In the case of Daewoong Pharmaceutical Co. Ltd. & Anr. vs Controller General of Patents [C.A.(COMM.IPD-PAT) 23/2022], the Delhi High Court set aside the refusal of  patent application number 201817048074, entitled “Method of Producing Diphenylmethane Derivative” and remanded the matter for fresh consideration in light of additional efficacy data filed at the appellate stage. The decision is significant for its treatment of post-filing evidence in overcoming Section 3(d) objection and for clarifying the procedural flexibility available under the patent law.

The claimed invention relates to an improved method for producing diphenylmethane derivative useful as an SGLT inhibitor. The compound of Formula C28 was already known from prior art D1 cited in the First Examination Report (FER), and was presented in the application as a crystalline Form-A characterised by XRD data, with the applicant asserting that such form led to improved therapeutic efficacy.

The Controller refused the application noting that while the data demonstrating improvement in stability, non-hygroscopicity, solubility, dissolution rate etc. was sufficient to meet the requirements of Section 2(1)(ja), it failed to establish enhanced therapeutic efficacy. The Controller characterised the comparative data as reflecting pharmacokinetic properties/ physical properties, and not therapeutic efficacy as required under Section 3(d).

Before the High Court, the central issue was whether the applicant could be permitted to cure this evidentiary deficiency at the appellate stage. Notably, during the pendency of the appeal, the Court allowed the Appellants to place additional data on record by way of an affidavit under Order XLI Rule 27 of the Code of Civil Procedure, 1908.

The Court observed that the rejection under Section 3(d) was not based on a substantive finding that enhanced efficacy was absent, but rather on the applicant’s failure to meet the evidentiary threshold at the time of consideration. The deficiency identified by the Controller was thus evidentiary in nature, and not intrinsic to the invention itself.

In addressing the permissibility of such additional evidence, the Court relied on its appellate powers under Order XLI CPC, Rules 27 to 29, which permit the admission of new evidence and its evaluation either by the Appellate Court or by referring the said evidence to a sub-ordinate Court to take such evidence and re-transfer the same to the Appellate Court for a final decision. The Court emphasised that the additional data should, in the first instance, be considered by the Controller. While it is settled that an Appellate Court may itself evaluate additional evidence after affording an opportunity for rebuttal, it may also remand the matter for limited to recording evidence on the additional evidence and recall the matter for final disposal after evidence has been recorded.

A further equitable dimension was introduced through the Appellants’ explanation that the additional data could not be furnished earlier due to disruptions caused by the COVID-19 pandemic. The Court accepted this justification as reasonable in the circumstances.

Importantly, the Court also reinforced that patent law does not prohibit the submission of additional data to overcome objections. In doing so, it relied on the IPAB’s decision in University of Miami vs Controller of Patents, which recognised the permissibility of filing supplementary evidence to address examination objections. This approach aligns Indian practice with international prosecution norms, where post-filing data is often admissible to substantiate asserted technical effects.

On this basis, the Court set aside the impugned order and remanded the matter to the Controller for de novo consideration limited to the objection under Section 3(d). It preserved the Controller’s finding on inventive step under Section 2(1)(ja), thereby narrowing the scope of reconsideration. The Controller was directed to assess the additional data and afford a fresh hearing to the appellants.