Cellectis Buys Runway to 2028 But In Vivo Editing Remains Preclinical Promise

Cellectis Updates on Q3 2026 Financials and In Vivo Gene Editing Programs

Cellectis announced its financial results for the third quarter ended September 30, 2026, alongside a comprehensive update on its activities, highlighting a strategic pivot towards in vivo gene editing. The company reported a cash position of $149 million, extending its cash runway into the second half of 2028, supported by an operational realignment including a significant workforce reduction. Key preclinical data for its lead in vivo gene editing programs, .HEAL-101 for severe hypertriglyceridemia and .HEAL-201 for severe hypercholesterolemia, were presented, demonstrating promising efficacy and specificity. Both programs are on track for investigator-initiated Phase 1 trials in China, with initial clinical data expected in late 2027 and early 2028, respectively.

• Cellectis's .HEAL-101 program, targeting severe hypertriglyceridemia (sHTG) through in vivo APOC3 base editing, demonstrated robust preclinical efficacy. Data presented at ESGCT 2026 showed up to 70% in vivo APOC3 editing in humanized mouse models and a consistent 76% reduction in triglycerides in disease models. The program is progressing towards an investigator-initiated Phase 1 trial in China, with preliminary clinical data anticipated in the second half of 2027.
• The .HEAL-201 program, focused on in vivo epigenetic editing of PCSK9 for severe hypercholesterolemia (sHC), also reported strong preclinical results. Studies in humanized mouse models showed a profound reduction of over 90% in plasma PCSK9 levels following intravenous administration of the TALEM mRNA. Cellectis plans to initiate an investigator-initiated Phase 1 trial for .HEAL-201 in China, with initial clinical data expected in the first half of 2028.
• Cellectis is actively implementing a strategic transformation to become a pure-play in vivo gene editing company. This includes halting previous clinical programs (lasmé-cel and éti-cel) and an operational realignment projected to reduce the workforce by up to 70% by 2027. The company's financial position remains stable with $149 million in cash, cash equivalents, and term deposits as of September 30, 2026, extending its cash runway until the second half of 2028.

Why Current Severe Hypertriglyceridemia Treatments Fall Short

Severe hypertriglyceridemia remains difficult to control despite lifestyle modification and conventional lipid-lowering therapies. Most patients do not achieve adequate triglyceride control with lifestyle interventions or conventional lipid-lowering therapies, leaving them exposed to persistent complications including recurrent acute pancreatitis.

• Inadequate control and persistent risk: Despite an aggressive use of statin and fenofibrate with greater reductions in TG (-65.9 ± 13.7% vs. -27.9 ± 30.5%; p < 0.01), patients with type V hyperlipoproteinemia had persistent HTG (440.1 ± 239.0 mg/dL vs. 173.9 ± 94.8 mg/dL; p < 0.01) and an increase in LDL-C (28.3 ± 57.2% vs. -19.5 ± 32.0%; p < 0.01). The risk of acute pancreatitis persists with elevated triglyceride levels of over 500 mg/dL and a marked increase in risk with a triglyceride level of greater than 880 mg/dL.

• Safety and tolerability constraints: Due to the concurrent use of statin and fibrates, the patient subsequently developed an acute liver injury, oral medications had to be stopped, and the patient was admitted to the hospital for an insulin drip. DHA-containing formulations may also increase low-density lipoprotein cholesterol, though this is not accompanied by increased non-high-density lipoprotein cholesterol.

• Limited cardiovascular benefit of current add-ons: Randomized clinical trials have not demonstrated incremental ASCVD benefit of fibrates on background of statin therapy, but fibrates are used to help prevent pancreatitis in patients with severe hypertriglyceridemia. Currently, the only US Food and Drug Administration approved medication for CV risk reduction in patients with hypertriglyceridemia is icosapent ethyl.

• Dependence on secondary-factor correction and adherence: Correcting obesity, uncontrolled diabetes, alcohol misuse, and optimizing lifestyle choices, including dietary modification, is important before starting drug treatment. Due to non-compliance at home, the patient subsequently developed pancreatitis requiring treatment with an insulin drip, and even during hospital course triglyceride levels showed resistance to the recommended dose of insulin and required a higher insulin dose.

