Announcement • Aug 29
CRISPR Therapeutics AG Presents Phase 1A Data for Ctx310 Demonstrating Deep and Durable Angptl3 Editing, Triglyceride and LDL Lowering
CRISPR Therapeutics presented durability data from its Phase 1a clinical trial evaluating CTX310, an investigational, in vivo CRISPR/Cas9 gene editing therapy targeting ANGPTL3. A single-course treatment with CTX310 produced deep and durable reductions in circulating ANGPTL3, triglycerides (TG), and low-density lipoprotein (LDL) that were sustained through one year of follow-up. At the highest dose, mean reductions from baseline were 79% (maximum 89%) for ANGPTL3, 48% (maximum 78%) for TG, and 53% (maximum 84%) for LDL. These extended follow-up data demonstrate the durability of CTX310's effect and support its potential to deliver long-lasting lipid lowering after a single intravenous (IV) infusion. The Phase 1a portion of the study was an open label, dose-escalation trial evaluating single-course IV doses of CTX310 ranging from 0.1 to 0.8 mg/kg (lean body weight) targeting ANGPTL3 in four patient groups: homozygous familial hypercholesterolemia (HoFH), severe hypertriglyceridemia (sHTG), heterozygous familial hypercholesterolemia (HeFH), or mixed dyslipidemias (elevated TG and LDL). Eligible participants had uncontrolled TG levels >150 mg/dL and/or LDL cholesterol >100 mg/dL (or >70 mg/dL for those with established ASCVD) despite background standard of care per local guidelines. The majority of participants were receiving statins and/or ezetimibe, while 40% were taking PCSK9 inhibitors. The trial was designed to evaluate safety and tolerability as primary endpoints, with changes in circulating ANGPTL3 protein, TG, and LDL as secondary endpoints. Single-course ascending doses of CTX310 were administered to 15 participants across sequential cohorts, and all participants completed at least one-year of follow-up as of the data cutoff. CTX310 was generally well tolerated, and no dose-limiting toxicities or serious adverse events related to treatment. Adverse events were generally mild to moderate. As previously reported in Laffin et al. (2025), one participant experienced an allergic reaction that resolved the following day with supportive care. Infusion-related reactions occurred in three participants (two at 0.6 mg/kg and one at 0.8 mg/kg dose), all Grade 2. All events resolved, and all participants completed their infusions. Beyond the transient aminotransferases elevation previously reported in one participant shortly after treatment, there were no liver function test elevations throughout the remainder of the trial. The safety events described above were previously reported in Laffin et al. (New England Journal of Medicine, 2025) and reflect the initial treatment period of the Phase 1a clinical trial. No new treatment-related safety events were observed during extended follow-up. These new results build upon previously disclosed clinical data from 15 participants across four sequential cohorts, corresponding to lean body weight-based doses of DL1 [0.1 mg/kg], DL2 [0.3 mg/kg], DL3 [0.6 mg/kg], DL3.5 [0.7 mg/kg] and DL4 [0.8 mg/kg]. All participants had at least one-year of follow-up. Dose dependent reductions in circulating ANGPTL3 protein were sustained through one-year following CTX310 infusion. Among participants treated at 0.8 mg/kg, ANGPTL3 reductions of up to 89% were observed, with a mean reduction of 79% at one-year following CTX310 infusion. The Phase 1b portion of the trial examines a fixed flat dose regimen of CTX310 equivalent to the most efficacious dose in Phase 1a (0.8mg/kg). CRISPR Therapeutics continues to anticipate sharing an update from the CTX310 Phase 1b clinical trial in the second half of 2026, focused on severe hypertriglyceridemia patients. CRISPR Therapeutics has established a proprietary lipid nanoparticle (LNP) delivery platform to enable gene editing in the liver using both CRISPR/Cas9 and its novel, proprietary SyNTase editing technology. The Company's in vivo portfolio includes three cardiovascular programs: CTX310, targeting angiopoietin-related protein 3 (ANGPTL3), in development for heterozygous and homozygous familial hypercholesterolemia, mixed dyslipidemias, and severe hypertriglyceridemia; CTX340, targeting angiotensinogen (AGT), in development for refractory hypertension; and CTX321, targeting LPA, in development for patients with elevated lipoprotein(a) [Lp(a)]. In addition, the Company's disclosed development candidates also include CTX460, targeting SERPINA1 using SyNTase editing, for the treatment of alpha-1 antitrypsin deficiency (AATD). Reference: Laffin L, et al. Phase 1 Trial of CRISPR-Cas9 Gene Editing Targeting ANGPTL3. The New England Journal of Medicine. 2025.