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Introduction
On 22 August 2025 Justice Senthilkumar Ramamoorthy of the Madras High Court delivered a significant judgment in Amgen Inc. v. Assistant Controller of Patents & Intas Pharmaceuticals Ltd. (CMA (PT) No. 28 of 2023). The case concerned Amgen’s Indian national phase application No. 5857/CHENP/2008 for a lyophilised therapeutic peptibody composition used for chronic immune thrombocytopenic purpura (ITP). After a pre-grant opposition from Intas and objections by the Patent Office, the Controller rejected claims 1–13 citing lack of inventive step and non-patentability under sections 3(d) (“mere use of a known process”), 3(e) (mere admixture), 2(1)(ja) (inventive step) and 10(4) (sufficiency of disclosure). Amgen appealed under section 117A of the Patents Act.
The court’s decision not only addressed four common grounds for refusal but also clarified the evidence required to demonstrate synergy and inventive step for pharmaceutical compositions.
Factual background
The invention:
The claimed invention is a lyophilised therapeutic peptibody composition comprising a buffer (10 mM histidine at pH 5), a bulking agent (4 % w/v mannitol), a stabilising agent (2 % w/v sucrose) and a surfactant (0.004 % w/v polysorbate-20) where the therapeutic peptibody has the structure denoted Formula V. Formula V encompasses 52 TPO mimetic peptide sequences (see Table 6 of the specification), although the experimental data provided (Example 7, Tables 39–41) focused on one sequence, SEQ ID No. 459 and its related peptibodies. Independent claim 9 is a method for preparing the lyophilised peptibody using the specified excipients and concentrations.
Examination, opposition and refusal
The First Examination Report (FER) raised objections under sections 3(d), 3(e) and lack of inventive step. Amgen responded, but Intas filed a pre-grant opposition alleging obviousness (s. 25(1)(e)), non-patentability (s. 25(1)(f)) and insufficiency (s. 25(1)(g)). After hearings, the Controller refused claims 1–13 on the grounds that:
1. Claim 9 (method) was mere use of a known process under s. 3(d) because lyophilisation and the peptibody were known.
2. Claims 1–8 were a mere admixture lacking synergy under s. 3(e).
3. Claims 1–13 lacked inventive step, being obvious over prior arts D1–D6 (particularly D4 and D5).
4. The specification was insufficient under s. 10(4) because experimental data were provided for only one peptibody sequence among 52.
Amgen appealed, emphasising EPO decisions and internal data demonstrating synergy and non-obviousness, while the respondents relied on prior art disclosures and alleged optimisation without inventive merit.
Issues before the Court
The court framed four issues:
1. Section 3(d): Whether claim 9 was merely the use of a known process.
2. Section 3(e): Whether the composition was a mere admixture lacking synergy.
3. Inventive step (s. 2(1)(ja)): Whether the claimed formulation would have been obvious to a person skilled in the art (PSITA) in view of prior arts.
4. Section 10(4): Whether the disclosure sufficiently enabled the invention across the claimed scope.
Court’s findings
1. Rejection under Section 3(d) – “mere use of a known process”
The Controller had concluded that claim 9 “is mere use of a known process” because lyophilisation is widely known. The court disagreed, noting that while prior art D4 disclosed the therapeutic peptibody (Formula V), it merely suggested that compositions could be in “dried powder, such as lyophilised form” without any method or specific excipient selection. D5 disclosed lyophilised IL-12 compositions with excipients but did not describe lyophilising the Formula-V peptibody. Importantly, claim 9 recited specific excipients (buffer, bulking agent, stabiliser and surfactant) at specific concentrations. The court held that such a process is not a generic lyophilisation step but a tailored method; therefore, Section 3(d) did not apply and the rejection was unsustainable.
Practice point:
Section 3(d) should not be invoked merely because a process involves a known technique. Unless the exact process is disclosed and there is no new product or reactant, claim 9 cannot be dismissed as “mere use”.
2. Rejection under Section 3(e) – “mere admixture” and synergy
The Controller held that Amgen failed to show synergy because Tables 40 and 41 lacked pre and post lyophilisation comparison and used different protein concentrations. The court rejected this reasoning on two grounds:
1. Relevance of pre-lyophilisation data: The court noted that the objective of the invention was to improve stability via lyophilisation, not to concentrate the protein (unlike prior art D3). Thus, pre and post-lyophilisation comparisons were unnecessary.
2. Evidence of synergy: Tables 39–41 showed that using sucrose at a threshold concentration reduced chemical degradation, and adding polysorbate-20 dramatically decreased aggregation across different protein concentrations. These results demonstrated that the excipients interacted to provide stability beyond their individual effects, evidencing synergy.
Accordingly, the rejection under s. 3(e) was set aside. The court stressed that comparative pre and post formulation data is not mandatory; demonstrating interaction between ingredients suffices to show synergy. Minor optimisation or absence of comparative data cannot diminish synergy once experimental results show improved stability.
