Overall survival of patients with cHL who progress after autologous stem cell transplant: results in the novel agent era.

In the pre-novel agent era, the median postprogression overall survival (PPS) of patients with classic Hodgkin lymphoma (cHL) who progress after autologous stem cell transplant (ASCT) was 2 to 3 years. Recently, checkpoint inhibitors (CPI) and brentuximab vedotin (BV) have improved the depth and durability of response in this population. Here, we report the estimate of PPS in patients with relapsed cHL after ASCT in the era of CPI and BV. In this multicenter retrospective study of 15 participating institutions, adult patients with relapsed cHL after ASCT were included. Study objective was postprogression overall survival (PPS), defined as the time from posttransplant progression to death or last follow-up. Of 1158 patients who underwent ASCT, 367 had progressive disease. Median age was 34 years (range, 27-46) and 192 were male. Median PPS was 114.57 months (95% confidence interval [CI], 91-not achieved) or 9.5 years. In multivariate analysis, increasing age, progression within 6 months, and pre-ASCT positive positron emission tomography scan were associated with inferior PPS. When adjusted for these features, patients who received CPI, but not BV, as first treatment for post-ASCT progression had significantly higher PPS than the no CPI/no BV group (hazard ratio, 3.5; 95% CI, 1.6-7.8; P = .001). Receipt of allogeneic SCT (Allo-SCT) did not improve PPS. In the era of novel agents, progressive cHL after ASCT had long survival that compares favorably with previous reports. Patients who receive CPI as first treatment for progression had higher PPS. Receipt to Allo-SCT was not associated with PPS in this population.

Peripheral T-Cell Lymphomas Involving the Central Nervous System: A Report From the Czech Lymphoma Study Group Registry.

Introduction: We analyzed the incidence, risk factors of central nervous system (CNS) relapse, and outcome of CNS involvement in patients with peripheral T-cell lymphomas (PTCL) from the Czech Lymphoma Study Group Registry NiHiL (Clinical Trial gov. NCT03199066). Materials and Methods: Out of 1,040 patients with PTCL, we identified 29 patients (2.79%) with CNS involvement: 2 patients with primary CNS T cell lymphoma, 11 patients with CNS and systemic disease at diagnosis, and 16 patients (1.54%) at CNS relapse. The most common histology with CNS disease was PTCL, not otherwise specified. Progression-free survival (PFS) was defined as the time interval from diagnosis to progression or death. PFS-2 was defined as the interval from the date of a new relapse until the next relapse. Results: Patients with testicular involvement received intrathecal prophylaxis with methotrexate. High-dose methotrexate-based treatment was administered in 44.8% of patients with CNS disease. Median follow-up was 71.3 months. The difference between the median PFS of 1,027 patients without initial CNS disease (32.6 months) and 11 patients with initial CNS and systemic disease (4.8 months) was significant (p = 0.04). The difference between the median PFS2 in CNS relapses (10.1 months) and 493 relapses outside of CNS (9.1 months) was not significant (p = 0.6). Risk factors for CNS relapses included the following: involvement of more than one extranodal site (p = 0.008), soft tissue involvement (p = 0.003), testicular involvement (p = 0.046), and the presence of B symptoms (p = 0.035). The difference between the median OS of 1,027 patients without initial CNS disease (46.0 months) and 11 patients with initial CNS and systemic disease (18.2 months) was significant (p = 0.02). The median OS2 in CNS relapses was 11.8 months and that in relapses outside of CNS was 21.3 months. CNS involvement was not associated with a significantly worse OS compared to relapsed/refractory patients without CNS involvement (p = 0.1). Conclusions: The incidence of CNS disease at the time of diagnosis and at relapse in PTCL is low and usually associated with other systemic involvement. The prognosis of PTCL with initial CNS involvement is significantly worse when compared to patients without CNS disease at diagnosis. The outcome of CNS relapse is comparable with relapsed PTCL outside of CNS. The optimal treatment is not defined yet.

Polatuzumab vedotin plus bendamustine and rituximab in patients with relapsed/refractory diffuse large B-cell lymphoma in the real world.

