SULFALAR Drug Patent Profile

Which patents cover Sulfalar, and what generic alternatives are available?

Sulfalar is a drug marketed by Parke Davis and is included in one NDA.

The generic ingredient in SULFALAR is sulfisoxazole. There are three drug master file entries for this compound. Additional details are available on the sulfisoxazole profile page.

Summary for SULFALAR

US Patents:	0
Applicants:	1
NDAs:	1

US Patents and Regulatory Information for SULFALAR

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Parke Davis	SULFALAR	sulfisoxazole	TABLET;ORAL	084955-001	Approved Prior to Jan 1, 1982		DISCN	No	No

SULFALAR (Sulfasalazine) Investment Scenario and Fundamentals Analysis

Last updated: April 24, 2026

What is SULFALAR and where does it sit in the drug landscape?

SULFALAR is a brand name for sulfasalazine, a long-established oral anti-inflammatory and immunomodulatory medicine. Sulfasalazine is used primarily in inflammatory bowel disease (ulcerative colitis, Crohn’s disease) and rheumatoid arthritis, with the drug’s commercial profile shaped by:

• Generic competition (global standard of care for sulfasalazine is typically generic)
• Patent expiration history for the active ingredient (sulfasalazine is not a “new molecular entity” program)
• Brand positioning that is usually driven by local regulatory status, supply continuity, and formulary access, not proprietary innovation

From an investment standpoint, SULFALAR behaves like a late-cycle small molecule exposed to margin compression and volume volatility tied to payer and hospital procurement dynamics.

What is the product’s commercial driver profile?

For sulfasalazine-based brands, revenue tends to be driven by four fundamentals:

1. Volume stability in chronic indications
   • Ulcerative colitis and rheumatoid arthritis both involve long treatment durations.
2. Payor and formularies
   • Generic substitution pressures are the dominant pricing constraint.
3. Supply chain continuity
   • Shortages can temporarily lift realized pricing for branded stock lots.
4. Local regulatory and reimbursement
   • Some markets protect certain brands through tendering mechanics, disease-program budgets, or switching restrictions.

Implication for investors: the core upside is usually share retention and working-capital efficiency rather than premium pricing or meaningful time-to-market innovation.

How does generic pressure affect valuation mechanics?

Because sulfasalazine is widely generic, the investment case typically relies on:

• Brand cost leadership (manufacturing scale, input cost control, stable procurement)
• Distribution leverage
• Low marketing leakage relative to competitors
• Contracted pricing in public tenders or institution-level agreements

A typical late-cycle valuation lens treats SULFALAR-like assets as:

• Cash-flow durable but
• Multiple-compressing if new entrants increase bid competition or if price ceilings tighten.

What are the key demand signals investors should track?

Even without proprietary trial catalysts, demand for sulfasalazine brands is measurable via system-level indicators:

• Incidence and prevalence proxies for ulcerative colitis and rheumatoid arthritis in the target geography
• Persistence and switching rates to alternative oral 5-ASA or biologics in UC
• Tender outcomes and pharmacy benefit manager policy changes
• Erosion speed of branded share after generic resets

What is the competitive set and how does it impact substitution risk?

Sulfasalazine competes on both therapeutic class and route/tolerability:

• Within UC and IBD: mesalamine (5-ASA) formulations are the most common substitution pathway where payers prefer them for tolerability.
• Within RA: conventional DMARDs compete similarly, while biologics and targeted synthetic DMARDs compete at the more severe end.

Investment implication: SULFALAR share is sensitive to formulary design that favors 5-ASA selectivity and to RA treatment patterns that shift toward agents with better tolerability or faster efficacy.

What does the risk map look like for SULFALAR?

Regulatory and safety

Sulfasalazine has a long-established safety profile. Risk is mostly operational:

• Labeling updates and pharmacovigilance signals can change prescriber confidence
• Supply disruptions or batch quality events can cause short-term demand loss

Pricing and reimbursement

The largest financial risk is pricing compression driven by:

• Tender rebids
• Generic reallocation and stocking incentives
• Changes in reference pricing

Manufacturing and input costs

Sulfasalazine economics are exposed to:

• API availability and yields
• Excipient supply constraints
• Sterility and packaging changes at scale

Clinical substitution

Even if sulfasalazine remains effective, payers can drive substitution through:

• Coverage limits
• Step therapy requirements
• Preference for 5-ASA in UC

Investment scenario framework (base, bull, bear)

Because SULFALAR is not defined by near-term patent-driven exclusivity, scenario modeling should center on market share, realized pricing, and distribution and costs.

