Regression of AIDS-related Kaposi's sarcoma following antiretroviral therapy with protease inhibitors: biological correlates of clinical outcome

HIV protease inhibitors as new treatment options for Kaposi's sarcoma

A reduced incidence and regression of Kaposi's sarcoma (KS) and other tumours has been reported in Acquired Immune Deficiency Syndrome (AIDS) patients treated with antiretroviral combination therapies containing Human Immunodeficiency Virus (HIV) protease inhibitors (PIs) such as indinavir or saquinavir. Indeed, evidence indicates that although PIs were designed to selectively inhibit the HIV protease activity, they can interfere with several cellular pathways and can inhibit tumour growth. In particular, our recent results indicate that doses of indinavir or saquinavir similar to those employed to treat AIDS patients can induce regression of experimental KS by directly blocking two fundamental steps of KS initiation and progression: new blood vessel formation (angiogenesis) and KS tumour cell invasion. This is because indinavir or saquinavir inhibit the activation of matrix metalloproteinase-2 (MMP-2), a basement membrane-degrading enzyme, which is required for the progression of most tumours. Based on these results, a multicentre clinical trial is now starting in Italy, which will assess PI effects on the progression of KS in HIV-uninfected individuals (classical KS).

AIDS-related Kaposi's Sarcoma: evaluation of potential new prognostic factors and assessment of the AIDS Clinical Trial Group Staging System in the Haart Era--the Italian Cooperative Group on AIDS and Tumors and the Italian Cohort of Patients Naive From Antiretrovirals

PURPOSE

To assess potential new prognostic factors and to validate the AIDS Clinical Trials Group (ACTG) for AIDS-related Kaposi's sarcoma (AIDS-KS) staging system in the highly active antiretroviral therapy (HAART) era.

PATIENTS AND METHODS

We collected epidemiologic, clinical, staging, and survival data from 211 patients with AIDS-KS enrolled in two prospective Italian human immunodeficiency virus (HIV) cohort studies. We included in the analysis all patients with the diagnosis of KS made from January 1996, the time at which HAART became available in Italy.

RESULTS

In the univariate analysis, survival was not influenced by sex, age, level of HIV viremia at KS diagnosis, HAART at KS diagnosis (HAART-naïve v HAART-experienced), or type of HAART combination. Regarding ACTG classification, the 3-year survival rate was 85% for T0 patients and 69% for T1 patients (P =.007), 83% for S0 patients and 63% for S1 patients (P =.003), and 83% for I0 patients and 71% for I1 patients (P =.06). In the multivariate analysis, only the combination of poor tumor stage (T1) and poor systemic disease (S1) risk identified patients with unfavorable prognosis. The 3-year survival rate of patients with T1S1 was 53%, which was significantly lower compared with the 3-year survival rates of patients with T0S0, T1S0, and T0S1, which were 88%, 80%, and 81%, respectively (P =.0001).

CONCLUSION

In the era of HAART, a refinement of the original ACTG staging system is needed. CD4 level does not seem to provide prognostic information. Two different risk categories are identified: a good risk (T0S0, T1S0, T0S1) and a poor risk (T1S1).

Update on Kaposi's Sarcoma: A Gammaherpesvirus- induced Malignancy

Since the beginning of the AIDS epidemic, Kaposi's sarcoma (KS) has been one of the most visible manifestations of this disease and one of the most distressing for affected patients. The discovery in 1994 of a new gammaherpesvirus, called Kaposi's sarcoma-associated herpesvirus, has led to increased understanding of the pathogenesis of this disease and the potential for new specific therapy. In addition, the development of highly active antiretroviral therapy has had a substantial impact on the incidence of KS in countries where it is available and on the course of established disease. Finally, recent advances in our understanding of angiogenesis have the potential of leading to new KS therapies. In this article we review some of the recent advances in the epidemiology and pathogenesis of KS, review the current treatment of this disease, and discuss several therapeutic approaches that are now under development.

