ARIMIDEX Drug Patent Profile

Which patents cover Arimidex, and when can generic versions of Arimidex launch?

Arimidex is a drug marketed by Ani Pharms and is included in one NDA.

The generic ingredient in ARIMIDEX is anastrozole. There are twenty-four drug master file entries for this compound. Twenty-four suppliers are listed for this compound. Additional details are available on the anastrozole profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Arimidex

A generic version of ARIMIDEX was approved as anastrozole by ACCORD HLTHCARE on June 28^th, 2010.

Summary for ARIMIDEX

US Patents:	0
Applicants:	1
NDAs:	1

US Patents and Regulatory Information for ARIMIDEX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Ani Pharms	ARIMIDEX	anastrozole	TABLET;ORAL	020541-001	Dec 27, 1995	AB	RX	Yes	Yes

International Patents for ARIMIDEX

See the table below for patents covering ARIMIDEX around the world.

Country	Patent Number	Title	Estimated Expiration
Hong Kong	1000206
New Zealand	225037	SUBSTITUTED HETEROCYCLIC DERIVATIVES AND PHARMACEUTICAL COMPOSITIONS
Finland	882882
Canada	1337420	COMPOSES HETEROCYCLIQUES (SUBSTITUES EN ARALKYLE) ((SUBSTITUTED ARALKYL) HETEROCYCLIC COMPOUNDS)
South Africa	8803691
Japan	2609290

Supplementary Protection Certificates for ARIMIDEX

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0296749	97C0032	Belgium		PRODUCT NAME: ANASTROZOLUM; NAT. REGISTRATION NO/DATE: 624 IS 94 F 3 19961216; FIRST REGISTRATION: GB 12619/0106 19950811
0296749	SPC/GB96/004	United Kingdom		PRODUCT NAME: ANASTROZOLE OPTIONALLY IN THE FORM OF A PHARMACEUTICALLY ACCEPTABLE ACID ADDITION SALT; REGISTRATION NO/DATE: UK 12619/0106 19950811
0296749	C970012	Netherlands		PRODUCT NAME: ANASSTROZOLUM, DESGEWENST IN DE VORM VAN EEN FARMACEUTISCH AANVAARDBAAR ZUURADDITIEZOUT; NAT. REGISTRATION NO/DATE: RVG 19123 19960905; FIRST REGISTRATION: GB 12619/0106 19950811
0296749	97C0023	France		PRODUCT NAME: ANASTROZOLE, EVENTUELLEMENT SOUS LA FORME D UN SEL D ADDITION ACCEPTABLE EN MEDECINE PHARMACEUTIQUE; NAT REG. NO/DATE: NL 21126 19961227; FIRST REG.: 12619/0106 19950811
0296749	09C0055	France		PRODUCT NAME: ANASTROZOLE, EVENTUELLEMENT SOUS LA FORME D’UN SEL D’ADDITION ACCEPTABLE EN MEDECINE PHARMACEUTIQUE; REGISTRATION NO/DATE IN FRANCE: NL 21126 DU 19961227; REGISTRATION NO/DATE AT EEC: 12619/0106 DU 19950811

Investment Scenario and Fundamentals Analysis for ARIMIDEX (Anastrozole)

Last updated: February 21, 2026

What Is ARIMIDEX and Its Market Position?

ARIMIDEX (anastrozole) is an oral aromatase inhibitor developed by AstraZeneca. It is FDA-approved for hormone receptor-positive breast cancer treatment in postmenopausal women. It is also prescribed for adjuvant therapy and metastatic cases. The drug’s primary mechanism inhibits estrogen production, reducing tumor growth in hormone-sensitive cancers.

Market penetration remains substantial, supported by established indications and continued post-market sales. The global breast cancer market projects compound annual growth rates (CAGR) of approximately 7% over the next five years, driven by increasing awareness, aging populations, and expanding treatment indications.

