Mr. Thomas Mehrling reports

HELIX BIOPHARMA CORP. ANNOUNCES PUBLICATION IN FRONTIERS IN ONCOLOGY ON THE EFFECTS OF L-DOS47 AS MONOTHERAPY IN NSCLC

Helix BioPharma Corp. has published a peer-reviewed article in Frontiers in Oncology titled "Safety of unconventional antibody-drug conjugate L-DOS47 in a Phase I/II monotherapy study targeting advanced NSCLC."

The publication reports results from a previously completed phase I/II clinical study of L-DOS47 as a single agent in patients with advanced non-small cell lung cancer (NSCLC). Initiated in 2012 with clinical sites in Poland and later, academic institutions in Canada, the study evaluated the safety, tolerability and preliminary efficacy in NSCLC of monotherapy with L-DOS47, Helix's lead candidate. L-DOS47 is first-in-class antibody-enzyme conjugate (AEC) designed to selectively target CEACAM6-expressing solid tumours and locally neutralize the pH of the acidic tumour microenvironment (TME), which is increasingly recognized as a critical barrier to efficacious therapy.

The phase I/II open-label study demonstrated that L-DOS47 was well tolerated at doses up to 13.55 microgram/kilogram. While no complete or partial responses were observed, posthoc exploratory analyses in phase I revealed that patients receiving higher doses experienced a statistically significant extension in progression-free survival (PFS), with median PFS reaching 4.1 months (approximately 16 weeks) in the highest dosing quartile (P equals 0.0203). This finding is particularly notable given that over 90 per cent of these patients had received two or more prior lines of therapy. Immunohistochemical tumour tissue analysis of an unrelated cohort also revealed that CEACAM6 was highly expressed in nearly half of NSCLC cases, supporting the exploration of biomarker-driven patient selection for future trials. For reference, median PFS with pembrolizumab monotherapy in previously treated NSCLC populations typically ranges from two to 6.3 months, depending on PD-L1 expression levels.

"This study supports the safety profile of L-DOS47 and highlights the importance of CEACAM6 as a new biomarker for biologics for the treatment of lung cancer," said Brenda Lee, corresponding author and clinical director at Helix. "It lays the groundwork for further development of L-DOS47 as part of combination strategies in CEACAM6-expressing cancers."

"We're excited to build on these findings by advancing L-DOS47 into a new clinical study in combination with the PD-1 inhibitor pembrolizumab," said Thomas Mehrling, MD, PhD, chief executive officer of Helix BioPharma. "By neutralizing tumour acidity, L-DOS47 has the potential to create a more favourable tumour microenvironment for immunotherapies like checkpoint inhibitors to work more effectively. We have just received positive feedback from the FDA on our planned phase I/II study in combination with pembrolizumab, and we are now laser-focused on executing this next crucial step in the development of L-DOS47 in NSCLC."

About Helix BioPharma Corp.

Helix BioPharma is an oncology company that innovates from strength to bring near-term solutions for today's hardest-to-treat cancers. The company's pipeline is led by tumour Defense Breaker L-DOS47, a clinical-stage antibody-enzyme conjugate designed to prime CEACAM6-expressing tumours for increased sensitivity to therapy and augment the effectiveness of today's front-running anti-cancer treatments. L-DOS47 has completed phase Ib studies in non-small cell lung cancer (NSCLC) and shares its CEACAM6-targeting foundation with Helix's next-generation bispecific antibody-drug conjugates (ADCs), currently in discovery. The company also advances two pre-IND candidates: (i) Leumuna, an oral immune checkpoint modulator aimed at achieving durable remission in posttransplant leukemia relapse, and (ii) Gemceda, a first-in-class oral gemcitabine prodrug with bioavailability on a par with IV, designed to expand treatment options for advanced cancers.

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