What is RNA interference (RNAi) and how do Arrowhead's drugs work?

RNA interference (RNAi) is a natural cellular mechanism that regulates gene expression — discovered by Andrew Fire and Craig Mello in 1998 (Nobel Prize 2006). How RNAi works: genes are transcribed from DNA into messenger RNA (mRNA) which carries the genetic instructions to ribosomes where proteins are made; the RNAi pathway uses small interfering RNA (siRNA) molecules that are complementary to a specific mRNA target; when siRNA binds to its target mRNA, an enzyme complex (RISC — RNA-Induced Silencing Complex) cleaves and degrades the mRNA; without mRNA, the ribosome cannot make the corresponding protein. Drug application: if a disease is caused by too much of a specific protein (e.g., PCSK9 that reduces LDL receptors causing high cholesterol, or APOC3 that elevates triglycerides), an RNAi drug can silence the gene producing that protein; the therapeutic goal is to knock down a disease-causing protein by degrading its mRNA before the protein is produced. Arrowhead's approach: Arrowhead uses GalNAc (N-acetylgalactosamine) conjugation to deliver siRNA specifically to liver cells; GalNAc binds to ASGPR receptors on liver cell surfaces; this liver targeting is why Arrowhead's current pipeline focuses on liver-expressed proteins (APOC3, ANG3, HSD17B13 — fatty liver target).

What is H. pylori and why is Voquezna's H. pylori indication significant?

Helicobacter pylori (H. pylori) is a gram-negative bacteria that infects the stomach lining of approximately 44% of the global population — making it one of the most common human bacterial infections. H. pylori pathology: in most infected individuals, H. pylori is asymptomatic; however, H. pylori causes: peptic ulcer disease (the primary cause of stomach and duodenal ulcers), chronic gastritis (stomach inflammation), and is a significant risk factor for gastric cancer (classified as a Group 1 carcinogen by IARC). Standard H. pylori treatment: the classic regimen is PPI triple therapy — a proton pump inhibitor (twice daily) + clarithromycin + amoxicillin for 14 days; eradication rates with PPI triple therapy have declined to approximately 70-80% in the U.S. due to antibiotic resistance (particularly clarithromycin resistance). Why vonoprazan may improve H. pylori eradication: antibiotics work better in near-neutral pH environments; vonoprazan achieves higher and more sustained gastric pH than PPIs; clinical trials in Japan (where clarithromycin resistance is higher than the U.S.) showed vonoprazan triple therapy eradication rates of approximately 85-92% versus approximately 70-78% for PPI triple therapy; if vonoprazan can improve eradication rates from ~75% to ~88% in the U.S., that's a compelling clinical advantage in approximately 6 million H. pylori treatment courses annually in the U.S.

What are the approved RNAi drugs and how do they validate Arrowhead's pipeline?

Approved RNAi drugs demonstrate clinical proof-of-concept for the therapeutic modality: Patisiran (Onpattro, Alnylam Pharmaceuticals) — first approved RNAi drug (2018); treats hereditary transthyretin amyloidosis (hATTR); targets TTR mRNA in liver to reduce misfolded transthyretin protein that deposits in organs. Givosiran (Givlaari, Alnylam) — treats acute hepatic porphyria; silences ALAS1 gene reducing toxic metabolite accumulation. Lumasiran (Oxlumo, Alnylam) — treats primary hyperoxaluria type 1; silences HAO1 gene reducing oxalate overproduction. Inclisiran (Leqvio, Novartis/Alnylam) — lowers LDL cholesterol by silencing PCSK9; given twice annually by subcutaneous injection; used for cardiovascular risk reduction; represents the first large cardiovascular market RNAi drug. Vutrisiran (Amvuttra, Alnylam) — next-generation hATTR treatment. Fitusiran (Alhemo, Sanofi/Alnylam) — hemophilia A and B treatment. Relevance for Arrowhead: these approvals validate that RNAi drugs can be developed, manufactured, delivered to patients, and approved by the FDA; each approval reduces de-risking concerns about the modality; Arrowhead's partnership with J&J (fazirsiran for AATD) and AstraZeneca (olezarsen for hypertriglyceridemia) benefits from large pharma confidence in RNAi following Alnylam's commercial success.

brimindinvest.com / compare / phat-vs-arwrLIVE

PHAT

Phathom Pharmaceuticals, Inc. · Healthcare - Specialty Pharmaceuticals

$10.88

-4.56% this month

VERSUS

⟷

COMPARE

ARWR

Arrowhead Pharmaceuticals, Inc. · Healthcare - RNA Interference (RNAi) Therapeutics

$81.82

+11.81% this month

Scoreboard verdict

Across AI score, momentum, valuation, upside, operating margin

PHAT

1

ARWR

3

ARWR LEADS 3/5

Comparison scoreboard

ARWR LEADS 3/5

AI Score

PHAT 24.5

ARWR ✓57.1

1Y Return

PHAT -0.18%

ARWR ✓+423.82%

Fwd P/E

PHAT 7.56

ARWR ✓-18.87

Target Up.

