IONIS PHARMACEUTICALS INC
IONS evidence brief
What we can confirm
What it means
What to watch
Prepared research question
What matters most for IONS—catalysts, financial risk and supporting evidence?
Traceable citations · Unknowns marked
BioSniper AI · IONS
Ionis Pharmaceuticals is a biotech company focused on RNA-targeted therapeutics, with a pipeline in neurology, cardiology, and other areas, and a marketed portfolio including QALSODY, SPINRAZA, TEGSEDI, and WAYLIVRA.
Key risk: Dependence on funding
BioSniper Score
Based on 6 of 6 signals
Financial data as of Jun 30, 2026.
Tracking 4 pipeline candidates · 38 clinical trials · 15 catalysts · 2 FDA decisions for IONIS PHARMACEUTICALS INC.
Similar companies
Ionis Pharmaceuticals is a biotech company focused on RNA-targeted therapeutics, with a pipeline in neurology, cardiology, and other areas, and a marketed portfolio including QALSODY, SPINRAZA, TEGSEDI, and WAYLIVRA.
- Ionis has a large, diverse pipeline of over 40 first-in-class or best-in-class medicines [sec · filed 2019-08-08].
- The company achieved three positive mid-stage pipeline readouts and advanced one wholly-owned program to Phase 3 development in 2025 [sec · filed 2026-04-23].
- As of 2026-06-30, Ionis reported cash & equivalents of $350.1M, total revenue of $267.9M, and a net loss of -$114.6M [sec].
- Ionis has upcoming PDUFA and Phase 3 topline readouts for several programs, including zilganersen (PDUFA 2026-09-22), donidalorsen, and olezarsen [upcoming catalysts].
- The company exceeded its 2025 annual revenue budget target and obtained on-time EU approval for FCS with a competitive label [sec · filed 2026-04-23].
What works
- Ionis has a sustained and growing revenue stream from marketed medicines and partnerships, supporting its pipeline development [sec · filed 2019-08-08].
- The company's drug discovery platform is broadly applicable and has produced a rich late- and mid-stage pipeline in neurology, cardiology, and other areas [sec · filed 2025-04-25].
- Ionis significantly outperformed the Nasdaq Biotechnology Index in 2025, with stock performance at 134% versus the NBI median of 27% [sec · filed 2026-04-23].
What to weigh
- Ionis has a history of net losses, reporting a net loss of -$114.6M as of 2026-06-30 [sec].
- The company faces risks related to obtaining timely funding; if it fails to meet commercialization goals, it may need additional funding and could curtail or abandon some programs [sec · filed 2023-08-09].
- Many of Ionis's medicines are in early stages of development and will require significant additional research, clinical testing, and regulatory approval before commercialization [sec · filed 2023-08-09].
From the filings
Quoted directly from source documents.
Ionis has a large, diverse pipeline of over 40 medicines.
“Our large, diverse and advanced pipeline of over 40 first-in-class and/or best-in-class medicines addresses diseases across a broad range”
SEC filings · August 8, 2019
Ionis exceeded its 2025 annual revenue budget target.
“Exceeded specified annual revenue budget target”
SEC filings · April 23, 2026
Ionis has a rich late- and mid-stage pipeline in neurology, cardiology and other areas.
“we have a rich innovative late- and mid-stage pipeline in neurology, cardiology and sel”
SEC filings · April 25, 2025
Catalyst timeline
- 2026-09-22 · PDUFA · zilganersen — PDUFA date for zilganersen; approval decision will determine market entry for this neurology candidate.
- 2027-03-01 · Phase3_Topline · donidalorsen — Phase 3 topline readout for donidalorsen in prophylactic treatment; results will inform efficacy and safety profile.
- 2027-03-01 · Phase3_Topline · olezarsen — Phase 3 topline readout for olezarsen; data will support potential regulatory submission.
- 2027-06-01 · Phase3_Topline · akcea-apociii-lrx — Phase 3 topline readout for AKCEA-APOCIII-LRx; results will guide further development in cardiology.
- 2028-02-01 · Phase3_Topline · akcea-apociii-lrx — Phase 3 topline readout for AKCEA-APOCIII-LRx extension study; long-term safety data expected.
