Sunshine Biopharma and University of Arizona Develop a Potent New Series of Protease Inhibitors for Treatment of SARS Coronavirus Infections

Rhea-AI Summary

Sunshine Biopharma (NASDAQ:SBFM) and the University of Arizona announced a new series of orally active, non‑covalent PLpro protease inhibitors that show dose‑dependent antiviral activity in mice infected with SARS‑CoV‑2. The compounds are potent against the PLpro enzyme, exhibited dose‑dependent efficacy in cellular SARS‑CoV‑2 models, and displayed favorable pharmacokinetic profiles in mice, rats and dogs. The program follows an initial PLpro library published in August 2024 in Journal of Medicinal Chemistry. Ongoing work includes dose‑dependent efficacy analysis in infected mice and further preclinical evaluation.

Positive

• New series of orally active PLpro inhibitors showing dose‑dependent antiviral activity in mice
• Compounds potent against PLpro in cellular SARS‑CoV‑2 models
• Favorable pharmacokinetic profiles reported in mice, rats and dogs
• Prior PLpro library research published in August 2024 in Journal of Medicinal Chemistry

Negative

• Dose‑dependent efficacy in SARS‑CoV‑2 infected mice is still under analysis
• No clinical (human) trial results or regulatory approvals reported

Insights

Drug discovery scientist

Preclinical PLpro inhibitors show oral activity and dose‑dependent antiviral effects in cells and mice; results are promising but early.

The collaboration between Sunshine Biopharma and the University of Arizona reports a second chemical series of non‑covalent, orally active PLpro inhibitors with favorable pharmacokinetics and dose‑dependent antiviral activity in cellular assays and mice, as stated on October 9, 2025. The work includes prior publication in Journal of Medicinal Chemistry and reproducible in vivo oral exposure across multiple species, which supports the molecules' developability as small‑molecule antivirals.

Key dependencies and risks include the early preclinical stage: efficacy in K18‑hACE2 or other mouse models does not guarantee human efficacy or safety, and no clinical data or toxicology endpoints are reported here. Critical unknowns are tolerability margins, off‑target effects, dose required for therapeutic effect, and scalability of synthesis.

Concrete near‑term items to watch are completion and detailed reporting of the stated dose‑dependent mouse infection studies, formal GLP toxicology results, and any IND‑enabling plans or timelines; expect relevant readouts over the next 6–18 months if progression continues.

FORT LAUDERDALE, FL / ACCESS Newswire / October 9, 2025 / Sunshine Biopharma Inc. (NASDAQ:SBFM) (the "Company"), a pharmaceutical company offering and researching life-saving medicines in a variety of therapeutic areas including oncology and antivirals today announced that it has developed a new series of orally active, non-covalent protease inhibitors with dose-dependent antiviral activity in mice infected with SARS Coronavirus (SARS-CoV-2). This work was carried out at the University of Arizona as part of an ongoing collaboration between the Company and the University.

Coronavirus remains a formidable global health threat, not only due to its ability to cause severe illness (particularly in older adults and those with underlying conditions) but also because of its potential to evolve into new variants that may spark future pandemics. The virus's high mutation rate and global reach make it a persistent concern, as even minor genetic shifts can affect transmissibility, resistance to existing treatments, and vaccine efficacy. As such, ongoing investment in antiviral research, rapid-response vaccine platforms, and novel therapeutic approaches is vital to outpace emerging strains and reduce the potentially devastating impact of future outbreaks. Developing smarter, more adaptable treatments is essential for safeguarding global health for tomorrow.

SARS-CoV-2 is the etiologic agent of COVID-19 and one of three types of Coronavirus that cause Severe Acute Respiratory Syndrome (SARS). The other two are SARS-CoV and MERS-CoV. For persons exposed to SARS-CoV-2, blocking early infection at home may prevent rapid disease progression and reduce hospitalization. PLpro is an alternative therapeutic target for developing antiviral compounds against proteolytic processing activity of SARS-CoV-2. PLpro is a virus encoded protease essential for viral replication and is responsible for suppression of the human immune system following infection, leading to a more severe disease outcome.

