not be linear to radiation dose. Therefore, the ideal dose of TAT that induces strongest anti-tumor efficacy with ICIs in melanoma needs to be further elucidated.

The poster will be presented during Poster Session 2A: Radionuclide Therapy on Wednesday May 24, 5:30PM – 6:15 PM HST in Kalākaua Ballroom A, by Samuel Rodman PhD, Research Scientist, Perspective Therapeutics.

Poster presentation #2: “Optimizing ²⁰³Pb cyclotron production and availability: The ideal SPECT imaging theranostic partner for ²¹²Pb targeted alpha therapy”

This poster discusses the Company’s continued work with its multi-institutional collaborators in order to improve the production methods for the SPECT isotope Pb-203 as part of its matched isotope theranostic pairing with Pb-212 targeted alpha therapy. The goal of this work is to ensure the availability of isotope supplies with high purity for ongoing imaging studies and for the Company’s pipeline of emerging products. In conclusion:

• Nuclear medicine centers with a 24 MeV cyclotron can produce and purify large ²⁰³Pb activities sufficient for clinical applications. This represents an attractive route to produce ²⁰³Pb for theranostic use as a SPECT radionuclide alongside ²¹²Pb targeted alpha therapy. The [²⁰³Pb]Pb(OAc)₂ product can be produced with high radiochemical purity – and radiolabeling experiments demonstrate strong potential for preclinical and clinical ²⁰³Pb radiopharmaceutical applications.

The poster will be presented during Poster Session 2A: Targetry on Wednesday May 24, 5:30PM – 6:15 PM HST in Kalākaua Ballroom A as presented by Bryce Nelson, University of Alberta.

Poster presentation #3: “Analysis of Radiochemical Stability and In Vivo Distribution of Recoiled ²¹³Bi from [²²⁵Ac]Ac-DOTATATE in Preclinical Model”

Targeted alpha-particle radiotherapies (TATs) have been evolving as promising treatments in management of cancers. Within this context, due to four alpha-particle emissions along the decay chain, ²²⁵Ac-based TATs have demonstrated superior tumor-killing efficacy compared with beta-particle emitters. However, the complex decay and recoil of daughters following the alpha-particle emission results in ambiguity in understanding the toxicity of these radiopharmaceuticals. In this study, we aimed to assess the ingrowth and radiochemical stability of ²¹³Bi and potential in vivo redistribution following the injection of [²²⁵Ac]Ac-DOTATATE in preclinical model. In conclusion:

• Although ²¹³Bi can be labeled initially, decoupling of ingrown free ²¹³Bi was inevitable with the decay of [²²⁵Ac]Ac-DOTATATE and significantly different biodistributions between the labeled ²²⁵Ac product and free ²¹³Bi are observed. Therefore, it is hypothesized that the radiochemical stability and biodistribution of recoiled daughters need to be characterized to better understand the potential toxicity resulted from injection of ²²⁵Ac -based TATs.

The poster will be presented during Poster Session 3: Radionuclide Therapy on Friday May 26, 2:45 PM – 3:30 PM HST in Kalākaua Ballroom A by Dijie Liu PhD DVM, Principal Research Scientist.

About Perspective Therapeutics, Inc.

Perspective Therapeutics, Inc., is a medical technology and radiopharmaceutical company that is pioneering advanced treatment applications for cancers throughout the body. The Company is the sole producer of Cesium-131 brachytherapy seeds and has a proprietary technology that utilizes the isotope Lead-212 to deliver powerful alpha radiation specifically to cancer cells via specialized targeting peptides. The Company is also developing complementary imaging diagnostics that incorporate the same targeting peptides which provide the opportunity to personalize treatment and optimize patient outcomes. This “theranostic” approach enables the ability to see the specific tumor and then treat it to potentially improve efficacy and minimize toxicity associated with many other types of cancer treatments.

The Company’s melanoma (VMT01) and neuroendocrine tumor (VMT-α-NET) programs are entering Phase 1/2a imaging and therapy trials for the treatment of metastatic melanoma and neuroendocrine tumors at several leading academic institutions. The Company has also developed a proprietary Lead-212 generator to secure key isotopes for clinical trial and commercial operations.

For more information, please visit the Company’s website at www.perspectivetherapeutics.com .

Safe Harbor Statement

Statements in this news release about Perspective Therapeutics’ future expectations, other than historical facts, are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995 (“PSLRA”). This statement is included for the express purpose of availing Perspective Therapeutics, Inc. of the protections of the safe harbor provisions of the PSLRA. It is important to note that actual results and ultimate corporate actions could differ materially from those in such forward-looking statements based on such factors as whether additional studies are released that support the conclusions of the studies discussed in this news release, whether ongoing patient results are favorable and in line with the conclusions of clinical studies and initial patient results, physician acceptance, training and use of our products, whether we, our distributors and our customers will successfully obtain and maintain all required regulatory approvals and licenses to market, sell and use our products in its various forms, changes in laws and regulations applicable to our products, and other risks detailed from time to time in Perspective Therapeutics, Inc. reports filed with the U.S. Securities Exchange Commission. Unless required to do so by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Investor Relations Contact:

LifeSci Advisors

Chuck Padala

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