Patent Infringement, Defences and Remedies

1. What infringes

The Act does not define infringement; it follows from s.48. Any unauthorised making, using, offering for sale, selling or importing of the patented product, or use of the patented process or dealing in its direct product, in India, during the term, infringes, unless a defence applies. Infringement is judged by comparing the defendant's product or process with the claims, not with the patentee's commercial product.

• Literal infringement: the defendant's product contains every element of the claim.
• Purposive construction: claims are read as a skilled person would understand the patentee to have meant (Catnic, House of Lords, 1981; Kirin-Amgen, 2004). Indian courts follow this and the older “pith and marrow” doctrine: taking the essential features of the invention is infringement even if inessential features are changed.
• Equivalents: the UK Supreme Court in Actavis UK Ltd. v. Eli Lilly & Co. (2017) held that a variant infringes if it achieves substantially the same result in substantially the same way and the skilled person would see that, unless the patentee clearly meant strict compliance. In the US, the doctrine of equivalents (Graver Tank v. Linde Air, 1950; Warner-Jenkinson v. Hilton Davis, 1997) is limited by prosecution history estoppel (Festo v. Shoketsu, 2002). Delhi High Court decisions accept equivalents in substance.

In F. Hoffmann-La Roche Ltd. v. Cipla Ltd. the Delhi High Court Division Bench (2015) reversed the single judge and found infringement of Roche's erlotinib patent: the patent claimed the compound, and Cipla's product contained the compound whatever its polymorphic form, so testing the product against a different polymorph (Form B) was the wrong comparison.

2. The suit

• Who sues: the patentee, an exclusive licensee (s.109) and a compulsory licensee in some cases (s.110), with the patentee joined.
• Where (s.104): a court not lower than a District Court having jurisdiction; but where a counter-claim for revocation is made, the suit and counter-claim go to the High Court. Patent suits are commercial disputes under the Commercial Courts Act, 2015, with strict timelines.
• When: only after grant, but damages may cover the period from publication (s.11A(7)).
• Burden (s.104A): in a suit on a process patent, the court may direct the defendant to prove that his process is different, where the product is new or the patentee proves that a substantial likelihood exists that the product was made by the process and he could not determine the process used, despite reasonable efforts. The court must protect the defendant's manufacturing and business secrets.

3. Defences

1. Invalidity: every ground on which the patent may be revoked under s.64 is available as a defence (s.107(1)), usually with a counter-claim.
2. Non-infringement: the product falls outside the claims, properly construed.
3. Statutory exceptions: experiment, research and teaching (s.47(3)); the Bolar exception (s.107A(a)); parallel imports from an authorised seller (s.107A(b)); foreign vessels (s.49).
4. Government use under s.47 or s.100 (s.107(2)).
5. Licence or consent, express or implied, and exhaustion by an authorised sale.
6. Restrictive conditions in a licence in force at the time (s.140(3)).
7. Innocent infringement limits remedies (s.111): no damages or account where the defendant proves he was unaware of the patent and had no reasonable grounds to believe it existed; marking an article “patented” without the number does not give notice.
8. Gibbs defence: the defendant's act was already known or obvious at the priority date, so that a claim covering it would be invalid.

4. Interim injunctions

The general test is a prima facie case, balance of convenience and irreparable harm, from American Cyanamid Co. v. Ethicon Ltd. (House of Lords, 1975), adopted in India by the Supreme Court in Wander Ltd. v. Antox India (P) Ltd. (1990), which also held that an appellate court should not substitute its own discretion for that of the trial court unless the discretion was exercised arbitrarily or perversely. Patent cases add special features:

• Credible challenge. Because grant raises no presumption of validity (Biswanath, 1978), a defendant who raises a credible challenge to validity may defeat an interim injunction, even without showing the patent is probably invalid. The Delhi High Court has treated survival of opposition and long, unchallenged enjoyment of the patent as factors in the patentee's favour.
• Public interest. In Roche v. Cipla (Delhi High Court, 2008, upheld by the Division Bench in 2009) the court refused an interim injunction partly because Cipla's erlotinib was about a third of Roche's price and an injunction would deny patients access to a cancer drug. The court directed Cipla to keep accounts. Critics said public interest could make patents unenforceable for drugs; later Delhi decisions, such as Merck Sharp & Dohme v. Glenmark (2015) on sitagliptin, granted injunctions where infringement was clear, saying public interest also lies in enforcing valid patents.
• Pro-tem security. In SEP and pharmaceutical cases the Delhi High Court has ordered defendants to deposit money or pay a provisional royalty pending trial, in place of an injunction.

5. Final relief (s.108)

• Injunction, subject to such terms as the court thinks fit;
• damages or an account of profits, at the patentee's option;
• the court may order that goods found to be infringing, and materials and implements predominantly used to create them, be seized, forfeited or destroyed, without compensation.

Damages aim to put the patentee in the position he would have been in but for the infringement: lost profits on sales he would have made, or a reasonable royalty on the infringer's sales. An account of profits strips the infringer's gains. Indian courts have increasingly awarded substantial damages and costs in patent cases under the Commercial Courts Act, and have used the Delhi High Court IP Division Rules for expert assistance in technical cases.

6. Other remedies and offences

• Declaration of non-infringement (s.105): a person may seek a declaration that his process or product does not infringe, after asking the patentee for an acknowledgement and being refused.
• Groundless threats (s.106): a person threatened with infringement proceedings may sue for a declaration that the threats are unjustifiable, an injunction and damages, unless the patentee shows that the acts complained of infringe a valid claim.
• Offences (ss.118–124): contravention of secrecy directions, falsification of register entries, unauthorised claim of patent rights (s.120), wrongful use of the words “patent office”, and refusal to furnish information (s.122). Infringement itself is not an offence in India, unlike trademark and copyright infringement.

7. Comparative note

In the US, eBay Inc. v. MercExchange (Supreme Court, 2006) rejected an automatic injunction after a finding of infringement and required the four-factor equity test, reducing injunctions for non-practising patentees; damages may be trebled for wilful infringement (35 U.S.C. §284). In the UK an injunction follows infringement as a matter of course, but the court may award damages in lieu where an injunction would be disproportionate. EU Enforcement Directive 2004/48/EC harmonises remedies and requires proportionality.

How this is examined

For the short note, sections 2, 3 (list), 4 (test and Roche) and 5 (s.108). For an essay on infringement, add claim construction and the comparisons. Read with the note on SEPs, where the remedies debate is sharpest.