Sanofi gave back rights to Hanmi Pharmaceutical’s efpeglenatide after global Phase 3 trials. Hanmi didn’t just reclaim its patents. It also got the clinical data, regulatory files, and know-how built up over years. That detail changed everything. Hanmi is now pushing for a South Korean launch for obesity. The company avoided starting over from zero.
This is where biotech licensing deals can turn. Ji-yeon Kim, partner at KAI Patent & Law Firm, calls the reversion clause the most important—and most ignored—part of any technology transfer. If the contract skips over data and know-how, a company might get its patents back but lose the ability to move forward. The asset stalls.
Hanmi positioned efpeglenatide, under the brand name Efe, as the first GLP-1 drug for obesity developed in South Korea, leveraging local clinical data and an internal supply chain.
Why patents alone fall short
Kim’s talk at KOREA LIFESCIENCE WEEK in Seoul cut through industry wishful thinking. She said, “If Hanmi had regained the rights without access to any of the clinical data, it could have had to restart clinical development from the beginning, significantly delaying further development.” Patents are just the start. The real power sits in the supporting files: clinical trial data, regulatory submissions, and technical know-how. These decide if a company can pick up where the licensee left off or must repeat years of work.
Hanmi’s efpeglenatide story proves the point. After Sanofi returned the rights in 2020, Hanmi ran its own Phase III trial in South Korea. The Ministry of Food and Drug Safety (MFDS) approved it as a randomized, double-blind, placebo-controlled study with 420 adults with obesity but no diabetes. The trial measured efficacy, safety, and tolerability. Results showed an average weight loss of 9.75% after 40 weeks among 448 adults. But these numbers can’t be directly compared to other GLP-1 drugs like Wegovy or Mounjaro. The studies used different populations, timeframes, and dosing, as The Korea Herald reported.
Kim breaks IP due diligence into three parts: ownership and disposal rights, validity and scope, and contract duties. But the reversion clause is the safety net. It lets the original rights holder step in and keep going if a deal ends. Efpeglenatide is not a one-off. It’s a warning. A patent alone is not enough.
By September 30, 2026, efpeglenatide (Efe) was in the final stage of review by the MFDS, with Hanmi having submitted its registration application in December 2025 and responding to additional regulatory requests. The company anticipated approval in October and planned to begin distribution before the end of 2026.
Hidden IP risks that kill deals
Even the best reversion clause can’t fix a broken patent. Kim points to a common trap. Sometimes, the product a company wants to sell isn’t covered by the patent claims. In gene therapy, a key sequence might get dropped during prosecution. The licensee is left with no real protection. “If the issue is serious enough, the deal may not happen at all,” Kim warns. Filing a patent isn’t enough. The claims must actually cover the asset.
Third-party IP risks are another danger. If a licensee finds out that selling the product could infringe another company’s patents, the deal can collapse. Legal and financial risks can end talks fast. Companies need to check these risks early. If there’s a problem, they must show a real workaround to keep the deal alive. Internal ownership can also get messy. Technology made by employees doesn’t always belong to the company unless the paperwork is solid. Kim says clear inventor agreements and records are a must to avoid fights later.
Not every IP risk is a dealbreaker. But trust depends on honesty. Kim puts it simply: “When a patent-related risk is identified, proactively explaining that the problematic patent exists but can be designed around in a certain way can strengthen credibility and increase the likelihood that the deal will move forward.”
Building IP portfolios that earn royalties
Patents are more than legal shields. They are the currency of biotech. Kim says one patent rarely does the job. The best companies build layered portfolios. They protect everything: the molecule, the process, the formulation, the dosing, and combinations. The story of lazertinib (Lazcluze) from Genosco, Oscotec, Yuhan, and Janssen shows this. Each step in development added new patents. The runway got longer.
In advanced biotech, core technologies can block rivals. Layered protection is essential. For gene therapies, patents must cover more than sequences. They need to protect delivery systems, vector-cassette pairs, and how the product is made. Stem cell therapies need broad coverage too: the cells, how they’re isolated, grown, and stored. Kim is blunt. “An IP portfolio is not built all at once, so companies need a strategy of gradually adding patents as follow-on technologies are developed.”
Smart IP portfolios do more than defend turf. They push up royalty rates and give companies leverage at the table. In a market where deals and values can shift overnight, only companies that treat IP due diligence as a living process—not a checklist—come out ahead. The recent biotech market swings, as reported earlier, make these basics even more urgent.
Biotech licensing isn’t luck. The winners treat reversion clauses, third-party risks, and layered patent portfolios as must-haves. Anything less means losing control of your science. Or your future market. Simple as that.
