Serum-free production of anti-huCD20(hγ1)-IL2no-alpha immunocytokine: a promising therapeutic for B-NHL

Introduction: Mammalian cell cultures are widely used for producing complex biopharmaceuticals that require human-like post-translational modifications, such as antibody-based therapeutics. Traditionally, serum-supplemented media support high cell viability and productivity; however, regulatory and scientific requirements demand serum-free conditions for clinical-grade manufacture. Recently, a novel fusion protein, the anti-huCD20(hγ1)-IL2no-alpha immunocytokine (IC), was presented as a promising therapeutic alternative, mostly for relapsed or refractory (r/r) B-cell non-Hodgkin lymphoma (B-NHL) patients, considering currently approved therapies. Methods: Three Chinese hamster ovary clones (K1 strain) producing the anti-huCD20(hγ1)-IL2no-alpha IC were generated and adapted to serum-free suspension culture. We performed a kinetic characterization of one clone in two culture media with different nutritional compositions, evaluating cell growth, productivity, cell cycle progression and mTOR signaling. The IC was purified by Protein A, then evaluated for identity, aggregation profile, CD20 recognition, CTLL-2 cytokine activity, ex vivo B-cell depletion in PBMC from r/r B-NHL patients and antitumor efficacy in immunocompetent C57BL/6 mice bearing EL4-hCD20- cells. Results: The results demonstrated noticeable differences in cell growth and productivity in both batch and pseudo-perfusion performance, likely due to an influence on cell-cycle progression and mTOR signaling. The purified IC maintained its structural integrity while exhibiting an improved aggregation profile compared to serum-containing cultures. Furthermore, key biological activities, including B-cell depletion and antitumoral effects, remained intact. Discussion: This research highlights the successful serum-free production of a functional anti-huCD20(hγ1)-IL2no-alpha IC, reinforcing its potential for biopharmaceutical development.