Contreras-Hernandez, I

Davila-Loaiza, G

Mould-Quevedo, J

Rely, K

Elsevier - Publisher Connector 

A116 Abstracts
PIN33
COST EFFECTIVENESS OF SWITCHING TO SECOND LINE THERAPY
WITH LOPINAVIR/RITONAVIR (LPV/R) IN KENYA
Simpson KN1, Dietz B2, Rahim S3, Rajagopalan R3
1Medical University of South Carolina, Charleston, SC, USA, 2Abbott GmbH & Co., 
Ludwigshafen, Germany, 3Abbott Laboratories, Abbott Park, IL, USA
OBJECTIVES: Recent reports from the DART study (Chimbete et al, CROI
2008, poster 642) indicate substantial immunological responses for patients failing 
a ﬁ rst-line regimen who switch to a protease inhibitor (PI)-based antiretroviral
(ARV) regimen with LPV/r. However, the long-term health and economic conse-
quences expected from this switch in ARV are not known. This study will examine
the cost effectiveness of using 2nd line therapy in Kenya. METHODS: We used a 
Markov model to combine population data on CD4 T-cell response, infectious
disease events, death rates, health-related quality of life, cost of care, and drug
costs to estimate the cost effectiveness of switching to a LPV/r regimen, as compared 
to remaining on a ﬁ rst failed NNRTI regimen, or to discontinuing all ARV drugs.
These treatment options are compared in the base estimate assuming a cost of $500/
year for LPV/r, $200/year for ﬁ rst-line regimen, $3 per CD4 T-cell test, concurrent 
use of cotrimoxazole, 4% annual drop out from therapy, and a 10% annual incidence 
of malaria in Kenya. RESULTS: The base model estimates an improvement of 
19 months in average survival for the LPV/r group at an incremental cost effectiveness
ratio (ICER) of $1483/QALY. The ICER increases to $1571/QALY if dropout rate is 
16%, and to $1517 if CD4 tests cost $25, the survival beneﬁ t decreases to 13.3 months 
and the ICER is $1393/QALY gained when we assume no use of cotrimoxazole. 
CONCLUSIONS: Under the WHO benchmark for cost effective ICERs based on two 
times a country’s per capita GDP, with Kenya’s 2007 GDP of $1700 (International 
Monetary Fund) a switch to a LPV/r regimen using very stringent clinical or immu-
nological failure criteria appears to be quite cost effective for a country such as 
Kenya.
PIN34
DOES COMBINING ANTIRETROVIRAL AGENTS IN TO A SINGLE DOSAGE
FORM (CO-FORMULATIONS) ENHANCE QUALITY OF LIFE OF HIV/AIDS
PATIENTS – A COST UTILITY STUDY
Ganguli A, Wang J, Gourley D
University of Tennessee Health Science Center, Memphis, TN, USA
OBJECTIVES: Combining various antiretroviral agents into one single pill has been 
a strategy to reduce the pill burden thus enhance medication adherence among HIV/
AIDS patients. The study aims to analyze the cost effectiveness and cost utility of the
co-formulated ﬁ xed dose (FXD) strategy over multiple free dose combination (FRC) 
of antiretroviral agents from a health care system’s perspective. METHODS: The 
Medical Expenditure Panel Survey (MEPS; 2001–2006) was used to identify HIV/
AIDS patients (ICD-9-CM code 042, 043, V08) on at least one active antiretroviral 
medication. Patients on FXD were matched in 1 : 1 ratio with FRC group using pro-
pensity score method. All medical costs excluding those paid by patients and families 
were included. A patient without any ER visit was taken as the effectiveness measure.
Utility was measured using SF-6D scores based on the SF-12 questionnaire. RESULTS:
Nine FXD formulations were in the market from the period from 2001 to 2006. One 
hundred and seventy HIV patients were identiﬁ ed as study population of which 53% 
(n  92) were on at least one FXD formulation during the study period. Upon match-
ing, 70 patients from FXD had a match from the FRC group. Both groups had no 
signiﬁ cant differences in terms of socio-demographic characteristics and health status.
Fifty three patients (76.09%) in FXD did not have an ER visit versus 46 (65.82%) in 
the FRC. The mean annual cost for FXD patients was $15,749.91 and $11,890.01
for FRC patients. The mean utility for FXD group was 0.6741 and 0.6112 for FRC 