The efficacy of ritonavir in the prevention of AIDS-related Kaposi's sarcoma

Angiogenesis is thought to play a major role in the development of Kaposi's sarcoma (KS), considered by many to be a hyperplastic disorder caused in part by local production of inflammatory cytokines. The antiangiogenic effects of protease inhibitors, in particular ritonavir, have been suggested in laboratory work to lead to regression of KS, and recent data have shown the importance of ritonavir as a model of pharmaceutical development. As our clinical cohort data has shown that non-nucleoside reverse transcriptase inhibitor-based regimens are not inferior to protease inhibitor-based therapy in the prevention of KS, we investigated the specific contribution of ritonavir to chemoprevention of this AIDS-defining illness. In a logistic regression analysis, we found that ritonavir-based therapy confers no advantages compared to other regimens in the prevention of KS. This is consistent with data suggesting that regression of KS is mediated by an overall improvement in immune function and not by the effects of specific antiretrovirals.

Recent advances in the treatment of AIDS-related Kaposi's sarcoma

Kaposi's sarcoma (KS) is the most common malignancy associated with HIV infection and is considered an AIDS defining condition by the US Centers of Disease Control Guidelines. Several advances in the treatment of AIDS-related KS have been achieved over the past few years, even though a gold standard therapy for KS has not yet been defined and treatment must be tailored to individual needs. Since the availability of highly active antiretroviral therapy (HAART), a dramatic clinical response has been documented in patients with KS, making HAART an essential approach in the management of KS in most, if not all, patients with AIDS-related KS. However, in case of aggressive, visceral, and/or life-threatening KS, more complex therapeutic schedules have to be taken into account, including chemotherapy, radiotherapy, and/or immunotherapy. In general, systemic treatment for KS is limited to widespread, symptomatic disease, whereas local interventions are indicated for minimal, cosmetically troublesome lesions. Among new cytotoxic agents, liposomal anthracyclines and paclitaxel are highly effective molecules for KS and have been approved by the US Food and Drug Administration (FDA) as first-line and second-line monotherapy, respectively, for advanced KS. Furthermore, a greater understanding of the pathogenesis of KS has lead to the development of an array of new experimental agents. Many antiangiogenic agents such as AGM 1470 (TNP 470), thalidomide, and glufanide disodium (IM 862) have produced encouraging responses in patients with KS and large clinical trials are in progress. Retinoic acids may also block neoangiogenesis as well as proliferation of KS cells in vitro, and they have been used either systemically or topically with a high response rate. Thus, a topical compound 0.1% alitretinoin gel was approved in 1999 by the FDA for the treatment of skin lesions associated with KS. Human chorionic gonadotropin, a hormonal agent, has shown a strong inhibitory activity in KS cells, but its role in the regression of KS lesions is not clear. Finally, the identification of a novel gamma-herpesvirus, human herpesvirus-8, as a causative agent for KS, together with novel antiangiogenic compounds, such as metalloproteinase inhibitors, may offer promising targets for the therapy of KS.

Kaposi's sarcoma and other manifestations of human herpesvirus 8

Kaposi's sarcoma (KS) was described by Moritz Kaposi in 1872 and was known for an entire century as a rare disorder of older men usually of Eastern European, Mediterranean, and/or Jewish origin. In the early 1980s, the prevalence of KS began to increase dramatically and soon became the most common malignancy in patients with AIDS, especially those who were male homosexuals. In 1994, a new human herpesvirus (HHV) was found to be present in almost 100% of KS lesions. This virus was found to be a gammaherpesvirus, closely related to Epstein-Barr virus, and was designated HHV-8. Subsequently, HHV-8 DNA was found in almost all specimens of classic KS, endemic KS, and iatrogenic KS, as well as epidemic KS (ie, AIDS KS). It is now believed that HHV-8 is necessary, but not sufficient, to cause KS and that other factors such as immunosuppression play a major role. The use of highly active antiretroviral therapy (HAART) since 1996 has markedly reduced the prevalence of AIDS KS in western countries, but because 99% of the 40 million patients with AIDS in the world cannot afford HAART, KS is still a very common problem. Primary effusion lymphoma and multicentric Castleman's disease are also thought to be due to HHV-8. Although HHV-8 DNA has been described in a number of other cutaneous disorders, there is little evidence that HHV-8 is of etiologic significance in these diseases. The mechanism by which HHV-8 causes KS, primary effusion lymphoma, and multicentric Castleman's disease is not well understood but is thought to involve a number of molecular events, the study of which should further our understanding of viral oncology. (J Am Acad Dermatol 2002;47:641-55.)

LEARNING OBJECTIVE

At the completion of this learning activity, participants should be familiar with Kaposi's sarcoma and other manifestations of human herpesvirus 8.

