12 February 2026
Bangkok, Thailand
The Thai Network of People Living with HIV/AIDS (TNP+) has achieved a major victory for public health and access to affordable medicines, following a final decision issued on 29 December 2025 by the Thai Patent Board rejecting Patent Application No. 0801001634 related to sofosbuvir, a key medicine used in the treatment of hepatitis C. The decision highlights the critical role of civil society in using pre-grant patent opposition to challenge evergreening practices, correct flawed decisions, and promote access to lifesaving medicines.
TNP+ began examining the patent application after identifying concerns that it could create unjustified patent barriers affecting access to treatment. Acting in the public interest, TNP+ filed a pre-grant opposition, raising both legal and substantive objections, including the applicant’s lack of legal right to file the application, as well as problems related to the scope of the claims.
Although the Department of Intellectual Property (DIP) initially dismissed the opposition in its first decision, TNP+ continued to pursue the case through the appeal process. In its final ruling (Patent Board Decision No. 65/2568), the Patent Board reversed the first decision and concluded that the application violated Section 10 of the Thai Patent Act.
The rejected patent application sought protection over sofosbuvir-related compounds and their use in treating hepatitis C. In simple terms, the claims attempted to cover a modified chemical form of the medicine designed to convert into the active drug inside the body (a prodrug), as well as the way the medicine is used to treat patients. Some of these claims went beyond what Thai law allows, particularly by seeking protection over methods of medical treatment, which are not patentable in Thailand.
The Patent Board found that the applicant did not have the legal right to file the patent application at the time of filing. When the application was filed in Thailand on 28 March 2008, Pharmasset, Inc. had not yet received the patent rights, even though the application was filed in the name of Gilead Sciences, Inc., which later acquired Pharmasset. The transfer of rights took place on 25 April 2008. The Board stressed that the right to apply for a patent must exist on the filing date and cannot be created retroactively. For this reason, the application was rejected.
The case also reflects longstanding concerns about the scope of the patent claims. During the examination process, and as highlighted in the opposition filed by TNP+, the DIP had already ordered the applicant to remove claims related to use and methods of treatment, which are not patentable under Thai law. As a result of these orders, the number of claims in the application was reduced from 24 to 15. These issues were also raised and reinforced by TNP+ in its pre-grant opposition, as part of broader concerns about attempts to extend patent protection beyond what is allowed under the law.
“Even after authorities ordered the removal of treatment-related claims, companies may try to repackage the same monopoly through different legal wording,” said Chalermsak Kittirakul, Access to Medicines Manager at the Thai Network of People Living with HIV/AIDS (TNP+). “This is exactly why patent opposition by civil society is so important—public scrutiny helps ensure that patent law is applied based on substance, not just form.”
Because the application ultimately failed to meet the basic legal requirement under Section 10, the Patent Board stated that it was unnecessary to consider other objections raised by TNP+, including lack of novelty, lack of inventive step, or whether the remaining claims still amounted, in substance, to prohibited treatment claims. The Board made clear that the application had already failed at a fundamental legal level.
In reaching its conclusion, the Patent Board also referred to Supreme Court case law in trademark cases, which establishes that legal authority must exist at the time an action is taken and cannot be created retroactively. By applying this principle to patent law, the Board reinforced a clear and consistent interpretation of Section 10 of the Patent Act.
“This case shows that civil society engagement really matters,” said Yupha Sukreuang, Chairperson of the Thai Network of People Living with HIV/AIDS (TNP+). “Even when an initial decision goes against the public interest, communities can use legal tools to challenge it. Patent opposition is not just about one application—it is about stopping weak or evergreening patents from blocking generic competition and delaying access to affordable medicines.”
This outcome demonstrates how community-led patent opposition can both expose problematic patent practices and overturn flawed decisions. By successfully challenging an unlawful and potentially evergreening patent application, TNP+ has helped protect competition in the pharmaceutical market and strengthened the prospects for more affordable hepatitis C treatment in Thailand.