OBJECTIVES: Polatuzumab vedotin with bendamustine and rituximab (Pola-BR) was approved for treatment of transplant-ineligible patients with relapsed/refractory DLBCL (R/R DLBCL). However, the number of patients treated in the GO29365 trial including the extension cohort was limited, and more data evaluating the efficacy of this treatment regimen is needed. METHODS: We analyzed 21 patients with R/R DLBCL to determine real-life efficacy and safety of Pola-BR regimen. Data of all patients entered the database of the NiHiL project (NCT03199066). RESULTS: Median overall survival was 8.7 months, and progression-free survival 3.8 months. The overall response rate was 33%. Grade 3-4 neutropenia was detected in 29%, thrombocytopenia in 38%, anemia in 19%, infections in 24% cases, and peripheral neuropathy in 5%. Discontinuation of treatment was caused by progression in 50%, adverse events in 31%, and intended bridging to CAR-T therapy in 19%. CONCLUSION: Although the outcome of patients is worse than in GO29365 trial, the use of Pola-BR regimen in the real world demonstrates tolerable toxicity profile and efficacy in transplant-ineligible patients with R/R DLBCL. Moreover, this regimen might represent a perspective option as a bridge to CAR-T therapy.

Burkitt lymphoma-a retrospective analysis of data from the Registry of the Czech Lymphoma Study Group with external validation of the Burkitt lymphoma International Prognostic Index.

Burkitt lymphoma (BL) is a rare subtype of non-Hodgkin's lymphoma with an aggressive course. To refine the individual patient's prognosis, the International Prognostic Index for BL (BL-IPI) was recently developed and 4 risk factors (RF) were determined as optimal prognostic cut-off by multivariate analysis: age ≥40 years, lactate dehydrogenase >3× upper limit of normal, ECOG performance status ≥2, and central nervous system involvement. The BL-IPI distinguishes 3 prognostic groups, low (without RF), intermediate (1 RF), and high risk (2-4 RF), with significant differences in survival. The aim of the current project was to perform an external validation of the BL-IPI in 101 patients from the Registry of Czech Lymphoma Study Group diagnosed between 1999 and 2016 (median age, 45 years). The median follow-up was 50.4 months. The induction treatment included rituximab plus chemotherapy in 82% and chemotherapy alone in 18%. The overall response rate was 78% and the complete remission rate was 73%. According to BL-IPI, low/intermediate/high risk was present in 21/35/45% of patients, showing high similarity to the training BL-IPI US (United States) dataset (18/36/46%). There were significant differences in progression-free survival (PFS) and overall survival (OS) between patients with high vs. intermediate risk (PFS: hazard ratio 0.16, 95% confidence interval 0.08-0.31, p<0.0001; OS: hazard ratio 0.17, 95% confidence interval 0.09-0.35, p<0.0001) but not between patients with low vs. intermediate risk. The 3-year OS probability according to BL-IPI with low/intermediate/high risk was 96/76/59% in the BL-IPI training dataset vs. 95/85/45% in our external validation cohort; the 3-year PFS probability with low/intermediate/high risk was 92/72/53% in the BL-IPI training dataset vs. 95/85/42% in our cohort. In summary, our external validation of the BL-IPI confirmed a good separation of high-risk patients, who have a poor prognosis and for whom the new therapeutic approaches are needed; patients with low and intermediate risk had favorable clinical outcomes, and differences between these groups were not significant, likely due to a small number of patients.

The interval between progression and therapy initiation is the key prognostic parameter in relapsing diffuse large B cell lymphoma: analysis from the Czech Lymphoma Study Group database (NIHIL).