Treatment of Kaposi's sarcoma--an update

Kaposi's sarcoma (KS) is an angioproliferative disease of multifactorial origin arising in different clinic-epidemiologic forms, which show the same histopathological features. It generally starts as a hyperplastic reactive-inflammatory and angiogenic process, which may evolve into monomorphic nodules of KS cells that can be clonal (late-stage lesions) and resemble a true sarcoma. Infection with the human herpesvirus 8, cytokine- and angiogenic factor-induced growth together with an immuno-dysregulated state represent fundamental conditions for the development of this tumor. Several local therapies are used to eradicate early and confined skin lesions, whereas widely disseminated, progressive or symptomatic disease requires a more aggressive treatment. Although different chemotherapeutic agents have been used to treat aggressive KS, the growing understanding of the pathogenetic factors participating in KS development has provided a strong rationale for using less- or non-cytotoxic agents that block the mechanisms involved in KS pathogenesis. The angiogenic nature of KS makes it particularly suitable for using therapies based on anti-angiogenic agents. Of note on this goal, recent studies indicate that the highly active anti-retroviral therapy, including at least one human immunodeficiency virus (HIV) protease inhibitor (PI), is associated with a dramatic decrease in the incidence of AIDS-KS and with a regression of KS in treated individuals. Consistent with this, results from preclinical studies indicate that PIs have potent and direct anti-angiogenic and anti-KS activities, suggesting that they should be further investigated, alone or combined with other therapies, as a novel treatment for KS in both HIV seropositive or seronegative individuals.

Effect of highly active antiretroviral therapy on survival among HIV-infected men with Kaposi sarcoma or non-Hodgkin lymphoma

The effect of highly active antiretroviral therapy (HAART) on survival in HIV-infected patients with Kaposi sarcoma (KS) or non-Hodgkin lymphoma (NHL) is unknown. Our study examines survival after HAART for these 2 malignancies. Analyses were performed using data from 387 HIV-infected men in the Multicenter AIDS Cohort Study (MACS) after a diagnosis of either KS or NHL in 1990-99. Potential prognostic factors, including HAART, were evaluated in univariate analyses using Kaplan-Meier survival curves and log-rank tests. Multivariate survival analyses were conducted using Cox's time-dependent proportional hazards models, adjusting for CD4(+) cell levels at the time of cancer diagnosis and other covariates. Forty-three of 287 KS patients (15%) and 13 of 100 NHL patients (13%) had been treated with HAART. HAART treatment was associated with improved survival for KS and NHL patients (log-rank p = 0.0001 for each group). In multivariate analyses, HAART was associated with an 81% reduced risk of death among KS patients [relative hazard (RH) 0.19, 95% confidence limits (CL) (0.08, 0.45)], compared to those not exposed to HAART and an 84% reduced risk [RH 0.16, 95% CL (0.04, 0.64)] among NHL patients. Relative hazards estimates were similar for those with HAART initiation before and after NHL diagnosis. The use of HAART prolongs overall survival among HIV-positive men diagnosed with KS and NHL. HAART appears to be effective in improving survival even when initiated after the diagnosis of NHL and KS.

HIV protease inhibitors are potent anti-angiogenic molecules and promote regression of Kaposi sarcoma

Treatment with HIV-1 protease inhibitors (PI) is associated with a reduced incidence or regression of Kaposi sarcoma (KS). Here we show that systemic administration of the PIs indinavir or saquinavir to nude mice blocks the development and induces regression of angioproliferative KS-like lesions promoted by primary human KS cells, basic fibroblast growth factor (bFGF), or bFGF and vascular endothelial growth factor (VEGF) combined. These PIs also block bFGF or VEGF-induced angiogenesis in the chorioallantoic membrane assay with a potency similar to paclitaxel (Taxol). These effects are mediated by the inhibition of endothelial- and KS-cell invasion and of matrix metalloproteinase-2 proteolytic activation by PIs at concentrations present in plasma of treated individuals. As PIs also inhibit the in vivo growth and invasion of an angiogenic tumor-cell line, these data indicate that PIs are potent anti-angiogenic and anti-tumor molecules that might be used in treating non-HIV KS and in other HIV-associated tumors.

Dynamics of Epstein-Barr virus in HIV-1-infected subjects on highly active antiretroviral therapy

OBJECTIVE

Patients infected with HIV-1 are at high risk of developing Epstein-Barr virus (EBV)-associated lymphoproliferative disorders. This study evaluated the impact of highly active antiretroviral therapy (HAART) on EBV infection.

