HISTALOG Drug Patent Profile

When do Histalog patents expire, and what generic alternatives are available?

Histalog is a drug marketed by Lilly and is included in one NDA.

The generic ingredient in HISTALOG is betazole hydrochloride. Additional details are available on the betazole hydrochloride profile page.

Summary for HISTALOG

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	64
Patent Applications:	37
DailyMed Link:	HISTALOG at DailyMed

US Patents and Regulatory Information for HISTALOG

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Lilly	HISTALOG	betazole hydrochloride	INJECTABLE;INJECTION	009344-001	Approved Prior to Jan 1, 1982		DISCN	No	No

Last updated: July 18, 2026

HISTALOG market dynamics and financial trajectory: sales trends, payer behavior, and exclusivity-driven risk

HISTALOG (histamine dihydrochloride) pricing and sales depend on a narrow, procedure-driven dermatology/skin-care market, limited retail uptake, and payor governance that prices to clinical endpoints rather than broad chronic use. Financial trajectory is dominated by (1) schedule and volume of procedures, (2) competitive substitution risk inside the same use profile, (3) supply continuity, and (4) patent and regulatory exclusivity that controls generic or competitor entry risk.

Because HISTALOG’s commercial value is concentrated in a limited segment, small changes in prescribing behavior, contract pricing, or reimbursement coverage can swing quarterly revenue more than in broad-based retail brands.

What is HISTALOG and how does it get reimbursed in the US market?

HISTALOG is used in dermatology settings tied to specific therapeutic protocols. Like other specialized drug products, its commercial path is shaped more by payer contracting and provider utilization than by consumer demand.

Reimbursement mechanics that drive revenue

• Coverage policy gates: Coverage decisions often depend on medical-necessity criteria aligned to labeling and clinical guidelines for the treated condition and administration setting.
• Contract pricing and ASP alignment: Revenue trajectory typically tracks contracted reimbursement levels more than list price.
• Site-of-care effects: Revenue is sensitive to whether use occurs in ambulatory clinics, dermatology practices, or hospital outpatient settings. Admin setting can change reimbursement and pharmacy benefits structure.
• Patient mix: Procedure volume and patient mix by severity can shift monthly demand.

How have HISTALOG sales evolved over time, and what does that imply about demand?

A product with a procedure-linked or specialty-use profile usually shows:

• Non-linear unit demand tied to seasonal outpatient flow and practice capacity.
• Headroom or saturation linked to guideline adherence and protocol consistency.
• Downward pressure when competitive alternatives expand formulary access or when payers tighten criteria.

Financial trajectory drivers

• Volume stability beats pricing growth: In specialty products, sustained increases in unit demand are harder; stable utilization matters more than list price increases.
• Short-cycle procurement: Clinics tend to reorder based on patient flow and inventory management, so revenue can jump with reorder cycles.
• Contract renewals: Each payer contract renewal can materially reset net price.

Net impact on the revenue curve

• If payer contracts remain favorable and utilization is steady, revenue typically tracks with procedure volume.
• If coverage tightens or substitution rises, revenue flattens, then declines stepwise at contract renewal or competitor adoption points.

What patent and exclusivity timelines protect HISTALOG’s market position?

Market protection for a drug like HISTALOG typically comes from a mix of:

• Drug substance and composition-of-matter patents (the core IP fence)
• Formulation and manufacturing patents (additional barriers to “work-alike” competitors)
• Method-of-use patents (coverage of specific clinical use patterns)

The market dynamics are usually most exposed at two points:

1. When composition/formulation IP expires, enabling faster entry paths for generics.
2. When regulatory exclusivity ends, reducing barriers to abbreviated pathways for follow-on products.

Why exclusivity matters commercially

• If exclusivity still holds, competitive pricing pressure stays muted and wholesaler fill rates remain stable.
• If exclusivity is gone, expected competitor entry can compress net price quickly via payer and provider switching.

What is the Orange Book status of HISTALOG, and where are the generic entry windows?

Orange Book listings typically determine:

• Whether there are approved drug products with listed patents
• Whether patents are tied to drug substance, formulation, or method of use
• The earliest challenge risk windows (Paragraph IV timing for small-molecule generics)

For market dynamics, the key is not just the number of patents, but:

• Patent expiration dates
• Whether patents include “blocking” method-of-use claims
• Whether multiple overlapping patents extend effective exclusivity

How do Paragraph IV challenges change HISTALOG’s financial outlook?

Paragraph IV dynamics drive revenue risk through:

• Filing-to-entry lag: Revenue can hold until the challenged product launches, but market expectations often price in the filing.
• Settlement effects: If lawsuits resolve via settlement, entry can be delayed. If a generic enters earlier than expected, net price can drop quickly.
• Payer switching: Payers often move to lower net-cost alternatives once they become available with stable supply.

Financial pattern after generic entry

• Abrupt net price compression and incremental share loss.
• Revenue declines that can be partially offset if the brand retains formulary positions or competes on contracting.

What generic or biosimilar risk exists for HISTALOG?

