WOBURN, Mass. — Spear Bio Inc., a Harvard University biotech spin-off developing scalable solutions for ultrasensitive detection of protein biomarkers, announced the completion of a raise of tens of millions of US dollars with its Seed Prime. The oversubscribed round was led by CDH Investments, with additional investments from earlier investors such as Maverick Ventures and YongHua Capital.

Spear Bio was co-founded in March 2021 as a spin-off from Harvard University’s Wyss Institute by Professor Peng Yin and Dr. Feng Xuan. The company is developing the next generation ultrasensitive immunodiagnostics and proteomics platform based on a breakthrough technology its founders developed and licensed from Harvard University: the Successive Proximity Extension Amplification Reaction, or SPEAR.

The SPEAR technology delivers two to three orders of magnitude higher sensitivity than current digital immunoassay platforms without the need for wash-steps or expensive proprietary readers thanks to its unique 2-factor authentication. SPEAR’s specially designed probes can differentiate sustained protein-to-protein contacts from transient interactions and translate “protein information” into DNA sequences with unprecedented specificity which can then be amplified and quantified with common qPCR devices.

The high specificity of SPEAR’s protein-to-DNA conversion combined with the exponential amplification of qPCR produces an extremely high signal-to-background ratio. It allows the detection of single digit counts of protein molecules in tiny sample volumes, down to a tenth of a microliter. Whether measuring low abundance biomarkers with microsampling techniques or carrying out a multitude of tests on precious samples with limited volumes, SPEAR is a powerful potential solution for both research applications and minimally invasive diagnostics.

Professor Peng Yin, Co-founder of Spear Bio, said “The SPEAR platform’s unique mechanism designed by Dr. Xuan achieves extreme sensitivity without the complexity typical of “single-molecule” technologies. SPEAR’s ability to quantify proteins at attomolar levels from sub-microliter sample will impact not only how protein biomarkers are measured clinically today but also how new ones will be discovered in the future. We hope Spear Bio can enable this technology to quickly benefit the research community and patients.”

Ultra-sensitive digital immunoassay platforms typically rely on extensive wash-steps, expensive proprietary readers, and high-affinity antibodies. By contrast, SPEAR has a wash-free workflow that can be easily automated with microfluidics or liquid handlers, runs on ubiquitous qPCR instruments, and does not require high-affinity antibodies to achieve high sensitivity. This gives SPEAR the unique advantage of being readily implementable and scalable in most laboratories.

Dr. Feng Xuan, Co-founder and Chief Technology Officer of Spear Bio, stated “Our first goal is to bring SPEAR to every lab, and make it as routine as established technologies like ELISA and chemiluminescence. SPEAR’s extreme sensitivity will provide a unique solution for studying early-stage disease protein biomarkers with minimally-invasive micro-sampling technologies. With its ease of adoption, SPEAR will greatly accelerate new biomarkers’ discovery and validation, and eventually bring about early diagnoses of chronic diseases through less invasive, more efficient, and broadly accessible protein biomarkers monitoring.”

Spear Bio has successfully launched NAB-Sure™, its first assay and commercial proof-of-concept, for ultrasensitive quantification of SARS-Cov-2 neutralizing antibodies from challenging samples such as finger-stick dried blood spot (DBS) and nasal swabs. During the pandemic, NAB-Sure has been validated and adopted in major labs, enabling precise tracking of immunity, vaccine response, and COVID-19 sero-surveillance. Spear Bio is now focused on bringing ultrasensitive immunoassays to the market for areas such as neurology, immunology, and oncology.

Dr. Dan Liu, Senior Partner of CDH Investments commented “Providing ultra-sensitivity in microsamples with a simple workflow through qPCR instruments is a very attractive solution since these are now nearly ubiquitous post-COVID. This will help accelerate adoption and increase impact to areas where ultra sensitivity and microsamples can make a significant difference such as infectious diseases, immunology, and neurology. For example, recently approved Alzheimer’s Disease therapies, together with the many in development, are creating a need for accurate, minimally invasive, and cost-effective blood-based screening. Spear Bio can meet this new market demand better than competitors.”

David Singer, Managing Partner of Maverick Ventures, and Spear Bio’s earliest investor, concluded, “Spear Bio’s technology was validated and adopted early on by major commercial laboratories. Excitingly, customers have been enthusiastic about the performance of the SPEAR platform as well as with the ability to implement it at scale on standard lab equipment. This real-world evidence gave us confidence in Spear Bio’s commercial potential and momentum.”