- 2028-03-01 · Phase3_Topline — Phase 3 topline readout for an undisclosed program; efficacy and safety data to be evaluated.
- 2029-06-01 · Phase3_Topline · donidalorsen — Phase 3 topline readout for donidalorsen in pediatric patients; pediatric efficacy and safety data.
- 2029-08-01 · Phase3_Topline — Phase 3 topline readout for eplontersen extension study; long-term safety data expected.
Risks & what to watch (3)›
Key risks
- Dependence on funding — If Ionis fails to obtain timely funding, it may need to curtail or abandon some programs [sec · filed 2023-08-09].
- Clinical and regulatory uncertainty — Many medicines are in early stages and require significant additional research, testing, and approval before commercialization [sec · filed 2023-08-09].
- Commercialization risks — Failure to successfully commercialize key medicines like QALSODY or SPINRAZA could require additional funding [sec · filed 2023-08-09].
What to watch
- PDUFA date for zilganersen on 2026-09-22 [upcoming catalysts].
- Phase 3 topline readouts for donidalorsen and olezarsen expected around 2027-03-01 [upcoming catalysts].
- Phase 3 topline readouts for AKCEA-APOCIII-LRx expected in 2027 and 2028 [upcoming catalysts].
- Ionis's ability to manage cash runway given net losses and upcoming development costs [sec].
Sources: SEC filings · Generated August 29, 2026 · How we verify sources →
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Evidence & data
Score breakdownBased on 6 of 6 signals · derived from public data
Profitable (positive operating cash flow)
D/E 5.81 · 0% dilution
Lead: Approved
4 candidates
15 upcoming, next in ~23d
2 buys · 63 sells (180d)
Catalysts
Pipeline
Regulatory
Financials
Institutional Holdings
Source: SEC Form 13F · as of Mar 2026Institutional holders
492
Total value held
$11.35B
| Holder | Shares | Value |
|---|---|---|
| fmr llc | 24,556,637 | $1.84B |
| vanguard capital management llc | 14,236,660 | $1.07B |
| blackrock, inc. | 10,442,476 | $784.1M |
| vanguard portfolio management llc | 7,808,902 | $586.4M |
| wellington management group llp | 6,391,816 | $480.0M |
| two sigma investments, lp | 5,857,629 | $439.8M |
| geode capital management, llc | 3,984,332 | $305.2M |
| state street corp | 3,995,564 | $300.0M |
| royal bank of canada | 3,801,815 | $285.5M |
| jpmorgan chase & co | 2,363,567 | $171.4M |
Showing top 10 of 492 institutional holders of IONIS PHARMACEUTICALS INC. Open the full 13F history after sign-in.
Short Interest
as of Apr 30, 2026- % of float
- 11.0%
- Days to cover
- 6.9
- Shares short
- 13,762,159
- Daily short volume
- -
Short percent of float and days-to-cover reflect reported short positioning. Daily short volume is the exchange-reported short share of a single day's trading volume and is noisier. See the most-shorted biotech ranking →
IONS short interestGovernance
Frequently asked questions
What is the AI investment thesis for IONIS PHARMACEUTICALS INC?
Ionis Pharmaceuticals is a biotech company focused on RNA-targeted therapeutics, with a pipeline in neurology, cardiology, and other areas, and a marketed portfolio including QALSODY, SPINRAZA, TEGSEDI, and WAYLIVRA.
What is IONIS PHARMACEUTICALS INC's lead drug candidate?
IONIS PHARMACEUTICALS INC's most advanced tracked candidate is dawnzera (Approved).
What is IONIS PHARMACEUTICALS INC's next catalyst?
IONIS PHARMACEUTICALS INC's next tracked catalyst is a PDUFA event — "PDUFA Date: zilganersen" — expected September 22, 2026.
Who is the CEO of IONIS PHARMACEUTICALS INC?
Dr. Brett P. Monia Ph.D. is the chief executive officer of IONIS PHARMACEUTICALS INC (IONS).
Where is IONIS PHARMACEUTICALS INC headquartered?
IONIS PHARMACEUTICALS INC (IONS) is headquartered in Carlsbad, CA, United States.
The AI overview and BioSniper Score are neutral, data-derived signals built from public SEC filings, ClinicalTrials.gov and FDA records — not investment advice.