Introduction The World Intellectual Property Organisation reported more than 9750 patents of ritonavir from the discovery in December 1993. This intellectual property right aimed to encourage innovation. However, heatstable formulations or combinations with other chemicals might be patented and marketed at higher price and also when the original patent is about to expire, a so called evergreening strategy. We aimed to determine the financial incentive of marketing heatstable formulation using the proprietary melt-extrusion (Meltrex) technology allowing in addition to reduce the pill count from 6 to 4 per day. The Meltrex technology was applied to ritonavir stand alone formulation in Oktober 2010 almost 4 years after the lopinavir/ritonavir (December 2006).

Methods Frequency of administration and dosage for all patients under ritonavir and lopinavir/ritonavir were collected from the Geneva Swiss HIV Cohort Study from January 2003 to June 2016. Extracosts were calculated for three different scenarios assuming the replacement with the corresponding Swiss market price de-escalation of (1) lamivudine (2) lamivudine/zidovudine and (3) efavirenz over time. Prices were adjusted by the inflation rate.

Results Over the study period the total cost was USD2,805,135 for the ritonavir and USD13,351,886 for the lopinavir/ritonavir. The increase in cost for the Meltrex technology per patient was 17% for ritonavir 4% for lopinavir/ritonavir, leading to an extracost of USD166’358 and USD368’255 respectively.Theoretical savings if generic ritonavir would enter the market after original ritonavir patent termination would be USD994’080 for lamivudine price de-escalation, USD750,917 for lamivudine/zidovudine and USD600,741 for efavirenz.

Conclusions The financial incentive encourage the pharmaceutical firm to be innovative leading to negotiate higher prices and at the same time to extent of the originator patent. The consequence is a financial impact for the society by preventing competition from generic equivalent and the delay in the accessibility of innovation for the patient.