There are many circumstances where a patent aims to cover a dosage level, a formulation, or a method of administration of a therapeutic drug.  In some cases, this is a second round of patents, and the initial filing has already covered the active ingredient.  In other cases, the new patent may be aimed at repurposing a known compound for a new indication or new mode of administration.

I often get questions about these types of patents.  The most common one being – aren’t these types of claims obvious?  The answer is sometimes yes and sometimes no.  It’s a very fact specific determination.  Given that the facts are driving the bus here, there are some strategies you can take to make the claims less obvious.  Keeping in mind, though, that the facts themselves are what they are.

Let’s take the example of the recent Federal Circuit case Endo Pharmaceuticals Solutions vs. Custopharm.  The Endo patents concerned a long-acting injectable testosterone drug for men suffering from hypogonadism (low testosterone levels).  Endo’s patents had three types of claims at issue: (i) specific dosages; (2) a formulation of 2 co-solvents; and (3) a 2-phase dosing schedule.  The court found all 3 types of claims nonobvious.  Why?

First, keep in mind that it is the challenger’s burden to prove invalidity by clear and convincing evidence.  In other words, here, Custopharm had to bring forward enough facts to tip the scale well in its favor towards invalidity.  Just because Custopharm couldn’t prove the claims invalid doesn’t mean everyone else would be in the same position.  Stronger and different arguments could prevail.  But, let’s take it as it came and see how it shook out.

The dosage claims. Testosterone had been dosed at 1000 mg at the time of the patent.  The patent claims covered a 750 mg dose.  Although one set of medical guidelines advocated for less testosterone, the 1000 mg dose fell into the range promoted by the most prevalently used guidelines at the time from the FDA.  The court rejected the other guidelines because there was no evidence that they would have been used in place of the FDA information.  The court stopped there and did not need to consider a second, likely pertinent question, namely even if one would have been motivated to lower the dose, why select 750 rather than 500, 250 or lower?

The formulation claims.  The Endo claims require a mixture of 40% castor oil and 60% benzyl benzoate.  Two arguments by the challenger went by the wayside here.  The first involved a publication of results from a small clinical study.  The publication disclosed the drug and the castor oil but did not say anything about the benzyl benzoate in the formulation.  Several years after the publication, and importantly, after the filing of the Endo patents, it became known that benzyl benzoate also was a component in the formulation.   Custopharm’s argument that the publications therefore inherently disclosed the formulation did not fly.  The court concluded that no one outside the study would have known at the time that the formulation contained this ingredient or the proportions of the 2 co-solvents.  Secondly, there were many choices of a co-solvent to mix with castor oil, so why choose benzyl benzoate?  The only publications with a castor oil-benzyl benzoate mix were not long-lasting injectables, not steroids and not used to treat men with hypogonadism (one was for pregnant women).  No motivation to mix and match here.

Dosing schedule claims.  These claims had 2 phases of dosing, the first 2 doses at 4 weeks apart and then a maintenance phase with injections every 10 weeks.  The facts here were fairly weak.  None of the prior art had such a dosing schedule and arguing it would have been obvious to choose this 2 phase solution was not supported. The art cited here consisted of other studies with testosterone.  Custopharm did not try comparing to schedules for other long-lasting injectable drugs.

The take-homes:

  • Claims for dosing, dosing schedules and formulations can provide a viable strategy to increase the strength and breadth of your IP protection.
  • Describing distinguishing features for formulations and dosing as compared to the prior art can strengthen your position against obviousness challenges.

Considerations for developing patent claims and supporting non-obvious arguments:

  • Dosing
    • What was the prevalent dose at the time?
    • What makes a dose (increase or decrease) non-obvious? Are the results unexpected from the prior dose in use?
    • Are there guidelines or other well-accepted guidance in the field that steer the dosing to a certain range?
  • Formulations
    • Many possibilities or few?
    • What makes the formulation for the drug of interest different from prior formulations and different from known formulations for other drugs?
    • Are the proportions of formulation ingredients important to achieve certain properties or activity?
  • Dosing schedules
    • Does the administration regime include changing doses or administration protocols over time?
    • Is the dosing regimen repeated/changed depending on the course of the disease or the result of a companion diagnostic?


The content of this blog is for informational purposes only and does not offer legal advice. Circumstances are fact-specific and you should consult an attorney for legal advice concerning your individual issues.