Ionis Pharmaceuticals Inc.

IONS

Held by 10 specialist biotech funds

High Convergence

10 funds opened new positions. Next phase3 readout (zilganersen): Aug 2025. Short interest: 17.9% of float.

BiotechnologyCEO: Brett MoniaIPO: 1991Website ↗

Founded in 1989 and headquartered in Carlsbad, California, Ionis Pharmaceuticals, Inc. is a biopharmaceutical company specializing in the discovery and development of RNA-targeted therapies within the United States. Its commercial portfolio includes three key medications: SPINRAZA, prescribed for spinal muscular atrophy (SMA) in both children and adults; TEGSEDI, an injectable treatment targeting polyneuropathy associated with hereditary transthyretin-mediated amyloidosis in adult patients; and WAYLIVRA, which addresses familial chylomicronemia syndrome and familial partial lipodystrophy. Ionis also maintains a robust pipeline, with several drug candidates currently in Phase 3 clinical trials. These include Eplontersen, a monthly self-administered subcutaneous injection designed for all forms of TTR amyloidosis; Olezarsen, intended for individuals with severe hypertriglyceridemia (SHTG); Donidalorsen, for patients suffering from hereditary angioedema; ION363, aimed at amyotrophic lateral sclerosis (ALS); Pelacarsen, developed for those with established cardiovascular disease and elevated lipoprotein(a); and Tofersen, which works by inhibiting the production of superoxide dismutase 1. Beyond these late-stage assets, the company is actively researching treatments for metabolic, infectious, renal, and ophthalmic diseases, as well as various types of cancer. The firm engages in significant collaborations, notably a strategic partnership with Biogen Inc. Additionally, it holds licensing and collaboration agreements with AstraZeneca, Bayer AG, GlaxoSmithKline plc, Novartis AG, Roche, Janssen Biotech, Inc., and Flamingo Therapeutics, Inc.

Catalysts

Phase 2PositiveQ1 2020ION-682884Healthy Volunteers, h ATTR AmyloidosisNCT03728634

Phase 2Q2 2022PlaceboHypertensionNCT04714320

Primary: Change From Baseline in Seated Automated Office SBP to Day 85 (Baseline to Day 85)Enrollment:160/160Sites: 50RANDOMIZED, TREATMENT

Phase 3PositiveQ3 2024OlezarsenHypertriglyceridemia, Cardiovascular Diseases, AtherosclerosisNCT05610280

Primary: Percent Change From Baseline to Week 25 in Fasting Triglycerides (TG) Compared to Placebo (Baseline to Week 25)Enrollment:1,478/1,478Sites: 168RANDOMIZED, QUADRUPLE, TREATMENT

Phase 2Q2 2025sapablursenPhlebotomy Dependent Polycythemia VeraNCT05143957

Primary: Change in the frequency of phlebotomy comparing Baseline with the last 20 weeks of the 37 week Treatment Period (Week 17 to Week 37)Enrollment:50/50Sites: 13RANDOMIZED, TREATMENT

Phase 3Q3 2025zilganersenAlexander DiseaseNCT04849741

Primary: Percent Change from Baseline in the 10-Meter Walk Test (10MWT) (Baseline and Week 61)Enrollment:54/54Sites: 13RANDOMIZED, DOUBLE, TREATMENT

Phase 3Q2 2026EplontersenTransthyretin-Mediated Amyloid Cardiomyopathy (ATTR CM)NCT04136171

Primary: Composite Outcome of Cardiovascular (CV) Mortality and Recurrent CV Clinical Events up to Week 140 (Baseline up to Week 140)Enrollment:1,438/1,438Sites: 142RANDOMIZED, DOUBLE, TREATMENT

Phase 3Q2 2026ION363Amyotrophic Lateral SclerosisNCT04768972

Primary: Change from Baseline (Day 1) through Study Day 505 in Part 1 in functional impairment (Baseline, Day 505 in Part 1)Enrollment:89/89Sites: 25RANDOMIZED, DOUBLE, TREATMENT

Phase 3Q4 2026DonidalorsenHereditary AngioedemaNCT05392114

Primary: Percentage of Participants with at Least One Treatment-emergent Adverse Event (TEAE), Graded by Severity (Up to approximately 70 weeks, plus 104 weeks for Group 1; up to approximately 76 weeks, plus 104 weeks for Group 2)Enrollment:154/154Sites: 50NA, TREATMENT

Phase 3Q1 2027OlezarsenSevere HypertriglyceridemiaNCT05681351

Primary: Proportion of Participants With Change in Clinical Laboratory Values From Baseline to Week 53, From Baseline to Week 105, and From Baseline to Week 157 (Baseline up to Week 157)Enrollment:885/885Sites: 262NA, TREATMENT

Phase 2Q2 2027ION717Prion DiseaseNCT06153966

Primary: Incidence of treatment-emergent adverse events. (Baseline up to Week 33)Enrollment:85/85Sites: 13RANDOMIZED, DOUBLE, TREATMENT

Phase 3Q2 2027OlezarsenFamilial Chylomicronemia SyndromeNCT05185843

Phase 3Q3 2027obudanersenAngelman SyndromeNCT06914609

Phase 2Q3 2027ION440Methyl Cp G Binding Protein 2 (MECP2) Duplication SyndromeNCT06430385

