Bruton tyrosine kinase inhibitors for the frontline treatment of chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (cll) is the most commonly diagnosed adult leukemia in Canada. Biologic heterogeneity of cll between patients results in variable disease trajectories and responses to therapy. Notably, compared with patients lacking high-risk features, those with such features-such as deletions in chromosome 17p, aberrations in the TP53 gene, or unmutated immunoglobulin heavy chain variable region genes-experience inferior outcomes and responses to standard chemoimmunotherapy. Novel agents that target the B cell receptor signalling pathway, such as Bruton tyrosine kinase (btk) inhibitors, have demonstrated clinical efficacy and safety in patients with treatment-naïve cll, particularly those with high-risk features. However, given the current lack of head-to-head trials comparing btk inhibitors, selection of the optimal btk inhibitor for patients with cll is unclear and requires consideration of multiple factors. In the present review, we focus on the efficacy, safety, and pharmacologic features of the btk inhibitors that are approved or under clinical development, and we discuss the practical considerations for the use of those agents in the Canadian treatment landscape.

Management of chronic lymphocytic leukemia in Canada during the coronavirus pandemic.

The emergence of the covid-19 disease pandemic caused by the 2019 novel coronavirus has required a re-evaluation of treatment practices for clinicians caring for patients with chronic lymphocytic leukemia (cll). The American Society for Hematology (ash) has provided a series of recommendations for the treatment of patients with cll during the pandemic, covering a range of topics, including testing for covid-19, cll treatment initiation and selection, use of immunoglobulin therapy, in-person monitoring, and treatment of patients with cll and covid-19. We summarize the ash recommendations and discuss their applicability as guidelines for the treatment of cll during the covid-19 pandemic in Canada.

Emerging therapies for the treatment of relapsed or refractory diffuse large B cell lymphoma.

Diffuse large B cell lymphoma (dlbcl) is an aggressive non-Hodgkin lymphoma, accounting for approximately 30% of lymphoma cases in Canada. Although most patients will achieve a cure, up to 40% will experience refractory disease after initial treatment, or relapse after a period of remission. In eligible patients, salvage therapy followed by high-dose therapy and autologous stem-cell transplantation (asct) is the standard of care. However, many patients are transplant-ineligible, and more than half of those undergoing asct will subsequently relapse. For those patients, outcomes are dismal, and novel treatment approaches are a critical unmet need. In this paper, we present available data about emerging treatment approaches in the latter setting and provide a perspective about the potential use of those approaches in Canada.

Review of Bruton tyrosine kinase inhibitors for the treatment of relapsed or refractory mantle cell lymphoma.

Mantle cell lymphoma (mcl) is a rare subtype of aggressive B-cell non-Hodgkin lymphoma that remains incurable with standard therapy. Patients typically require multiple lines of therapy, and those with relapsed or refractory (r/r) disease have a very poor prognosis. The Bruton tyrosine kinase (btk) inhibitor ibrutinib has proven to be an effective agent for patients with r/r mcl. Although usually well tolerated, ibrutinib can be associated with unique toxicities, requiring discontinuation in some patients. Effective and well-tolerated alternatives to ibrutinib for patients with r/r mcl are therefore needed. Novel btk inhibitors such as acalabrutinib, zanubrutinib, and tirabrutinib are designed to improve on the safety and efficacy of first-generation btk inhibitors such as ibrutinib. Data from single-arm clinical trials suggest that, compared with ibrutinib, second-generation btk inhibitors have comparable efficacy and might have a more favourable toxicity profile. Those newer btk inhibitors might therefore provide a viable treatment option for patients with r/r mcl.

Observation as the initial management strategy in patients with mantle cell lymphoma.

