NIST-FDA Cell Counting 

Workshop: Sharing practices in 

cell counting measurements

Judith Arcidiacono, M.S.

International Regulatory Expert and Standards Liaison

Office of Tissues and Advanced Therapies

CBER/FDA
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Office of Tissues and Advanced 

Therapies (OTAT)

Office of the Director

Division of Plasma 

Protein Therapeutics

Division of Human 

Tissues

Division of Regulatory 

Project Management

Division of Clinical 

Evaluation and 

Pharmacology/Toxicology

Division of 

Cellular and Gene 

Therapies
The 21st Century Cures Act: 

Title III, 3033-3036: Regenerative 

Medicine Provisions
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21st Century Cures Act: 

Title III, Sections 3033-3036

• Regenerative medicine provisions:

– Section 3033: Creates pathway for designation as a 

regenerative medicine advanced therapy

– Section 3034: Mandates that FDA develop guidance 

regarding devices used in the recovery, isolation, or 

delivery of regenerative medicine advanced therapies

– Section 3035: Mandates that FDA report yearly to 

Congress on regenerative advanced therapies

– Section 3036: Directs HHS, in consultation with NIST and 

stakeholders, to facilitate efforts around development of 

standards for regenerative medicine therapies and 

regenerative medicine advanced therapies
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Definition of Regenerative Medicine 

Therapies

Cell therapies, therapeutic tissue engineering 

products, human cell and tissue products, or 

combination products with any such therapies or 

products, except for those regulated solely under 

section 361 of the Public Health Service Act (PHS 

Act) (42 U.S.C. 264) and Title 21 of the Code of 

Federal Regulations, Part 1271 (21 CFR Part 1271). 
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Regulatory Challenges for Assessing 

RM Therapies

• Product Testing 

• Development of performance characteristics

• Testing methodologies

• Scientific protocols

• Compliance criteria
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Cell Counting

• Crucial for measurements of purity, identity, 

potency, and dosing

• Methods vary and depend on the product

• Validation of cell counting methods required for 

licensure

– Expected by Phase III, required for BLA

IND BLA

Development Preclinical Phase I Phase II Phase III Marketing

Pre-IND
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FDA Efforts in Regulatory Science

• International harmonization discussions with 

foreign regulatory authorities

• Standards development activities with ISO, ASTMi, 

ATCC, etc

• Regulatory focused research programs 

‒ New approaches for product manufacturing and quality

• Laboratory collaborations for standards 

development

– Inter-lab round-robin testing

– Collaborations with NIST
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Why is FDA interested in standards 

development for regenerative medicine 

therapies?

• National Technology Transfer and Advancement Act 

of 1995

• Standards can help developers of regenerative 

medicine therapies meet regulatory expectations

– Product characterization

– Potency Assessments

– Identity Testing

– Purity

– Etc.
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Benefits of Standards Use

 Help a sponsor of a regulatory submission 

meet regulatory requirements 

 Facilitate product characterization

 Reduce time to market by leveraging 

industry and government efforts
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When should a standard be developed?

• Does the base of scientific knowledge on the subject support the 

development of standardized approaches to methods, testing, 

etc. ?

• Is there consensus among the scientific community that the 

approaches proposed are appropriate to address the need for 

standardization?

NEED

KNOWLEDGE
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Outlook for Cell Counting

Identifying appropriate methods for cell counting 

and understanding the instrumentation available 

could lead the development of documentary 

standards and reference materials that can help to 

address cell counting challenges for regenerative 

medicine therapies.
OTAT Contact Information

Judith Arcidiacono, M.S.

International Regulatory Expert, Standards Liaison

Judith.Arcidiacono@fda.hhs.gov

240-402-8250

Regulatory Questions:

Contact the Regulatory Management Staff in OTAT at 

CBEROCTGTRMS@fda.hhs.gov

or Lori.Tull@fda.hhs.gov

240-402-8361

OCTGT Learn Webinar Series:

http://www.fda.gov/BiologicsBloodVaccines/NewsEvents/uc

m232821.htm