The enrollment for the potentially pivotal Phase 2 Alpha2 trial of ALLO-501A in large B-cell lymphoma is a significant milestone for Allogene Therapeutics. Positive results from this trial could lead to regulatory approval and commercialization of the drug, which would positively impact the company's stock price. However, the completion of enrollment is expected in H1 2024, so the impact on the stock price may not be immediate.