Why is Arcellx stock up 80% today? Gilead's $7.8B answer

Core Viewpoint - Arcellx's stock surged approximately 80% following Gilead Sciences' announcement to acquire the cancer-therapy developer for $7.8 billion in an all-cash deal, with a definitive buyout price set at $115 per share [1]. Deal Structure - Gilead will pay $115 per share in cash, plus a contingent value right (CVR) worth an additional $5 per share if Arcellx's lead therapy, anito-cel, achieves at least $6 billion in cumulative global net sales by the end of 2029 [1]. - The total offer represents a premium of about 87% over Arcellx's previous closing price, prompting immediate trading activity towards the buyout price [1]. - The transaction is structured as a tender offer followed by a second-step merger, already approved by both companies' boards [1]. Strategic Importance - Gilead is acquiring anitocabtagene autoleucel (anito-cel), a CAR-T therapy for relapsed or refractory multiple myeloma, which presents a significant commercial opportunity despite intense competition from established products like Johnson & Johnson's Carvykti [1]. - Analysts have previously noted supportive data for anito-cel's potential, with comparisons to Carvykti as the datasets have matured [1]. - The FDA is expected to make a decision on anito-cel by December 23, 2026, which positions the acquisition within a near-launch timeframe rather than a distant research phase [1]. Historical Context - Gilead and Arcellx have collaborated in cell therapy since 2022, making this acquisition a consolidation of a program that Gilead is already familiar with [1].