The changing face of HIV-associated lymphoma: what can we learn about optimal therapy inl the post highly active antiretroviral therapy era?

Hiv and Lymphoma: from Epidemiology to Clinical Management

Patients infected with human immunodeficiency virus (HIV) are at increased risk for developing both non-Hodgkin’s lymphoma (NHL) and Hodgkin’s lymphoma (HL). Even if this risk has decreased for NHL after the introduction of combination antiretroviral therapy (cART), they remain the most common acquired immune deficiency syndrome (AIDS)-related cancer in the developed world. They are almost always of B-cell origin, and some specific lymphoma types are more common than others. Some of these lymphoma types can occur in both HIV-uninfected and infected patients, while others preferentially develop in the context of AIDS. HIV-associated lymphoma differs from lymphoma in the HIV negative population in that they more often present with advanced disease, systemic symptoms, and extranodal involvement and are frequently associated with oncogenic viruses (Epstein-Barr virus and/or human herpesvirus-8). Before the introduction of cART, most of these patients could not tolerate the treatment strategies routinely employed in the HIV-negative population. The widespread use of cART has allowed for the delivery of full-dose and dose-intensive chemotherapy regimens with improved outcomes that nowadays can be compared to those seen in non-HIV infected patients. However, a great deal of attention should be paid to opportunistic infections and other infectious complications, cART-chemotherapy interactions, and potential cumulative toxicity. In the context of relatively sparse prospective and randomized trials, the optimal treatment of AIDS-related lymphomas remains a challenge, particularly in patients with severe immunosuppression. This paper will address epidemiology, pathogenesis, and therapeutic strategies in HIV-associated NHL and HL.

Clinical management of HIV-associated hematologic malignancies

HIV is associated with an excess risk for lymphoid malignancies. Although the risk of lymphoma has decreased in HIV-infected individuals in the era of effective combination antiretroviral therapy, it remains high. Treatment outcomes have improved due to improvements in HIV and cancer therapeutics for the common HIV-associated lymphomas. R-CHOP/R-EPOCH are the standard of care for HIV-associated diffuse large B-cell lymphoma. HIV-infected patients with Burkitt lymphoma and good performance status should receive dose-intensive regimens. HIV-infected patients with primary central nervous system lymphoma can respond favorably to high-dose methotrexate-based therapy. In many cases, treatment and expected outcomes for HIV-infected patients with either Hodgkin or non-Hodgkin's lymphomas are very similar to HIV-negative patients. There is currently no standard treatment for HIV-associated multicentric Castleman disease or primary effusion lymphoma. For those hematologic cancers in which transplantation is part of standard care, this modality should be considered an option in those with well-controlled HIV infection.

Dose-reduced busulfan, cyclophosphamide, and autologous stem cell transplantation for human immunodeficiency virus-associated lymphoma: AIDS Malignancy Consortium study 020

Intensive chemotherapy for human immunodeficiency virus (HIV)-associated non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) has resulted in durable remissions in a substantial proportion of patients. High-dose chemotherapy and autologous stem cell transplantation (AuSCT), moreover, has resulted in sustained complete remissions in selected patients with recurrent chemosensitive disease. Based on a favorable experience with dose-reduced high-dose busulfan, cyclophosphamide, and AuSCT for older patients with non-HIV-associated aggressive lymphomas, an AIDS Malignancy Consortium multicenter trial was undertaken using the same dose-reduced busulfan and cyclophosphamide preparative regimen with AuSCT for recurrent HIV-associated NHL and HL. Of the 27 patients in the study, 20 received an AuSCT. The median time to achievement of an absolute neutrophil count (ANC) of >or= 0.5 x 10(9)/L was 11 days (range, 9-16 days). The median time to achievement of an unsupported platelet count of >or= 20 x 10(9)/L was 13 days (range, 6-57 days). One patient died on day +33 posttransplantation from hepatic veno-occlusive disease (VOD) and multiorgan failure. No other fatal regimen-related toxicity occurred. Ten of 19 patients (53%) were in complete remission at the time of their day +100 post-AuSCT evaluation. Of the 20 patients, 10 were alive and event-free at a median of 23 weeks post-AuSCT. Median overall survival (OS) was not reached by 13 of the 20 patients alive at the time of last follow-up. This multi-institutional trial demonstrates that a regimen of dose-reduced high-dose busulfan, cyclophosphamide, and AuSCT is well tolerated and is associated with favorable disease-free survival (DFS) and OS probabilities for selected patients with HIV-associated NHL and HL.

Prediction of clinical benefits of ritonavir-boosted TMC114 from treatment effects on CD4 counts and HIV RNA

OBJECTIVE

The aim of the study was to predict reductions in progression to AIDS/death associated with the treatment benefit of antiretrovirals on CD4 counts and HIV RNA in the era of highly active antiretroviral therapy (HAART).

DESIGN

The study design was a pooled analysis of two trials (POWER 1 and POWER 2) of optimized background treatment plus either TMC114/ritonavir (TMC114/r) or control protease inhibitor (CPI).

METHODS

Across the two randomized trials (mean baseline CD4 count 114 cells/microL and HIV RNA 4.6 log(10) HIV-1 RNA copies/mL), CD4 counts rose by a mean of 98 cells/microL for TMC114/r 600/100 mg twice a day (bid) vs. 17 cells/microL for CPI at week 24; HIV RNA fell by a median of 1.90 and 0.49 log(10) copies/mL in the two groups, respectively. For the CD4 categorization method, cohort data on rates of progression to AIDS/death during HAART within preset CD4 ranges were used to predict rates of progression during TMC114/r and CPI treatment. For the regression method, data from clinical endpoint trials were used to correlate historical treatment effects on HIV RNA and CD4 with clinical benefits.

RESULTS

The CD4 categorization method predicted a 48% reduction in clinical progression to AIDS/death for TMC114/r vs. CPI. The regression method predicted a 55% reduction [95% confidence interval (CI) 45-66%] in the hazard of progression to AIDS/death based on CD4 counts, with a 47% reduction (95% CI 38-53%) predicted from effects on HIV RNA.

CONCLUSIONS

Independent methods generated similar predictions of a 47-55% reduction in progression to AIDS/death for TMC114/r vs. CPI treatment, based on the changes in CD4 counts and HIV RNA from the POWER 1 and POWER 2 trials. These methods could be used to estimate clinical benefits of other antiretrovirals.