SAB Biotherapeutics Highlights Diabetes Trial Progress, Human Antibody Platform

Key Points

• SAB Biotherapeutics’ Type 1 diabetes program is nearing a key milestone: Its 159-patient SAFEGUARD Phase IIb study is nearing enrollment completion, testing fully human anti-thymocyte globulin against placebo for preservation of C-peptide and improved HbA1c.
• SAB says its genetically engineered cattle platform produces fully human, targeted antibodies that may be redosed without the serum sickness risks associated with rabbit-derived ATG. Early Phase I and small patient-cohort results showed redosing was tolerated and C-peptide was preserved.
• Healios is preparing a Japanese conditional-approval filing for its MAPC cell therapy for ARDS while expanding manufacturing capacity, including a planned 500-liter Kobe facility designed to produce up to 40,000 doses annually; it also plans a global Phase III trial.

Executives from Healios and SAB Biotherapeutics NASDAQ: SABS outlined their approaches to developing scalable biologic therapies during a Chardan discussion focused on complex treatments designed for commercial manufacturing.

Healios Chief Financial Officer Rich Kincaid discussed the company’s multipotent adult progenitor cell, or MAPC, therapy for acute respiratory distress syndrome, while SAB BIO Chief Executive Officer Sam Reich described the company’s genetically engineered cattle platform for producing fully human polyclonal antibodies, including its lead Type 1 diabetes program.

Healios Details ARDS Cell Therapy and Manufacturing Plans

Kincaid said Healios’ MAPCs differ from pluripotent stem cells because they are “an end state cell” that does not differentiate after administration. The allogeneic therapy is delivered intravenously and is designed to counter acute inflammation. While the cells survive for only two to three days, Kincaid said their effects can continue by reducing inflammation and supporting repair.

In ARDS, an inflammatory cascade in the lungs can cause patients to require mechanical ventilation. Kincaid said the intravenously infused cells travel to the lungs on their first pass through the body, where they interact with inflammatory cytokines, T cells, neutrophils and macrophages. The intended effect is to shift the inflammatory environment toward a more neutral or anti-inflammatory state.

Healios’ Phase II studies showed that patients could come off ventilators faster and that mortality could be reduced, according to Kincaid. He said the therapy’s impact on inflammation may allow alveolar edema to subside and help patients resume breathing independently.

The company is pursuing commercialization in Japan, where it is preparing to seek conditional approval for ARDS. Kincaid said the company moved manufacturing from Lonza in Singapore to Minaris in Yokohama, Japan, and is conducting production runs intended to generate data for its filing. Following a filing, he said the expected review period would be approximately nine months.

Kincaid said Healios inherited manufacturing technology and assets from Athersys, including a bioreactor-based process for producing allogeneic stem cells. Healios acquired those assets through an Athersys bankruptcy process after making a $2.25 million debtor-in-possession loan in early 2024, he said. Kincaid noted that Athersys had spent $653 million on the platform.

• Healios currently uses a proprietary process in a 50-liter Sartorius bioreactor at Minaris in Yokohama.
• Kincaid said the 50-liter operation could produce roughly 1,000 doses annually and has commercially viable cost of goods for Japan.
• The company is also establishing a 500-liter commercial manufacturing facility in Kobe, Japan, supported by a $50 million Japanese government grant.
• According to Kincaid, the larger facility is designed to produce 40,000 doses annually, while one suite could produce 5,000 doses per year.

Healios expects to advance both its Japanese regulatory process and a global Phase III trial in pneumonia-induced ARDS. Kincaid said the study is expected to involve about 80 sites globally, with substantial enrollment planned in the United States as well as sites in Europe, Korea, Taiwan, Australia and potentially China.

SAB BIO Advances Fully Human Anti-Thymocyte Globulin

Reich described SAB BIO’s platform as a way to manufacture targeted, fully human intravenous immunoglobulin, or IVIG, using transchromosomic cattle. The company’s cattle do not produce bovine immunoglobulin G, he said, but instead produce human IVIG that can be purified from plasma after the animals are vaccinated with a selected antigen.

Reich contrasted the approach with conventional IVIG products derived from human plasma donors and animal-derived IVIG therapies. He said animal IVIG can be targeted through vaccination but may cause serum sickness and generally cannot be repeatedly administered. SAB’s approach, he said, seeks to combine the targeting capability of animal-based production with a fully human antibody product intended to be redosed.

The company’s Type 1 diabetes candidate is a fully human anti-thymocyte globulin, or ATG. Reich said the program builds on studies of Sanofi’s rabbit-derived Thymoglobulin, which he described as having demonstrated preservation of C-peptide and reductions in HbA1c in two randomized, double-blind trials, TN19 and MELD-ATG.

However, rabbit-derived ATG cannot be redosed and has adverse effects that may not be acceptable for Type 1 diabetes, according to Reich. SAB’s human ATG candidate is intended to address those limitations.

Reich said SAB conducted a Phase I program involving more than 80 subjects and patients. In healthy volunteers, the company observed that its treatment could be redosed without serum sickness, he said. In a small, open-label cohort of Type 1 diabetes patients, Reich said treated patients had preserved C-peptide, with an average absolute increase in C-peptide.

Registrational SAFEGUARD Study Nears Enrollment Completion

SAB is enrolling patients in its SAFEGUARD study, which Reich described as a Phase IIb pivotal trial with registrational endpoints. The study includes 159 newly diagnosed Type 1 diabetes patients between ages 5 and 40, divided equally among a higher-dose group, a lower-dose group and a placebo group.

The primary endpoint is preservation of C-peptide versus placebo. The key secondary endpoint is HbA1c, which Reich said is intended to measure whether preserved endogenous insulin production translates into improved glycemic control. Reich said the company has an agreement with the U.S. Food and Drug Administration that the study’s endpoints and data package could support approval.

Reich also cited the FDA’s approval of Tzield based on C-peptide as an important regulatory precedent. He said Tzield received accelerated approval despite missing other secondary endpoints, while noting that the product must still demonstrate clinical benefit after marketing.

In addition, SAB has begun the PRISE study, led by Dr. Haller and supported by Breakthrough T1D. The trial is designed to study patients beyond the 100-day period following diagnosis included in SAFEGUARD. Reich said PRISE includes cohorts ranging from within 100 days of diagnosis to one year after diagnosis and from one to two years after diagnosis. If successful, he said the study could support treatment eligibility for patients up to two years after diagnosis.

About SAB Biotherapeutics (NASDAQ:SABS)

SAB Biotherapeutics, Inc is a clinical-stage biotechnology company focused on developing antibody-based medicines for infectious diseases, immune disorders and other serious health conditions. The company's approach is designed to produce fully human polyclonal antibodies that can recognize and neutralize multiple targets associated with a disease.

SAB's technology platform, known as DiversitAb, uses genetically engineered cattle with human immune-system components to generate human antibodies.

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