HISTALOG is a small-molecule product, so biosimilar risk is not the primary vector. The commercial risk vector is:

• Generic small-molecule entry after expiration of relevant patents and/or exclusivity.
• Authorized generics via licensing arrangements that can still erode brand margins.
• Competitive substitutions through alternative protocols that use different agents or different dosage forms.

How does HISTALOG compare with alternative dermatology therapies on cost and coverage?

In specialized dermatology markets, “comparability” is typically decided by:

• Clinical endpoint relevance (response rate, time-to-response, tolerability)
• Administration and workflow fit (clinic compatibility, protocol integration)
• Net cost (contract pricing, patient assistance availability, payer preferred status)

Brand products with narrow use profiles can face faster loss of share if alternatives:

• get preferred status,
• offer easier administration,
• or show payer-friendly evidence packages.

What manufacturing and supply-chain issues could affect HISTALOG revenue?

Specialty products can have outsized revenue impact from:

• Raw material supply constraints
• Batch release and QA bottlenecks
• Distribution lead times that cause missed dosing windows and lost procedure opportunities

Supply shocks typically translate into:

• Short-term revenue dips from backorders or delayed availability
• Reordering spikes when supply returns, creating a “catch-up” effect

Which business segments drive HISTALOG revenue: hospitals, ambulatory, or specialty pharmacies?

Specialty and procedure-adjacent drugs often rely on:

• Healthcare provider purchasing through distributor channels
• Clinic-administered utilization that is not purely pharmacy benefit-driven
• Specialty pharmacy involvement when dispensing is required outside clinic administration

Commercial outcomes depend on which segment dominates:

• Provider-administered models are more sensitive to physician preference and clinic capacity.
• Pharmacy-administered models are more sensitive to plan formularies, PBM contracting, and patient access.

What payer policies most affect HISTALOG net pricing and contract stability?

Net pricing tends to be shaped by:

• Formulary tier placement and prior authorization requirements
• Medical necessity documentation criteria
• Provider reimbursement environment for the administration setting
• Annual contract resets and rebids

For a niche product, even a one-tier movement can change uptake materially. Net revenue sensitivity is typically higher for lower-volume products because fewer contracts drive a higher share of sales.

How strong is the patent estate for HISTALOG, and what does that imply for near-term risk?

A strong patent estate usually means:

• Multiple overlapping patents across substance/formulation/method-of-use
• Clear blocking claims tied to labeled or protocol-consistent use
• Fewer design-around opportunities for generic competitors

A weaker estate shows up commercially as:

• Earlier-than-expected generic market chatter
• More frequent litigation or licensing activity around closely related patents
• Faster payer switching once approvals appear

What patent litigation affects HISTALOG market dynamics, settlements, or launch timing?

Patent litigation affects the commercial curve in two ways:

1. Delay mechanisms: court injunctions or settlement-based entry delays keep price pressure contained.
2. Uncertainty discount: market participants price litigation risk into competitor behavior and payer contracting decisions.

Revenue is typically most volatile around:

• complaint and claim construction milestones,
• settlement announcements,
• and final court outcomes that unlock or block entry.

How could HISTALOG’s revenue perform under a generic launch scenario?

A generic launch scenario usually results in:

• Immediate net price compression via payer formulary changes and competitive contracting.
• Share redistribution toward the lowest net-cost supplier among generics.
• Brand margin erosion even if the brand retains some share through established provider familiarity.

For a narrow-use drug, total market shrink can happen if:

• providers reduce usage due to protocol shifts,
• payers restrict medical necessity criteria after competitor availability,
• or substitution reduces the addressable patient cohort.

Key Takeaways

• HISTALOG’s financial trajectory is governed by narrow procedural utilization, payer contracting, and supply continuity more than by broad retail demand.
• Patent and exclusivity timing determines when net price pressure accelerates through generic entry or authorized generics.
• The biggest revenue swing risks are contract renewals, litigation-settled entry timing, and launch execution by generic competitors.
• Market protection depends on the strength and overlap of drug substance, formulation, and method-of-use patents listed for HISTALOG.

FAQs

1) What factors determine HISTALOG’s net price versus its list price?

Contract coverage status, formulary tiering, prior authorization burden, and reimbursement rules by administration site.

2) How sensitive is HISTALOG revenue to payer contract renewals?

High, because narrow specialty utilization means fewer contracts and provider channels can drive a disproportionate share of sales.

3) What signals typically precede generic competition for a niche specialty drug like HISTALOG?

Orange Book patent expiry countdowns, patent litigation filings, and competitor procurement signaling in distributor ordering patterns.

4) What risks matter most for maintaining HISTALOG supply?

Raw material sourcing continuity, batch release timelines, and manufacturing capacity and QA throughput.

5) How should investors model revenue for HISTALOG through exclusivity to the first generic wave?

Model a stable utilization base up to expiry, then step-down in net price and share aligned to launch timing, payer switches, and settlement outcomes.

References (APA)

1. U.S. Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. FDA.
2. U.S. Food and Drug Administration. Drug Approval Reports and related regulatory records for HISTALOG. FDA.