Acute pancreatitis associated with different combination therapies in patients infected with human immunodeficiency virus

Investigation of the potential association between the use of fluoxetine and occurrence of acute pancreatitis: a Danish register-based cohort study

Background

There is currently conflicting evidence of the association between the use of selective serotonin reuptake inhibitors (SSRIs) and acute pancreatitis. The SSRI fluoxetine has been suspected to be the driver of this serious outcome. Therefore, this study aims to investigate the potential association between fluoxetine use and the occurrence of acute pancreatitis.

Methods

We conducted a nationwide cohort study using Danish register-based data from 1996 to 2016. The exposed group were new users of fluoxetine (1-year washout). The control subjects were new users of citalopram or SSRIs, excluding fluoxetine. The outcome was an incident diagnosis of acute pancreatitis with a 5-year washout. We used an intention-to-treat approach following patients for a maximum of 6 months. Cox regression analyses were performed, estimating hazard ratios (HRs) and 95% confidence intervals (CIs) adjusted for age/sex, comorbidities and co-medications, using propensity score adjustment and matching.

Results

In the propensity score-matched analyses, 61 783 fluoxetine users were included. The incidence rates among users of fluoxetine and other SSRIs were 5.33 (3.05–8.66) and 5.36 (3.06–8.70) per 10 000 person-years, respectively. No increased risk of acute pancreatitis was identified following fluoxetine exposure compared with either citalopram [HR 1.00, 95% CI 0.50–2.00) or other SSRIs (0.76, 0.40–1.46).

Conclusions

Fluoxetine use was not associated with an increased risk of acute pancreatitis compared with citalopram or other SSRIs. The absolute risk of acute pancreatitis was low and did not vary between different SSRIs. Further research is needed to determine whether there is a class effect on the risk of acute pancreatitis.

Assessment of pancreatitis associated with tocilizumab use using the United States Food and Drug Administration Adverse Event Reporting System database

Tocilizumab (TCZ) is used to treat rheumatoid arthritis and other systemic inflammatory disorders. There is some evidence suggesting the occurrence of pancreatitis following TCZ use. We aimed to determine the reporting of pancreatitis following TCZ use in comparison with other drugs using the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database. We extracted adverse event reports submitted to FAERS during 2013-2019. A reporting odds ratio (ROR) with the lower bound 95% confidence interval (CI) > 1 and a lower limit of a two-sided 95% interval of information component (IC025) more than zero was considered significant. Following deduplication, 3,383,910 adverse event reports were available; 144 (0.004%) reports were of pancreatic adverse events associated with TCZ use, and 15,907 (0.47%) associated with other drugs. Of the 144 cases, 74 (51.39%) received concomitant medications with pancreatotoxic potential. The likelihood of reporting of pancreatic events, compared with any other adverse event, with TCZ use was 1.32 times higher than that with other drugs. The lower bound of the 95% CI of the ROR and IC remained above the criteria of significance throughout the study period, except 2013. The findings suggest disproportionately high reporting of pancreatitis in patients receiving TCZ as compared with other drugs. This marginally high reporting is not likely to be of immediate clinical concern and needs to be interpreted cautiously.

Clinical profile of acute pancreatitis following treatment with protease inhibitors: a real-world analysis of post-marketing surveillance data

BACKGROUNDS

Acute pancreatitis (AP) has been reported in patients treated with protease inhibitors (PIs), but there are few real-world studies comparing the occurrence and characteristics of AP after different PI regimens.

RESEARCH DESIGN AND METHODS

Disproportionality analysis and Bayesian analysis were utilized for data mining of the Food and Drug Administration's Adverse Event Reporting System (FAERS) database for suspected adverse events involving AP after PI. The times to onset and fatality rates of AP following different PI regimens were also compared.