group. The Incremental cost-utility ratio for the FXD treatment over FRC treatment
was $45,586.13 per QALY. CONCLUSIONS: This study concludes that co-formulat-
ing antiretroviral drugs in a combination therapy enhances the quality of life in HIV/
AIDS patients and is cost effective as per the generally accepted threshold of $50k per
QALY.
PIN35
COST-EFFECTIVENESS OF MARAVIROC FOR HIV IN MEXICO
Contreras-Hernandez I1, Becker DL2, Chancellor JV3, Kühne F4, Mould–Quevedo J5, 
Marfatia S6
1Social Security Mexican Institute, Mexico City, Mexico, 2i3 Innovus, Burlington, ON, Canada, 
3i3 Innovus, Uxbridge, Middlesex, UK, 4i3 Innovus, Uxbridge, UK, 5Pﬁ zer Mexico, Mexico City, 
Mexico, 6Pﬁ zer, New York, NY, USA
OBJECTIVES: Maraviroc (MVC) is the ﬁ rst CCR5 antagonist licensed for antiretro-
viral therapy of patients with CCR5-tropic HIV-1. The objective of this study was to
predict the long-term clinical impact and cost-effectiveness of MVC in treatment-
experienced adults with HIV/AIDS in Mexico. METHODS: The AntiRetroviral Analy-
sis by Monte Carlo Individual Simulation (ARAMIS) model was adapted to the 
Mexican context to predict clinical and economic outcomes of treating with optimized
background therapy (OBT) versus testing for viral tropism status and treating with
OBT o MVC accordingly in treatment-experienced adults in Mexico. Baseline char-
acteristics and efﬁ cacy were from the MOTIVATE trials’ screening cohort. Costs and
population mortality data were speciﬁ c to Mexico collected from the Social Security 
Mexican Institute (IMSS). Results were reported from the perspective of health care 
payers using a 5% rate for discounting. Utility values for the quality adjustment 
of survival were obtained from published literature. Deterministic sensitivity analyses 
were conducted by means of repeat microsimulations. RESULTS: Compared to
treatment with OBT alone, treatment with OBT o MVC contingent on tropism test 
result increased projected undiscounted life expectancy and discounted quality-
adjusted life expectancy from 7.54 to 8.71 years and 4.42 to 4.92 quality-adjusted 
life years (QALYs), respectively, at an incremental cost of $21,329 USD. The resultant
incremental cost-effectiveness ratio (ICER) was $42,429 USD per QALY gained.
The ICER was considerably lower when MVC was modeled as a protease inhibitor
replacement in individuals with HIV susceptible to a2 components of OBT ($29,737 
USD); the ICER was higher in individuals susceptible to q3 OBT components ($67,171
USD). CONCLUSIONS: In treatment-experienced individuals with HIV/AIDS in
Mexico, a strategy of OBT o MVC contingent on tropism test result may be cost-
effective compared to OBT alone, particularly in individuals with limited options for 
active ART.
PIN36
THE ECONOMIC IMPACT OF MARAVIROC FOR ANTIRETROVIRAL
TREATMENT-EXPERIENCED HIV-INFECTED INDIVIDUALS IN MEXICO
Contreras-Hernandez I1, Rely K2, Mould–Quevedo J3, Davila-Loaiza G3
1Social Security Mexican Institute, Mexico City, Mexico, 2Pharmacoeconomic Consultor, 
Mexico City, Mexico, 3Pﬁ zer Mexico, Mexico City, Mexico
OBJECTIVES: Over the past 20 years, development of antiretroviral (ARV) therapy 
for HIV-infection has been dynamic, with continuous development in existing new 
ARV drug-classes as well as the introduction of new ARV drug-classes with a new
mode of action. Maraviroc (MVC) represents the ﬁ rst oral licensed CCR5 co-receptor
antagonist. The aim of this study was to estimate the cost-effectiveness of a strategy
of testing and treating with optimized-background-therapy (OBT)MVC according to 
tropism test results, compared to treating with OBT alone from the Mexican payer’s 
perspective. METHODS: A four-state Markov model was performed to estimate 
health and economic consequences during a time horizon of ﬁ ve years(6-month cycles). 
Effectiveness measures were progression-free-months (PFM) and quality adjusted life 
years (QALYs) gained. Transition probabilities and utilities were obtained from a