BACKGROUND: Patients with mantle cell lymphoma (MCL) follow a heterogeneous clinical course. While they generally require treatment initiation shortly after diagnosis, it is unclear whether deferring treatment in selected patients with an indolent clinical behavior affects their overall outcome. PATIENTS AND METHODS: In this population-based study, all patients diagnosed with MCL during 1998-2014 were identified in the British Columbia Cancer Agency Lymphoid Cancer Database. The associations between clinico-pathologic characteristics, including the expression of Ki67, SOX11, and TP53, and time to treatment (TtT) and OS were analyzed. RESULTS: A total of 440 patients with MCL were evaluated: 365 (83%) received early treatment and 75 (17%) were observed ≥3 months. In the observation group, 54 (72%) patients had a nodal presentation, 16 (21%) a non-nodal presentation, and 5 (7%) had only gastrointestinal involvement. Characteristics associated with deferred treatment included good performance status, no B symptoms, low LDH, non-bulky disease, non-blastoid morphology, and lower Ki67 values. The median TtT in the observation group was 35 months (range 5-79), and 60 (80%) patients were observed beyond 12 months. The median OS was significantly longer in the observation group than in the early treatment group (72 versus 52.5 months, respectively, P = 0.041). In multivariable analysis, treatment decision was not associated with OS [HR 0.804 (95% CI 0.529-1.221), P = 0.306]. CONCLUSIONS: A subgroup of patients with MCL may be safely observed from diagnosis without negatively impacting their outcomes, including patients with non-nodal presentation as well as asymptomatic patients with low burden nodal presentation and a low proliferative rate.

International Working Group consensus response evaluation criteria in lymphoma (RECIL 2017).

In recent years, the number of approved and investigational agents that can be safely administered for the treatment of lymphoma patients for a prolonged period of time has substantially increased. Many of these novel agents are evaluated in early-phase clinical trials in patients with a wide range of malignancies, including solid tumors and lymphoma. Furthermore, with the advances in genome sequencing, new "basket" clinical trial designs have emerged that select patients based on the presence of specific genetic alterations across different types of solid tumors and lymphoma. The standard response criteria currently in use for lymphoma are the Lugano Criteria which are based on [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography or bidimensional tumor measurements on computerized tomography scans. These differ from the RECIST criteria used in solid tumors, which use unidimensional measurements. The RECIL group hypothesized that single-dimension measurement could be used to assess response to therapy in lymphoma patients, producing results similar to the standard criteria. We tested this hypothesis by analyzing 47 828 imaging measurements from 2983 individual adult and pediatric lymphoma patients enrolled on 10 multicenter clinical trials and developed new lymphoma response criteria (RECIL 2017). We demonstrate that assessment of tumor burden in lymphoma clinical trials can use the sum of longest diameters of a maximum of three target lesions. Furthermore, we introduced a new provisional category of a minor response. We also clarified response assessment in patients receiving novel immune therapy and targeted agents that generate unique imaging situations.

A Canadian perspective on the use of immunoglobulin therapy to reduce infectious complications in chronic lymphocytic leukemia.

Infections are a major cause of morbidity and mortality in patients with chronic lymphocytic leukemia (cll), who typically have increased susceptibility because of hypogammaglobulinemia (hgg) related to their disease and its treatment. Immunoglobulin replacement therapy (igrt) has been shown to reduce the frequency of bacterial infections and associated hospitalizations in patients with hgg or a history of infection, or both. However, use of igrt in cll is contentious. Studies examining such treatment were conducted largely before the use of newer chemoimmunotherapies, which can extend lifespan, but do not correct the hgg inherent to the disease. Thus, the utility of igrt has to be re-evaluated in the current setting. Here, we discuss the evidence for the use of igrt in cll and provide a practical approach to its use in the prevention and management of infections.

The value of routine bone marrow biopsy in patients with diffuse large B-cell lymphoma staged with PET/CT: a Danish-Canadian study.

BACKGROUND: The added diagnostic and prognostic value of routine bone marrow biopsy (BMB) in patients with diffuse large B-cell lymphoma (DLBCL) undergoing positron emission tomography combined with computed tomography (PET/CT) staging is controversial. PATIENTS AND METHODS: Patients with newly diagnosed DLBCL who underwent both staging PET/CT and BMB were retrospectively identified in British Columbia, Aalborg, and Copenhagen. Original written PET/CT and pathology reports were retrospectively reviewed to determine Ann Arbor stage and outcomes, with and without the contribution of BMB. RESULTS: A total of 530 patients were identified: 146 (28%) had focal bone marrow (BM) lesions on PET/CT and 87 (16%) had positive BMB. Fifty-two of 146 patients (36%) with positive PET/CT had a positive BMB [39 DLBCL, 13 indolent non-Hodgkin lymphoma (iNHL)], while 35 of 384 patients (9%) with negative PET/CT had positive BMB (12 DLBCL, 23 iNHL). BMB upstaged 12/209 (6%) of stage I/II patients to stage IV, although this was the case for only 3 (1%) patients with DLBCL in the BMB. PET/CT identified BM involvement by BMB with sensitivity 60%, specificity 79%, positive predictive value 36%, and negative predictive value 91%. Concordant histological involvement of the BM by DLBCL was associated with worse overall survival and progression-free survival than discordant or no involvement in univariate and multivariate analyses. CONCLUSIONS: In patients with DLBCL, staging PET/CT can miss BM involvement with concordant DLBCL (less common) or discordant iNHL (more common). Routine BMB does not add relevant diagnostic or prognostic value over PET/CT alone in the majority of patients with DLBCL.