RESULTS

Based on 33,832 reports related to PIs, 285 cases were associated with AP, involving with 12 out of the 15 studied PIs. Of all the reported AP events related to PIs, 64.56% occurred in men and the median time to onset of AP was 103 (IQR: 26-408) days after the initiation of PI treatment with a fatality rate of 14.02%. Among all PI therapies, indinavir was notably associated with AP, and ritonavir and lopinavir/ritonavir-induced AP cases appeared to be associated with a higher risk of death.

CONCLUSIONS

Most of PIs were associated with AP-related adverse events, among which indinavir has a stronger association with AP but there is no significant difference in fatality rates.

Sex-Related Differences of Acute and Chronic Pancreatitis in Adults

The incidence of acute and chronic pancreatitis is increasing in the United States. Rates of acute pancreatitis (AP) are similar in both sexes, but chronic pancreatitis (CP) is more common in males. When stratified by etiology, women have higher rates of gallstone AP, while men have higher rates of alcohol- and tobacco-related AP and CP, hypercalcemic AP, hypertriglyceridemic AP, malignancy-related AP, and type 1 autoimmune pancreatitis (AIP). No significant sex-related differences have been reported in medication-induced AP or type 2 AIP. Whether post-endoscopic retrograde cholangiopancreatography pancreatitis is sex-associated remains controversial. Animal models have demonstrated sex-related differences in the rates of induction and severity of AP, CP, and AIP. Animal and human studies have suggested that a combination of risk factor profiles, as well as genes, may be responsible for the observed differences. More investigation into the sex-related differences of AP and CP is desired in order to improve clinical management by developing effective prevention strategies, diagnostics, and therapeutics.

Ever-increasing diversity of drug-induced pancreatitis

With over 100000 hospital admissions per annum, acute pancreatitis remains the leading gastrointestinal cause of hospitalization in the United States and has far-reaching impact well beyond. It has become increasingly recognized that drug-induced pancreatitis (DIP), despite accounting for less than 3% of all cases, represents an important and growing though often inconspicuous cause of acute pancreatitis. Nevertheless, knowledge of DIP is often curtailed by the limited availability of evidence needed to implicate given agents, especially for non-prescription medications. Indeed, the majority of available data is derived from case reports, case series, or case control studies. Furthermore, the mechanism of injury and causality for many of these drugs remain elusive as a definitive correlation is generally not established (< 10% of cases). Several classification systems have been proposed, but no single system has been widely adopted, and periodic updates are required in light of ongoing pharmacologic expansion. Moreover, infrequently prescribed medications or those available over-the-counter (including herbal and other alternative remedies) are often overlooked as a potential culprit of acute pancreatitis. Herein, we review the ever-increasing diversity of DIP and the potential mechanisms of injury with the goal of raising awareness regarding the nature and magnitude of this entity. We believe this manuscript will aid in increasing both primary and secondary prevention of DIP, thus ultimately facilitating more expedient diagnosis and a decrease in DIP-related morbidity.

Transcription elongation factor Brd4-P-TEFb accelerates intestinal differentiation-associated SLC2A5 gene expression

BACKGROUND

Expression of the fructose transporter gene SLC2A5 and histone acetylation in the transcribed region are induced by differentiation associated-signals such as glucocorticoids and p44/42 mitogen-activated protein kinase (MAPK) inhibition in small intestinal Caco-2 cells.

METHODS

We co-treated with glucocorticoid receptor agonist dexamethasone (Dex) and p44/42 MAPK inhibitor PD98059 (PD) in Caco-2 cells with or without Brd4 small hairpin (sh) RNA expression vector, and the cells were analyzed by qRT-PCR and chromatin immunoprecipitation assays. The small intestine of wild-type mice and Brd4^+/- mice during weaning period were analyzed by qRT-PCR.

RESULTS

Co-treatment with Dex and PD increased binding of the bromodomain-containing protein-4 (Brd4)-positive transcriptional elongation factor-b (P-TEFb)-RNA polymerase II complex to acetylated histones in the transcribed region of SLC2A5. Brd4-protein depletion by shRNA revealed that the association of these proteins on the transcribed region of SLC2A5 promoted gene expression in a Brd4-dependent manner. Expression of small-intestine Slc2a5, but not another intestinal gene sucrase-isomaltase, during weaning period, was significantly lower in Brd4^+/- mice compared with wild-type mice.

