Can you re-invent the invention after filing?

Of course Not!!! But if there is hint in the specification about the possible advantages- it is possible to supplement with post-filing data. An example is the recent case of brigatinib – a judgement handed down by the Calcutta High court in May 25. Brigatinib as you know, was developed by Takeda  and is a globally celebrated compound.

Here the Patent office refused the application on the ground that the data provided was subsequent to the filing of the application and violated section 10(4) and other provisions. At the heart of the dispute was whether the Patent Office can ignore post-filing experimental data that substantiates the technical advancement or enhanced efficacy of a claimed invention. Takeda had submitted detailed data after the initial filing to demonstrate Brigatinib’s superior selectivity for ALK over similar kinases, most notably the insulin receptor.

Such selectivity is crucial: it ensures targeted action against cancer cells while minimizing toxic side effects. But the Patent Office dismissed this data outright, alleging that the invention was obvious and insufficiently disclosed.

The Core Issue: Post-Filing Data—Ignore It, Violate Natural Justice

In a landmark judgment that brings Indian patent jurisprudence in step with global standards, the Calcutta High Court held that ignoring post-filing data during patent prosecution violates principles of natural justice.  

The Calcutta High Court was unambiguous: post-filing data must be considered, especially when it directly supports the assertions made in the original specification. The Controller’s failure to do so, the Court held, amounted to a gross procedural irregularity and a denial of natural justice.

Echoes from Europe: A Consistent International Approach

What’s notable is how this ruling brings Indian jurisprudence closer to European Patent Office (EPO) practice. European case law—particularly the landmark T 1329/04 (Factor-9/John Hopkins) and T 609/02 (Salk Institute) decisions—has consistently held that post-published data may be used to support a technical effect, provided the application, on its filing date, makes a plausible disclosure of that effect.

These cases make a critical distinction: while you can't invent your invention after filing, you can certainly prove its advantages more fully later—as long as those advantages were hinted at or suggested in the original document.

The Calcutta High Court adopted a similarly balanced approach. It reaffirmed that the Indian Patents Act does not prohibit the submission of post-filing data and emphasized that any data substantiating technical advancement or therapeutic efficacy must be considered—especially when the claims themselves are properly disclosed in the original application.

This approach is also consistent with Astrazeneca vs Eris where the Delhi High Court had held that post-filing data can only be relied upon if there was a hint or “seed” sown in the specification.

Why This Judgment Matters

This ruling is a wake-up call for the Indian Patent Office, which has often taken a rigid, formalistic approach to post-filing submissions. It reminds decision-makers that the goal of the patent system is to reward innovation, not to frustrate it through narrow procedural gatekeeping.

The Court's firm stance signals a paradigm shift in how Indian patent authorities must approach supplementary evidence filed after a patent application. It also echoes the position long established by European patent law, where post-filing (or post-published) data is routinely accepted, provided  there is basis in the original application.

What’s Next?

The Court ordered the Patent Office to reconsider Takeda’s application afresh, this time giving due weight to post-filing evidence and ensuring a reasoned, transparent process.   There are some pre-grant oppositions against this application and thus, the application is pending.