The US FDA has remarkably granted full and accelerated approval to Precigen’s gene therapy Papzimeos for treating recurrent respiratory papillomatosis (RRP), a rare disease characterized by benign respiratory tract tumors caused by HPV 6 and 11 infections. This regulatory milestone is unprecedented for this condition and underscores the agency’s flexibility in approving therapies for rare diseases without requiring confirmatory randomized trials. The approval, announced ahead of schedule, highlights the unmet clinical need and strong data from an open-label study. The therapy is expected to generate substantial sales growth, reflecting its significant market potential given the estimated 1,000 annual new RRP cases in the US. Precigen’s breakthrough not only marks a key first for RRP but also sets a precedent for expedited development of nonreplicating adenoviral vector-based immunotherapies.