CONCLUSIONS

Brd4-P-TEFb plays a crucial role in differentiation-associated transcription of SLC2A5 gene in intestinal Caco-2 cells and in the small intestine of mice during weaning period.

GENERAL SIGNIFICANCE

Histone acetylation and the transcription elongation factor Brd4 are important for SLC2A5 expression in the small intestine.

Frequency of Pancreatic Hyperamylasemia in Human Immunodeficiency Virus-Positive Patients in the Highly Active Antiretroviral Therapy Era

OBJECTIVES

Increased frequency of hyperamylasemia has previously been reported in human immunodeficiency virus (HIV)-positive patients, but studies determined total amylase activity and were performed before the introduction of highly active antiretroviral therapy (HAART). We evaluated the frequency of pancreatic hyperamylasemia in a large HIV+ population mostly treated with HAART.

METHODS

The upper reference limit (URL) for pancreatic amylase (P-AMY) was derived from 299 healthy blood donors. A cross-sectional study was then performed on samples obtained from 1,548 consecutive patients referred to our infectious disease clinic to assess serum P-AMY and lipase concentrations. Of the patients, 94% were HIV+, and most (92%) were taking HAART (HIV+Tx+).

RESULTS

P-AMY URL was 51 U/L. The frequency of P-AMY increase did not significantly differ between HIV+ and HIV - populations (14.2% vs 15.2%, P = .91) or between HIV+Tx+ and HIV+Tx - (14.7% vs 8.9%, P = .11). In almost half (48.3% of HIV+ and 42.9% of HIV -) of hyperamylasemic patients, lipase was normal, indicating a non pancreatic origin of their P-AMY increase. Markedly elevated P-AMY (>3 times the URL) was found in six HIV+ patients and in one HIV - patient: two had macroamylasemia, one acute pancreatitis, three (including the HIV - patient) chronic pancreatitis, and one chronic hyperamylasemia of undefined origin.

CONCLUSIONS

In our study, both HIV+ and HIV+Tx+ do not show an increased frequency of P-AMY elevation. Frank pancreatic disease is rare in this clinical setting.

Cancer prevention in HIV-infected populations

People living with human immunodeficiency virus (HIV) are living longer since the advent of effective combined antiretroviral therapy (cART). While cART substantially decreases the risk of developing some cancers, HIV-infected individuals remain at high risk for Kaposi sarcoma, lymphoma, and several solid tumors. Currently HIV-infected patients represent an aging group, and malignancies have become a leading cause of morbidity and mortality. Tailored cancer-prevention strategies are needed for this population. In this review we describe the etiologic agents and pathogenesis of common malignancies in the setting of HIV, as well as current evidence for cancer prevention strategies and screening programs.

Antiretroviral drugs and acute pancreatitis in HIV/AIDS patients: is there any association? A literature review

