MACRILEN Drug Patent Profile

When do Macrilen patents expire, and when can generic versions of Macrilen launch?

Macrilen is a drug marketed by Aeterna Zentaris and is included in one NDA. There is one patent protecting this drug.

This drug has eleven patent family members in ten countries.

The generic ingredient in MACRILEN is macimorelin acetate. Two suppliers are listed for this compound. Additional details are available on the macimorelin acetate profile page.

DrugPatentWatch^® Generic Entry Outlook for Macrilen

Macrilen was eligible for patent challenges on December 20, 2021.

Indicators of Generic Entry

Summary for MACRILEN

International Patents:	11
US Patents:	1
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	2
Raw Ingredient (Bulk) Api Vendors:	5
Clinical Trials:	2
Drug Prices:	Drug price information for MACRILEN
What excipients (inactive ingredients) are in MACRILEN?	MACRILEN excipients list
DailyMed Link:	MACRILEN at DailyMed

See drug prices for MACRILEN

Recent Clinical Trials for MACRILEN

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
VA Office of Research and Development	Phase 3
Novo Nordisk A/S	Phase 3
AEterna Zentaris	Phase 3

See all MACRILEN clinical trials

Pharmacology for MACRILEN

Drug Class	Growth Hormone Secretagogue Receptor Agonist
Mechanism of Action	Growth Hormone Secretagogue Receptor Agonists

US Patents and Regulatory Information for MACRILEN

MACRILEN is protected by one US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Aeterna Zentaris	MACRILEN	macimorelin acetate	FOR SOLUTION;ORAL	205598-001	Dec 20, 2017		DISCN	Yes	No					Y

Expired US Patents for MACRILEN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Aeterna Zentaris	MACRILEN	macimorelin acetate	FOR SOLUTION;ORAL	205598-001	Dec 20, 2017

International Patents for MACRILEN

When does loss-of-exclusivity occur for MACRILEN?

Based on analysis by DrugPatentWatch, the following patents block generic entry in the countries listed below:

Cyprus

Denmark

European Patent Office

Generics may enter earlier, or later, based on new patent filings, patent extensions, patent invalidation, early generic licensing, generic entry preferences, and other factors.

See the table below for additional patents covering MACRILEN around the world.

Country	Patent Number	Title	Estimated Expiration
Argentina	029941	COMPUESTOS UTILES PARA ELEVAR EL NIVEL PLASMATICO DE LA HORMONA DEL CRECIMIENTO Y LAS COMPOSICIONES FARMACEUTICAS QUE LAS CONTIENEN
Austria	302181
Austria	362472
Austria	370119

Supplementary Protection Certificates for MACRILEN

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
1289951	300999	Netherlands		PRODUCT NAME: MACIMORELIN; REGISTRATION NO/DATE: EU/1/18/1337 20190115
1289951	122019000074	Germany		PRODUCT NAME: MACIMORELIN, OPTIONAL IN FORM EINER ARZNEIMITTELZUSAMMENSETZUNG, OPTIONAL IN FORM EINES PHARMAZEUTISCH VERTRAEGLICHEN SALZES, INSBESONDERE MACIMORELIN ACETAT.; REGISTRATION NO/DATE: EU/1/18/1337 20190111
1289951	CA 2019 00037	Denmark		PRODUCT NAME: MACIMORELIN, EN FARMACEUTISK SAMMENSAETNING DERAF ELLER ET FARMACEUTISK ACCEPTABELT SALT DERAF; REG. NO/DATE: EU/1/18/1337 20190115
1289951	132019000000099	Italy		PRODUCT NAME: MACIMORELINA, OPZIONALMENTE NELLA FORMA DI UNA COMPOSIZIONE FARMACEUTICA, OPZIONALMENTE NELLA FORMA DI UN SALE FARMACEUTICAMENTE ACCETTABILE, COMPRESA MACIMORELINA ACETATO(MACIMORELIN AETERNA ZENTARIS - MACIMORELINA); AUTHORISATION NUMBER(S) AND DATE(S): EU/1/18/1337, 20190115

MACRILEN (macimorelin) market dynamics and financial trajectory: FDA commercialization, reimbursement pull-through, and generic/biosimilar exposure

Last updated: July 2, 2026

MACRILEN (macimorelin) is a niche oncology-adjacent diagnostic drug in the U.S., used to evaluate adult patients for growth hormone deficiency (GHD). Its market trajectory is structurally constrained by (1) the size of the diagnosed GHD population, (2) specialist-only prescribing, (3) diagnostic workflow dependence, and (4) payor reimbursement posture for endocrine testing. The commercial outlook is driven less by price volume expansion and more by diagnostic uptake, guideline adherence, and substitution risk once competitors or alternative testing approaches gain traction.

Why has MACRILEN’s market been limited by patient and workflow size?

Short answer: MACRILEN’s addressable market is constrained by the number of adult patients receiving formal evaluation for suspected GHD and the degree to which clinicians adopt macimorelin over other dynamic testing modalities.

How big is the clinical footprint for adult GHD testing?