Practice point: For compositions, applicants should provide experimental data showing functional interaction between components. Synergy can be established without pre/post-formulation comparison if the data reveal that combining ingredients yields superior stability or efficacy.
3. Inventive step (s. 2(1)(ja))
(a) Obviousness analysis
The key prior arts were D4 (Amgen’s own patent on thrombopoietic compounds) and D5 (Formulations for IL-12). The respondents argued that because D4 disclosed the peptibody and D5 disclosed excipients and similar concentrations, a PSITA would combine them to arrive at the claimed formulation. The court acknowledged that lyophilisation is a known technique and that buffering agent, surfactants and lyoprotectants are commonly used. However, it emphasised that selection and optimisation of excipients for biologics is highly protein specific and involves many permutations. Scientific literature cited in the judgment highlighted that each protein reacts differently with excipients and that formulation scientists must empirically determine optimal combinations.
The court concluded that:
• D4 discloses the peptibody but does not teach how to lyophilise it or which excipients to use.
• D5 deals with IL-12 (a heterodimeric cytokine for cancer), not TPO-RA peptibodies; thus a PSITA would not look to IL-12 literature for TPO-RA formulations.
• There was no teaching, suggestion or motivation linking D4 and D5. Without hindsight, a PSITA would search for literature on lyophilisation of TPO-RA peptibodies or peptides, not IL-12.
Therefore, it would not be obvious to choose the specific excipients and concentrations in the claimed invention. The court warned against retrospectively “mosaicking” prior arts; combining multiple references requires a clear pointer in the prior art and cannot be based on speculation or selection hindsight.
(b) Outcome
Because the specific selection of excipients and concentrations was not taught or suggested in the prior art, the claimed formulation involved an inventive step. The court held that the formulation is not obvious under section 2(1)(ja).
Practice point: In obviousness analysis of pharmaceutical formulations, courts will scrutinize whether the prior art provides a direction to select the claimed excipients and concentrations. Evidence of protein specific formulation challenges and absence of teaching to combine prior art references can establish inventiveness.
4. Sufficiency of disclosure (s. 10(4))
Section 10(4) requires the specification to fully describe the invention and the best method of performing it. The court noted that independent claims 1 and 9 were drafted broadly to cover all 52 TPO mimetic peptide sequences in Table 6, yet experimental data were provided only for SEQ ID No. 459. Because the other 51 sequences vary in amino‑acid composition and properties, the court held that without guidance or supporting data, a person skilled in the art could not reproduce the invention for those sequences. Thus the disclosure was only partly sufficient.
To align the scope of the claims with the enabled disclosure, the court ordered that claims 1 and 9 be amended to restrict Formula V to peptibodies comprising SEQ ID No. 459. With this amendment, the application satisfies sections 10 and 2(1)(j)/(ja) and is not excluded under sections 3(d) or 3(e). The court directed the Patent Office to proceed to grant the patent.
Practice point: When drafting broad claims covering multiple embodiments, applicants must ensure that the specification includes sufficient data or guidance across the scope. Failing to do so can lead to claim narrowing. India follows a strict enablement standard requiring experimental support or directions for each class of compounds.
Key takeaways:
1. Section 3(d) is not a catch all for process claims.
A method involving a known technique such as lyophilisation can be patentable if it uses specific reactants/excipients in defined concentrations and results in a new product or improved stability.
2. Synergy under section 3(e) must be supported by evidence of interaction.
Comparative pre and post-formulation data is not mandatory; experimental data demonstrating improved stability due to interactions among ingredients is sufficient.
3. Avoid hindsight mosaicking in obviousness.
Courts require a teaching, suggestion or motivation to combine prior art references. Where prior arts relate to different proteins or lack details on lyophilisation, it is unlikely that a PSITA would combine them.
4. Protein specific formulation challenges matter.
The judgment underscores that biologics react differently to excipients; selecting excipients and concentrations requires experimentation and cannot be assumed obvious. Evidence of such challenges can be persuasive.
5. Disclose sufficient data across claim breadth.
For formulations covering multiple sequences or compounds, provide experimental data or guidance for each class. Indian courts may restrict claims to enabled embodiments.
6. Amendments may salvage patentability.
Even where broad claims fail sufficiency, narrowing claims to enabled embodiments can lead to grant. Applicants should be prepared to propose amendments to align with disclosed data.
Conclusion
The Madras High Court’s decision in Amgen Inc. v. Assistant Controller of Patents clarifies several aspects of Indian patent law relevant to pharmaceutical and biologic formulations. The judgment affirms that claims should not be refused under section 3(d) or 3(e) without a detailed analysis of prior art and synergy; emphasises the need to avoid hindsight in obviousness; and reinforces the strict requirement for enablement. For patent attorneys, the case is a reminder to gather robust experimental evidence, anticipate objections under sections 3(d)/3(e), and ensure specifications sufficiently enable the entire claimed scope. With biologics becoming increasingly important, this decision provides valuable guidance on drafting and prosecuting patent applications for complex therapeutic formulations in India.
Prepared by : - Kunal Dalsania
Designation: Patent Attorney
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