Optimizing lyophilization cycle parameters for antibody-drug conjugate stability in Kansai region contract manufacturing facilities

How narrow is the operating window between a lyophilization cycle that preserves an antibody-drug conjugate and one that wrecks it? This research set out to map that boundary for a model ADC (trastuzumab-DM1 surrogate) processed at a contract manufacturing organization in the Kansai region of Japan. Four freeze-drying cycles conservative, moderate, aggressive, and a design-of-experiments-optimized variant were run on a pilot-scale lyophilizer (LyoStar 3, SP Scientific) loaded with 10 mL glass vials containing 25 mg/mL ADC in a sucrose-histidine formulation buffer. Residual moisture, cake appearance, reconstitution time, size-exclusion chromatography purity, drug-to-antibody ratio, and cytotoxic potency were measured at release and after 3 and 6 months of storage at 5 °C. The optimized cycle (Cycle D: freezing at -45 °C, primary drying at -30 °C shelf and 80 mTorr, secondary drying at 30 °C for 6 hours) produced cakes with 0.9% residual moisture, less than 1.2% aggregate by SEC, and a potency retention of 93.6% after 6 months well within the predefined 90% specification. Cake collapse occurred in the aggressive cycle when shelf temperature exceeded -25 °C during primary drying, correlating with loss of potency to 82.7% at 6 months. The results show that shelf temperature during primary drying is the single most influential parameter for ADC lyophilized cake quality and that a narrow band around -30 °C balances process efficiency against product stability.