Abpro Corporation to Go Public via SPAC Merger at $725M Valuation Five Years After Failed IPO

Recently, VCBeat learned that biotechnology company Abpro Corporation (hereinafter referred to as Abpro) announced a merger with special purpose acquisition company (SPAC) Atlantic Coastal Acquisition Corp. II (NASDAQ: ACAB), aiming for a Nasdaq listing next year. The two parties signed a term sheet for the final business combination. The transaction is expected to be completed in the second quarter of 2024, with an implied pre-merger equity valuation of Abpro at $725 million.

In April 2018, Abpro filed its IPO prospectus with Nasdaq, planning to go public in May 2018 by issuing 4 million shares to raise up to 73.6 million US dollars, but it did not succeed in listing. This time, Abpro hopes to return to the Nasdaq track through SPAC.

Abpro, founded in 2007, is a clinical-stage biotechnology company. Through its proprietary DiversImmune^®and MultiMab^™Antibody Discovery and Engineering Platform: The company focuses on developing novel antibody drugs for the treatment of cancer, ophthalmology, infectious diseases, and autoimmune disorders.

With DiversImmune^®and MultiMab^™Platform, Abpro has laid out multiple core pipelines, with ABP 300, ABP 201, ABP 102, and ABP 100 as its main R&D candidate drugs. In addition, its unique antibody development platform and R&D pipeline have also attracted investment collaborations from AstraZeneca, Zhengdatianqing, and South Korean pharmaceutical company Celltrion.

"Monoclonal antibodies focus on targets, bispecific antibodies focus on platforms."

Abpro is utilizing its proprietary DiversImmune^®and MultiMab^™The platform has made further progress in the fields of monoclonal and bispecific antibodies.

DiversImmune^®The platform combines nanotechnology, next-generation sequencing, advanced engineering, and bioinformatics. Additionally, its front end is equipped with strong artificial intelligence and rapid methods for generating physical antibodies. The platform generates antibody "building blocks" with customized targeting antigens by using immunization methods (employing purified proteins, engineered cells, virus-like particles, and DNA) and co-stimulation strategies to elicit robust immune responses against target antigens.

Notably, DiversImmune^®The platform employs a variety of co-stimulation methods to optimize the immune response to each target. As a result, the antibody "components" generated can recognize different epitopes or binding regions on the same target protein with high affinity and high specificity.

After generating antibody "components," DiversImmune^®The platform utilizes the immune library of the natural immune system to create a large number of initial monoclonal antibodies. Subsequently, by employing the latest antibody technologies and processes, these antibodies are optimized and re-engineered on the platform to acquire the desired therapeutic properties, generating antibody formats for treating various indications.

According to the data published on Abpro's official website, as of now, DiversImmune^®The platform has successfully generated monoclonal antibody therapies for over 300 traditionally difficult targets for other biotechnology companies.

Abpro's R&D has not stopped at monoclonal antibodies but has utilized MultiMab based on the initial monoclonal antibodies.^™The platform develops a variety of bispecific and multispecific antibodies.

MultiMab™ Platform Can Integrate DiversImmune^®The initial monoclonal antibodies generated by the platform are engineered into bivalent, trivalent, or tetravalent bispecific forms, further constructing a variety of bispecific and multispecific antibodies. The tetravalent bispecific (TetraBi) antibody is its primary antibody molecular format.

TetraBi is a symmetric molecule with two identical heavy chains and two identical light chains. The "symmetric" design eliminates complications caused by potential chain mismatches in antibodies. TetraBi can simultaneously bind to tumor-specific antigens on tumor cells and CD3 on T cells, thereby tightly binding tumor cells and T cells, and then utilizing the immune response of T cells to kill tumor cells.

Compared with other bispecific antibody formats and T cell-based therapies, TetraBi has the following advantages. First, increased safety: TetraBi can specifically bind to CD3 while placing the CD3-binding domain in the hinge region of the molecule, which prevents the accidental activation of T cells by TetraBi in the absence of tumor cells, avoiding side effects such as cytokine release syndrome (CRS). Second, TetraBi is able to bivalently and monovalently co-engage different antigens simultaneously within the tumor microenvironment, enhancing its connectivity compared to molecules with only a single binding site.

Third, the administration is convenient. TetraBi contains the Fc region, which has a longer circulating half-life, allowing it to maintain a stable blood drug concentration for an extended period after administration. In addition, Abpro has introduced specific mutations in the Fc region of the antibody, which can reduce or eliminate immune effector functions mediated by the Fc region, avoiding adverse side effects such as cytokine release syndrome (CRS). Moreover, TetraBi is similar to natural human antibodies and exhibits low immunogenicity.

Currently, Abpro has laid out 8 pipelines, among which ABP 300, ABP 201, and ABP 100 are the main candidate drugs.

ABP 300 is a human neutralizing monoclonal antibody used to treat COVID-19, derived from patients who have recovered after SARS-CoV-2 infection. It neutralizes COVID-19 by binding to the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, blocking the interaction between the virus and the host angiotensin-converting enzyme 2 (ACE2) receptor.

ABP 300's unique mechanism of action enables more effective viral neutralization and demonstrates higher efficacy against a wide range of strains. Additionally, it exhibits a lower Antibody-Dependent Enhancement (ADE, a potential side effect of monoclonal antibody therapy), reducing the likelihood of severe pathological reactions and offering greater safety.