systematic review employing international published literature(MOTIVATE-1 and -2 
trials included). MVC 150 mg/day BID was used and OBT therapy could include up 
to six different ARV. Resource use and costs were obtained from 637 randomized 
hospital records from the Social Security Mexican Institute(IMSS) and ofﬁ cial institu-
tional databases. Costs include outpatient and inpatient services, drug, tropism test,
etc. The model was validated according to international guidelines. Probabilistic sen-
sitivity analyses were performed employing second-order Monte Carlo simulation. 
Acceptability curves were constructed. RESULTS: MVCOBT showed the highest
number of estimated PFM and QALYs (56.1 and 4.29) vs. OBT alone (34.5 and 2.96) 
(p  0.05). Although MVCOBT showed higher mean expected costs(US$50,028.5 o
US$852.8) than OBT alone (US$27,846.1 o US$700.2) (p  0.05), the incremental
cost-effectiveness ratio(ICER) per QALYs resulted in US$15,384.6[CI95% US$9,307.6-
US$23,076.9]. Sensitivity analyses showed that MVCOBT could be a cost-effective 
treatment compared with OBT alone with a probability over 80% using accepted 
thresholds (US$12,500–US$37,500). Component analyses and net monetary beneﬁ ts 
showed the robustness of these results. CONCLUSIONS: MVC is a cost-effective 
option improving current ARV efﬁ cacy in Mexican individuals with few active treat-
ment options.
INFECTION – Patient-Reported Outcomes Studies
PIN37
SELF-REPORTED PILL BURDEN AS A PREDICTOR FOR ADHERENCE IN
HIV-INFECTED PATIENTS
Wagner S1, Gupta S2, Waterman F3, Zoe-Powers A4, Oza D5, Grimm K5, Kim E5
1Consumer Health Sciences International, Princeton, NJ, USA, 2Consumer Health Sciences, 
Princeton, NJ, USA, 3Consumer Health Sciences, New York, NY, USA, 4Bristol-Myers Squibb, 
Mahwah, NJ, USA, 5Bristol-Myers Squibb, Plainsboro, NJ, USA
OBJECTIVES: To assess the association between self-reported pill burden and adher-
ence to Antiretroviral (ARV) Therapy in HIV-infected patients. METHODS: Adults 
reporting HIV infection during the 2005–2007 US National Health and Wellness
Surveys on at least one ARV component drug participated in this study. For the mul-
tivariate analysis, respondents needed to be on an ARV regimen that contained at least 
two nucleoside reverse transcriptase inhibitors and at least one protease inhibitor or 
non-nucleoside reverse transcriptase inhibitor. Respondents were classiﬁ ed as adherent 
if they either never missed or skipped an antiretroviral dose or did so less than once 
per week, and complete adherence if they never missed or skipped a dose, otherwise
they were considered non-adherent. Resource use was deﬁ ned by ER visits and hos-
pitalizations. Chi-square tests were used for comparisons of percents and t-tests for
comparisons of means. Logistic regression models were run controlling for possible 
confounders, with complete adherence the dependent variable of interest. RESULTS:
A total of 788 patients were included (73.6% male, 26.4% female; average age  43 
years). The mean duration of HIV/AIDS diagnosis was 10.3 years; median number of 
ARV pills taken daily was 4.0, and median number of non-ARV medications was 2.0. 
Signiﬁ cantly higher percent hospitalizations (37% vs. 13%; p  0.001) and ER visits 
(47% vs. 23%; p  0.0001) respectively were reported by the non-adherent group. 
Using a complete adherence model, a higher number of pills decreased the likelihood 
of complete adherence signiﬁ cantly [OR  0.945; 95% CI:(0.906, 0.986); p  0.009]. 
CONCLUSIONS: Increased pill burden resulted in lower adherence to antiretroviral 
therapy and may lead to a negative impact on health care resource use.


PIN36 THE ECONOMIC IMPACT OF MARAVIROC FOR ANTIRETROVIRAL TREATMENT-EXPERIENCED HIV-INFECTED INDIVIDUALS IN MEXICO 

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PIN36 THE ECONOMIC IMPACT OF MARAVIROC FOR ANTIRETROVIRAL TREATMENT-EXPERIENCED HIV-INFECTED INDIVIDUALS IN MEXICO

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