After a patent assignment in India, who can sue? Cadila v Abburi Ramaiah

Who can sue for patent infringement in India after the patent has been assigned? On 5 November 2026 a Division Bench of the Telangana High Court answered that the assignor cannot. In Cadila Healthcare v Abburi Ramaiah, it rejected the plaint. The plaintiff had assigned the patent, and the assignee was on the register.

The case is Cadila Healthcare Limited (now Zydus Lifesciences Limited) v Abburi Ramaiah and another, C.R.P. No. 1623 of 2026. Justice T. Vinod Kumar and Justice Anil Kumar Jukanti heard the revision petition. Judgment was reserved on 30 October 2026 and pronounced on 5 November 2026.

The facts

Dr Abburi Ramaiah held Indian Patent No. 239632. He sued Cadila Healthcare and another defendant in 2017 before the Commercial Court at Hyderabad, as C.O.S. No. 44 of 2017. He sought an injunction and ₹1 crore in damages for infringement. The plaint relied on sections 48, 104 and 108 of the Act.

Before the suit, on 12 April 2014, he had executed an assignment deed in favour of Samastha Laboratories Private Limited. The public register showed the assignment taken on record on 16 April 2014. It named Samastha Laboratories as patentee and Dr Ramaiah as grantee. The plaint, however, said the assignment was still pending before the Patent Office.

Cadila applied to reject the plaint for want of standing. On 6 April 2026 the Commercial Court dismissed that application and left the point for trial. Cadila filed a revision petition in the High Court. The patent had expired in 2024.

What the court decided

Assignment takes effect on execution. The court compared section 68 before and after the Patents (Amendment) Act, 2005. Before 2005, an assignment was valid only if it was in writing and an application to register it was filed within the prescribed time. Today, section 68 requires only that the assignment is in writing and duly executed. The court said that "the assignee steps into the shoes of the assignor" on execution of the deed. The Commercial Court was therefore wrong to treat the unregistered assignment as ineffective.

Only one patentee at a time. Section 2(1)(p) defines the patentee by reference to the register entry "as the grantee or proprietor of the patent". The plaintiff argued that he remained the patentee as grantee. The court rejected this. It read "or" as meaning that only one class of person holds the status at a time. Once Samastha Laboratories was entered as proprietor, Dr Ramaiah could no longer sue as patentee.

The register can be read on a rejection application. Under Order VII Rule 11, a court usually looks at the plaint alone. The court held that it may also look at public records to detect camouflage or suppression. It relied on recent Supreme Court authority to that effect. Dr Ramaiah produced nothing to show the assignment was pending. He did not deny the register entry in his reply. The court drew an adverse inference and held that the cause of action was illusionary.

The court allowed the revision, set aside the Commercial Court's order and rejected the plaint. It made no order as to costs.

What the court did not decide

• It did not decide whether Patent No. 239632 was valid or infringed.
• It did not decide whether Samastha Laboratories, as assignee, could sue for the same acts.
• It did not discuss section 69(5), which limits the use of unregistered documents as evidence of title.
• It did not address an assignment that is executed but never entered on the register. Here the register already named the assignee.

Section 69: why registration still matters

The ruling does not make registration optional in practice. Under section 69(1), a person who acquires a patent or an interest in it must apply to the Controller to register the title. Under section 69(5), a document that is not registered cannot be admitted as evidence of title by the Controller or any court. The only exception is where the Controller or court directs otherwise for reasons recorded in writing.

So the two provisions work together. Section 68 decides when the transfer takes effect between the parties. Section 69 decides what the assignee can prove before the Controller and the courts. An assignee who has not recorded its title may find it hard to enforce the patent. An assignor who has executed a deed has nothing left to enforce.

Licensees are in a different position. Under section 109, an exclusive licensee may sue for infringement after the date of the licence. The patentee must then be joined as a defendant if it is not a plaintiff.

How the US, Europe and the UK compare

United States. Under 35 U.S.C. § 261, patents and applications are assignable by an instrument in writing. An unrecorded assignment is void against a later purchaser or mortgagee for value without notice. That rule does not apply if the assignment is recorded at the USPTO within three months, or before the later purchase. A party that has assigned all substantial rights generally lacks standing to sue for later infringement. Claims for earlier infringement stay with the assignor unless the deed transfers them.

Europe. Under Article 72 of the European Patent Convention, an assignment of a European patent application must be in writing and signed by the parties. After grant, a European patent takes effect as national patents in each state. After grant, transfers are governed by national law. Infringement actions go to national courts, or to the Unified Patent Court where it has jurisdiction.

United Kingdom. Under section 30(6) of the 1977 Act, assignments are void unless in writing and signed by or on behalf of the assignor. Section 68 adds a penalty for late registration. If the patent is infringed before the transaction is registered, the new proprietor or exclusive licensee cannot be awarded costs or expenses. The bar does not apply if registration follows within six months. It also does not apply if earlier registration was impracticable and it followed as soon as practicable.

The common thread is that a written assignment moves the right to sue to the assignee. Registration then protects the assignee against later dealings, and in the UK it also protects its costs.

Practical steps

• Assignors should check the public register and their own deeds before suing. A plaint that hides an assignment can be rejected at the outset.
• Assignees should apply to register their title under section 69 soon after the deed is executed. Keep the stamped and executed deed safe.
• Licensors and licensees should state in the licence who controls enforcement. An exclusive licensee can sue under section 109, but the patentee must be joined.
• Buyers and investors should search the register and ask for every assignment in the chain during due diligence. A gap in recorded title can delay enforcement for years.
• Defendants should check the register as soon as a patent suit is served. A standing objection can end the case before trial.

We prepare and record assignments and act in patent enforcement across India. See our patent services and our guide to filing a patent in India. For a related licence dispute, see our note on trademark licence arbitration in India.

Frequently asked questions

Is a patent assignment valid in India without registration?

Yes, between the parties. Since 2005, section 68 requires only a written and duly executed assignment. The Telangana High Court held in Cadila v Abburi Ramaiah that it takes effect on execution. Registration under section 69 is still needed to prove title before the Controller and the courts.

Can the original inventor sue after assigning a patent in India?

No. Once the patent is assigned and the assignee is entered as proprietor, the assignor is no longer the patentee under section 2(1)(p). The court held that he has no standing to sue for infringement.

Who can sue for patent infringement in India?

The patentee, meaning the person entered on the register as grantee or proprietor. An exclusive licensee may also sue under section 109, with the patentee joined as a party.

Official source

• Cadila Healthcare Ltd v Abburi Ramaiah, Telangana High Court, C.R.P. No. 1623 of 2026 (5 November 2026)
• The Patents Act, 1970, section 68 (IP India)
• The Patents Act, 1970, section 69 (IP India)
• The Patents Act, 1970, section 109 (IP India)
• 35 U.S.C. § 261
• Article 72 EPC
• Patents Act 1977, section 30 and section 68