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Has this patent expired?

Publication number US5870405 A
Publication type Grant
Application number US 08/610,184
Publication date Feb 9, 1999
Filing date Mar 4, 1996
Priority date Nov 30, 1992
Fee status Paid

I think the patent expired 20 years from the priority date (this is a divisional patent) which would be November 30, 2012 (edited). Is that correct?

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No. The law for patent term changed as of 1995 with the Uruguay round of the WTO TRIPS treaty. It is now 20 years from the first claimed priority filing (excluding provisionals). Before that it was 17 years from grant. The patent in question was caught in the middle of the change and is the later of those two calculations. 1999 + 17 = 2016 so the 17 years from grant would govern. This could be less if there was a terminal disclaimer filed. If it had been for a pharmaceutical then time waiting for FDA approval can also be involved in the calculation.

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Thanks George. Your statement that the patent is "caught in the middle" does not match what I read on the PTO website. Quote: "All patents (other than design patents) that were in force on June 8, 1995, or that issued on an application that was filed before June 8, 1995, have a term that is the greater of the “twenty-year term” or seventeen years from the patent grant. See 35 U.S.C. 154(c)." This patent was filed in 1996 - so it is 20 years from filing. Since it is a divisional patent - its priority date is the filing date of the parent patent (as seen when logged onto PAIR). – Guest Dec 10 '13 at 2:18
(continuing) Had this patent been filed on or before June 8, 1995 - I'd understand the 1999+17 year calculation. Have I misunderstood what I've read? I am going in part on what I've read here: [link] I've read your answers to others' questions. They are most helpful. – Guest Dec 10 '13 at 2:26
Ouch! I see one glaring mistake. I meant to say "November 30, 1992" - not March 4. – Guest Dec 10 '13 at 3:04
I believe the effective filing date is, in this case, the priority date of Nov 30 1992 which is the filing date of the parent application. – George White Dec 10 '13 at 18:35

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