Unpacking .HEAL-101's APOC3 Gene Editing Mechanism

Severe hypertriglyceridemia reflects a spectrum from rare monogenic to predominant polygenic architecture. Familial chylomicronemia syndrome follows a biallelic inheritance pattern in which an individual inherits two pathogenic loss-of-function alleles of one of the five causal genes — LPL (in 60-80% of patients), GPIHBP1, APOA5, APOC2, and LMF1 — leading to the absence of lipolytic activity. In two independent cohorts of 251 and 312 Caucasian patients with severe HTG, 1.1% had biallelic (homozygous or compound heterozygous) rare variants, 14.4% had heterozygous rare variants, 32.0% had an extreme accumulation of common variants (ie, high polygenic risk), and 52.6% remained genetically undefined. Patients with HTG were 5.77 times (95% CI [4.26-7.82]; P < .0001) more likely to carry one of these types of genetic susceptibility compared with controls. Common variants associated with mild TG variation are also associated with severe HTG, including genotypes of APOA5 S19W, APOA5 -1131T > C, APOE, GCKR, TRIB1 and TBL2/MLXIPL, GALNT2 rs4846914, TBL2/MLXIPL rs17145738, TRIB1 rs17321515, ANGPTL3 rs12130333, GCKR rs780094, APOA5 rs3135506 (S19W), APOA5 rs662799 (-1131T > C) and LPL rs328 (S447X), with about one-quarter of the explained variation in disease status associated with these genotypes.

At the molecular and cellular level, clearance of triglyceride-rich lipoproteins depends on formation of lipolytic complex depending on the multiple positive (glycosylphosphatidylinositol-anchored high-density lipoprotein binding protein 1 [GPIHBP1], apolipoprotein C-II [APOC2], APOA5, heparan sulfate proteoglycan [HSPG], lipase maturation factor 1 [LFM1] and sel-1 suppressor of lin-12-like [SEL1L]) and negative regulators (APOC1, APOC3, angiopoietin-like proteins [ANGPTL]3, ANGPTL4 and ANGPTL8). GPIHBP1 is a crucial molecule for the translocation of LPL from parenchymal cells to the luminal surface of capillary endothelial cells, and maintenance of lipolytic activity; that is, hydrolyzation of triglyceride into free fatty acids and monoglyceride, and conversion from chylomicron to chylomicron remnant in the exogenous pathway and from very low-density lipoprotein to low-density lipoprotein in the endogenous pathway. The null mutation of GPIHBP1 causes severe hypertriglyceridemia and pancreatitis. Insulin resistance drives the increase in the three main sources of TG for VLDL synthesis: fatty-acid flux from adipose tissue, de novo lipogenesis, and uptake of remnant lipoproteins. Overproduction of VLDL, predominantly triglyceride-rich large VLDL1 particles, induces the cascade of events which lead to abnormalities of other plasma lipoproteins, while accumulation of VLDL in plasma and decreased activity of lipoprotein lipase (LPL) impair the catabolism of chylomicrons.

Progression to severe hypertriglyceridemia and the chylomicronemia syndrome results from a cluster of minor genetic variants causing polygenic hypertriglyceridemia, which is exacerbated by conditions or medications which increase triglyceride levels beyond the saturation point of triglyceride removal systems. These aggravating factors include common conditions such as uncontrolled diabetes, overweight and obesity, alcohol excess, chronic kidney disease and pregnancy and several medications, including diuretics, non-selective beta blockers, estrogenic compounds, corticosteroids, protease inhibitors, immunosuppressives, antipsychotics, antidepressants, retinoids, L-asparaginase, and propofol. In patients with type 2 diabetes, the elevated serum triglyceride levels negatively correlate with circulating LPL levels, and positively with circulating APOC1, APOC3, ANGPTL3, ANGPTL4 and ANGPTL8 levels. Heterozygosity contributes to 15-25% of multifactorial chylomicronemia syndrome (MCS) cases, with triglyceride phenotypes varying widely both between individuals and within the same individual over time, ranging from completely normal levels to severe hypertriglyceridemia, consistent with saturation of compromised lipolytic reserve modulated by polygenic background and secondary factors.