Relapsing diffuse large B cell lymphomas (rDLBCL) represent a heterogeneous disease. This heterogeneity should be recognized and reflected, because it can deform the interpretation of clinical trial results. DLBCL patients with the first relapse and without CNS involvement were identified in the Czech Lymphoma Study Group (CLSG) database. Interval-to-therapy (ITT) was defined as the time between the first manifestation of rDLBCL and the start of any treatment. The overall survival (OS) of different ITT cohorts (< 7 vs. 7-21 vs. > 21 days) was compared. In total, 587 rDLBCLs (51.8% males) progressed with a median of 12.8 months (range 1.6 to 152.3) since the initial diagnosis (2000-2017). At the time of relapse, the median age was 67 years (range 22-95). First-line therapy was administered in 99.3% of the patients; CHOP and anti-CD20 were given to 69.2% and 84.7% of the patients, respectively. The salvage immune/chemotherapy was administered in 88.1% of the patients (39.2% platinum-based regimen). The median ITT was 20 days (range 1-851), but 23.2% of patients initiated therapy within 7 days. The 5-year OS was 17.4% (range 10-24.5%) vs. 20.5% (range 13.5-27.4%) vs. 42.2% (range 35.5-48.8%) for ITT < 7 vs. 7-21 vs. > 21 days (p < 0.001). ITT was associated with B symptoms (p 0.004), ECOG (p < 0.001), stage (p 0.002), bulky disease (p 0.005), elevated LDH (p < 0.001), and IPI (p < 0.001). The ITT mirrors the real clinical behavior of rDLBCL. There are patients (ITT < 7 days) with aggressive disease and a poor outcome. Conversely, there are rDLBCLs with ITT ≥ 21 days who survive for a long time.

Rituximab maintenance significantly reduces early follicular lymphoma progressions in patients treated with frontline R-CHOP.

Twenty percent of patients with high-tumor-burden (HTB) follicular lymphoma (FL) develop progression/relapse of disease (POD) within 24 months of frontline immunochemotherapy. Unfortunately, about 50% of these patients die within 5 years since POD event. Rituximab maintenance was proven to reduce relapse rate in responding FL, but its role on preventing POD was not defined. We analyzed 1360 HTB-FL patients from the Czech Lymphoma Study Group registry treated with frontline rituximab-containing regimen. Of those, 950 cases received rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and achieved complete or partial remission: 712 patients received rituximab maintenance (MAINT) and 238 were a historical observational cohort (OBS). We have proposed a modified POD24 (mPOD24) endpoint for the chemosensitive patients calculated from the end-of-induction (EOI). Survival rates since EOI were as follows: 5-year overall survival (OS) 86.2% versus 94.5% in the OBS and MAINT groups, respectively (P < .001) and 5-year progression-free survival 58.5% (OBS) and 75.4% (MAINT) (P < .001). The Cox proportional hazards model showed a decrease in mPOD24 incidence in the MAINT group with the overall hazard rate reduced by 56% (hazard ratio = 0.44; P < .001). The cumulative incidence of mPOD24 was reduced from 24.1% in OBS to 10.1% in MAINT (P < .001). Comparison of non-mPOD24 cases showed OS similar to that in the general population. Rituximab maintenance given after R-CHOP resulted in a 2.4-fold reduction in mPOD24 incidence. Once the non-POD24 status is achieved, FL does not shorten the patients' life expectancy.

Treatment of Relapsed/Refractory Hodgkin Lymphoma: Real-World Data from the Czech Republic and Slovakia.

Introduction: Clinical trials have demonstrated the effectiveness of the CD30-targeted antibody-drug conjugate brentuximab vedotin (BV) for the treatment of relapsed/refractory Hodgkin lymphoma (R/R HL). In this study, we report on outcomes with BV in a real-world setting using data collected in clinics in the Czech Republic and Slovakia. Patients and Methods: Clinical and epidemiological data for patients with R/R HL who received treatment with BV at eight centers across the Czech Republic and Slovakia were examined. Data were amalgamated and analyzed retrospectively. Results: Clinical data for 58 patients (median age: 30.5 years) with R/R HL who received BV during the course of their treatment were collected and analyzed. Patients had received a median of 3 prior treatment regimens and most (91%) were treated with BV after relapse following autologous stem cell transplantation. Therapeutic responses after BV included 19 (33%) complete responses (CRs) and 8 (14%) partial responses. CRs occurred more frequently in patients who had received fewer prior treatment regimens. The 1-, 2-, and 3-year overall survival (OS) rates from initiation of BV were 78%, 62%, and 41%, respectively. Conclusion: Response rates and OS in this analysis of BV in real-world settings in the Czech Republic and Slovakia were consistent with those reported for pivotal clinical trials and from previous studies outside the clinical trial setting. The results support the efficacy of BV for treatment of R/R HL in real-life clinical practice.

The Lymphoma-Associated Macrophage to Hodgkin-Reed-Sternberg Cell Ratio Is a Poor Prognostic Factor in Classic Hodgkin Lymphoma Patients.