METHODS

To measure EBV content in peripheral blood lymphocytes (PBL) and in plasma, we set up a quantitative analysis using the real-time PCR. EBV latent membrane protein 1 (LMP1) expression was determined by reverse transcriptase-PCR.

RESULTS

EBV levels were determined in 33 HIV-1- and EBV-coinfected patients at the start of HAART, and during therapy. At baseline, EBV content in PBL samples ranged from 8 to 14 532 copies/microg DNA. EBV levels transiently increased in nine out of 17 patients in whom HIV-1 plasmaviraemia declined to undetectable levels (virological response) and CD4 cell counts increased (immunological response), while they remained fairly stable or decreased in the other eight virological and immunological responders, and in seven patients who showed a virological response only. Of interest, a significant increase in EBV load was observed in five out of nine patients who showed an increase in CD4 cell counts but lack of HIV-1 suppression during HAART. This EBV increase was accompanied by the detection of both LMP1 transcripts in PBL and EBV DNA in plasma, and was paralleled by an increase in immunoglobulin levels, a marker of B-cell stimulation.

CONCLUSIONS

These findings suggest that peripheral immune reconstitution during HAART without a reduction in HIV-1 replication may increase B-cell stimulation and the number of EBV-infected B cells.

Viral load of human herpesvirus 8 in peripheral blood of human immunodeficiency virus-infected patients with Kaposi's sarcoma

Viral load is an important marker of activity of viral diseases for a number of viruses. We wished to evaluate whether the viral load of human herpesvirus 8 (HHV-8) in peripheral blood was a consistent feature of Kaposi's sarcoma (KS) patients and whether the viral load correlated with human immunodeficiency virus (HIV) RNA levels, CD4 counts, and/or the HHV-8 seroreactivity. Fifty-four consecutive plasma samples from 14 patients with KS were evaluated for HHV-8 viral load by quantitative real-time PCR. Samples were analyzed at the start of highly active antiretroviral therapy (HAART) and at different intervals during treatments. The median HHV-8 DNA load before HAART treatment was 8,998 (ranging from 170 to 40,100) copies/ml and 12,270 (ranging from 40 to 142,575) copies/ml during HAART. There were both increasing and decreasing trends. There was an association between HHV-8 DNA and HIV RNA viral loads (odds ratio [OR] = 5.40; 95% confidence interval [95% CI], 1.54 to 18.98) and between HHV-8 viral load and CD4 cell counts (OR = 7.24; 95% CI, 1.30 to 40.35). High HHV-8 viral load was also correlated with the titers of antibodies to the lytic HHV-8 antigen detected with immunofluorescence (P < 0.01), but not with antibodies to the latent HHV-8 antigen. In conclusion, we found that HHV-8 viremia in KS is associated with HIV viral load, CD4 cell counts, and lytic HHV-8 serological reactivity. HHV-8 viral load monitored by real time PCR might be useful for determination HHV-8 viral load during the follow-up of KS patients.

Response to liposomal doxorubicin and clinical outcome of HIV-1-infected patients with Kaposi's sarcoma receiving highly active antiretroviral therapy

PURPOSE

HIV-associated Kaposi's sarcoma (KS) may not resolve despite highly active antiretroviral therapy (HAART). Moreover, the therapeutic goal has shifted from palliative care to long-term durable complete remission. The objective of the study was to assess the impact of liposomal doxorubicin in the treatment of HIV-associated KS in the HAART era.

METHOD

In this prospective, noncomparative, multicenter study, patients with more than 10 cutaneous lesions or visceral disease were treated with 20 mg/m(2) of liposomal doxorubicin (Caelyx) every 3 weeks in addition to their antiretroviral therapy. In addition to tumor measurements and laboratory tests, human herpes virus 8 (HHV-8) polymerase chain reaction (PCR) in peripheral blood mononuclear cells (PBMC) was performed.

RESULTS

Out of 79 participants enrolled in the study, 47 (59%) had stage T(1), 41 (52%) I(1), and 32 (40%) S(1). Nine individuals were not evaluable for response, 32 (40%) had complete response, 30 (38%) partial response, 5 (6%) stable disease, and 3 (4%) progression. Regression analysis did not find any statistically significant factor predicting response. HHV-8 PCR was positive in 37/53 (70%) patients with available PBMC samples, and HHV-8 viremia cleared in 14/27 (52%) without correlation with clinical response. Eleven (14%) participants experienced a relapse of KS, while at the last update of data, 49 (62%) remained stable. The only risk factor for recurrence identified was the follow-up time (odds ratio [OR] 1.21, 95% CI 1.07-1.36; p =.002).

