Cullinan Therapeutics (CGEM) Soars 17.47% as Phase 1 AML Trial Data, FDA Fast Track Spark Pre-Market Rally

Cullinan Therapeutics (CGEM) surged 17.4693% in pre-market trading on Dec. 9, 2025, following the release of Phase 1 clinical data for its FLT3xCD3 bispecific T cell engager, CLN-049, which showed 25% complete response (CR)/CR with hematologic improvement (CRh) at doses ≥6 µg/kg in relapsed/refractory AML patients.

The trial, presented at the 67th ASH meeting, highlighted a 31% CR/CRh rate at the highest tested dose (12 µg/kg) and favorable safety profile, with 63% of responders maintaining durable responses for over 16 weeks. The drug received FDA Fast Track designation, accelerating its development timeline, with expansion cohorts planned in early 2026.

Positive data included measurable residual disease (MRD) negativity in 30% of patients and manageable side effects, such as grade 1-2 cytokine release syndrome in 35.6% of cases. These results position CLN-049 as a potential first-in-class therapy for AML, particularly for high-risk subtypes like TP53-mutated cases, where treatment options remain limited.

Analysts are optimistic about the long-term potential of CLN-049, given the high unmet need in AML treatment and the molecule’s differentiated mechanism. The company is also preparing for regulatory consultations to define the path forward for pivotal trials. Meanwhile, short-term market reactions may be influenced by broader biotech sector sentiment and upcoming data reads in 2026.

With its recent momentum and the potential to attract partnerships or licensing deals, CGEM is drawing attention from both institutional and retail investors. However, investors are reminded of the inherent risks in early-stage biotech investments, including the variability of clinical outcomes and regulatory hurdles.