BACKGROUND: Despite the relatively high rate of curability, approximately 20% to 30% of patients with classic Hodgkin lymphoma relapse. Hodgkin-Reed-Sternberg (HRS) cells:lymphoma-associated macrophages (LAMs) cross talk promotes tumor growth and resistance to therapy. The aim of the study was to assess the prognostic role of the LAM to HRS ratio (LHR) in lymph node biopsies using a novel automated system for scanning large sample areas. PATIENTS AND METHODS: High-quality tissue samples obtained from 71 patients and stained with anti-CD30 and anti-CD68 were analyzed using the TissueFAXS (TissueGnostics). RESULTS: A high LHR was associated with inferior 5-year progression-free survival (PFS; 50.0% vs. 79.3%; P = .032) and overall survival (OS; 65.4% vs. 92.3%; P = .012). Multivariate Cox regression identified the high LHR as an unfavorable prognostic factor for PFS (hazard ratio [HR], 3.07; P = .029) and OS (HR, 4.56; P = .025). CONCLUSION: A high LHR at diagnosis is associated with a higher risk of lymphoma progression or death. Automated image analysis is a new tool that can overcome technical limitations of by microarray samples in lymphomas with high intratumor heterogeneity.

Identification of spatial magnetic inhomogeneities by nuclear forward scattering of synchrotron radiation.

Spatially confined magnetic inhomogeneities were revealed by measuring nuclear forward scattering time spectra on the same sample in two different geometric arrangements. They differ by 180° rotation of the sample around one of the polarization axes. A basic theoretical description of this phenomenon and its relation to a spatial distribution of nuclei featuring different magnetic moments is provided. From an experimental point of view, the violation of rotational invariance was observed for an inhomogeneous Fe81Mo8Cu1B10 metallic glass. The development of magnetic inhomogeneities and their relation to the evolution of time spectra was studied during thermal annealing.

First-line therapy for T cell lymphomas: a retrospective population-based analysis of 906 T cell lymphoma patients.

Peripheral T cell lymphomas (PTLs) have a globally poor prognosis. The CHOP regimen shows insufficient efficacy; first-line consolidation with autologous stem cell transplantation (auto-SCT) is a promising strategy but has never been confirmed by randomized data. We analyzed retrospectively 906 patients diagnosed with PTL between 1999 and 2015. Chemotherapy was given to 862 patients, and 412 of them were < 60 years. In this subset, we compared induction with CHOP (n = 113) vs. CHOEP (n = 68) and tested auto-SCT (n = 79) vs. no SCT (n = 73) in the intent-to-treat analysis. The median age of the whole cohort at diagnosis was 60 years (range; 18-91); the median follow-up was 4.3 years (range; 0.1-17.8). A shorter overall survival (OS) was associated with the male gender, age ≥ 60 years, stage III/IV, performance status ≥ 2, bulky tumor ≥ 10 cm, and elevated LDH. CHOEP induction showed a better 5-year PFS (25.0% vs. 32.9%; p.001), and 5-year OS (65.6% vs. 47.6%; p.008) than CHOP. Auto-SCT compared to no SCT brought a 5-year OS of 49.2% vs. 59.5% (p.187). Auto-SCT did not influence the OS in low-risk or low-intermediate risk PTLs. The high-intermediate and high-risk IPIs displayed a worse 5-year OS in auto-SCT arm (17.7% vs.46.2%; p.049); however, 73.9% of the patients never received planned auto-SCT. Our population-based analysis showed the superiority of CHOEP over CHOP in first-line treatment. We confirm the 5-year OS of around 50% in PTLs undergoing auto-SCT. However, the intended auto-SCT could not be given in 73.9% of the high-risk PTLs.

On the Formation of Nanocrystalline Grains in Metallic Glasses by Means of In-Situ Nuclear Forward Scattering of Synchrotron Radiation.

Application of the so-called nuclear forward scattering (NFS) of synchrotron radiation is presented for the study of crystallization of metallic glasses. In this process, nanocrystalline alloys are formed. Using NFS, the transformation process can be directly observed during in-situ temperature experiments not only from the structural point of view, i.e., formation of nanocrystalline grains, but one can also observe evolution of the corresponding hyperfine interactions. In doing so, we have revealed the influence of external magnetic field on the crystallization process. The applied magnetic field is not only responsible for an increase of hyperfine magnetic fields within the newly formed nanograins but also the corresponding components in the NFS time spectra are better identified via occurrence of quantum beats with higher frequencies. In order to distinguish between these two effects, simulated and experimental NFS time spectra obtained during in-situ temperature measurements with and without external magnetic field are compared.

