Deuterated drugs; updates and obviousness analysis.

INTRODUCTION: The pharmacokinetics and/or toxicity of many known drugs can be modified by selective deuteration, an area of significant commercial interest and scientific and regulatory progress. Areas covered: This review firstly discusses recent developments in deuterated drugs including the FDA approval of deutetrabenazine. Secondly, it discusses 35 U.S.C. §103 'obviousness' as it relates to recent patent prosecution, and also to Inter Partes Review (IPR). IPR is a new post-award review of patentability under §102 or §103, two IPR petitions upon deuterated drugs have been instituted and included §103 arguments. Finally, an extended analysis of §103 obviousness based upon the practices of major pharmaceutical companies is provided, that supports rather late priority dates, while §102 is also discussed. Expert opinion: The total value of transactions involving deuterated drugs is close to $5 billion. While the importance of §103 'obviousness' rejections remains in patent applications under current prosecution, IPR of issued patents is developing and will affect likely affect §103 interpretations in this area. However, patents are still issuing with later priority dates, and further litigation will likely occur.