Validation of Selective Target Engagement
Cytosolic Hsp Sparing (Critical De-Risking Data)
Direct comparative studies versus 17-AAG demonstrate:
Marker | 17-AAG | Gam-05 |
Akt degradation | ↓ | Unchanged |
Chk1 degradation | ↓ | Unchanged |
Heat shock response | ↑ | Not induced |
Conclusion: Gam-05 does not inhibit cytosolic Hsp, confirming true compartmental selectivity.
Sensitive Signaling Readout: Src Phosphorylation
- Src kinase is highly dependent on cytosolic Hsp for stability.
- Even subtle cytosolic Hsp inhibition rapidly alters p-Src
- Gam-05 shows no disruption of Src phosphorylation, further confirming absence of off-target cytosolic effects.
This level of mechanistic validation is uncommon at Phase I entry and significantly reduces class-associated risk.
