Delivering oxygen-supersaturated solutions to the body: US Pat. No. 7,641,628

U.S. Patent No. 7,641,628, issued on January 5, 2010 to TherOx, Inc. of Irvine, CA, discloses a system and method for generating a gas-supersaturated fluid and delivering it at high pressures without bubble formation.

An oxygen-supersaturated solution can be infused into a patient to provide oxygen to regions or systems of the patient’s body in need of oxygen (e.g., blood downstream of a balloon angioplasty site).  The patent discloses a way to generate this high-pressure solution and to controllably deliver it at a specified rate and pressure to prevent bubble formation. 

This patent provides a good example of mining a single patent application to obtain multiple patents with claims of varying scope.  But first, a bit of background:  Most of the time, in a first office action from the USPTO, the examiner will reject some or all of the claims of the application for not satisfying the legal requirements for patentability in an “office action.”  The applicant then has the opportunity to file a response which (i) explains how the rationale of the rejection is legally flawed, (ii) amends the claims to address the rejection, or both.  If the examiner is convinced by this response, the examiner will allow the patent to issue.  If the examiner remains unconvinced, a subsequent office action will be sent out by the USPTO.  This office action may be deemed to be a “Final Office Action” by the USPTO, but there are still opportunities to respond or perhaps to appeal the examiner’s rejection to continue pursuing the allowance of the application.

In this case, back in 1998, the examiner reviewed the original patent application, and instead of rejecting the application in an office action, the USPTO sent out a “Notice of Allowance,” and a first U.S. patent was issued in 1999.  Such “first-action allowances” are good news to the applicant; after all, the patent issued without having to argue with the examiner or amending the claims to satisfy the examiner’s view of patentability.  However, it’s possible that the examiner would have allowed even broader claims to issue.  By receiving the first-action allowance and not a rejection, the applicant doesn’t get information regarding the examiner’s view of how broad is too broad.

To avoid leaving money on the table, as it were, by having the issued claims more narrow than what might have been obtainable, a “continuation” application can be filed to pursue additional claims.  The scope of these claims can be different from those of the original patent application, but they must be fully supported by the specification as originally filed.  (There can be other reasons to file a continuation application, which I won’t discuss now.)  In this case, two continuation applications were subsequently filed, resulting in a second U.S. patent issuing in 2000 and a third U.S. patent issuing in 2001. 

We’re not done yet, though.  If the examiner reviews the claims of a patent application and determines that there are actually multiple inventions being claimed, the examiner will issue a “Restriction Requirement,” which requires that the applicant identify which of the multiple inventions they wish to pursue in the application.  The other inventions can be pursued in one or more “divisional” applications.  In this case, three divisional applications were subsequently filed, resulting in a fourth U.S. patent issuing in 2004, a fifth U.S. patent issuing in 2006, and a sixth U.S. patent (the subject of this blog post).  So the original patent application filed in 1997 resulted in six issued U.S. patents, all claiming priority to the original 1997 filing date.

TherOx is a private, venture-financed medical device company that flirted with an IPO in late 2008, but withdrew its filing in early 2009.  In March 2009, in a 9-5 split decision, an FDA advisory committee recommended against approval of TherOx’s Downstream oxygen delivery system for patients after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) but sought further clinical trial data.  I presume that TherOx has since begun to gather additional data to bring back to the FDA, but in my internet searching, I haven’t found any reference to such efforts.