Prosecution Insights
Last updated: October 25, 2026

USPTO Art Unit 1644: Examiners and Allowance Rates

43 examiners • 11 with pending office actions • Biotechnology & Pharmaceuticals (Tech Center 1600)

Art unit baseline (last 5 years, 5,045 dispositions): 36% allowance rate • 4.0 office actions per allowance • 1,191 days median pendency
ExaminerAllowance rateResolved casesPending apps
Julie Zhen Qin Wu100.0%20
Amy Marie Chattin100.0%20
Bridget E Bunner100.0%10
Gregory S Emch100.0%10
Docket Central100.0%10
Kaijiang Zhang100.0%10
Ilia I Ouspenski77.3%1,12938
Lindsay Michelle Dunn75.0%423
David A Saunders67.9%1650
Estella M Gustilo66.7%30
Hilary Ann Petrash65.6%6416
Maureen Varina Driscoll64.5%9318
Michail A Belyavskyi63.9%1,11937
Brian Hartnett63.6%1430
James Ryland Melchior62.2%7429
Yunsoo Kim61.5%7010
Zachary S Skelding59.8%83540
Phuong N Huynh59.4%9500
Peter N. Johansen59.1%22547
James L Rogers57.2%4000
Lia Elan Taylor56.5%620
Michael Edward Szperka53.0%6640
Nora Maureen Rooney51.8%5080
Lea S O'Brien50.0%40
Sharon X Wen48.7%4500
Phillip Gambel46.4%6640
Julia Anne Lorrain Rossi45.7%350
Chun Wu Dahle45.7%5100
Anne Gussow45.5%110
Brianna Kendall Swartwout45.2%621
Amy E Juedes44.7%92640
Dennis Cherian George42.9%1410
Maher M Haddad42.0%7730
Marianne Dibrino33.3%4690
Francois P Vandervegt31.2%160
Gerald R Ewoldt28.6%5210
Katherine Ann Holtzman25.0%80
Daniel E Kolker21.8%550
Ronald B Schwadron18.9%4080
Samira Jm Jean-Louis0.0%40
Ram R Shukla0.0%20
Patricia Ann Duffy0.0%10
Brenda Libby Coleman0.0%10

Frequently Asked Questions

What is the allowance rate in USPTO Art Unit 1644?

35.9% over the last five years, across 5,045 resolved applications.

Which examiners in Art Unit 1644 have the highest allowance rates?

Among examiners with at least 30 resolved applications: Ilia I Ouspenski (77.3%, 1,129 resolved), David A Saunders (67.9%, 165 resolved), Hilary Ann Petrash (65.6%, 64 resolved).

Which examiners in Art Unit 1644 have the lowest allowance rates?

Among examiners with at least 30 resolved applications: Ronald B Schwadron (18.9%, 408 resolved), Daniel E Kolker (21.8%, 55 resolved), Gerald R Ewoldt (28.6%, 521 resolved).

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month