Adult GHD evaluation is a specialist workflow dominated by endocrinologists. Adoption depends on:

• Referral volume from primary care and specialty clinics for suspected pituitary disease or treatment-related hypopituitarism.
• Choice of stimulation testing strategy in endocrinology practice.
• The proportion of clinicians willing to replace or complement traditional dynamic tests (clinical practice patterns vary by country and institution).

Which clinical settings drive real MACRILEN volume?

Volume is concentrated in:

• Academic endocrine centers and tertiary referral hospitals
• High-volume endocrinology practices that can standardize dynamic testing protocols
• Sites with diagnostic infrastructure for standardized follow-up of suspected pituitary disorders

Market penetration tends to be “site-dependent,” not purely “brand-dependent,” which caps network effects.

What drives payer coverage for endocrine dynamic testing?

Coverage and reimbursement dynamics are typically determined by:

• Whether the test is coded and billed consistently to reflect accepted clinical use
• Prior authorization requirements and medical-necessity thresholds
• Plan-specific policies on coverage for diagnostic pharmacologic stimulation tests
• Local MAC and commercial plan interpretation of test value

When plans tighten coverage for diagnostic indications, uptake drops even if prescriber intent remains high.

What does MACRILEN’s financial trajectory look like versus typical specialty launches?

Short answer: MACRILEN is expected to show specialty-diagnostic economics: high per-test pricing, limited volume scaling, and slower ramp than high-prevalence therapeutics.

Revenue drivers that usually matter most for MACRILEN

For diagnostic dynamic testing, revenue is primarily driven by:

• Number of tests ordered and completed (not just prescriptions written)
• Site adoption and protocolization
• Persistence of coverage and reimbursement adequacy
• Competition from alternative dynamic testing strategies

Revenue headwinds that usually dominate for MACRILEN

Key headwinds include:

• Conservative reimbursement for diagnostic-only products
• Budget impact scrutiny under medical benefit testing policies
• Difficulty expanding beyond high-volume endocrine centers without payer alignment
• Any perceived test performance limitations in subgroups affecting clinician confidence

What leverage does inventory and distribution have?

For niche products, distribution leverage depends on:

• Pharmacy channel availability for timely fulfillment
• Consistent supply reliability at specialty distributors
• Cold-chain or handling requirements (if any) that can restrict adoption

A product with limited use often faces less stocking risk tolerance by distributors, which can amplify stock-out effects and delay uptake.

What is the competitive landscape for growth hormone deficiency diagnostic testing?

Short answer: MACRILEN competes within the broader ecosystem of GHD assessment approaches, where alternative dynamic stimulation tests and imaging or lab strategies can substitute for or reduce macimorelin test share.

What competitors compete for the same clinical decision?

In practice, clinicians can choose among:

• Other dynamic stimulation tests used to assess GHD
• Diagnostic algorithms that incorporate insulin-like growth factor-1 (IGF-1), clinical features, and pituitary imaging
• Biochemical monitoring strategies that reduce stimulation-test frequency in some patients

MACRILEN’s share depends on whether it is viewed as easier, safer, or workflow-friendlier relative to alternatives.

How does “substitution risk” affect MACRILEN’s pricing power?

When payors or clinicians view alternatives as clinically comparable, pricing power weakens. Diagnostic products face:

• Higher scrutiny of cost-effectiveness
• Policy-driven reimbursement caps
• Competitive formularies even when there is no direct “generic” substitute yet

How do oncology-adjacent patterns affect MACRILEN?

Macimorelin is used in endocrine evaluation tied to pituitary disorders often caused by:

• Tumor mass effects and prior therapy
• Radiation-induced hypopituitarism
• Post-surgical pituitary dysfunction

If competitor tests offer similar workflow benefits, MACRILEN’s niche positioning becomes fragile.

What patents protect MACRILEN, and how does IP coverage affect market durability?

Short answer: The durability of MACRILEN’s U.S. market depends on the remaining term of composition, method-of-use, and formulation patents listed in the FDA Orange Book, plus any exclusivity that can extend barriers to generic entry.

What matters for generic entry risk

For a niche diagnostic drug, generic threats typically come from:

• Paragraph IV ANDAs for small-molecule macimorelin
• Orange Book-listed patent challenges that eliminate blocking patents
• Design-arounds that pursue non-infringing formulations or methods

What to track in the Orange Book for MACRILEN

Market stakeholders should monitor:

• Composition-of-matter patent expirations
• Method-of-use and diagnostic protocol patents
• Formulation and manufacturing method patents
• Any pediatric exclusivity or other statutory extensions that delay generic entry

When does MACRILEN lose exclusivity, and what does that imply for generic launch timing?

Short answer: Generic launch timing is driven by the last expiring listed patent and any exclusivity periods that run beyond the primary patent term.

How to model the practical generic timeline

Generic launch outcomes typically follow this sequence:

1. Orange Book patent wall remains intact past the earliest expiration dates
2. At challenge resolution, the generic approval can occur while patent disputes continue (depending on infringement outcomes and settlement terms)
3. If a settlement allows early launch “at-risk” or on a fixed date, brand revenue declines at that date

For specialty diagnostics, brand revenue can drop sharply once a lower-cost version is accessible in covered settings.

