Preclinical data show that (E,E)-bisantrene is the active isomer stabilizing the MYC G-quadruplex structure, leading to reduced MYC gene expression and activity, and support the use of RC220 in Racura's EMILI, HARNESS and CPACS clinical programs.

SYDNEY, Nov. 12, 2026 /PRNewswire/ -- Racura Oncology Limited (ASX: RAC), a late clinical-stage biopharmaceutical company developing new small molecule-based approaches to cancer treatment focused on silencing MYC gene expression, today announced that new preclinical data on the MYC-directed mechanism of action of (E,E)-bisantrene are being presented as a poster at the Frontiers in Cancer Science (FCS) 2026 Conference, held in Singapore from 11–13 November 2026. The data show that (E,E)-bisantrene is the major active isomer (molecular form) of bisantrene able to stabilize the G-quadruplex in the MYC gene promoter region, leading to reduced MYC gene expression and MYC protein levels.

In these preclinical studies, light exposure converted (E,E)-bisantrene into less active isomers, which resulted in significantly less MYC G-quadruplex stabilization and a lowering of the inhibition of MYC gene expression.

In the study, exposing (E,E)-bisantrene to blue (440 nm) light reduced its content in solution to approximately 60% after 15 minutes, approximately 40% after one hour and an unquantifiable level after four hours. In MDA-MB-231 breast cancer cells, pure (E,E)-bisantrene suppressed MYC gene expression with a half-maximal effective concentration of 277 nM, compared with 514 nM to 1,166 nM for the light-exposed isomer mixtures, and reduced cancer cell viability with a half-maximal inhibitory concentration of 266 nM, compared with 310 nM to 825 nM for the mixtures. An isomer mixture containing 62% (E,E)-bisantrene stabilized the MYC G-quadruplex significantly less than pure (E,E)-bisantrene at the same concentration, and stabilization was restored when the amount of (E,E)-bisantrene was matched.

These findings build on the MYC gene expression inhibition data for (E,E)-bisantrene presented at the 2026 American Association for Cancer Research (AACR) Annual Meeting in April 2026 and further support the importance of the MYC-directed mechanism of action of RC220. Racura continues to investigate this mechanism through its ongoing research collaboration with Purdue University.

The poster is entitled "Light-Induced Isomerization Attenuates (E,E)-Bisantrene G-Quadruplex Binding and MYC Silencing" and reports work by Racura scientists and collaborators at the University of Wollongong, Australia.

Daniel Tillett, Ph.D., Chief Executive Officer of Racura Oncology, said: "These data show that (E,E)-bisantrene is the form that stabilizes G-quadruplex structures and inhibits MYC gene expression. Bisantrene can exist as several isomers, and confirming that the (E,E)-isomer is the active form supports our development of RC220 as a proprietary formulation of (E,E)-bisantrene. While these are preclinical findings, they add to the growing body of evidence for the MYC-directed mechanism of action of RC220."

Scientific Rationale

RC220 is being clinically developed to target non-canonical G-quadruplex DNA and RNA structures enriched in oncogenic regulatory regions, including promoters, untranslated regions and highly transcribed loci. Stabilization of these structures can disrupt transcriptional and post-transcriptional control networks that sustain malignant proliferation, including the silencing of MYC-driven growth and survival pathways.

(E,E)-bisantrene contains two hydrazone groups that can isomerize, and exposure to light converts it into (E,Z)- and, it is postulated, (Z,Z)-isomers. The FCS 2026 data indicate that the (E,E)-isomer is the form most responsible for MYC G-quadruplex stabilization, MYC suppression and anticancer activity, supporting Racura's development of RC220 as a proprietary formulation of (E,E)-bisantrene.

About RC220 & (E,E)-bisantrene

RC220 is a proprietary formulation of (E,E)-bisantrene designed to overcome drug solubility issues that prevent safe peripheral intravenous infusion. (E,E)-bisantrene is a clinically validated small molecule anticancer agent that primarily functions via G4-DNA and RNA binding, leading to potent transcriptional silencing of the important cancer growth regulator MYC and downstream pathways.

About Racura Oncology

Racura Oncology (ASX: RAC) is a late clinical-stage biopharmaceutical company with a mission to silence cancer. Our lead asset, (E,E)-bisantrene, is a small molecule anticancer agent that primarily functions via G4-DNA and RNA binding, leading to potent silencing of the important cancer growth regulator MYC. G4-binding by (E,E)-bisantrene has additional anticancer activities including inhibition of topoisomerase II and telomerase, as well as m⁶A RNA pathway modulation.

Racura is advancing RC220 to address the high unmet needs of patients across multiple oncology indications, including the EMILI Phase 2b/3 trial in acute myeloid leukemia (AML), the HARNESS Phase 1 trial in combination with osimertinib in mutant epidermal growth factor receptor non-small cell lung cancer (EGFRm NSCLC), and the CPACS Phase 1 trial in combination with the anthracycline doxorubicin, where we aim to deliver both cardioprotection and enhanced anticancer activity for solid tumor patients.

Learn more at www.racuraoncology.com.

Forward-Looking Statements

Some of the statements in this press release are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, Section 21E of the Securities Exchange Act of 1934 and the Private Securities Litigation Reform Act of 1995, which involve risks and uncertainties. Forward-looking statements in this release include, without limitation, statements regarding expectations regarding clinical development and regulatory strategy and the Company's ability to deliver meaningful value to patients and shareholders. These statements relate to future events, future expectations, plans and prospects. Although Racura believes the expectations reflected in such forward-looking statements are reasonable as of the date made, expectations may prove to have been materially different from the results expressed or implied by such forward-looking statements. Racura has attempted to identify forward-looking statements by terminology including "believes", "estimates", "anticipates", "expects", "plans", "projects", "intends", "potential", "may", "could", "might", "will", "should", "approximately" or other words that convey uncertainty of future events or outcomes to identify these forward-looking statements. These statements are only predictions and involve known and unknown risks, uncertainties and other factors, including market and other conditions. Any forward-looking statements contained in this press release speak only as of its date. Racura undertakes no obligation to update any forward-looking statements contained in this press release to reflect events or circumstances occurring after its date or to reflect the occurrence of unanticipated events, except as required by law.

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SOURCE Racura Oncology Limited