Isabella Mariam

The High Court of Delhi Single Bench of Justice Tejas Karia, in an order dated November 24, upheld the Patent Office’s refusal to grant Amylin Pharmaceuticals LLC and AstraZeneca Pharmaceuticals LP a patent for a sustained-release exenatide injection for the treatment of diabetes. The Court dismissed the appeal against the Assistant Controller of Patents and Designs, holding that the claimed microsphere formulation, comprising exenatide, a sugar-based stabilizer and a non-aqueous triglyceride carrier, would be apparent to a person skilled in the art in light of prior scientific disclosures. After examining earlier literature on microsphere delivery systems and premixed peptide–sugar formulations, the Court concluded that the application did not involve the inventive step required for patent protection and affirmed the rejection.

The appeal was filed under Section 117A of the Patents Act, 1970 challenging the order dated 10.07.2018 by the Assistant Controller of Patents and Designs rejecting Patent Application titled “Sustained Release Formulations Using Non-Aqueous Carriers”. The applicants had filed the national phase application on 01.05.2011 with claims 1–32 and later submitted amended claims in response to the First Examination Report and post-hearing submissions. The Controller rejected the application on the grounds of lack of inventive step under Section 2(1) (ja) and being hit by Section 3(d).

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The appellants contended that the Controller failed to consider their submissions, misapplied the prior art, and did not appreciate that the claimed one-component injectable microsphere formulation was non-obvious and offered advantages over existing two-component systems. They argued that cited documents D1–D4 neither disclosed the specific non-aqueous carrier comprising triglycerides of C6–C12 fatty acids nor taught the claimed combination of exenatide, sugar, and PLGA microspheres.

The respondent argued that the cited prior art collectively disclosed all features of Claim 1, and a person skilled in the art could arrive at the claimed invention through routine experimentation. The respondent further submitted that no therapeutic efficacy data demonstrating improvement over known exenatide formulations was produced.

The Court examined whether the Controller had provided adequate reasoning and whether the claimed invention met the requirements of inventive step under Section 2(1) (ja). It recorded that the subject application disclosed that “injectable sustained release formulations offer the opportunity to provide therapeutic amounts of active pharmaceutical ingredients over an extended period of time from a single injection” and that conventional microsphere formulations led to “a large burst release following injection, which causes an undesirable in vivo release of active pharmaceutical ingredient in a single burst.”

On the claimed non-aqueous carrier, the Court stated that Paragraph [0068] of D1 teaches that “sterile, fixed oils are conventionally employed as a solvent or suspending medium… including synthetic mono- or diglycerides” and that fatty acids such as oleic acid are disclosed. It observed that this disclosure allowed a skilled person to consider triglyceride-based non-aqueous carriers. It recorded that the applicants’ argument of teaching-away could not be accepted, noting that “the oils mentioned in Paragraph No. [0068] of D1 would also include the specified oils mentioned in the Complete Specification.”

With respect to exenatide, the Court noted that D2 disclosed “the terms… ‘exenatide’… to indicate the respective actives” and discussed sustained-release needs for GLP-1 analogues. It further stated that Paragraph [0087] of D2 disclosed sugars such as sucrose as stabilising additives.

Regarding microspheres, the Court recorded that D3 described “a novel in-situ method for the preparation of injectable biodegradable PLGA microspheres for the controlled delivery of drugs.”  Addressing D4, the Court observed that it disclosed “a biocompatible polymer having dispersed therein a biologically active polypeptide and a sugar.”

The Court summarised the cumulative disclosures in D1–D4 and stated that “it would be obvious for PSITA to use the triglyceride fatty acid of carbon chain lengths ranging from 6 to 12” and that the arguments based on absence of explicit disclosure of C6–C12 triglycerides could not succeed.

It further recorded that although the appellants relied on advantages such as long shelf-life, ease of administration and sustained release, “no such results have been disclosed in the Complete Specification except the storage and stability of exenatide”, and therefore inventive step could not be acknowledged.

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The Court recorded that “the Subject Application has rightly been refused by the learned Controller under Section 2(1)(j) of the Act, and does not require interference.” It further stated that “the Subject Application of the Appellant cannot be termed as an invention under Section 2(1)(j) of the Act. The Impugned Order dated 10.07.2018 passed by the learned Controller does not require interference and is hereby upheld.”

“The present Appeal is dismissed.”

Advocates Representing The Parties

For the Petitioners: Mr. Saransh Vijay with Mr. Daksh Oberoi, Advocates.
For the Respondents: Ms. Rukhmini Bobde, CGSC with Mr. Amlaan Kumar, Mr. Vinayak Aren and Mr. Jatin Dhamija, Advocates.

Case Title: Amylin Pharmaceuticals, LLC & Anr. v. Assistant Controller of Patents and Designs
Neutral Citation: 2025: DHC:10342
Case Number: C.A. (COMM.IPD-PAT) 76/2022
Bench: Justice Tejas Karia