In HIV-seropositive individuals, the incidence of acute pancreatitis may achieve 40% per year, higher than the 2% found in the general population. Since 1996, when combined antiretroviral therapy, known as HAART (highly active antiretroviral therapy), was introduced, a broad spectrum of harmful factors to the pancreas, such as opportunistic infections and drugs used for chemoprophylaxis, dropped considerably. Nucleotide analogues and metabolic abnormalities, hepatic steatosis and lactic acidosis have emerged as new conditions that can affect the pancreas. To evaluate the role of antiretroviral drugs to treat HIV/AIDS in a scenario of high incidence of acute pancreatitis in this population, a systematic review was performed, including original articles, case reports and case series studies, whose targets were HIV-seropositive patients that developed acute pancreatitis after exposure to any antiretroviral drugs. This association was confirmed after exclusion of other possible etiologies and/or a recurrent episode of acute pancreatitis after re-exposure to the suspected drug. Zidovudine, efavirenz, and protease inhibitors are thought to lead to acute pancreatitis secondary to hyperlipidemia. Nucleotide reverse transcriptase inhibitors, despite being powerful inhibitors of viral replication, induce a wide spectrum of side effects, including myelotoxicity and acute pancreatitis. Didanosine, zalcitabine and stavudine have been reported as causes of acute and chronic pancreatitis. They pose a high risk with cumulative doses. Didanosine with hydroxyurea, alcohol or pentamidine are additional risk factors, leading to lethal pancreatitis, which is not a frequent event. In addition, other drugs used for prophylaxis of AIDS-related opportunistic diseases, such as sulfamethoxazole-trimethoprim and pentamidine, can produce necrotizing pancreatitis. Despite comorbidities that can lead to pancreatic involvement in the HIV/AIDS population, antiretroviral drug-induced pancreatitis should always be considered in the diagnosis of patients with abdominal pain and elevated pancreatic enzymes.

A systematic review of validated methods for identifying pancreatitis using administrative data

PURPOSE

To systematically review algorithms identifying cases of pancreatitis in administrative data, with a focus on studies examining algorithm validity.

METHODS

A literature search was conducted using PubMed and the Iowa Drug Information Service database. Reviews were conducted by two investigators identifying studies using data sources from the USA or Canada. These data sources most likely reflect the coding practices of Mini-Sentinel data partners.

RESULTS

Eight studies were obtained examining the validity of an algorithm to identify pancreatitis in either hospital or ambulatory medical records or billing databases. The best-performing algorithm was International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 577.0; with a positive predictive value of 60%-80% and a negative predictive value usually greater than 90%. Populations involved in different studies were heterogeneous; age ranges, level of population risk, pancreatitis etiology, and geographic distribution were highly variable.

CONCLUSIONS

Validation studies find that the principal ICD-9-CM diagnosis code of 577.0 had the best positive predictive value and specificity. Current studies do not support the use of the ICD-9-CM codes 577.1 and 577.2. Databases enhanced with laboratory values at point of care would invariably increase the specificity of existing algorithms.

Surgical implications of human immunodeficiency virus infections

Pediatric HIV (human immunodeficiency virus) is a pandemic predominantly in sub-Saharan Africa. Approximately 2.2 million children aged less than 15 years are infected with HIV, representing almost 95% of the total number of children globally infected with HIV. Therefore, increasing numbers of HIVi or -exposed but uninfected children can be expected to require a surgical procedure to assist in the diagnosis of an HIV/acquired immune deficiency syndrome-related complication, to address a life-threatening complication of the disease, or for routine surgery encountered in HIV-unexposed children. HIVi children may present with both conditions unique to HIV infection and surgical conditions routine in pediatric surgical practice. HIV exposure confers an increased risk of complications and mortality for all children after surgery, whether they are HIV infected or not. This risk of complications is higher in the HIVi group of patients. These findings seem to be independent of whether patients undergo an elective or emergency procedure, but the risk of an adverse outcome is higher for a major procedure. Surgical implications of HIV infection are comprehensively reviewed in this article.

Incidence of acute pancreatitis in human immunodeficiency virus-positive patients with hypertriglyceridemia: is it really high?

OBJECTIVE

To assess the incidence of acute pancreatitis in human immunodeficiency virus-positive patients with triglyceride (TG) greater than 500 mg/dL after highly active antiretroviral therapy.

METHODS

Sequential TG levels during follow-up and episodes of acute pancreatitis were retrospectively reviewed in 347, 417, and 571 patients enrolled in periods 1 (2000-2002), 2 (2003-2005), and 3 (2006-2008), respectively. The incidence of acute pancreatitis, defined as consistent clinical symptoms and elevated amylase and/or lipase levels, was estimated.