Emerging therapies for the treatment of relapsed or refractory follicular lymphoma.

With no treatment standard having been established for relapsed and refractory follicular lymphoma, a number of therapeutic approaches are used in Canada. In patients who relapse early or who eventually become resistant to subsequent treatment, prognosis is poor, and new approaches are needed. A number of novel therapies are being examined in this setting, including monoclonal antibodies, immunoconjugates, immunomodulatory agents, and signal transduction inhibitors. With the body of evidence for those emerging therapies accumulating and the standard upfront treatment changing from rituximab and chop (cyclophosphamide-doxorubicin-vincristine-prednisone) or rituximab and cvp (cyclophosphamide-vincristine-prednisone) to bendamustine and rituximab, treatment decisions in the relapsed and refractory setting have become more complex. The choice of subsequent treatment must consider type of upfront treatment; duration of remission; and patient-related factors such as age, comorbidities, and treatment preferences. This paper summarizes the evidence for novel therapies and proposes recommendations for subsequent treatment options by remission duration after induction and maintenance.

Outcome of patients with primary refractory diffuse large B cell lymphoma after R-CHOP treatment.

Primary refractory diffuse large B cell lymphoma (DLBCL) following R-CHOP chemotherapy is a major concern. We identified 1126 patients with DLBCL treated with R-CHOP from 2000 to 2009, of whom 166 (15 %) had primary refractory disease. Of the 75/166 (45 %) who were age <70 years and had been planned for stage-directed curative therapy, 43 (57 %) were primary nonresponders and 32 (43 %) relapsed within 3 months of completing R-CHOP. Thirty of 75 (40 %) patients had serious comorbidity and organ dysfunction precluding intensive treatment and had palliative treatment only. Twelve of 45 (27 %) patients responded to second-line treatment and underwent ASCT. The median overall survival for the 75 patients was 10 months with only seven patients alive without evidence of disease at follow-up ranging from 14 to 106 months. Primary refractory DLBCL after R-CHOP has a very poor outcome with only anecdotal survivors independent of the intended treatment approach.

Chemoresistance can be overcome with high-dose chemotherapy and autologous stem-cell transplantation for relapsed and refractory Hodgkin lymphoma.

BACKGROUND: High-dose therapy and autologous stem-cell transplant (HDT/ASCT) is the preferred treatment of chemosensitive relapsed/refractory Hodgkin lymphoma (HL). The role for HDT/ASCT in chemoresistant HL is less well defined. We evaluated long-term outcomes of relapsed/refractory HL patients whose disease was refractory to secondary chemotherapy preceding HDT/ASCT. PATIENTS AND METHODS: All HL patients who underwent HDT/ASCT in British Columbia for primary progression (PP, defined as progression within 3 months of initial therapy completion) or first relapse (REL1) were reviewed. Patients were grouped based on response to secondary chemotherapy as sensitive (S), resistant (R), and untested/unknown (U). RESULTS: A total of 256 patients underwent HDT/ASCT for PP (35%) or REL1 (65%) between 1985 and 2011. At median follow-up of 11.7 years, 58% were alive without HL, 36% relapsed; 6% died of transplant-related mortality, 3% secondary malignancies, and 3% unrelated causes. For PP/S, PP/R, and PP/U groups, 10-year FFS were 47%, 31%, and 38%; 10-year OS were 52%, 29%, and 37%, respectively. For REL1/S, REL1/R, and REL1/U groups, 10-year FFS were 64%, 51%, and 81%; 10-year OS were 71%, 59%, and 79%, respectively. In multivariate analysis, resistance to secondary chemotherapy predicted for post-transplant mortality in the PP (P = 0.04) but not REL1 (P = 0.16) groups. CONCLUSION: In this large uniformly treated cohort of HL patients with long-term follow-up, chemoresistance preceding HDT/ASCT was identified as a poor prognostic factor; however, this factor can be partially overcome by HDT/ASCT, resulting in cure in 30%-50% of patients. HDT/ASCT should therefore be considered in all transplant eligible patients, regardless of responsiveness to salvage chemotherapy.