PHAT ✓+117.83%

ARWR +8.88%

Op. Margin

PHAT N/A

ARWR N/A

Metrics last refreshed: 6/20/2026

Quick take

PHAT vs ARWR Stock Comparison: AI Score, Valuation, Performance and Upside

PHAT (Phathom Pharmaceuticals) and ARWR (Arrowhead Pharmaceuticals) are both specialty pharma companies at different development stages — Phathom is commercial-stage with Voquezna (vonoprazan) launched in the U.S. for acid-related diseases, fighting for formulary access against generic PPIs, while Arrowhead is clinical-stage with a broad RNAi pipeline partnered with J&J and AstraZeneca targeting cardiovascular and metabolic diseases. Phathom carries commercial execution risk; Arrowhead carries clinical development risk.

PHAT vs ARWR is commercial-stage P-CAB acid blocker facing formulary access headwinds (Phathom's Voquezna/vonoprazan seeking to displace entrenched generic PPIs in a massive acid reflux and H. pylori market) versus clinical-stage RNAi platform with major pharma validation (Arrowhead's gene silencing pipeline partnered with J&J and AstraZeneca targeting cardiovascular and metabolic disease with durable protein knockdown) — commercial launch risk versus binary clinical event risk.

Live analysis · updated 6/20/2026

ARWR holds the edge across 3 of 5 key metrics in this comparison. ARWR leads on both 1-year return (+423.82%) and forward P/E (-18.87x vs 7.56x for PHAT), a relatively favorable combination of momentum and valuation. Analyst consensus implies meaningfully more upside for PHAT (+117.83%) than for ARWR (+8.88%).

Normalized 1Y performance

PHAT

ARWR

Recent returns

PHAT

ARWR

Analyst price targets & sentiment

PHAT · 10 analysts

STRONG BUYHOLDSTRONG SELL

Strong Buy (1.4/5.0)

Price target range

analyst low$13.00
analyst high$29.00
analyst mean$23.70
current price$10.88

+117.8% upside to analyst mean

ARWR · 12 analysts

STRONG BUYHOLDSTRONG SELL

Buy (1.6/5.0)

Price target range

analyst low$46.00
analyst high$110.00
analyst mean$89.08
current price$81.82

+8.9% upside to analyst mean

Who should consider this stock?

PHAT may suit investors who:

→Believe vonoprazan's clinical advantages over PPIs (faster onset, more complete acid suppression, better H. pylori eradication) will eventually translate into formulary wins and prescriber adoption despite generic PPI entrenchment
→Are willing to accept commercial launch risk and cash burn uncertainty in exchange for a revenue-generating specialty pharma with a differentiated product in the large acid reflux market
→See the successful P-CAB commercial track record in Japan (Takeda's Takecab) as de-risking the mechanism's clinical utility, with U.S. commercialization as the key remaining question

ARWR may suit investors who:

→Believe RNAi gene silencing represents a transformative therapeutic modality with applicability across cardiovascular, metabolic, and rare diseases, with Arrowhead's platform providing multiple clinical shots on goal
→Value the J&J and AstraZeneca partnership validation as de-risking Arrowhead's technology platform and providing non-dilutive capital to fund continued pipeline development
→Are comfortable with clinical-stage binary event risk and are positioned for multiple data readout catalysts that could rapidly re-rate Arrowhead's stock upon positive results

Performance & AI score

Metric	PHAT	ARWR
AI score	24.5	57.1
AI rank	#3099	#221
Latest close	$10.88	$81.82
1M return	-4.56%	+11.81%
6M return	-29.17%	+26.27%
1Y return	-0.18%	+423.82%

$10,000 invested — hypothetical growth (dividends reinvested)

How much would $10,000 be worth today if invested at the start of each period, with all dividends reinvested?

Period	PHAT	ARWR
1Y ago	$9.98K (-0.2%) started 2025-06-18	$52.38K (+423.8%) started 2025-06-18
5Y ago	$3.11K (-68.9%) started 2021-06-18	$9.55K (-4.5%) started 2021-06-18
10Y ago	$4.42K (-55.8%) started 2019-10-25	$139.15K (+1291.5%) started 2016-06-20

Hypothetical — past performance does not guarantee future results.