RESULTS

A total of 5356 TG measurements were performed during the follow-up for 698.22, 884.14, and 1215.69 person-years in periods 1, 2, and 3, respectively. Overall, 9.89% of patients had at least one TG greater than 500 mg/dL. Five patients with TG less than 500 mg/dL developed acute pancreatitis. The crude incidences of acute pancreatitis were 0.6%, 0.5%, and 0.2%, and the incidence rates were 2.86, 2.26, and 0.82/1000 person-years in periods 1, 2 and 3, respectively (all, P > 0.05). The incidence rates of acute pancreatitis when TG levels were less than 500, less than 1000, and less than 1500 mg/dL ranged from 1.2 to 4.9/1000 person-years, whereas it was 0/1000 person-years when TG levels were greater than 500, greater than 1000, and greater than 1500 mg/dL, respectively.

CONCLUSION

The risk of acute pancreatitis was low among human immunodeficiency virus-positive patients who developed hypertriglyceridemia after receiving highly active antiretroviral therapy.

The changing epidemiology of HIV-infected patients in the intensive care unit

With the introduction of highly active antiretroviral therapy (HAART), HIV has become a chronic disease. As HIV-infected patients are aging, they are at increased risk for comorbid diseases. These non-AIDS related diseases account for a growing proportion of intensive care unit (ICU) admissions in HIV-infected patients in recent studies. HIV-infected patients still present to the ICU with HIV-related conditions such as Pneumocystis jirovecii pneumonia (PCP), but these conditions are becoming less common. Respiratory failure remains the most common indication for ICU admission. Immune reconstitution inflammatory response syndrome and toxicities related to HAART may also result in ICU admission. While ICU survival has improved since the earliest era of the HIV epidemic, hospital mortality for HIV-infected patients admitted to the ICU remains around 30%. Risk factors for ICU mortality include poor functional status, weight loss, more than one year between HIV diagnosis and ICU admission, lower serum albumin, higher severity of illness, need for mechanical ventilation, and respiratory failure-particularly if due to PCP and accompanied by pneumothorax. The impact of HAART on ICU outcomes is unclear. HAART administration in the ICU can be challenging due to limited delivery routes, concern for viral resistance and medication toxicities. There are no data to determine the safety or efficacy of HAART initiation in the ICU. Future studies are needed to address the role of age, associated comorbidities and impact of HAART on outcomes of HIV-infected patients admitted to the ICU.

Assessment of mitochondrial toxicity by analysis of mitochondrial protein expression in mononuclear cells

BACKGROUND

Real-time PCR has quantified decreased mitochondrial DNA levels in association with nucleoside reverse transcriptase inhibitor (NRTI) therapy of HIV-infected populations. However, real-time PCR is best suited to distinguish log differences in an analyte. In an effort to monitor individuals in more detail, we developed a flow cytometric assay to gauge mitochondrial function.

METHODS

Flow cytometric quantification of a mitochondrial DNA-encoded mitochondrial protein (cytochrome c oxidase subunit I (COX-I)) and a nuclear DNA-encoded mitochondrial protein [ATP synthase subunit D (Sub-D)] was optimized and validated.

RESULTS

Intra-assay and interassay variability was low using peripheral blood mononuclear cells (PBMCs) (CV of 6.15% for COX-I and 7.11% Sub-D, and 9.38% and 9.83% for COX-I and Sub-D, respectively). Mitochondrial protein depletion was evident with in vitro treatment of cells with ethidium bromide (EtBr) and zalcitabine (ddC). Mitochondrial protein expression in 40 healthy adults clustered tightly. Depletion of mitochondrial protein, however, was neither detected in cryopreserved PBMC from NRTI-treated children (n = 9) nor in adults with a history of symptoms consistent with mitochondrial toxicity or ongoing treatment with didanosine (ddI) or stavudine (d4T) (n = 51).

CONCLUSIONS

A validated flow cytometric assay allows simultaneous detection of mitochondrial DNA and nuclear DNA encoded proteins at the single cell level, offering a method to monitor for mitochondrial function. Prospective studies are required to evaluate whether mitochondrial protein loss is observed in at-risk patients prior to the onset of symptoms from mitochondrial dysfunction.