Previously we had reported that the Company's lead compound had favorable pharmacokinetics properties, including oral availability, in mice, rats and dogs. It was found to be efficacious in a K18-human-ACE2 transgenic mouse model to block SARS-Cov-2 infection in a dose-dependent manner. In August 2024, Sunshine Biopharma published initial research results on its PLpro inhibitors library in the Journal of Medicinal Chemistry (J. Med. Chem. 2024, 67, 13681−13702).

Currently, we report that we have successfully designed and synthesized a second novel chemical series of PLpro inhibitors, which are potent against the PLpro enzyme and exhibited dose-dependent efficacy in cellular models of SARS-CoV-2 infection. These new molecules are orally active in mice and have displayed favorable pharmacokinetics profiles. Work is currently in progress to analyze their dose-dependent efficacy in mice infected with SARS-CoV-2.

"There are still unmet medical needs for agents to combat SARS Coronavirus infections," said Dr. Steve Slilaty, CEO of Sunshine Biopharma. "The development of this new series of highly effective PLpro inhibitors marks a major advancement in antiviral therapeutics. In collaboration with Dr. Gregory Thatcher and Dr. Rui Xiong at the University of Arizona, our dedicated research team has worked relentlessly to identify new compounds that effectively target the viral PLpro enzyme, a key factor in replication and immune system evasion. The promising results demonstrate the potential to significantly curb infection progression and lead to transformative treatments for patients. This achievement is a testament to the unwavering dedication of the University of Arizona team and ours, as we continue to drive innovation in global healthcare."

About Sunshine Biopharma Inc.

Sunshine Biopharma currently has 74 generic prescription drugs on the market in Canada and 12 additional drugs scheduled to be launched in 2026. In addition, Sunshine Biopharma is conducting a proprietary drug development program which is comprised of (i) K1.1 mRNA, an mRNA-Lipid Nanoparticle targeted for liver cancer, and (ii) SBFM-PL4, a small molecule inhibitor of PLpro protease for treatment of SARS Coronavirus infections. For more information, please visit: www.sunshinebiopharma.com.

Safe Harbor Forward-Looking Statements

This press release contains forward-looking statements which are based on current expectations, forecasts, and assumptions of Sunshine Biopharma Inc. (the "Company") that involve risks as well as uncertainties that could cause actual outcomes and results to differ materially from those anticipated or expected. These statements appear in this release and include all statements that are not statements of historical fact regarding the intent, belief or current expectations of the Company, including statements related to the Company's drug development activities, financial performance, and future growth. These risks and uncertainties are further described in filings and reports by the Company with the U.S. Securities and Exchange Commission (SEC). Actual results and the timing of certain events could differ materially from those projected in or contemplated by the forward-looking statements due to a number of factors detailed from time to time in the Company's filings with the SEC. Reference is hereby made to cautionary statements and risk factors set forth in the Company's most recent SEC filings.

For more information, please contact:

Camille Sebaaly, CFO
Direct Line: 514-814-0464
camille.sebaaly@sunshinebiopharma.com

SOURCE: Sunshine Biopharma Inc.

View the original press release on ACCESS Newswire

FAQ

What did Sunshine Biopharma (SBFM) announce on October 9, 2025 about PLpro inhibitors?

The company announced a second novel series of orally active, non‑covalent PLpro inhibitors with dose‑dependent antiviral activity in mice and potency in cellular SARS‑CoV‑2 models.

Are Sunshine Biopharma's new PLpro compounds orally available and what animals showed PK data?

Yes; the announcement reports oral activity and favorable pharmacokinetics in mice, rats and dogs.

Has Sunshine Biopharma published prior PLpro research and when?

Yes; initial PLpro library results were published in August 2024 in Journal of Medicinal Chemistry.

Do the new PLpro inhibitors have demonstrated efficacy in SARS‑CoV‑2 infected animals?

The compounds showed dose‑dependent antiviral activity in mice, and work is ongoing to analyze dose‑dependent efficacy in infected mice.

Who collaborated with Sunshine Biopharma on this research?

The work was carried out in collaboration with researchers at the University of Arizona, including Dr. Gregory Thatcher and Dr. Rui Xiong.

Does the October 9, 2025 announcement include clinical trial or regulatory approval details for SBFM?

No; the announcement describes preclinical results and ongoing analysis but does not report clinical trial results or regulatory approvals.