From R&D to GMP: Successful Clinical-Grade Manufacturing of an NK Cell Therapy

Context and Challenge

Cell Easy’s client, a European biotech working on an allogeneic NK cell immunotherapy, had initially developed their process in an academic research setting suitable for small-scale R&D and exploratory work. However, it lacked robustness, reproducibility, and regulatory rigor required for clinical trials. The company’s key objective was to adapt and scale up their process under GMP conditions to support a First-in-Human (FIH) clinical trial. The final product needed to meet strict quality attributes such as safety, potency, and stability without compromising the unique biological properties of NK cells.

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Our Approach:

01. Ex Vivo expansion of NK Cells

Challenge: NK cells are known for their inherent biological complexity and relatively low proliferative capacity compared to other immune cell types like T cells. Achieving their expansion without loss of cytotoxic function posed significant challenges due to the risk of cell exhaustion under GMP conditions, where process flexibility is limited and culture durations tend to be longer.

Our solution: We optimized media composition and feeding schedules to maintain ideal cytokine and nutrient levels, carefully calibrated feeder cell ratios and seeding densities to enhance expansion while minimizing exhaustion and implemented strategic timing for interventions to preserve NK cell phenotype and maximize overall yield.

Fig 1: Harvest Density During NK Cell Expansion Scale-up – Cell Easy

02. Feeder Cell Process Development

Challenge: Scaling a feeder-dependent process to GMP manufacturing required the creation of both a Master and a Working Cell Bank for feeder cells. This had to be done while addressing key challenges: limited feeder cell availability, the limitations of small-scale academic protocols, and the operational complexity of maintaining consistency at large scale.

Our solution: We scaled up from small culture formats to large bioreactors, then we implemented a two-tier expansion strategy with an intermediate feeder cell bank. This allowed the feeder cell quantity to improve sixfold. This significantly improved cost-efficiency and process consistency.

Fig 2: Fold Expansion during Feeder Cell Scale-Up– Cell Easy

03. Cryopreservation and Stability

Challenge: A critical requirement for the client’s allogeneic NK therapy was maintaining NK cell viability and cytotoxic activity following cryopreservation at –150 °C. This is particularly challenging due to the cells’ high sensitivity to osmotic stress, limitations of commonly used cryoprotectants, and the risk of intracellular ice formation during freezing, all of which can compromise product quality upon thawing.

Our solution: We established a controlled-rate freezing protocol designed to minimize intracellular ice formation, safeguarding cell integrity during cryopreservation. A custom cryoprotectant formulation was developed and optimized for NK cell preservation, improving post-thaw viability and potency. In parallel, we standardized thawing procedures to ensure reproducible recovery and consistent functional performance across clinical sites, supporting product deployment in multicenter trials.

Fig 3: NK Cell Recovery After Thawing– Cell Easy

04. GMP-Compliant Sourcing and Regulatory Strategy

Challenge: Bringing this NK cell therapy from early-stage development to clinical readiness required overcoming multiple hurdles simultaneously: securing a reliable supply of GMP-grade starting material, ensuring full traceability, and navigating complex regulatory and CMC requirements—all while adapting the process to a new scale and maintaining product quality.

Our solution: Cell-Easy delivered an integrated approach combining supply chain reliability with expert regulatory and CMC support. This included sourcing GMP-compliant cord blood through trusted European partners, embedding quality and traceability into the supply process, qualifying key subcontractors, conducting preclinical toxicology studies, managing regulatory interactions with ANSM, and finalizing the IMPD.

Results and outcome

Over a 28-month collaboration, Cell-Easy successfully transformed a research-stage NK cell program into a GMP-compliant manufacturing process ready for clinical application. This achievement included the production and qualified release of one GMP engineering batch and two GMP clinical batches-each meeting all predefined quality and release specifications.

By integrating process development with rigorous quality assurance and regulatory oversight, we ensured full alignment with European GMP standards throughout the project lifecycle. These coordinated efforts culminated in the successful submission and approval of the client’s Clinical Trial Application (CTA), enabling the initiation of Phase 1 patient dosing. This milestone marks a significant step toward bringing a novel NK cell therapy to patients.

Complete process
redevelopment

From academic R&D to GMPcompliant scale-up

3 GMP batches produced

One engineering and two
clinical batches

Integrated quality and regulatory workflows

Ensuring full compliance with European regulations

CTA
approved

Authorizing initiation of Phase 1 patient dosing

Conclusion

This collaboration illustrates Cell-Easy’s capacity to deliver comprehensive, GMP-compliant solutions for complex cell therapy products. From feeder-based process development to regulatory approval, we provided a seamless end-to-end service enabling clinical translation.

As a specialized CDMO in cell therapies, Cell-Easy accelerates product development by combining deep scientific expertise, GMP manufacturing capabilities, and regulatory insight. Whether your program is in early discovery or near clinical transition, we are ready to be your trusted partner in bringing advanced therapies to life.

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