You are using an outdated browser and your browsing experience will not be optimal. Please update to the latest version of Microsoft Edge, Google Chrome or Mozilla Firefox. Install Microsoft Edge

Atthachai Homhuan

Director, Regulatory Affairs


Dr. Atthachai Homhuan is the director of the regulatory affairs group at Tilleke & Gibbins. He assists biotechnology, chemical, life sciences, and pharmaceutical companies to draft and review patent claims and specifications and advises patent agents on amending claims and providing responses to office actions. Atthachai frequently drafts counterstatements against opposing parties in trademark and patent applications and his practice also includes advising on pre-litigation and litigation matters involving the life sciences, medical devices, and pharmaceuticals. He has presented before the IP&IT Court as a witness in chemistry and life sciences patent litigation. Based on his expertise, he is recognized as a leading patent lawyer in Thailand by IAM Patent.

In addition to patent work, Atthachai prepares healthcare product dossiers for registration and helps international companies develop market entry strategies for countries in Southeast Asia. His broad experience allows him to evaluate the feasibility of product registrations, conduct plant audits, and coordinate preclinical and clinical trials in accordance with international guidelines and standards. Atthachai also reviews healthcare product labeling for food, cosmetics, medical devices, and drug products in Thailand and other Southeast Asian countries.

Prior to joining the firm, Atthachai was a postdoctoral researcher in Japan and Taiwan, focusing on stem cell therapies and vaccine development. He applied his technical expertise to the industry when he became a project manager for a Thai vaccine manufacturing company, where he led the firm’s R&D efforts. His industry background also includes serving as a formulation manager at the subsidiary of a well-known American pharmaceutical innovator, where he was the group leader in charge of the company’s R&D and production functions.

A Thai-licensed attorney, Atthachai holds a PhD in Pharmaceutical Technology from Thailand’s Mahidol University, and he frequently lectures on pharmaceutical and chemical patents at universities across Thailand. He has completed the FICPI Southeast Asian Drafting Training Course.


  • Assisted pharmaceutical companies in drafting sale and purchasing agreements and held discussions with the Ministry of Public Health with regard to the purchasing agreements of COVID-19 drug products.
  • Advised pharmaceutical companies about the Thailand Emergency Use Authorization (EUA) approval requirements of COVID-19 drug products and vaccines.
  • Revised guidelines for Thai patent officers examining chemical and pharmaceutical patents.
  • Implemented a quality-control system and addressed GMP-related topics for the manufacturing of vaccines. This involved working closely with the Department of Medical Sciences of the Thai FDA with regard to biohazard manufacturing and audits, in order to obtain approval.
  • Worked with companies in the agricultural and chemicals industries with regard to complaints on substandard products raised by the Ministry of Agriculture.
  • Reviewed clinical trial agreements and bioequivalence studies for new drugs and conventional products, and ensured that the trials/studies and protocols were in accordance with Good Regulatory Practices and Good Clinical Practices.
  • Assisted life sciences and chemical companies to draft a variety of complex patents involving the manufacturing process for creating polymers from waste gas and patents related to biological vaccines, among others.
  • Audited leading pharmaceutical companies to ensure that their product registration dossiers and advertising campaigns comply with Thai legislation.
  • Registered new biological product dossiers at the Thai FDA and received approvals within 1.5 years—a relatively short period of time to obtain approval for a new drug in Thailand.
  • Registered medical devices, food products, and cosmetics with the Thai FDA for domestic and international companies.
  • Worked with the firm’s litigation team and won a disputed patent litigation case for a chemical glass company, in which the opposing party claimed damages exceeding THB 50 million.
ABOUT Atthachai


Life Sciences






    PhD, Mahidol University

    BSc, Chulalongkorn University

    LLB, Ramkhamhaeng University


Awards & Rankings

Other Professionals