Valuation & upside potential

Metric	PHAT	ARWR
Market cap	$867.74M	$11.52B
Trailing P/E	N/A	N/A
Forward P/E	7.56	-18.87
Price/Sales	4.24	18.53
EV/Revenue	5.85	16.67
Analyst target	$23.70	$89.08
Target upside	+117.83%	+8.88%

Growth, profitability & risk

Metric	PHAT	ARWR
Revenue growth	104.40%	-86.40%
Earnings growth	N/A	N/A
EPS growth	N/A	N/A
FCF margin	-37.84%	-7.41%
Operating margin	N/A	N/A
Profit margin	-76.77%	-48.38%
ROIC proxy	N/A	-42.37%
Return on equity	N/A	-42.37%
Dividend yield	0.00%	0.00%
Beta	0.51	1.27
Debt/equity	N/A	231.05
Current ratio	2.21	6.23
Quick ratio	2.09	6.09

Drawdown & downside risk

Lower drawdown and smaller single-period drops generally indicate a smoother ride, though they do not guarantee lower future risk.

1Y risk snapshot

PHAT max drawdown48.89%

ARWR max drawdown24.64%

PHAT max wkly drop20.80%

ARWR max wkly drop20.96%

5Y risk snapshot

PHAT max drawdown93.78%

ARWR max drawdown88.94%

PHAT max wkly drop50.86%

ARWR max wkly drop32.69%

10Y risk snapshot

PHAT max drawdown95.81%

ARWR max drawdown88.96%

PHAT max wkly drop50.86%

ARWR max wkly drop70.60%

Performance metrics by period

Period	Metric	PHAT	ARWR
1Y	Growth	-0.18%	+423.82%
	CAGR	-0.18%	+424.41%
	Sharpe ratio	0.23	2.80
	Max drawdown	48.89%	24.64%
	Max daily drop	13.72%	12.23%
	Max wkly drop	20.80%	20.96%
5Y	Growth	-68.91%	-4.46%
	CAGR	-20.84%	-0.91%
	Sharpe ratio	0.14	0.24
	Max drawdown	93.78%	88.94%
	Max daily drop	31.11%	26.85%
	Max wkly drop	50.86%	32.69%
10Y	Growth	-55.77%	+1291.50%
	CAGR	-11.55%	+30.14%
	Sharpe ratio	0.25	0.69
	Max drawdown	95.81%	88.96%
	Max daily drop	31.11%	67.20%
	Max wkly drop	50.86%	70.60%

Business comparison

Category	PHAT	ARWR
Company	Phathom Pharmaceuticals, Inc.	Arrowhead Pharmaceuticals, Inc.
Sector	Healthcare - Specialty Pharmaceuticals	Healthcare - RNA Interference (RNAi) Therapeutics
Industry	N/A	N/A
Core business	Phathom Pharmaceuticals is a commercial-stage specialty pharmaceutical company focused on acid-related diseases. Phathom's lead product Voquezna (vonoprazan fumarate) is a potassium-competitive acid blocker (P-CAB) approved by the FDA for: erosive esophagitis (acid reflux causing esophageal damage), H. pylori (Helicobacter pylori) eradication (in combination with antibiotics), and on-demand treatment of heartburn. Vonoprazan was developed by Takeda Pharmaceutical in Japan (where it's marketed as Takecab) and licensed to Phathom for U.S. and European commercialization. P-CABs represent a newer class than traditional proton pump inhibitors (PPIs like omeprazole, pantoprazole) with potentially faster onset and more complete acid suppression.	Arrowhead Pharmaceuticals develops RNA interference (RNAi) therapeutics — drugs that silence specific disease-causing genes by targeting messenger RNA (mRNA) before it can produce disease-causing proteins. Arrowhead's clinical pipeline includes: JNJ-75220795 (fazirsiran — licensed to Johnson & Johnson) for alpha-1 antitrypsin deficiency (AATD) lung disease, ARO-APOC3 (olezarsen — licensed to AstraZeneca) for high triglycerides/hypertriglyceridemia, ARO-ANG3 for dyslipidemia, ARO-HIF2 for renal cell carcinoma, ARO-HSD for fatty liver disease, and multiple other RNAi programs. Arrowhead's SEQUOIA delivery platform enables subcutaneous injection of GalNAc-conjugated RNAi drugs targeting the liver.
Investor focus	Investors track Voquezna's commercial launch progress (prescription volume growth, formulary wins with health insurance payers), net product revenue trajectory, cash burn rate and funding runway, and the potential to penetrate the large PPI market with a differentiated mechanism.	Investors track Arrowhead's clinical pipeline milestone progression (Phase 2/3 data readouts), licensing deal structures and milestone payments from J&J and AstraZeneca, and the validation of RNAi as a therapeutic modality across cardiovascular and metabolic diseases.

