Positive Initial Clinical Data from Phase 1 Trial with ALN-PCSsc

Alnylam and The Medicines Company reported positive initial results from the ongoing Phase 1 clinical trial with ALN-PCSsc, an investigational RNAi therapeutic targeting PCSK9 for the treatment of hypercholesterolemia.  Subcutaneous administration of ALN-PCSsc resulted in an up to 83% lowering of LDL-C, with an up to 64 ± 5% mean maximum reduction, comparable to published results for anti-PCSK9 monoclonal antibodies (Zhang XL., et al., BMC Med, 2015).  Similar reductions in LDL-C were seen in patients on and off concomitant statin therapy.  The effects of ALN-PCSsc were highly durable, with clinically significant and clamped reductions in LDL-C maintained for over 140 days, supportive of a once-quarterly and possibly bi-annual subcutaneous dose regimen. Maximal lowering effects on LDL-C were consistently achieved at a dose of 300 mg associated with a low injection volume of 1.5 mL. Importantly, ALN-PCSsc was generally well tolerated with no clinically significant adverse events to date.

We believe that ALN-PCSsc, a first-in-class PCSK9 synthesis inhibitor, has a highly competitive profile as compared with anti-PCSK9 monoclonal antibodies that are labeled for twice-monthly dosing. In particular, we believe that a maximally efficacious and well tolerated quarterly or potentially bi-annual, low volume subcutaneous dosing regimen could address the unmet needs for hypercholesterolemia management in a massive, at-risk, often non-adherent population worldwide.  Moreover, we imagine that ALN-PCSsc has the potential to open new innovation horizons with patients, providers, and payers by linking the temporal cycle of LDL-C monitoring with administration of therapy. Overall, we believe that ALN-PCSsc potentially represents an innovative, differentiated, and well validated approach for the treatment of hypercholesterolemia.