Base case (most likely)

• Gradual branded share erosion under generic reference pricing
• Stable chronic demand offsets volume losses
• EBITDA margin gradually compresses but remains supported by manufacturing scale and procurement

Key watchpoints

• Tender cycles and pharmacy contracting
• Hospital and specialty pharmacy formularies

Bull case (upside)

• Brand holds share despite generic pressure via:
  • Better formulary retention
  • Strong distribution coverage
  • Tender wins due to competitive bid economics
• Pricing stabilizes through contracted procurement and supply reliability

Key watchpoints

• Multi-year contracts with public buyers
• Outperformance versus local generic benchmarks

Bear case (downside)

• Faster reference pricing resets and aggressive tender underbids
• Increased switching to 5-ASA in UC or other DMARDs in RA
• Margin compression accelerates due to lower realized prices and higher logistics or packaging costs

Key watchpoints

• Breaks in supply continuity
• Abrupt tender outcomes that reallocate volumes to lower-cost SKUs

What fundamentals matter most for underwriting SULFALAR?

Underwriting should prioritize:

1. Realized price vs. generic reference
   • Track blended price movement at the SKU level.
2. Volume retention in institutions
   • Measure share in hospitals and clinics, not just retail.
3. Gross margin stability
   • Latent API cost volatility shows up here first.
4. Operating cost discipline
   • Marketing spend elasticity matters more than launch-style spending.
5. Working capital efficiency
   • Slow-moving inventory risk increases with late-cycle price compression.

How should investors benchmark returns versus generic pipelines?

SULFALAR’s investability is strongest when the company can demonstrate:

• Lower unit costs
• Better distribution density
• Contracted revenue durability
• Limited switching in target institutions

Relative performance should be compared against:

• Other late-cycle oral generics in the same therapeutic area
• Locally dominant competitors at the tender level
• Any branded incumbents still protected by local contracting mechanics

What catalysts exist outside patents?

For sulfasalazine brands, “catalysts” are usually operational:

• Tender award cycles that lock volumes at stable pricing
• Supply normalization that restores fill rates and reduces lost prescriptions
• Formulary wins in high-volume hospital networks
• Cost-down initiatives in manufacturing or packaging

If none of these move, equity upside tends to remain limited and driven by valuation re-rating rather than fundamental expansion.

Key metrics dashboard for investment monitoring

Use a quarterly dashboard focused on hard economics:

Metric	Why it matters	What to look for
Blended realized price	Generic pressure shows up here	Sequential price stability or decline rate
Volume (units or TRxs)	Demand durability	Share retention versus local generics
Gross margin	API and packaging economics	Trend vs. prior tender cycles
Inventory turns	Late-cycle obsolescence	Deterioration after price resets
Contract coverage	Revenue stability	Share of volume under multi-month or multi-year procurement

What does the “fundamentals” conclusion mean for investors?

SULFALAR is best treated as a cash-yielding, late-cycle branded generic where the most actionable investment question is not “Will the drug work?” but “Can the brand defend economics under reference pricing and tender competition?”

A credible investment stance requires:

• Evidence of realized pricing resilience despite generics
• Volume retention in institutional channels
• Gross margin control through manufacturing and supply chain execution
• Operating cost discipline aligned with shrinking differentiation

Key Takeaways

• SULFALAR is sulfasalazine, a mature small molecule with heavy generic competition and limited exclusivity-driven upside.
• The investment case depends on market-share defense, tender outcomes, realized pricing, and gross margin discipline, not new clinical catalysts.
• Build an underwriting model around contract coverage, inventory risk, and unit cost execution.
• Upside scenarios come from formulary/tender wins and supply continuity; downside comes from faster reference pricing resets and substitution to 5-ASA or other DMARD strategies.

FAQs

1. Is SULFALAR a patent-protected growth asset?
   Sulfasalazine is a mature active ingredient; branded performance typically hinges on market and contracting mechanics rather than patent exclusivity.

2. What most affects SULFALAR profitability?
   Realized pricing versus generic reference and unit manufacturing costs drive gross margin, while tender and channel mix shape volume.

3. Which indications drive demand for sulfasalazine brands?
   Ulcerative colitis and rheumatoid arthritis are the primary commercial demand anchors.

4. What is the biggest competitive threat?
   Generic substitution and formulary preference shifts toward alternative oral therapies, especially in UC where 5-ASA options are common.

5. What are the most practical near-term “catalysts” for SULFALAR investors?
   Tender award outcomes, formulary retention, supply continuity, and cost-down execution.

References

[1] FDA. “Sulfasalazine” (drug labeling and pharmacology resources). U.S. Food and Drug Administration.
[2] EMA. European Medicines Agency. “Sulfasalazine” (public assessment and product information resources). European Medicines Agency.
[3] Drugs@FDA. “Sulfasalazine” drug listings. U.S. Food and Drug Administration.
[4] WHO. World Health Organization. ATC classification entries for sulfasalazine. World Health Organization.