SiVEC Biotechnologies’ BactPac platform uses non-pathogenic normal flora bacteria engineered not only to produce a diverse range of therapeutic nucleic acids, proteins, and gene editors, but also to serve as the vehicle that delivers them to specific tissues.
BactPac can target cells that express a particular surface marker, such as integrin beta-1 (also known as CD29). The vehicle enters cells via receptor-mediated phagocytosis after ligand–receptor binding. Once inside the cell, bacterial lysis and perforation of the phagosome allow the release of the therapeutic cargo into the cytoplasm where it can modify intracellular processes (Fig. 1).
“Receptor-mediated targeting means that BactPac can be directed with unparalleled therapeutic precision to where it’s needed most, including a wide range of cell types in organs and tissues beyond the liver that are traditionally considered difficult to target with conventional drug-delivery systems,” explained Lyndsey Linke, SiVEC’s CEO and co-founder. “BactPac enables targeted intracellular delivery of biotherapeutics, offering greater safety and versatility than current industry standards.”
In addition to its ability to generate and deliver a large and varied therapeutic cargo, BactPac is engineered to evade immune recognition, preventing undesirable immune responses and enabling repeat dosing. BactPac can be administered directly to target tissues or systemically for broader distribution, with no risk of hepatotoxicity.
Fig. 1 | The BactPac drug delivery platform. mRNA, messenger RNA; shRNA, short-hairpin RNA; siRNA, small-interfering RNA.
From manufacturing and commercialization perspectives, BactPac offers significant advantages. It is produced using standard bacterial fermentation processes and, because it produces the therapeutic cargo during fermentation, there is no need for expensive separate cargo synthesis and vehicle packaging. “BactPac is the only complete solution for production and targeted intracellular delivery of biologics,” said David Sherris, a biotech executive with deep expertise in drug delivery. “It is unlike any other drug-delivery platform, and will redefine the biotherapeutics landscape due to its targeting ability, demonstrated safety, as well as its simple and low-cost manufacturing requirements.”
A new paradigm in cancer treatment
Several features make BactPac ideal for treating cancer. It can target cell-surface markers and accumulate in the tumor microenvironment, minimizing off-target effects in healthy tissue. Moreover, unlike most other bacterial delivery systems, BactPac delivers its cargo intracellularly to directly modulate cancer-driving pathways, including rat sarcoma virus protein (RAS) signaling.
Leveraging these features, SiVEC is pioneering first-in-class therapies with a focus on oncology and gene editing. The company’s lead asset, SVC-KRAb, delivers a circular messenger RNA (mRNA) directly into tumor cells where it is translated to produce a potent nanobody that targets and inhibits over 20 cancer-driving mutant RAS proteins. “This underlies its usefulness in a broad range of cancer types,” explained Ashley Williams, SiVEC’s director of research and development. “In preclinical in vivo studies, SVC-KRAb demonstrated remarkable efficacy, reducing solid tumor volume by over 80% compared to untreated controls with no side effects—the world’s first successful targeting of a mutant KRAS protein by a pan-RAS biologic.” SVC-KRAb is currently in investigational new drug (IND)-enabling studies, with clinical trials expected to begin in the third fiscal quarter (Q3) of 2026.
While SVC-KRAb is poised to transform cancer treatment, the next-generation BactPac system (currently in development) will enable targeted biologic delivery with unprecedented single-cell precision, unlocking a new era of specificity and safety in therapeutic delivery, according to Williams.
Expanding horizons
Beyond cancer, BactPac’s versatility in biologic cargo production and targeted delivery provide opportunities for enabling therapeutics across a wide variety of indications, including genetic, infectious, and chronic diseases.
Capitalizing on this, SiVEC is developing SVC-IAV, an inhaled live biotherapeutic product, which can deliver two siRNAs to provide broad, fast-acting antiviral activity against seasonal and pandemic influenza A.
Also in its pipeline is SVC-Survivin, a nanobody-based chemotherapy enhancer that blocks the anti-apoptotic effects of the survivin protein in cancer cells to enhance chemotherapy efficacy, thereby reducing the therapeutic dose and limiting adverse effects.
Currently, SiVEC is expanding its pipeline and seeking biopharma partners to leverage BactPac for safe, tissue-targeted delivery of their biologics. “By engineering bacteria for precise delivery, we’re enabling next-generation therapeutics and redefining cancer treatment,” said Linke. “BactPac is a unique, safe, and versatile platform poised to revolutionize treatment for even the toughest diseases.”