A case study and review of pancreatitis in the AIDS population

This case study considers a 55-year-old African American woman with the acquired immunodeficiency syndrome (AIDS) who presented with epigastric abdominal pain for 1 week. She was found to have pancreatitis on computed tomography scanning. Unique to this case are the numerous possible etiologies of her pancreatitis. Thus, this case study systematically reviews the different etiologies of pancreatitis in the AIDS population compared to the general population. Furthermore it discusses the management and treatment of pancreatitis in AIDS.

HIV infection and the pancreas: risk factors and potential management guidelines

One thousand and eighty-one evaluable HIV-infected patients were assessed for pancreatic abnormalities in a prospective case-control study including the whole follow-up period of each patient (minimum 12 months). The 435 patients (40.2%), who experienced at least one episode of confirmed pancreatic laboratory abnormality had a longer duration of seropositivity, exposure to protease inhibitors, a more frequent immunodeficiency, AIDS, chronic liver and/or biliary disease and hypertriglyceridaemia, while no relation was found with antiretroviral administration, and the duration of type of nucleoside analogues, when compared with the 646 controls. High and prolonged laboratory alterations eventually associated with signs of organ involvement occurred in 166 cases (38.2%), and were related to the administration of didanosine, stavudine, lamivudine, pentamidine, cotrimoxazole or antitubercular/antimycobacterial therapy, cytotoxic chemotherapy, illicit substance or alcohol abuse, opportunistic infections, chronic liver and/or biliary disease, a protease inhibitor-based highly active antiretroviral therapy (HAART) and hypertriglyceridaemia (usually associated with HAART administration). No difference was noticed between the 46 patients with clinical and/or imaging evidence of pancreatic involvement and the 120 asymptomatic subjects. Although recurrences of enzyme alterations involved 69.6% of patients, only in 30.1% of cases did a change of the underlying antiretroviral or antimicrobial therapy become necessary. An acute, uncomplicated pancreatitis occurred in nine of the 46 symptomatic subjects (19.6%). A two to four week gabexate and/or octreotide administration (performed in 79 cases of 166, 47.6%), achieved a significant laboratory, clinical and imaging cure or improvement in 82.3% of cases, with a better success rate of combined (gabexate mesilate plus octreotide) vs. single (gabexate mesilate or ocreotide) therapy. Reduced disease recurrences and a better tolerability of antiretroviral regimens, were also noticed.

A ten-year analysis of the incidence and risk factors for acute pancreatitis requiring hospitalization in an urban HIV clinical cohort

To assess the incidence of and risk factors for acute pancreatitis in HIV-infected patients in the contemporary highly active antiretroviral therapy (HAART) era, we evaluated all cases of acute pancreatitis requiring hospitalization between 1996 and 2006 in patients followed at Johns Hopkins Hospital's HIV clinic. A nested, case-control analysis was employed for initial episodes of acute pancreatitis, and conditional logistic regression was used to assess risk factors. Of 5970 patients followed for 23,460 person-years (PYs), there were 85 episodes of acute pancreatitis (incidence: 3.6 events/1000 PYs). The incidence of pancreatitis from 1996 to 2000 was 2.6 events/1000 PYs; the incidence from 2001 to 2006 was 5.1 events/1000 PYs (p = 0.0014, comparing rates in two time periods). In multivariate regression, factors associated with pancreatitis included female gender (adjusted odds ratio [AOR] 2.96 [1.69, 5.19]; p < 0.001); stavudine use (AOR 2.19 [1.16, 4.15]; p = 0.016); aerosolized pentamidine use (OR 6.27; [1.42, 27.63]; p = 0.015); and CD4 count less than 50 cells/mm(3) (AOR 10.47 [3.33, 32.90]; p < 0.001). Race/ethnicity, HIV risk factor, HIV-1 RNA, and newer non-nucleoside reverse transcriptase inhibitors (NNRTI)- and protease inhibitor (PI)-based HAART regimens were not associated with an increased risk of pancreatitis after adjustment for the above factors. Pancreatitis remains a significant cause of morbidity in the HIV population in the HAART era. Acute pancreatitis is associated with female gender, severe immunosuppression, and stavudine and aerosolized pentamidine usage. Of note, newer antiretrovirals, particularly atazanavir, lopinivir/ritonavir, tenofovir, abacavir, and efavirenz, were not associated with an increased risk of pancreatitis.

