Mayne Pharma (ASX:MYX) Settles IMVEXXY Patent Litigation with Sun Pharma, Locking In Exclusivity Through October 2032

Sonal Goyal

30 September 2026 12:40 PM AEST

Mayne Pharma (ASX:MYX) Settles IMVEXXY Patent Litigation with Sun Pharma, Locking In Exclusivity Through October 2032

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Key Highlights

• Mayne Pharma settled US Paragraph IV Patent litigation with Sun Pharma over IMVEXXY FDA Orange Book patents.

• The settlement establishes a generic IMVEXXY market entry date of 21 October 2032, or earlier under specified conditions.

• No financial payment or upfront monetary consideration was exchanged between the parties.

• IMVEXXY net sales grew 8% to US$29.3 million in the twelve months to 30 June 2026, with prescriptions up 6%.

Mayne Pharma Group Limited (ASX:MYX), the Adelaide-based specialty pharmaceutical company, announced on 30 September 2026 that it has resolved US Paragraph IV patent litigation with Sun Pharmaceutical Industries Ltd (Sun Pharma) relating to IMVEXXY, its estradiol vaginal insert product for the treatment of menopausal dyspareunia. The settlement, which does not include any financial payment between the parties, establishes an agreed pathway for a Sun Pharma generic product to enter the market from 21 October 2032, subject to court approval.

About Mayne Pharma

Mayne Pharma is an ASX-listed specialty pharmaceutical company focused on the commercialisation of novel medicines, with particular expertise in dermatology and women's health in the United States. The company also provides contract development and Manufacturing services globally. IMVEXXY is a key product within its Women's Health franchise, and its protection underpins the company's medium-term Revenue planning in the menopause segment.

Settlement Terms and Context

The litigation between Mayne Pharma, TherapeuticsMD, and Sun Pharma was commenced in July 2024 following Sun Pharma's filing of an Abbreviated New Drug Application (ANDA) under the Hatch-Waxman framework. Sun Pharma's Paragraph IV certification alleged that one or more of the FDA Orange Book-listed patents covering IMVEXXY were invalid, unenforceable, or not infringed.

The settlement resolves that litigation and provides for a potential generic entry date of 21 October 2032, or earlier under certain circumstances. No upfront or milestone payment was exchanged. Mayne Pharma stated that the resolution reinforces the validity and enforceability of its IMVEXXY patent portfolio, which has a last-expiring patent in February 2034. Following this settlement, one further Paragraph IV litigation matter for IMVEXXY remains ongoing.

IMVEXXY Commercial Performance

In the twelve months to 30 June 2026, IMVEXXY total prescriptions grew 6% over the prior corresponding period, while net sales rose 8% to US$29.3 million. The product sits within Mayne Pharma's Women's Health Franchise and is supported by access, adherence, and prescriber engagement initiatives. Despite the ongoing commercial execution, a competing generic entry date from 2032 introduces a long-term revenue horizon that investors and analysts will Factor into any assessment of IMVEXXY's contribution to company Earnings beyond that point.

Patent Lifecycle and Strategic Implications

The settlement effectively secures IMVEXXY's protected commercial window through to at least October 2032, giving Mayne Pharma approximately six years of exclusivity ahead of potential generic competition from Sun Pharma under these terms. The last expiring IMVEXXY patent runs until February 2034, and the company indicated it will continue to actively defend its intellectual property estate.

The resolution of this matter removes a near-term litigation risk while leaving a defined pathway for future generic competition. Whether additional parties file ANDAs and trigger further Paragraph IV challenges will be a key factor to monitor.

Key Takeaways

Mayne Pharma's settlement with Sun Pharma over IMVEXXY establishes clarity around the patent protection timeline for one of its key Women's Health products. With no financial consideration changing hands and a generic entry date locked in at October 2032, the company retains a defined exclusivity window, though one further litigation matter remains active. IMVEXXY's ongoing prescription and revenue growth will be watched alongside any new intellectual property challenges as the competitive landscape evolves.

FAQs

Q: What is the IMVEXXY settlement between Mayne Pharma and Sun Pharma?

A: The two companies resolved US Paragraph IV patent litigation, agreeing that Sun Pharma may enter the generic IMVEXXY market from 21 October 2032, or earlier under certain conditions, with no financial payment between the parties.

Q: What is Paragraph IV litigation?

A: Under the US Hatch-Waxman framework, a Paragraph IV certification is filed by a generic manufacturer claiming that brand-name drug patents are invalid or not infringed. This can trigger patent infringement proceedings and a temporary stay of generic approval for up to 30 months.

Q: How is IMVEXXY performing commercially?

A: In the twelve months to 30 June 2026, IMVEXXY net sales increased 8% to US$29.3 million, with total prescriptions rising 6% over the prior corresponding period.

Q: Does Mayne Pharma have other ongoing litigation for IMVEXXY?

A: Yes. After the Sun Pharma settlement, the company noted that one further Paragraph IV litigation matter relating to IMVEXXY remains ongoing.

Q: When does the last IMVEXXY patent expire?

A: The last expiring patent in the IMVEXXY portfolio runs until February 2034, providing a legal framework for continued IP defence beyond the agreed Sun Pharma generic entry date.

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