In studies using non-human primate models, ABP 300 demonstrated significant efficacy. Research findings indicate that a single dose of ABP 300 can block SARS-CoV-2 infection in rhesus macaques and eliminate the virus within three days. Results from its Phase I clinical trial also show that ABP 300 has favorable safety and pharmacokinetic profiles.

In 2020, Abpro initiated a global Phase II/III clinical trial for ABP 300, which will enroll 2,000 patients to evaluate its safety, tolerability, efficacy, and pharmacokinetics in treating early mild or moderate COVID-19 patients. Currently, no specific clinical data from this study has been disclosed.

ABP 201 is a preclinical bispecific antibody targeting angiopoietin-2 and vascular endothelial growth factor (Ang2-VEGF). It inhibits tumor angiogenesis and normalizes damaged blood vessels by targeting VEGF and ANG2. It is primarily used to treat common macular diseases, including wet age-related macular degeneration (AMD) and diabetic macular edema (DME).

Clinical studies have shown that, compared with existing VEGF therapies, ABP 201 can significantly improve patient outcomes and compliance. Currently, ABP 201 is in the Investigational New Drug (IND) application stage.

ABP 201 is being advanced in development by AbMed, a subsidiary of Abpro, while AbMed was jointly established in 2016 through a collaboration between MedImmune, a subsidiary of AstraZeneca, and Abpro.

According to the terms of the agreement signed by the two parties, AbMed, operating as a subsidiary of Abpro, will obtain the majority of global development and commercialization rights for the ABP 201 project. MedImmune will receive milestone payments for development, regulatory, and sales progress, as well as royalties, and will also acquire a minority stake in AbMed.

ABP 100 is a TetraBi antibody targeting HER2 and CD3, with high specificity for HER2+ tumors, used to treat patients with HER2+ breast cancer, gastric cancer, and pancreatic cancer.

In HER2+ cancer mouse models, tumors were alleviated at doses as low as 0.1 mg/kg without recurrence, demonstrating that ABP-100 has effective anti-tumor activity.

In preclinical studies, Abpro compared ABP-100 with clinically-stage HER2 and CD3 monovalent heterodimeric antibodies. The results showed that ABP-100 was able to bind bivalently to tumor antigens (HER2, GPC3, CLDN18.2) on tumor cells, and ABP-100 demonstrated cytokine release effects comparable to those of the heterodimeric molecules both in vitro and in vivo.

Currently, ABP 100 is in the IND application stage.

In addition to the aforementioned pipelines, ABP 102 is also an important investigational candidate being advanced by Abpro. ABP 102 is a T-cell engager, designed for the treatment of patients with HER2+ breast cancer, gastric cancer, and pancreatic cancer.

In 2022, Abpro and Celltrion established a strategic partnership for the ABP 102 project. According to the agreement, Abpro will receive payments of up to $1.75 billion, including equity investment, development and commercial milestone payments, as well as global profit sharing. Celltrion will be responsible for the development of ABP 102 and hold global commercialization rights.

In addition, in 2019, Abpro reached an agreement with Zhengda Tianqing. Both parties will utilize Abpro's DiversImmune technology.^®The platform develops a variety of innovative antibody therapies. Under the agreement, Nanjing Chia Tai Tian Qing paid Abpro a $600 million research and development fund, with additional potential milestone payments and royalties to be paid later. The total cumulative payments could reach up to $40 billion.

In 2022, a total of five bispecific antibody drugs were approved globally, surpassing the total number in the past 12 years. As of September 2023, 12 bispecific antibody drugs have been approved worldwide. Bispecific antibody drugs have entered a period of rapid growth, with the market size continuing to expand.

According to the "Innovative Drug Special Report — Bispecific Antibody Wave, Advancing Rapidly" released by Southwest Securities, the global bispecific antibody market was $4 billion in 2021. As the approval and market entry of bispecific antibody drugs continue to accelerate, the global bispecific antibody market size is expected to rise rapidly, reaching $80.7 billion by 2030, with an average compound annual growth rate (CAGR) of 39.6% from 2022 to 2030.

Facing this super-billion-dollar bispecific antibody market, many innovative pharmaceutical companies want a piece of the "cake." According to incomplete statistics from the Cortellis database, as of July 2021, there were a total of 980 bispecific antibody drugs globally. Excluding those that have been suspended, terminated, or have no updates on their R&D status, there are currently 712 bispecific antibody drugs in active development. Among them, projects in the preclinical and discovery stages account for over 75%, while projects in clinical stages account for only 24%.

However, the majority of the bispecific antibody market is currently held by established multinational corporations (MNCs) such as Roche, Johnson & Johnson, Amgen, and AbbVie, as well as China-based biotech companies like Akeso Biopharma, BeiGene, and Alphamab Oncology.

According to the third-quarter financial reports released by Roche, Amgen, and Akeso Biopharma, the total sales of their bispecific antibody drugs in the first three quarters reached $6.2 billion, with an expected annual total exceeding $8.5 billion. Among them, Roche's two bispecific antibody drugs—FIX/FX bispecific antibody and VEGF/Ang2 bispecific antibody—accounted for $5.5 billion of the market size.

Currently, bispecific antibody drugs have achieved clinical breakthroughs across multiple fields and mechanisms of action. Despite fierce competition, pharmaceutical companies are still heavily involved in this "battle," with new entrants continuously accelerating their research and development efforts.

And who will eventually capture more market share, we will wait and see.