Yifan Mao / 毛亦凡

Yifan Mao focuses her practice on patent counseling, prosecution, and due diligence matters in the chemistry and life sciences industries, focusing on areas relating to diagnostics, large molecule therapeutics, devices, sequencing, and bioinformatics.

Ms. Mao was a senior patent agent at an agriculture biotechnology company where she developed the company’s patent portfolio on genomics, bioenergy and trait improvement technologies before joining the firm. She held research positions at Genentech and Genencor International (now DuPont Industrial Biosciences) prior to her legal career.

Ms. Mao is an executive board member for the Fremont Union High Schools Foundation, and she serves as the Foundation’s Grant Chair and Outreach Co-Chair.

Ms. Mao was recognized as a Northern California “Rising Star” in 2022 and the four years immediately preceding for Intellectual Property by Super Lawyers magazine. Her native language is Mandarin Chinese.


Advised patent owners and international companies in post-grant review (PGR) proceedings, successfully defended the validity of their commercially valuable patents against their competitors, resulting in the outright dismissal of the competition by the Patent Trial and Appeal Board Opponent’s PGR application.

Represented a biopharmaceutical company in obtaining patent protection for its core oncology drug in the United States and elsewhere. The drug has been commercialized in China and is currently under FDA review in the United States.

Advised a major international company in obtaining patent protection for sequencing technology and advising on patent-related transactions.

Represented and provided patent protection for digital diagnostics and devices to an emerging company, and developed and advised on its global patent portfolio.

Advising international clients in Singapore, Korea and China on patent sourcing and free-roaming consulting on technologies related to diagnostics and protein therapy.

Advising public and private agricultural companies on conservation trait improvement technologies, advising on strategies to protect utility programs and plant patents.

Provided patent infringement litigation support for a pesticide company on claims composition, infringement analysis, invalidation defense and other issues.

Advised multiple companies on patent sourcing and consulting at all stages of diagnostic and therapeutic technologies protecting oncology indications and infectious diseases.


Santa Clara University School of Law, J.D., High Tech Law Certificate with honors (2014) magna cum laude, Dean’s List, Best Oral Advocate Award, CALI Awards, Witkin Awards, Emery Law Scholarship

Michigan State University, M.S., Biochemistry (2000)

Wuhan University, PR. China, B.S., Microbiology (1995)

Work experience

U.S. District Court for the Northern District of California – Judge Beth Labson Freeman (August-December 2014)


California (2015)

Court Admissions

U.S. Patent and Trademark Office (2007)

Professional & Community Activities

San Francisco Intellectual Property Inn of Court, Member

Asian Pacific American Bar Association of Silicon Valley, Member


The Dilemma of Drug Invention: A Written Description of a Healthy Dose, February 8, 2022

Voices of Silence: Applying for Patents to Protect Features That Don't Exist, January 26, 2022

Invention statement or "hunting expedition"? : Support for Claims Involving Intervals, 10 January 2022

Federal Circuit Rules Teva-Lilly Spat for Antibody Compositions and Methods, August 31, 2021

U.S. Patent Trial and Appeal Board Denies Petitioner's Request for Post-Grant Review Withdrawal on the Grounds of 'Too Late', August 25, 2021

Exploring key differences in U.S. and European patent protection strategies for therapeutic antibodies, April 28, 2021

Not Too Late | Submitting Post-Application Data During the Patent Examination Process in Certain Jurisdictions, March 16, 2021

Drug to Biologics Migration: Is Purple the New Orange? February 19, 2021

Things to watch in 2021: Big changes for Chinese pharma companies, 11 Jan 2021

Five takeaways: How can we ensure effective antibody protection? October 22, 2018

Obviousness needs to be clearly described; routine optimizations are not sufficient. August 30, 2017