Tuesday, January 29, 2008

Your Comments

Subsequent to our post on Tarceva Patent Litigation Analysis IV, Patent Circle received a very informative email from one of the readers, who also happens to be one of my friends in patent profession. I reproduce the email below, and would surely be interested to hear what other readers have to say about it. Such efforts by readers will surely make a difference and do help in shaping patent practice in India.

"Is Erlotinib a derivative of Gefitinib?

1. I agree with your 29th Jan posting.

2. Erlotinib is not a derivative of Gefitinib.

3. It is not even analogue so to say.

4. Since chronologically Erlo came before Gefi, hence one may quote Erlo while describing Gefi.

In fact while I write this note, one interesting fact came to my mind.

Can one call Aceclofenac a derivative of diclofenac?

Yes. It can be (& it is) derived from Diclofenac. But it is not an analogue of diclofenac.


Because, although both are antiinflammatory, their mechanism of action is different.

Hence even structural similarity not necessarily ensures that the structures would be analogous.

Imagine Aceclofenac product patent application comes to Indian patent office.

Just because Aceclofenac is an "ester' derivative of diclofenac, would you reject it pending rigorous proof of 25-30%plus efficacy vs Diclofenac?

No. Section 3(d) wording is extremely loose and legally reckless.

Derivative: Two structures should be related by simple transformations (bio or chemical) say by 2 to 3 steps. Their functional group transformation should be short easily demonstrable or part of the common knowledge in that field. Shortness is the key. Otherwise all aromatic compounds can be termed as "derivatives" of benzene: that is absurd.


Analogue: Two facets: Structural: Inspite of structural changes, function is same. Functional: Some property verifying agent like a bio-surface/lectin certifies the functional closeness. Analogue should always be seen in the light of external/third party/biosurface/or some property verifying agent."

1 comment:

  1. I think though it is discussed that
    Gifitinib and Erlotinib are not analog,but there Mechanism of Action is almost same.both inhibits the intracellular phosphorylation of tyrosine kinase associated with the epidermal growth factor receptor (EGFR)