Where .HEAL-101 Fits in the Evolving sHTG Landscape

Severe hypertriglyceridemia (sHTG) has remained difficult to control with conventional agents, prompting re-evaluation of older classes alongside development of targeted therapies. Standard therapies with statins, fibrates, omega-3 fatty acids, and niacin may be insufficient to reduce elevated TG levels and improve clinical outcomes in patients with HTG. The REDUCE-IT trial showed that the addition of icosapent ethyl, a highly purified form of eicosapentaenoic acid (EPA), can reduce vascular events among statin-treated individuals with elevated triglycerides who have either clinical ASCVD or diabetes plus another risk factor, while the fibric acid derivative, pemafibrate, failed to reduce cardiovascular events despite significant reductions (~ 25-35%) in triglyceride levels and despite background statin therapy. In the ENHANCE-IT Study, EPA+DPA-FFA and EPA-EE reduced least squares geometric mean triglycerides from baseline: 20.9% and 18.3%, respectively (P=not significant), and in a multicenter, randomized, double-blinded, double-dummy, active-control, and noninferiority trial, the percent reduction from baseline in TG levels at week 12 was significantly higher in the saroglitazar group (least square mean = -55.3%; SE = 4.9) compared with the fenofibrate group (least square mean = -41.1%; SE = 4.9; P = 0.048).

The most substantive shift has come from apolipoprotein C-III (apoC-III) inhibition with antisense oligonucleotides and small interfering RNA. On December 19, 2024, the Food and Drug Administration approved olezarsen (Tryngolza), an antisense oligonucleotide targeting apolipoprotein C-III (apoC-III), for adults with FCS, administered monthly via subcutaneous injection. In the Phase 3 BALANCE trial, olezarsen reduced fasting triglycerides by approximately 60% at 12 months in patients with familial chylomicronemia syndrome (FCS), with a marked decrease in pancreatitis events versus placebo. In CORE-TIMI 72a and CORE2-TIMI 72b, the placebo-adjusted least-squares mean change from baseline in the triglyceride level was -62.9 percentage points in the olezarsen 50-mg group and -72.2 percentage points in the olezarsen 80-mg group in the CORE-TIMI 72a trial and was -49.2 percentage points in the olezarsen 50-mg group and -54.5 percentage points in the olezarsen 80-mg group in the CORE2-TIMI 72b trial (P<0.001 for all comparisons of olezarsen with placebo), and the incidence of acute pancreatitis was lower with olezarsen than with placebo (mean rate ratio, 0.15; 95% confidence interval, 0.05 to 0.40; P<0.001). For plozasiran, an APOC3-targeted small interfering-RNA (siRNA) drug, the SHASTA-2 phase 2b randomized clinical trial showed placebo-adjusted least squares (LS)-mean reductions in triglyceride levels of -57% (95% CI, -71.9% to -42.1%; P < .001) at week 24 with the highest dose, and among plozasiran-treated patients, 144 of 159 (90.6%) achieved a triglyceride level of less than 500 mg/dL. Across 14 randomized trials comprising 3,422 participants, treatment with apoC3 inhibitors resulted in significant reductions in triglyceride levels compared with placebo (mean difference -58.7%; 95% CI -62.3 to -55.1) and was associated with a significantly lower risk of acute pancreatitis (odds ratio 0.20; 95% CI 0.10 to 0.40).

Angiopoietin-like protein 3 (ANGPTL3) inhibition has evolved as a parallel pathway, with more heterogeneous results by modality and population. After the failure of vupanorsen, a new angiopoietin-like protein 3 (ANGPTL3) inhibitor, zodasiran, demonstrated the potential to decrease TG levels in patients with moderate HTG. In a phase 2 trial (NCT03452228) in severe hypertriglyceridemia, evinacumab reduced triglycerides in cohort 3 by a mean (s.e.m.) of -27.1% (37.4) (95% confidence interval -71.2 to 84.6), but the prespecified primary end point was not met. In a 16-week phase 1 trial of zodasiran, an ANGPTL3-targeting small interfering RNA, all cohorts showed reductions at week 16 (12 weeks postdosing) in serum ANGPTL3 (≤-85.4%) and triglycerides (≤-67.1%), and at their longest clinical trial follow-up, the highest doses of olezarsen, plozasiran, and zodasiran lowered TG by 55.2%, 50.57%, and 51.2% of baseline levels. Meanwhile, the fibroblast growth factor 21 (FGF21) analog, pegozafermin, became another candidate for the treatment of severe HTG, and the newest innovation is CRISPR-mediated disruption of ANGPTL3 (CTX310), with genome-editing approaches (e.g. VERVE-201 and CTX310) positioned as potential one-time correction strategies if long-term efficacy and tolerability are confirmed in phase 3 trials.