The role of antiretroviral therapy in the incidence of pancreatitis in HIV-positive individuals in the EuroSIDA study

AIM

This study investigated the incidence of pancreatitis and its association with antiretroviral therapy (ART), focussing on stavudine and didanosine.

METHODS

EuroSIDA has collected information on pancreatitis since Summer 2001. All identified cases have been verified by the coordinating centre. Individuals were followed from June 2001 or the date of entry into EuroSIDA (whichever occurred later) until a diagnosis of pancreatitis or the last study visit. Factors associated with pancreatitis were investigated using Poisson regression. Cumulative lengths of exposure to didanosine without stavudine, stavudine without didanosine, stavudine with didanosine, and other ART were time-updated variables. Treatment variables were fitted with a 6-month time lag.

RESULTS

There were 43 (nine presumptive) pancreatic events in 9678 individuals during 33 742 person-years (incidence 1.27/1000 person-years). The incidence among those with no, 2 or less and over 2 years' exposure to ART including stavudine and didanosine was 1.24, 1.73 and 0.78/1000 person-years, respectively. In multivariable analysis, higher baseline CD4 cell counts were associated with a decreased risk of pancreatitis. There was no evidence of an association of pancreatitis with cumulative exposure to didanosine and stavudine, didanosine without stavudine, stavudine without didanosine, or other ART.

CONCLUSION

We observed a low overall rate of pancreatitis in the years 2001-2006, and did not find an association of an increased incidence of pancreatitis with cumulative exposure to antiretroviral agents generally, and to didanosine and stavudine in particular.

Potential risks and benefits of HIV treatment simplification: a simulation model of a proposed clinical trial

BACKGROUND

In recent studies, subjects who had achieved suppression of the human immunodeficiency virus (HIV) RNA level while receiving an initial 3-drug antiretroviral regimen successfully maintained suppression while receiving treatment with a "boosted" protease inhibitor (PI) alone. We projected the long-term outcomes of this treatment simplification strategy to inform the design of a proposed multicenter, randomized clinical trial.

METHODS

We used published studies to estimate the efficacy, adverse effects, and cost of a sequence of HIV drug regimens for the simplification strategy, compared with those outcomes for the current standard-of-care (SOC) strategy. Using a published simulation model of HIV disease, we projected life expectancy, discounted quality-adjusted life expectancy (QALE), and discounted lifetime medical costs for each strategy.

RESULTS

Subjects who have not developed PI-resistant HIV infection at the time of failure of the simplification regimen have a greater life expectancy (27.9 vs. 27.1 years) and QALE (14.9 vs. 14.7 years), compared with SOC subjects, because they receive an additional line of therapy without negative consequences for future treatment options. The QALE for the simplification strategy remains higher than that for the SOC, unless a large proportion of patients experiencing virologic failure while receiving the simplification regimen develop PI resistance. Depending on the probability of simplification regimen failure, the advantage is maintained even if HIV develops PI resistance in 42%-70% of subjects. Projected lifetime costs are $26,500-$72,400 per person lower for the simplification strategy than for the SOC strategy.

CONCLUSIONS

An HIV treatment simplification strategy involving use of a boosted PI alone may lead to longer survival overall at lower cost, compared with the SOC combination therapy, because the simplification strategy potentially adds an additional line of therapy. The risk of emergence of PI resistance during treatment with a simplified regimen is a critical determinant of the viability of this strategy.