German pharmaceutical giant Bayer has secured an exclusive worldwide license to develop, manufacture, and commercialize a novel PRMT5 inhibitor from Suzhou Puhe BioPharma, a clinical-stage Chinese biotechnology company. The deal, announced Wednesday, centers on an orally available small molecule that selectively targets MTAP-deleted tumors.
The compound, previously known as PH020 and now designated BAY 3713372, exploits a specific vulnerability in cancer cells that have lost the MTAP gene, which occurs in approximately 10-30% of all cancers. Financial terms of the agreement were not disclosed.
Strategic Importance of MTAP-Deleted Tumor Targeting
MTAP (metabolic enzyme 5'-deoxy-5'-methylthioadenosine phosphorylase) plays a critical role in cell metabolism. When the MTAP gene is deleted, it leads to elevated levels of methylthioadenosine (MTA) in tumor cells. BAY 3713372 is specifically designed to bind to the PRMT5-MTA complex, exploiting this tumor vulnerability while sparing healthy cells.
"Loss of the MTAP gene occurs in a variety of tumor types, including those with few treatment options and poor prognosis, such as pancreatic cancer and glioblastoma," explained Dominik Ruettinger, M.D., Ph.D., global head of research and early development for oncology at Bayer's Pharmaceuticals Division.
The selective targeting mechanism represents a significant advancement in precision oncology, potentially offering improved efficacy with reduced toxicity compared to conventional treatments.
Clinical Development Already Underway
Bayer has already enrolled the first participant in a global Phase I first-in-human dose escalation study investigating BAY 3713372 for the treatment of MTAP-deleted solid tumors. The clinical program aims to evaluate safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary clinical activity.
"We are looking forward to explore the potential of the PRMT5 inhibitor, which could improve outcomes for patients with MTAP-deleted tumours who often have a poor prognosis," said Juergen Eckhardt, M.D., head of business development and licensing at Bayer's Pharmaceuticals Division.
Unique Properties and Competitive Landscape
BAY 3713372 has demonstrated competitive selectivity for PRMT5 bound to MTA in preclinical studies. Notably, the compound features brain penetration capabilities, potentially allowing it to target central nervous system metastases and primary brain tumors—a significant advantage in treating aggressive cancers like glioblastoma.
"We see great potential in MTA-cooperative PRMT5 inhibitors in treating MTAP-deleted tumours. Our MTA-cooperative PRMT5 inhibitor has demonstrated competitive selectivity for PRMT5 bound to MTA and activity in preclinical studies, as well as brain penetration capabilities," said Yongqi Guo, CEO of Puhe BioPharma.
The deal puts Bayer in direct competition with several other pharmaceutical companies pursuing similar approaches. AstraZeneca is currently conducting the Phase I/II PRIMROSE trial for its candidate AZD3470, while Bristol Myers Squibb is advancing MRTX1719 through Phase I and I/II trials. Amgen is also recruiting patients for a Phase I trial of its compound AMG 193.
Growing Trend of East-West Pharmaceutical Partnerships
This agreement represents the latest in a growing trend of Western pharmaceutical companies forming partnerships with Chinese biotechs to strengthen their pipelines. For Bayer, the deal aligns with its stated mission to build "one of the most transformative and differentiated precision oncology pipelines in the industry."
Puhe BioPharma, headquartered in Suzhou, China, focuses on developing innovative small-molecule precision therapeutics for high-incidence, high-mortality cancers and other chronic diseases. The partnership with Bayer provides the biotech with global reach for its promising compound.
Mechanism of Action and Scientific Rationale
PRMT5 (protein arginine methyltransferase 5) plays a crucial role in modifying proteins that control the cell cycle. In normal cells, PRMT5 activity is regulated by various mechanisms, including interaction with MTA.
In MTAP-deleted cancer cells, MTA accumulates due to disruption of the methionine salvage pathway. BAY 3713372 is designed to selectively inhibit PRMT5 in the presence of elevated MTA levels, creating a synthetic lethality that specifically targets cancer cells while sparing normal tissues.
This targeted approach represents a sophisticated application of precision medicine principles, exploiting specific genetic alterations to develop treatments with improved therapeutic windows.
As the compound advances through clinical development, it could potentially address significant unmet needs in oncology, particularly for patients with aggressive cancers characterized by MTAP deletion who currently have limited treatment options.