CONCLUSION

The response rate of AIDS-associated KS to liposomal doxorubicin administered with HAART was high, and most often the response was durable. HHV-8 viremia did not correlate well with clinical outcome.

Telomerase activity in Kaposi's sarcoma, squamous cell carcinoma, and basal cell carcinoma

Patients with acquired immune deficiency syndrome (AIDS) often develop Kaposi's sarcoma (KS), an unusual skin tumor. The malignant nature of KS has long been disputed. Telomerase activity that maintains telomere length and ensures chromosomal stability, a frequently appearing marker in human malignancies, has been proposed to play a critical role in supporting continued cell growth, hence formation of tumors. We examined telomerase activity in tissue extracts from 22 KS, 10 squamous cell carcinoma (SCC), and 22 basal cell carcinoma (BCC) using the telomeric repeat amplification protocol (TRAP). All of the tumor tissues were previously cryopreserved at -80 degrees C. In this study, all tumor samples tested were positive for telomerase activity. Consistent with the presence of the enzyme activity, the skin tumors had relatively long telomeres. Inhibitors in the tissue extracts of some samples needed to be diluted or extracted by phenol before the enzyme activity was detected in the TRAP assay. All KS as well as two other skin carcinoma samples revealed positive telomerase activity. Our finding supports telomerase's role in tumor cell immortality and suggests the true neoplastic nature of KS.

Impact of HAART on the clinical management of AIDS-related cancers

The development of HIV-related disease has changed dramatically since the introduction of highly active antiretroviral therapy (HAART) into clinical practice. Since the use of protease inhibitors became widespread, a 30-50% reduction in Kaposi's sarcoma (KS) has been observed. The results of recent studies indicate that HAART may be a useful alternative both to immune response modifiers during less aggressive stages of KS disease and to systemic cytotoxic drugs in the long-term maintenance therapy of advanced KS. The impact of HAART regimens on the incidence of systemic lymphoma (NHL-HIV) remains unclear, but it can be hypothesised that patients treated with HAART may survive longer with continued B cell stimulation and dysregulation resulting in an increased incidence of lymphoma over time. The impact of HAART on survival in patients affected by NHL-HIV has recently been evaluated and a positive correlation between HAART and outcome in these patients has been found. The spectrum of cancers in patients with HIV infection may develop further since these patients survive longer with HAART and with a better control of opportunistic infections. With the increasing use of HAART, the dilemma is whether to institute or continue protease inhibitors use during chemotherapy. Based on the advances in our understanding of HIV-related disease and the availability of new antiretroviral therapies, the choice for anti-HIV agents in patients receiving chemotherapy is important.

Long-term chemotherapy of HIV-associated Kaposi's sarcoma with liposomal doxorubicin

The aim of this study was to examine the outcome, adverse events and clinical complications of long-term chemotherapy with pegylated liposomal doxorubicin (PegLiposomal DOX) for human immunodeficiency virus (HIV)-associated Kaposi's sarcoma (KS) in the pre-highly active antiretroviral therapy (HAART) era. A phase II study over a 4-year period in a tertiary care university hospital was carried out. 52 acquired immunodeficiency syndrome (AIDS)-patients with advanced KS received long-term chemotherapy (71+/-51 weeks) with a mean of 22.8+/-18.2 cycles and a mean cumulative liposomal doxorubicin dose of 456+/-364 mg/m(2) (120-1040 mg/m(2)). Tumour burden, duration and dosage of PegLiposomal DOX, adverse events, opportunistic infections, immunological parameters and HIV load were measured. A complete (10%) or partial response (56%) was achieved while on chemotherapy. 10 patients (19%) showed stable disease. Tumour progression was observed in 8 patients (15%). Importantly, chemotherapy with PegLiposomal DOX was also successful after previous cytostatic therapy with bleomycin and vincristine. The most common adverse events included leucopenia, neutropenia, anaemia, and increased liver function tests. 34 patients (65%) developed new opportunistic infections and 29 patients (56%) died during the study period. To conclude, pegylated liposomal doxorubicin is a safe and effective drug for long-term chemotherapy of advanced (AIDS) KS without adverse effects on CD4 cell counts and HIV viral load.