What does exclusivity loss mean for financial trajectory?

Even if volumes are modest, exclusivity loss can change:

• Provider ordering behavior due to cost pressure
• Payor preference and formulary placement
• Net price realization via rebates and reimbursement reclassification

How does Paragraph IV litigation risk affect MACRILEN’s commercial outlook?

Short answer: For MACRILEN, the primary litigation risk is that an ANDA challenge could trigger earlier generic availability, pressuring pricing and reducing brand test share.

Key litigation scenarios that typically impact brand cash flows

• Decision against brand: immediate or scheduled generic launch
• Settlement: brand pays or trades concessions for a delayed launch date
• Combination of partial design-around and partial allowance: segmented competition at certain dosages/forms
• Ongoing appeals: prolonged “stay” can delay generic entry, extending brand revenue visibility

How long-tail litigation can reshape revenue even without immediate entry

Even with delayed generic entry, pending challenges can:

• Increase discounting to maintain contracts
• Trigger payor procurement switching behavior
• Reduce brand willingness to invest in sales expansion

What formulations are protected for MACRILEN, and do they constrain generic design-arounds?

Short answer: Formulation and manufacturing patents can constrain generic attempts if they require specific release, stability, or preparation characteristics tied to the clinical protocol.

Where formulation patents usually appear in diagnostic small molecules

Look for protections around:

• Solid-state forms (polymorphs, amorphous grades)
• Stabilizers and excipients that support shelf-life
• Reconstitution and administration workflow compatibility
• Manufacturing process parameters that yield non-infringing intermediate products

If formulation IP is strong, generic entry may be delayed even if composition patents expire earlier.

What manufacturing and supply risks matter for MACRILEN market growth?

Short answer: Niche diagnostic drugs are sensitive to supply consistency; even short supply disruptions can break clinician adoption.

Why supply consistency matters more in diagnostics

Diagnostic adoption requires operational reliability:

• Scheduled test ordering depends on predictable drug availability
• Protocol standardization collapses if sites face intermittent shortages
• Payors may reassess coverage if providers report delays

How supply constraints typically feed into revenue trajectories

• Initial ramp can stall after adoption if shortages emerge
• Recovered supply can restart growth, but it often restarts at a lower baseline due to clinician memory of delays

What is the likely payer and contracting strategy for MACRILEN going forward?

Short answer: The brand’s best path is payer-friendly contracting that aligns reimbursement rules to testing value and ensures predictable patient access.

What payor dynamics shape net revenue more than list price

• Medical benefit versus pharmacy benefit coverage differences
• Prior authorization controls for endocrine stimulation testing
• Coding and billing rules that determine whether payors reimburse the test bundle
• Maximum allowable rates or lab carve-outs that cap reimbursement

What contracting levers can extend market durability

• Centers of excellence arrangements with endocrinology networks
• Site readiness programs tied to diagnostic protocol adherence
• Value-based contracting tied to clinical endpoints (where accepted)

In niche diagnostics, small shifts in coverage rules can move revenue more than pricing adjustments.

How does MACRILEN compare with alternative dynamic tests in commercial impact?

Short answer: Compared with broader endocrine lab approaches, MACRILEN’s differentiation is convenience and standardized testing, but its commercial impact is capped by the small population of adults who require dynamic GHD confirmation and payer willingness to reimburse stimulation testing.

Competitive comparison dimensions to monitor

• Test completion rate and protocol simplicity
• Safety profile and workflow impact (patient prep requirements, monitoring burden)
• Time-to-result and downstream decision-making integration
• Reimbursement stability across commercial and government plans

Key Takeaways

• MACRILEN’s market dynamics are driven by niche adult GHD evaluation and specialist workflow adoption, not broad primary-care demand.
• Financial trajectory is expected to show specialty-diagnostic patterns: high per-test pricing sensitivity to reimbursement, slow ramp, and abrupt step-down risk at generic entry.
• Exclusivity and Orange Book patent coverage determine the timing of generic ANDA threats; formulation and method patents can extend durability.
• Payer contracting and coverage policy are primary revenue levers, since reimbursement determines whether sites can consistently order the drug.

FAQs

1. What Orange Book patents for macimorelin most impact generic entry timing?
2. How do Paragraph IV ANDA challenges typically affect macimorelin’s net revenue before FDA approval of a generic?
3. What reimbursement policies influence adoption of macimorelin for adult growth hormone deficiency testing in the U.S.?
4. How do formulation or manufacturing patents constrain generic versions of macimorelin even after composition patent expiry?
5. What market indicators best predict MACRILEN volume growth in endocrine centers (e.g., specialist enrollment or test ordering trends)?

References

1. U.S. Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations (macimorelin). FDA.
2. U.S. Food and Drug Administration. Drug approvals and labeling for MACRILEN (macimorelin). FDA.