Skyhawk Therapeutics Announces Final Fifteen-Month Results from Phase 1/2 Clinical Trial of SKY-0515 in Huntington’s Disease Patients

• The fifteen-month dataset represents the final analysis from the Phase 1/2 study

• At the Month 15 primary timepoint, SKY-0515-treated patients showed a +1.59-point difference in Composite Unified Huntington’s Disease Rating Scale (cUHDRS) change from baseline versus overlap-weighted external natural history control

• Differences favoring SKY-0515 were statistically significant across all four cUHDRS components –Total Functional Capacity, Total Motor Score, Symbol Digit Modalities Test and Stroop Word Reading Test – and cUHDRS differences favored SKY-0515 at every prespecified timepoint in the study

• SKY-0515 has shown consistent average reductions in mutant huntingtin protein (mHTT)

throughout the study of more than 60% at the 9 mg dose

• SKY-0515 has shown consistent average reductions in PMS1 mRNA of more than 25% at the 9 mg dose

• The Company’s Phase 1/2 program and global Phase 2/3 FALCON-HD 004-ANZ + 004-WW

pivotal program for Huntington’s disease now have enrolled over 200 patients across twenty trial sites in ten countries.