From a French provisional to a PCT application: the timeline

The Patent Cooperation Treaty does not grant patents. It gives you one international application, one search, one written opinion, and — decisively — a single deadline of thirty months from your earliest priority date before you must choose the countries in which to pursue national or regional patents. For a biotech or pharma programme that will only know its lead indication at month twenty-four, that delay is the whole point.

A French provisional followed by a PCT is the most common European route: the provisional fixes the date at minimal cost, the PCT keeps 150+ contracting states open, and the national phases are paid only for the markets that still matter two and a half years later.

Article 4C of the Paris Convention gives you twelve months from the provisional's filing date to file applications claiming its priority. The PCT application can be filed at INPI acting as receiving office, at the International Bureau of WIPO, or, for a French applicant, at the EPO. Filing at INPI also satisfies the French foreign-filing rules of Article L612-9 CPI, under which an invention made in France must first be filed in France or authorised before it is filed abroad — a point that matters for defence-relevant technologies.

The PCT application should be a complete specification: description, claims, abstract, drawings, and where relevant an ST.26 sequence listing. It may add matter compared with the provisional — new examples, new data — but only the subject-matter already in the provisional keeps the earlier date. Everything new takes the PCT filing date.

If month twelve is missed, restoration of the right of priority under Rule 26bis.3 PCT can be requested within two months, on either an 'unintentional' or a 'due care' standard depending on the receiving office. The EPO, as designated office, only recognises restorations granted on the 'due care' standard. Do not plan on it.

The International Searching Authority — for applicants filing at INPI, the EPO — issues an international search report (ISR) and a written opinion, typically around month sixteen. This is the first independent view on novelty and inventive step, and it is the document your investors and licensees will read. The ISR also drives the strategy for the next fourteen months: amend claims under Article 19 PCT, request international preliminary examination, or simply carry the opinion into the national phases.

The international application is published by WIPO eighteen months from the priority date, together with the ISR. From this moment the content is prior art against everyone, including you, and the provisional's confidentiality is over. If a trade-secret strategy is preferred for part of the disclosure, the decision must have been taken before the PCT was filed, not before month eighteen — withdrawal to avoid publication is possible only before the technical preparations for publication are completed.

A demand for international preliminary examination (Chapter II) must be filed within twenty-two months from priority or three months from the ISR, whichever is later. It buys a dialogue with the examiner and an international preliminary report on patentability that some offices weigh heavily. Many applicants skip it and argue in the national phases; it is a cost-benefit decision that depends on how negative the written opinion was and how many countries are planned.

The national phase must be entered thirty months from the priority date in most offices — the United States, China, Japan, Korea, Canada among them — and thirty-one months at the European Patent Office and several others. Entry means paying the national fees, filing translations where required, and appointing local representatives. This is the moment the programme's real IP budget is committed, and the moment the list of countries should be reconciled with the FTO analysis and the commercial plan.

A European regional phase produces a single European application that, on grant, becomes either a bundle of national patents or, since June 2023, a Unitary Patent covering the participating EU states and litigated before the Unified Patent Court.

Because the PCT will typically claim several provisionals, and because each claim of the PCT only benefits from the earliest provisional that fully discloses it (G 2/98, with partial priority under G 1/15), a written priority matrix — claim by claim, provisional by provisional — should accompany the PCT draft. It is what lets you answer an examiner's or an opponent's priority attack in minutes rather than weeks, and it is what tells you whether an intervening publication of your own has become prior art against one of your claims.