Key Financial Parameters and Sales Trends

Metric	2020	2021	2022	2023 (Projected)	Notes
Annual global sales	$1.2B	$1.3B	$1.4B	$1.5B	Steady growth, driven by multiple indications
Market share (breast cancer)	35%	36%	37%	38%	Leading aromatase inhibitor
Patent status	Expired (2014)	Generic availability	Competition intensifies	Market saturation	Slight impact on pricing but maintained sales due to brand loyalty

Patent and Regulatory Environment

• Patent expiration: 2014, leading to generic competition.
• Regulatory approvals: Continued clearance in major markets (FDA, EMA, etc.).
• Biosimilar/pipeline entries: No biosimilars, but competitors include other aromatase inhibitors such as exemestane and letrozole.
• Reimbursement policies: Stable in developed regions, with cost-effectiveness confirmed in multiple health technology assessments (HTA).

Competitive and Market Dynamics

• Major competitors: Letrozole (Femara), exemestane (Aromasin).
• Differentiators: ARIMIDEX is often prescribed for early and advanced stages; has demonstrated favorable safety and efficacy profiles.
• Pricing strategy: Slight discounts post-patent expiry, but maintained by brand recognition and clinical preference.

R&D and Pipeline Considerations

• Existing label extensions for ovarian and other hormone-sensitive tumors.
• No significant pipeline updates or new formulations announced.
• Focus remains on mono therapy and combination with targeted agents.

Cost Structure and Profitability

• Manufacturing costs: Generally low due to generic competition.
• Pricing: Market prices average $5–$15 per daily dose in major markets.
• Margins: Gross margins declined post-patent expiry but stabilized around 50–60% in regulated markets.

Investment Outlook

Risks

• Market saturation due to generics. Price erosion affects revenue.
• Emergence of biosimilars and new therapeutics targeting hormone-resistant or triple-negative breast cancers.
• Regulatory, reimbursement changes that could impact profitability.

Opportunities

• Expanding indications in other hormone-dependent cancers.
• Combination therapy trials could boost sales, especially in oncology settings.
• Emerging markets: Growing healthcare infrastructure and oncology burden can drive future growth.

Valuation Metrics

Metric	2022 Actual	2023 Estimated	Notes
Revenue	$1.4B	$1.5B	Slight growth from expanding indications
Operating profit margin	50%	52%	Stabilization post-patent expiration
R&D spending	<$50M	Stable	Focused on pipeline optimization

Key Takeaways

• ARIMIDEX has a mature but stable market presence.
• Generic competition has pressured pricing but maintained revenue due to brand loyalty and clinical preference.
• Future growth hinges on expanding indications, combination therapies, and uptake in emerging markets.
• Patent expiration and biosimilar competition present ongoing risks.
• Financials indicate healthy margins, with ongoing cost control and moderate sales growth.

FAQs

Q1: How does patent expiration affect ARIMIDEX’s investment profile?
Patent expiry in 2014 led to generic entry, increasing competition and reducing margins but also expanding market access through lower prices, stabilizing overall revenue.

Q2: What are the key indications for ARIMIDEX?
Primarily hormone receptor-positive breast cancer in postmenopausal women, with some use in ovarian cancer as part of combination regimens.

Q3: What is the competitive landscape for aromatase inhibitors?
ARIMIDEX competes mainly with letrozole and exemestane, which have similar efficacy but different side effect profiles.

Q4: What pipeline developments could influence ARIMIDEX’s future value?
Current pipeline activity is limited; future improvements depend on label expansions or combination therapies rather than novel formulations.

Q5: How does healthcare reimbursement impact ARIMIDEX sales?
Affordability and reimbursement stability in Western markets support sales, though cost-control measures in emerging regions could constrain growth.

References

1. AstraZeneca. (2023). ARIMIDEX (anastrozole) prescribing information. Retrieved from https://www.astrazeneca.com

2. GlobalData. (2022). Breast cancer therapeutics market report.

3. IQVIA. (2023). Pharmaceutical market data and trends.

4. United States Food and Drug Administration. (2022). Drug approvals and label updates.

5. World Health Organization. (2022). Cancer statistics and burden.