Medivir AB (Nasdaq Stockholm: MVIR), a Stockholm-based pharmaceutical company focused on high unmet medical need, has announced that the United States Patent and Trademark Office (USPTO) has granted patent US12788771, covering the combination of fostroxacitabine bralpamide (fostrox) with lenvatinib for the treatment of hepatocellular carcinoma (HCC) and cancer metastases to the liver. A Patent Term Adjustment of 1,001 days has extended US market exclusivity to at least January 2044, nearly three years beyond the previously communicated date of April 2041. The grant follows the Notice of Allowance announced on 20 July 2026 and reinforces Medivir's intellectual property position in the world's largest pharmaceutical market at a clinically active stage of development.

Key Points

  • Medivir AB (0GP7 / Nasdaq Stockholm: MVIR) is a Swedish pharmaceutical company developing precision oncology and rare disease treatments
  • USPTO has granted patent US12788771 covering the fostrox plus lenvatinib combination for hepatocellular carcinoma and liver metastases
  • A Patent Term Adjustment of 1,001 days extends US protection to at least January 2044, up from April 2041
  • Investors may watch progress of the randomised phase 2 study FLEX-HCC, in which the fostrox plus lenvatinib combination is currently being evaluated

USPTO Grants Patent US12788771 for Fostrox and Lenvatinib Combination in Liver Cancer

The USPTO formally granted patent US12788771 to Medivir, covering the combination of fostrox with lenvatinib specifically for hepatocellular carcinoma and cancer metastases to the liver. The grant follows the Notice of Allowance confirmed on 20 July 2026. This US patent complements combination patents already secured in the European Union, Japan, Australia, and Canada, giving Medivir a broad multi-jurisdictional intellectual property framework around one of its two lead oncology programmes. The announcement states this addition is strategically significant given the United States represents the world's largest pharmaceutical market.

1,001-Day Patent Term Adjustment Pushes US Exclusivity to January 2044

A key element of the grant is the USPTO's determination of a Patent Term Adjustment of 1,001 days, awarded to compensate for administrative delays during the examination process. This adjustment extends US market exclusivity for the fostrox plus lenvatinib combination to at least January 2044, compared with April 2041 as previously communicated — an extension of almost three years. According to CEO Jens Lindberg, this adjustment "significantly strengthens the long-term commercial value of fostrox in the US" and coincides with the ongoing randomised phase 2 FLEX-HCC study evaluating the combination.

Fostrox as a Liver-Targeted, Orally Administered Precision Chemotherapy

Fostrox is designed as a liver-targeted inhibitor of DNA replication, coupling the chemotherapy agent troxacitabine with a prodrug tail that allows oral administration. The compound travels inactive to the liver, where activation and local release occur selectively within tumour tissue, aiming to minimise harm to healthy cells. A phase 1b monotherapy study previously established clinical proof-of-concept, and a phase 1b/2a combination study with lenvatinib completed in November 2024 showed encouraging anti-cancer efficacy alongside a good safety and tolerability profile, according to the announcement.

HCC's Global Disease Burden Underlines the Commercial Opportunity for Medivir

Primary liver cancer is the third leading cause of cancer-related deaths worldwide, with approximately 860,000 patients diagnosed annually. HCC is the most common form of primary liver cancer and the fastest growing cancer in the United States, where current five-year survival rates remain below 20 per cent. Existing therapies for advanced HCC offer limited overall benefit, contributing to significant unmet medical need. Medivir's ability to protect its fostrox combination commercially through to January 2044 in the US market may be material to the long-term value proposition presented to investors and potential development partners.