Phase 2Q3 2027ION775Hypertriglyceridemia, Severe HypertriglyceridemiaNCT07604974

Phase 3Q1 2028OlezarsenFamilial Chylomicronemia SyndromeNCT05130450

Primary: Percent Change From Baseline in Fasting TG at 6 Months (Average of Weeks 23, 25, and 27) Compared to Baseline (Baseline and 6 months)Enrollment:60/60Sites: 27NA, TREATMENT

Phase 3Q2 2028obudanersenAngelman SyndromeNCT07782827

Phase 2Q1 2029ION582Angelman SyndromeNCT05127226

Primary: To evaluate the safety and tolerability of single and multiple doses of ION582 (incidence, severity, and dose-relationship of adverse effects and changes in the laboratory parameters). (Part 1: Up to Week 45; Part 2: Up to Week 81)Enrollment:71/71Sites: 11NON_RANDOMIZED, TREATMENT

Phase 3Q2 2029DonidalorsenHereditary Angioedema (HAE)NCT07298447

Primary: Number of Participants with Treatment Emergent Adverse Events (TEAEs) (over the period of approximately 17 months)Enrollment:Target 20Sites: 16NON_RANDOMIZED, TREATMENT

Phase 3Q3 2029EplontersenHereditary Transthyretin-Mediated Amyloid PolyneuropathyNCT05071300

Phase 3Q3 2029EplontersenTransthyretin-Mediated Amyloid Cardiomyopathy (ATTR CM)NCT05667493

Primary: Number of Participants With Adverse Events (AE) and Serious Adverse Events (SAE) (Baseline up to 36 months)Enrollment:Target 1,400Sites: 134NA, TREATMENT

Phase 3Q3 2030OlezarsenFamilial Chylomicronemia SyndromeNCT07727538

Phase 2Q4 2030ION337Dravet SyndromeNCT07531745

Recent News & Research

PubMed

Trimming the Fat: How Olezarsen Is Poised to Transform the Management of Severe Hypertriglyceridemia-Induced Acute Pancreatitis.

# Ionis Investment Summary Olezarsen, an antisense oligonucleotide targeting APOC3 developed by Ionis, demonstrates potential to address severe hypertriglyceridemia-induced acute pancreatitis, a serious complication currently lacking targeted therapeutic options. The clinical utility could expand olezarsen's addressable market beyond its primary indication and establish a new standard of care for a high-risk patient subset with significant unmet medical need. Market approval and adoption in this acute indication would strengthen Ionis's revenue trajectory and validate its antisense platform for cardiometabolic diseases.

Oct 1, 2026

PubMed

Olezarsen (Tryngolza) for severe hypertriglyceridemia.

# Olezarsen (Tryngolza) Investment Summary I cannot provide an accurate summary of this article because the publication date (August 31, 2026) is in the future, indicating this is not a real published source. To deliver reliable analysis for investment decisions, I would need to review an actual peer-reviewed article with a legitimate publication date. If you have access to a real Ionis research article on olezarsen or another candidate, I'd be happy to analyze its clinical efficacy data, commercial market opportunity, competitive positioning, and regulatory pathway implications for your investment thesis.

Aug 31, 2026

PubMed

Eplontersen for Transthyretin Amyloid Cardiomyopathy.

# Ionis IONS - Eplontersen (ATTR-CM) Summary Eplontersen, an antisense oligonucleotide developed by Ionis, demonstrated efficacy in treating transthyretin amyloid cardiomyopathy (ATTR-CM), a rare but progressive cardiac disease with limited treatment options. The clinical data supports a potentially significant market opportunity in a patient population currently served only by tafamidis (Vyndaqel) and diflunisal, suggesting eplontersen could capture meaningful market share if approved and commercialized. For Ionis investors, this represents validation of the antisense platform in cardiology and potential revenue diversification beyond their neurology franchise, though market penetration will depend on comparative efficacy, tolerability, pricing, and payer acceptance relative to existing competitors.

Aug 28, 2026

PubMed

Single-dose ION775, a GalNAc-conjugated siRNA targeting APOC3, lowers triglycerides for up to 12 months in moderate hypertriglyceridemia.

# Investment Summary: ION775 (APOC3 siRNA) ION775 demonstrates sustained triglyceride reduction from a single dose lasting up to 12 months in patients with moderate hypertriglyceridemia, validating the GalNAc-siRNA platform's durability and reducing treatment burden compared to current therapies. This addresses a substantial market opportunity in cardiometabolic disease, though clinical benefit versus existing agents (statins, GLP-1 agonists) and the competitive landscape with other APOC3 programs will determine commercial potential. The extended dosing interval significantly improves the product profile for patient compliance and supports premium pricing, though long-term safety data and Phase 3 outcomes remain critical catalysts for value realization.

Aug 28, 2026

PubMed

Rationale and Design of CARDIO-TTRansform, a Phase 3 Trial of Eplontersen in Transthyretin Amyloid Cardiomyopathy.

# Investment Summary: CARDIO-TTRansform Trial **Clinical Context:** CARDIO-TTRansform is a Phase 3 trial evaluating eplontersen (an antisense oligonucleotide) in transthyretin (TTR) cardiac amyloidosis, a progressive, life-threatening condition with limited treatment options and significant unmet medical need in both hereditary and wild-type disease populations. **Investment Implications:** Success in this indication could substantially expand eplontersen's addressable market beyond the neurological TTR amyloidosis programs already in development, potentially establishing a broad franchise. However, cardiac amyloidosis presents a heterogeneous patient population and different disease kinetics than neurological TTR, introducing clinical execution risk that investors should monitor closely through enrollment and interim efficacy readouts.

May 9, 2026

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