A Canadian perspective on bendamustine for the treatment of chronic lymphocytic leukemia and non-Hodgkin lymphoma.

Despite the success of standard treatments in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), patients are often unable to tolerate aggressive regimens, and they require effective alternatives. Bendamustine is a bifunctional alkylator with unique properties that significantly distinguish it from other agents in its class. In untreated CLL, bendamustine has demonstrated rates of response and progression-free survival (PFS) that are superior to those with chlorambucil, with an acceptable toxicity profile. In the relapsed setting, combination treatment with bendamustine-rituximab (BR) has demonstrated promising activity in high-risk patients such as those refractory to fludarabine or alkylating agents. In untreated patients with indolent NHL and mantle cell lymphoma, BR has demonstrated a PFS significantly longer than that achieved with R-CHOP (rituximab-cyclophosphamide-doxorubicin-vincristine-prednisone), with significantly reduced toxicity. In the relapsed setting, br has demonstrated rates of response and PFS superior to those with fludarabine-rituximab, with comparable toxicity. In the United States and Europe, bendamustine has been approved for the treatment of CLL and indolent NHL; its approval in Canada is pending and eagerly awaited. Once available, bendamustine will benefit many Canadian patients with NHL and CLL.

Follicular non-Hodgkin lymphoma grades 3A and 3B have a similar outcome and appear incurable with anthracycline-based therapy.

BACKGROUND: The revised World Health Organization (WHO) classification maintains a histological grading system (grades 1-3) for follicular lymphoma (FL) and subdivides grade 3 into 3A (FL3A) and 3B (FL3B) subtypes. Optimal therapy of FL grade 3 and its potential curability with anthracycline-based chemotherapy remain uncertain. PATIENTS AND METHODS: We carried out a retrospective population-based analysis evaluating the clinical characteristics and outcome of FL3A and FL3B as strictly defined by WHO diagnostic criteria. Using the BC Cancer Agency Lymphoid Cancer Database, 161 patients with FL grade 3 were identified and, following detailed pathology review, composed of 139 with FL3A and 22 with FL3B. RESULTS: Patients with FL3B had a higher overall International Prognostic Index (IPI) score than FL3A patients (P = 0.03), though no significant difference in individual IPI risk factor frequencies was noted. More patients with FL3B received front-line anthracycline-containing chemotherapy (82% versus 36%, P ≤ 0.001). With median follow-up of 45 months, no difference in disease-specific survival (P = 0.74) or overall survival (OS) (P = 0.87) was found between FL3A and FL3B and no survival curve plateau was observed. Analysis limited to FL3A patients showed no OS advantage with front-line anthracycline use (P = 0.33). CONCLUSION: Using strict diagnostic criteria, there appears to be no difference in outcome between patients with FL3A and FL3B and no evidence of curability with anthracycline-based therapy.

Incidence and risk factors for central nervous system relapse in patients with diffuse large B-cell lymphoma: the impact of the addition of rituximab to CHOP chemotherapy.

BACKGROUND: The addition of rituximab to CHOP (R-CHOP; CHOP, cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy improves outcome in patients with diffuse large B-cell lymphoma (DLBCL). We evaluated the risk of central nervous system (CNS) relapse in the R-CHOP in a population-based cohort of patients with DLBCL. METHODS: Patients with DLBCL diagnosed from 1 September 1999 to 14 January 2005 at the British Columbia Cancer Agency (BCCA) were identified. Patients were included if they were > or =16 years old with advanced stage or any stage with testicular involvement and were treated with CHOP (1999-2001) or R-CHOP (2001-2005) with curative intent. RESULTS: Four hundred and thirty-five patients were identified; 126 (29%) were treated with CHOP and 309 (71%) with R-CHOP. With a median follow-up of 5.7 years, there were 31 CNS relapses in total with a trend to a reduced likelihood of CNS relapse in R-CHOP-treated patients (3-year risk 9.7% versus 6.4, P = 0.085). In multivariate analysis, the use of rituximab significantly reduced the risk of CNS relapse [hazard ratio (HR) 0.45, P = 0.034]; this benefit was more striking in patients who achieved a complete response (HR 0.18, P = 0.005). CONCLUSION: The use of R-CHOP appears to reduce the overall risk of CNS relapse in patients with DLBCL particularly in patients who achieve a complete response.

A clinicopathological retrospective study of 131 patients with primary bone lymphoma: a population-based study of successively treated cohorts from the British Columbia Cancer Agency.

