Patent Landscape Report on Ritonavir - WIPO

forms. However, with the recent developments in preparing amorphous crystalline Ritonavir,solid dosage forms have great patenting potential in the future.The first generation patent application WO1994014436, assigned to Abbott Laboratories, isthe first disclosure of Ritonavir. The ‘436 document claims a broad Markush structure describingRitonavir. This initial document only claims a retroviral protease inhibitor and doesnot describe structural considerations or conformational polymorphs of Ritonavir. A 1B referenceis also included in this innovation track. US5541206 claims a less broad Markushstructure that defines several antiviral analogs. This document is designated 1B because inaddition to claiming a large number of Markush compounds as in ‘436, this document alsolists over 50 specific compounds that are defined by standard IUPAC 1 chemical naming.The second generation contains two documents that claim solid dosage forms and methodsof preparation. All second generation documents are assigned to Abbott Laboratories andcite the ‘436 document. The broadest independent claim in US5559158 describes a solidpharmaceutical composition comprising a pharmaceutically acceptable adsorbent and Ritonavir.The most specific independent claim describes Ritonavir being present from 10 to40% by weight and having an adsorbent from about 25-75% by weight. The compositionalso comprises an unspecified acid. The specific adsorbent material is not described in anyindependent claim. This document claims very broad coverage for a wide range of soliddosage forms. The second second-generation document is WO1997001349 (Abbott), andcites the first generation patent. The ‘349 document claims a more narrowly focused inventionrelated to method of improving the pharmacokinetics of a drug, specifically Ritonavir.The independent claims again describe a combination of Ritonavir and another pharmaceuticalagent in a composition (claim 21) comprising a pharmaceutical carrier without specificallydescribing delivery method. This document is also important in the first innovation trackbecause it can be broadly interpreted as any dosage form.The third generation contains two documents assigned to Abbott Laboratories published in2008 and 2009. These documents could also be important to innovation track 3 becausethey describe the use of various crystalline forms in pharmaceutical compositions. There isa significant gap in filings related to solid dosage forms from 2000-2006. US7364752broadly claims a pharmaceutical composition comprising amorphous Ritonavir as a soliddispersion in a water soluble polymer. The broad claim language is used to increase protectionfor the ‘614 document. The second third-generation document describes a similar invention.The ‘269 document claims methods for preparing compositions employing Form IIcrystalline Ritonavir. These two documents broadly protect the use of crystalline Ritonavir insolid dosage forms for Abbott.The fourth generation is related to the third generation patents by IPC and ECLA classificationcodes. These documents describe solid dosage forms comprising a combination ofdrugs. US2011008429 (CIPA) describes a solid dosage form comprising two commonlyused antiretroviral drugs Ritonavir and darunavir. The second document WO2009153654(Aurobindo Pharmaceticals) also claims a combination with a water soluble polymer, similarto the claims of the third generation ‘752 patent. The ‘654 document describes the processesto prepare the solid dosage form in greater detail than the ‘752 document, specificallyfor solublizing Lopinavir and Ritonavir and spray drying the composition to form a solid dispersion.