The FDA has granted Anbogen Therapeutics clearance to initiate a Phase I/II clinical trial of its oral HDAC1/2/3 inhibitor, ABT-301, in combination with Tevimbra (tislelizumab) and Avastin (bevacizumab) for patients with metastatic colorectal cancer (mCRC). According to the company, ABT-301 has shown promising preclinical results, including enhanced immune response and tumor microenvironment modulation. Notably, the drug did not produce common toxicities associated with histone deacetylase inhibitors in a prior monotherapy trial.

What Potential does ABT-301 Offer for mCRC patients?

• The open-label, multi-center international trial will enroll 66 patients with proficient mismatch repair or non-microsatellite instability-high mCRC—subtypes representing approximately 95% of mCRC cases that typically respond poorly to current immunotherapies.
• The trial is expected to be conducted in Taiwan and Australia, with Tevimbra supplied by BeOne Medicines. The trial will assess the safety and preliminary efficacy of the triplet therapy.¹

Financing and Capital Raise

Following last year’s oversubscribed A+ financing round, the company has secured significant capital to fuel its ongoing growth and development efforts. In July 2024, the company announced that it successfully closed the funding round with $7.3 million, bringing its total funding raised to $19.8 million following the earlier $12.5 million Series A round in February 2024. Anbogen stated that the funds would mainly be used to advance the Phase II trial.²

"We are deeply grateful to our investors for their continued support and confidence in our mission," said Tsu-An Hsu, CEO, Anbogen Therapeutics, in a July 2024 press release. "This funding is crucial for the advancement of ABT-301 combo with immune checkpoint inhibitors treating solid tumors, and it validates our ongoing efforts to bring effective cancer treatments to patients in need."

Mechanism of Action and Preclinical Findings

ABT-301 is an oral inhibitor of HDAC1, HDAC2, and HDAC3 enzymes. According to Anbogen, preclinical studies have indicated that it may increase CD8+ cytotoxic T cell infiltration and activity, enhance antigen presentation, and decrease M-MDSCs cells, potentially modifying the tumor microenvironment from “cold” to “hot” and affecting response to immune checkpoint inhibitors.

The compound also appears to have pro-apoptotic, anti-angiogenic, and tumor metabolism regulatory effects. ABT-301 is being investigated as a multi-mechanism agent to be used in combination with two antibody therapies.¹

Colorectal Cancer Statistics and Trends

According to the American Cancer Society, colorectal cancer is the third-leading cause of cancer-related deaths in men and the fourth-leading cause in women in the United States. When combined, it ranks as the second most common cause of cancer death overall, with approximately 52,900 deaths estimated by the end of 2025.

The mortality rate from colorectal cancer has been decreasing among older adults for several decades. Increased screening has led to more frequent detection and removal of colorectal polyps before they become cancerous, as well as earlier diagnosis of cancers when treatment is more effective. Additionally, advances in colorectal cancer treatments have contributed to improved outcomes.

In contrast, death rates for individuals under 55 years of age have been rising by about 1% annually since the mid-2000s. On average, the lifetime chance of being diagnosed with colorectal cancer is approximately one in 24 for men and one in 26 for women.³

Future Development and Funding Plans

Moving forward, Anbogen plans to progress the clinical development of ABT-301 and explore licensing opportunities and partnerships to support its commercialization and entry into global markets. Additionally, the company is initiating a Series B funding round aimed at securing partners focused on advancing cancer treatment innovations and expanding its international presence.¹

References

1. Anbogen Receives FDA Clearance to Initiate Phase 1/2 Trial of ABT-301 Triplet Therapy for Advanced Colorectal Cancer. PRNewswire. August 4, 2025. Accessed August 4, 2025. https://prnmedia.prnewswire.com/news-releases/anbogen-receives-fda-clearance-to-initiate-phase-12-trial-of-abt-301-triplet-therapy-for-advanced-colorectal-cancer-302520494.html
2. Anbogen Therapeutics Announces Completion of A+ Round Financing to Advance ABT-301 Phase II Clinical Trial. Anbogen. July 1, 2024. Accessed August 4, 2025. https://anbogen.com/en/news/8A5d78aC6920
3. Key Statistics for Colorectal Cancer. American Cancer Society. Accessed August 4, 2025. https://www.cancer.org/cancer/types/colon-rectal-cancer/about/key-statistics.html#:~:text=About%20107%2C320%20new%20cases%20of,older%20adults%20for%20several%20decades.