BACKGROUND: Primary bone lymphoma (PBL) is a distinct clinicopathological entity. Although PBL has been reviewed in several small studies, few reflect recent improvements in primary treatment. METHODS: We used the British Columbia Cancer Agency Lymphoid Cancer Database to identify all patients with PBL (1983-2005). All were staged in a uniform manner and treated with era-specific protocols. RESULTS: We identified 131 patients with a median age of 63 years (18-87). One third had disease in long bones and another one third had disease in the spine, of which half presented with spinal cord compression. Patients with diffuse large-cell lymphoma (DLCL) (n=103, 79%) had 5- and 10-year overall survivals (OS) of 62% and 41%, respectively. Multivariate analysis identified three prognostic groups: age<60 with International Prognostic Index (IPI) 1-3 (n=43), age>or=60 with IPI 0-3 (n=23) and age>or=60 with IPI 4-5 (n=33), with markedly different 5-year OS of 90%, 61% and 25%, respectively (P<0.0001). Neither primary site nor pathological fracture at presentation had an impact on OS. The 3-year progression-free survival in patients who received rituximab plus combination chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOPR) chemotherapy was 88% compared with 52% in those who received CHOP-like chemotherapy without rituximab (P=0.005). The 10-year OS for those with advanced-stage disease who received irradiation plus chemotherapy was 25% versus 56% for those who received chemotherapy alone (P=0.025). Patients received irradiation if spinal cord compression was present or residual disease at the end of chemotherapy was thought to require it. CONCLUSIONS: PBL is usually of DLCL type and has an improved outcome with CHOPR. Younger patients with good IPI score have a favorable prognosis.

Comparative outcomes of T-cell-depleted and non-T-cell-depleted allogeneic bone marrow transplantation for chronic myelogenous leukemia: impact of donor lymphocyte infusion.

PURPOSE: Donor lymphocyte infusion (DLI) can restore complete remission in patients with chronic myelogenous leukemia (CML) who have relapsed after T-cell-depleted (TCD) allogeneic bone marrow transplantation (BMT). The existence of salvage treatment for patients with DLI after TCD allogeneic BMT prompted an evaluation of overall outcome after CD6+ -TCD allogeneic BMT for patients treated during the time when DLI has been available. PATIENTS AND METHODS: We performed a retrospective analysis of outcomes of 46 patients who underwent TCD allogeneic BMT for stable-phase CML and compared these outcomes with those of 40 patients who underwent non-TCD allogeneic BMT. All subjects were patients at one of two neighboring institutions during a period when DLI was available. All patients received marrow from HLA-identical sibling donors, underwent similar myeloablative regimens, and had similar pretreatment characteristics. RESULTS: After BMT, the TCD group had a lower incidence of grade 2 to 4 acute (15% v 37%, P = .026) and chronic graft-versus-host disease (GVHD) (18% v 42%, P = .024) than did the non-TCD group. The 1-year treatment-related mortality rates for the TCD group and the non-TCD group were 13% and 29%, respectively (P = .07). The estimated 3-year probability of relapse (cytogenetic or hematologic) was higher for patients in the TCD group than for patients in the non-TCD group (62% v 24%, P = .0003). Twenty-three patients (20 in the TCD group and three in the non-TCD group) received and were assessable for response to DLI. After DLI, 17 of 20 patients in the TCD group and two of three patients in the non-TCD group achieved complete remission. Donor lymphocyte infusion induced GVHD in nine of 23 patients. Thirty (65%) of 46 patients in the TCD group and 27 (69%) of 39 assessable patients in the non-TCD group remained alive without evidence of disease. The estimated 3-year overall survival rates were similar for the TCD group and the non-TCD group (72% v 68%, respectively; P = .38). At last follow-up, there was no difference in the overall prevalence of GVHD or the proportion of patients requiring immunosuppressive agents between groups. CONCLUSION: These results suggest that the combination of T-cell depletion and post-BMT DLI is a viable treatment option for patients undergoing allogeneic BMT for CML and should be prospectively compared with traditional forms of GVHD prophylaxis.

Pancreatitis during therapy of acute myeloid leukemia: cytarabine related?