PHAT strengths

→P-CAB mechanism may offer clinical advantages over PPIs — vonoprazan's potassium-competitive mechanism provides faster onset of acid suppression and more complete inhibition at high gastric pH; these properties may translate to better H. pylori eradication rates and erosive esophagitis healing
→Large addressable market — acid-related diseases affect tens of millions of Americans; PPIs (Prilosec, Nexium, generic omeprazole) are among the most commonly used prescription and OTC medications globally; capturing even a small share of this market represents significant revenue potential
→H. pylori triple therapy indication provides a compelling entry point — H. pylori eradication requires a combination antibiotic regimen; Voquezna triple therapy (vonoprazan + amoxicillin + clarithromycin) or dual therapy may offer improved eradication rates over PPI-based regimens

ARWR strengths

→RNAi platform creates a 'gene knockdown' approach that can silence disease-causing proteins durably — one subcutaneous injection can silence a liver-expressed protein for months; dosing every 3-6 months is far more convenient than daily oral medications; durable silencing provides sustained efficacy
→Partnerships with J&J and AstraZeneca validate the platform and provide non-dilutive capital — major pharma partnerships signal scientific validation; licensing fees and milestone payments fund Arrowhead's pipeline without requiring constant equity dilution
→Multiple shots on goal across cardiovascular and metabolic diseases — Arrowhead's pipeline targets high-prevalence conditions (hypertriglyceridemia, fatty liver, alpha-1 antitrypsin deficiency) with significant unmet need; if RNAi works in one cardiovascular target, the platform applicability to others increases confidence

Risks to watch — PHAT

→Commercial execution is challenging against entrenched generic PPIs — generic omeprazole and pantoprazole cost pennies per tablet; Voquezna must justify significantly higher pricing to payers; insurance coverage (formulary placement) has been the major commercial headwind
→Cash burn from commercial launch requires continued capital access — building a commercial pharmaceutical business is capital intensive; Phathom has operated at significant losses since launch and requires continued financing
→PPI generic competition is deeply entrenched with proven physicians' familiarity — prescribers have used PPIs for decades; changing prescribing habits requires compelling clinical differentiation and strong sales force education

Risks to watch — ARWR

→Clinical-stage pipeline creates binary risk at every data readout — RNAi programs can and do fail in clinical trials; each Phase 2/3 data readout is a binary event; multiple program failures would severely impair Arrowhead's valuation and pipeline narrative
→Competition from established RNAi companies (Alnylam Pharmaceuticals) and other genetic medicine platforms — Alnylam is the RNAi market leader with approved products (Onpattro, Givlaari, Leqvio marketed by Novartis); new gene silencing modalities (gene editing, antisense oligonucleotides) compete for the same genetic disease targets
→Liver targeting limitation — Arrowhead's GalNAc conjugation approach primarily enables liver-targeted drug delivery; diseases requiring delivery to other tissues (lung, heart muscle, brain) are harder to address with current platform technology

Frequently asked questions

Vonoprazan is a potassium-competitive acid blocker (P-CAB) — a newer class of acid suppression medication with a different mechanism than proton pump inhibitors (PPIs). How PPIs work: PPIs (omeprazole, pantoprazole, esomeprazole) irreversibly bind to and inhibit the hydrogen-potassium ATPase proton pump in stomach acid-secreting parietal cells; PPIs are prodrugs that require acid activation before binding; this means PPIs work best when taken 30-60 minutes before a meal (when parietal cells are most active); PPIs provide incomplete acid suppression (especially at night) because they only inhibit activated pumps. How vonoprazan works: vonoprazan competitively blocks the potassium-binding site of the proton pump directly without requiring acid activation; vonoprazan is not a prodrug — it works at any pH; onset is faster (acid suppression begins within hours vs. 3-5 days for full PPI effect); acid suppression is more complete at high pH; dosing may not require meal timing. Clinical implications: more rapid and complete acid suppression may help heal erosive esophagitis faster; higher gastric pH during H. pylori eradication therapy may improve antibiotic efficacy (antibiotics work better in a less acidic stomach); vonoprazan's P-CAB mechanism is the same used in the highly successful Japanese product Takecab.

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