Cell & Gene Therapy

New cell and gene therapies are now available for patients, some after decades of research. The culmination of these efforts will be novel treatments, and perhaps ultimately cures, for devastating and intractable illnesses. Greenleaf assists sponsors by optimizing FDA interactions and submissions to support development, manufacturing, quality, compliance, and regulatory review.

Cell & Gene Therapy Team

Greenleaf experts specializing in biologics and product quality, manufacturing, and compliance combine their deep knowledge to ensure that clients have integrated regulatory advice on cell and gene therapies — guided by decades of experience in senior FDA positions, global public health organizations, academia, and industry.

Our Cell & Gene Therapy Services

Product Development & Review


Members of Greenleaf’s Drug and Biological Products Team specialize in strategic communications with the FDA at every stage of product development ⎯ early INTERACT meetings, pre-IND and meetings throughout development, correspondence, clinical trial design, submissions, FDA review communications and labeling discussions, and postmarket requirements. The team also assists clients in preparing for milestone meetings.

Greenleaf helps sponsors understand and respond to FDA requirements for cellular products regulated as human tissues and for cellular products subject to additional regulation as biological products and/or medical devices.

In addition, our team monitors and analyzes the regulatory environment for emerging trends in cell and gene therapy regulation ⎯ including orphan drug designation and exclusivity, long-term follow-up requirements, companion diagnostics, the development and use of real-world evidence, and other agency policies and actions that could potentially impact current development programs ⎯ as well as changes to the competitive landscape for cell and gene therapies.

When issues arise related to comparability of early-phase and later-phase data, our experts help sponsors address the FDA’s questions and make the strongest arguments in support of their submission.

For sponsors developing cell and gene therapies to treat rare and ultra-rare diseases, Greenleaf provides guidance on ways to maximize trial design using appropriate clinical endpoints and natural history study data in support of efficient product development.

Greenleaf experts assist sponsors developing requests to the FDA for product development designations and approaches, including:

  • Orphan drug designation
  • Fast track designation
  • Regenerative medicine advanced therapy designation
  • Breakthrough therapy designation
  • Rare pediatric disease designation and other submissions related to priority review vouchers

The team also advises sponsors on accelerated approval and confirmatory studies when needed.

Learn more about the capabilities and services offered by Greenleaf’s Drug & Biological Products Team

Quality, Manufacturing & Compliance


For companies striving to introduce cell and gene therapy products to the market, establishing manufacturing and quality controls is one of the primary challenges. 

Greenleaf’s Product Quality, Manufacturing, and Compliance Team, along with its network of independent compliance experts, offers credible, informed guidance to help manufacturers of cell and gene therapies comply with the FDA’s multiple current GXP regulations. The team also assists clients with pre- and postapproval inspection readiness and FDA communications and facilitates engagement with CBER’s Advanced Technologies Team.

Greenleaf has effectively engaged with the FDA on behalf of clients to discuss, identify, and resolve potential technical and regulatory challenges related to emerging manufacturing technologies prior to regulatory submissions. Our team works with the Center for Biologics Evaluation and Research (CBER) Advanced Technologies Team (CATT) to support client development and implementation of cell and gene therapy manufacturing technology.

Manufacturers of cell and gene therapies are responsible for complying with multiple current GXP regulations, including: good manufacturing practice regulations (GMPs) and/or quality system regulations (QSRs); good laboratory practice regulations (GLPs); good clinical practice regulations (GCPs); and good tissue practice regulations (GTPs).

Greenleaf and our network of experts conduct compliance assessments and gap analyses at both the facility and corporate levels for manufacturing and quality practices and systems, including GMP, GCP, GTP, and QSR assessment, as well as:

  • Identification of critical quality attributes (CQA)
  • Chemistry manufacturing and controls (CMC) readiness
  • Manufacturing platform (e.g., manufacturing steps, implementing new technologies, and automated systems)
  • Quality- and compliance-related processes and procedures
  • Corporate training programs and corporate-wide quality systems
  • Audit programs
  • Risk management
  • Quality/compliance/clinical organizations

In these same areas, Greenleaf evaluates compliance assessments and delivers strategic and technical guidance and recommendations that will help the client implement system-wide quality enhancements.

Greenleaf and our network offer the following mock FDA inspection services to help clients prepare for routine GXP inspections and align the client’s organization with regulators’ expectations:

  • Preparing and conducting mock inspections
  • Conducting gap analyses
  • Facilitating communications with CBER’s Advanced Technologies Team
  • Identifying and prioritizing deficiencies
  • Providing corrective action support
  • Providing guidance during inspections
  • Assisting with revision and preparation of all relevant documents
  • Training and preparation in advance of an FDA inspection, covering such topics as: FDA inspection authority; inspection expectations; inspection terminology and guidelines; and inspection process, roles, and responsibilities

Greenleaf experts help clients prepare for and respond to identified GXP compliance problems with knowledgeable, objective analysis and evaluation of:

  • FDA Form 483s and company responses
  • Warning letters and company responses
  • Untitled letters and company responses
  • Internal and external audit reports
  • Establishment inspection reports
  • FDA regulatory correspondence and company responses
  • FDA communications relating to inspectional observations
  • Investigation and root cause analysis of deficiencies
  • Corrective and preventive action plans
  • Preparation for FDA meetings
  • Comprehensive corporate-wide and facility implementation plans

Learn more about the capabilities and services offered by Greenleaf’s Product Quality, Manufacturing, and Compliance Team

Advisory Services


Greenleaf understands the complex environment within which life science transactions take place and advises investors on potential issues and regulatory risks that may be identified during such transactions.

Learn more about the capabilities and services offered by Greenleaf’s Advisory Services Team

Success Stories

  • Evaluation & Development of a Cell and Gene Therapy Quality Management System

    A biopharmaceutical company well-versed in small molecule manufacturing processes requested Greenleaf’s support in building out its cell and gene therapy (CGT) manufacturing facility processes. Specifically, Greenleaf was asked to assist in developing the company’s Quality Management System (QMS) for new modalities in order to understand its positioning for sustainability and expansion of operations.  Greenleaf experts …

Cell & Gene Therapy Resources

View or download the PDFs below to learn more about Greenleaf and our cell and gene therapy capabilities.

Connect With an Expert

Greenleaf’s Cell & Gene Therapy Team is ready to help you achieve your regulatory goals. Please provide the information below and a team member will be in contact.

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