BACKGROUND: Acute pancreatitis in acute myeloid leukemia (AML) has been rarely associated with cytarabine therapy. This report attempts to characterize this toxicity. PATIENTS AND METHODS: Criteria for pancreatitis was prospectively defined. Seven patients with pancreatitis were identified from an AML database and a clinical study at two tertiary care centers (n = 134). Their records were retrospectively reviewed. RESULTS: Seven patients with pancreatitis complicating AML therapy were identified. Median age was 36 (range 25-73) years. Median amylase was 184 (range 77-552) U/l and median lipase was 1026 (range 630-6087) U/l. The patients had received high dose bolus cytarabine (2 g/m2 i.v. bolus every 12 hours; n = 2), and continuous infusion cytarabine followed by high-dose cytarabine (100 mg/m2 i.v. CI days 1-7 then 2 g/m2 i.v. bolus every 12 hours days 8-10; n = 2), or standard dose continuous infusion cytarabine (200 mg/m2/d; n = 3) prior to developing pancreatitis. Pancreatitis occurred at a median of 10 days following day one of cytarabine administration with resolution at a median of 11 days after initial diagnosis. Six patients did not suffer major complications. One patient died of causes unrelated to pancreatitis. Five of six patients was rechallenged and all remained free of pancreatitis. One patient subsequently did develop pancreatitis on a later rechallenge. CONCLUSIONS: Pancreatitis in the setting of AML therapy may be an infrequent and self-limited toxicity of cytarabine. A schedule dependent toxicity with cytarabine was not identified.

A phase II study of BTI-322, a monoclonal anti-CD2 antibody, for treatment of steroid-resistant acute graft-versus-host disease.

BTI-322, a rat monoclonal IgG2b directed against the CD2 antigen on T cells and natural killer (NK) cells, blocks primary and memory alloantigen proliferative responses in vitro. We have evaluated the pharmacokinetics and safety of BTI-322 during treatment of 20 transplant recipients with steroid-refractory acute graft-versus-host disease (GVHD). Treatment consisted of BTI-322 by intravenous (IV) bolus or 30-minute infusion at approximately 0.1 mg/kg/d for 10 days in addition to continuing high-dose steroids and tacrolimus or cyclosporine. Pharmacokinetic sampling was performed in 10 patients; the t1/2 +/- SE was 9.1 +/- 1.3 hours, the Cmax was 2,549 +/- 291 ng/mL, the Vd was 3.97 +/- 0.95 L, and the Vd/kg was 0. 05 +/- 0.01 L/kg. Ten patients experienced transient dyspnea sometimes accompanied by nausea, vomiting, diarrhea, and tachycardia shortly after the initial bolus dose of drug, but serious drug-related adverse events were not seen during the remainder of the infusions. At the end of treatment (day 11), there were six patients with complete responses and five with a reduction in grade of GVHD for a total response rate of 55% (95% confidence interval [CI], 32% to 77%). Antibodies targeting CD2 may be active in the treatment of acute GVHD, and evaluation of a humanized form of BTI-322 is warranted.

Primary diffuse large B-cell lymphoma of the mediastinum: outcome following high-dose chemotherapy and autologous hematopoietic cell transplantation.

We performed a retrospective analysis of 35 patients with primary diffuse large B-cell lymphoma of the mediastinum treated with high-dose cyclophosphamide, carmustine, and etoposide (CBV) plus autologous hematopoietic cell transplantation to determine outcome and prognostic features for progression-free survival (PFS). Thirty-five patients with primary diffuse large B-cell lymphoma of the mediastinum in first response (complete remission [CR] or partial remission [PR]) with poor prognostic features, with primarily refractory disease, or with relapsed disease following conventional chemotherapy, were treated with CBV and autologous hematopoietic cell transplantation. PFS and overall survival were assessed by the Kaplan-Meier method. Patient characteristics before transplantation were examined by univariate analysis using the log-rank test and by Cox's proportional hazards regression analysis to determine predictors of PFS. Estimated 5-year PFS varied significantly with patient disease status at transplantation. Patients transplanted in first response had an estimated 5-year PFS rate of 83%, compared with 58% and 27% for primarily refractory and relapsed patients, respectively (P = .02). The strongest predictor of PFS was chemotherapy responsiveness immediately before transplantation. Patients with chemotherapy-responsive disease had a significantly greater PFS rate than patients with chemotherapy-nonresponsive disease (risk ratio, 3.60; 95% confidence interval [CI], 1.14 to 11.4). No other factors were found to be significant on univariate or multivariate analysis. Patients with primary diffuse large B-cell lymphoma of the mediastinum can achieve prolonged PFS following high-dose chemotherapy and autologous hematopoietic cell transplantation. Outcomes are strongly correlated with disease status (first response v refractory v relapsed) at transplantation and chemotherapy responsiveness immediately before transplantation.