Merck & Co. (NSDQ:MRNA) scientists have explored fighting cancer by way of the STING (stimulator of interferon genes)-controlled innate immune pathway.
Now, the company has published research in Advanced Therapeutics detailing a preclinical study with its partner Vesselon Inc. that reported impressive pharmacokinetics results related to MSA-1, a STING agonist.
The researchers found that low intravenous doses of MSA-1 alone did not have anti-tumor properties. But pairing MSA-1 with Vesselon’s FDA-approved acoustically-active drug Imagent led to complete tumor regressions. Vesselon makes use of a phenomenon known as sonoporation, which involves a temporary opening of cell membranes as a result of ultrasound exposure.
Imagent is FDA approved as a contrast agent for diagnostic ultrasound.
Specifically, Merck scientists reported that sonoporation dramatically improved the pharmacokinetics of MSA-1, boosting tumor uptake 658% 15 minutes after ultrasound exposure when the drug was administered systemically.
The use of MSA-1 with Vesselon’s treatment also led to elevated cytokine production, including TNF-α, IFN-α and IFN-β. The experimental therapy also appears to have immunomodulatory benefits.
The scientist noted a complete regression of primary and distant tumors in 44% of subjects.
“We created a new field of therapeutics called ‘acoustically active drugs,’ that can raise the pharmacokinetics of drugs in virtually any therapeutic class,” said Clay Larsen, Vesselon president and CEO, in a release. “We look forward to conducting clinical trials of our drugs in several important and underserved immuno-oncology indications.”
In 2002, FDA approved Imagent, which was initially developed by a company known as Alliance Pharmaceuticals. Vesselon acquired rights to the drug in 2019, when it announced its intent to incorporate the drug into its Vascular Encapsulation Sonication Targeting (VEST) system.
While Merck is an oncology heavyweight given the popularity of Keytruda (pembrolizumab), the company is looking to diversify its portfolio of anti-cancer drugs.