Gilead Expands Virology Pipeline with Encequidar Acquisition

Gilead Sciences has made a significant move to bolster its virology portfolio, securing global rights to the P-glycoprotein (P-gp) inhibitor encequidar from Health Hope Pharma (HHP) in a deal worth up to $82.5 million. This strategic acquisition underscores Gilead's commitment to strengthening its position in the antiviral market and exploring innovative approaches to drug delivery.

Deal Structure and Financial Terms

The agreement sees Gilead paying an upfront fee of $10 million to HHP, with the potential for an additional $72.5 million in milestone payments. Hanmi Pharm, the original developer of encequidar, is also set to receive an undisclosed upfront payment and milestone-based compensation tied to development, regulatory approvals, and sales performance.

Encequidar's Potential in Virology

While encequidar's primary development has been in oncology, Gilead's interest lies in its potential applications within the virology space. The P-gp inhibitor's mechanism of action, which involves selective inhibition of P-gp in the gut, could have significant implications for antiviral drug delivery and efficacy.

Many antiviral drugs, including components of Gilead's blockbuster HIV treatment Biktarvy, are substrates of P-gp. Co-administration of these drugs with P-gp inhibitors like encequidar could potentially increase their absorption and plasma concentrations, leading to enhanced efficacy against pathogens such as HIV and hepatitis C.

Challenges and Considerations

The integration of encequidar into Gilead's virology pipeline is not without challenges. The company must navigate the complex interactions between P-gp inhibitors and antiviral drugs, which can sometimes be undesirable. For instance, the label for Gilead's HIV prevention drug Yeztugo recommends against co-administration with P-gp inhibitors.

Gilead's research and development teams will need to carefully evaluate the potential benefits and risks of combining encequidar with their existing and pipeline antiviral therapies. This work could open new avenues for improving HIV treatment by potentially allowing antivirals to penetrate pharmacological sanctuary sites such as the brain, a concept explored in earlier research dating back to 2001.