Maintenance rituximab in newly diagnosed mantle cell lymphoma patients: a real world analysis from the Czech lymphoma study group registry†.

We analyzed 495 MCL patients from the Czech Lymphoma Study Group data registry. With the median follow-up of 4.4 years, 51.7% patients progressed or relapsed and 34.1% died. Five-year overall survival reached 65.3% and five-year progression free survival 44.1% of the patients. Maintenance rituximab (MR) after first line therapy improved overall and progression free survival compared to the patients under observation only (both p < .001). Elevated beta-2-microglobulin (p = .003), presence of systemic symptoms (p = .002), ECOG >0 (p = .003), age (p = .014), and MIPI (p < .001) were associated with MR failure. Patients who did not achieve complete remission have had two-fold higher risk of MR failure (p < .001). Autologous stem cell transplant reduced the risk of MR failure by 69% (p < .001). The MIPI and the beta-2-microglobulin were identified as independent predictors of MR failure (p = .02 and p = .03, respectively). Patients who relapsed/progressed on MR reached shorter OS calculated from the MR start compared to patients without failure (HR = 15.0; p < .001).

miR-150 downregulation contributes to the high-grade transformation of follicular lymphoma by upregulating FOXP1 levels.

Follicular lymphoma (FL) is a common indolent B-cell malignancy with a variable clinical course. An unfavorable event in its course is histological transformation to a high-grade lymphoma, typically diffuse large B-cell lymphoma. Recent studies show that genetic aberrations of MYC or its overexpression are associated with FL transformation (tFL). However, the precise molecular mechanisms underlying tFL are unclear. Here we performed the first profiling of expression of microRNAs (miRNAs) in paired samples of FL and tFL and identified 5 miRNAs as being differentially expressed. We focused on one of these miRNAs, namely miR-150, which was uniformly downmodulated in all examined tFLs (∼3.5-fold), and observed that high levels of MYC are responsible for repressing miR-150 in tFL by binding in its upstream region. This MYC-mediated repression of miR-150 in B cells is not dependent on LIN28A/B proteins, which influence the maturation of miR-150 precursor (pri-miR-150) in myeloid cells. We also demonstrated that low miR-150 levels in tFL lead to upregulation of its target, namely FOXP1 protein, which is a known positive regulator of cell survival, as well as B-cell receptor and NF-κB signaling in malignant B cells. We revealed that low levels of miR-150 and high levels of its target, FOXP1, are associated with shorter overall survival in FL and suggest that miR-150 could serve as a good biomarker measurable in formalin-fixed paraffin-embedded tissue. Overall, our study demonstrates the role of the MYC/miR-150/FOXP1 axis in malignant B cells as a determinant of FL aggressiveness and its high-grade transformation.

The influence of maintenance therapy of rituximab on the survival of elderly patients with follicular lymphoma. A retrospective analysis from the database of the Czech Lymphoma Study Group.

The rituximab maintenance (RM) therapy for follicular lymphoma is effective and clinically well tolerated, however there is limited data regarding this from the elderly segment of the population. This analysis was performed to evaluate the efficacy of RM in elderly patients 65 years of age and older and to assess the influence of the induction therapy with immunochemotherapy (R-CHEMO) on the treatment outcome in a real world setting. A total of 232 consecutive patients treated with first-line R-CHEMO and RM (RM1 group; n = 158) or observation (RM0 group; n = 74) were analyzed. The effect of which induction therapy (R-CHOP vs. R-CVP) and the response of the patients to the first-line therapy were also evaluated. The addition of RM improved the treatment results in elderly patients. The 5- year overall survival rate in patients receiving R-CHEMO + RM1 compared to patients receiving R-CHEMO + RM0, was 83.7% (95% CI 76.1-89%) and 64.3% (95% CI 51.8-74.3%), respectively, p = 0.0012. The induction therapy with R-CHOP was found to be more effective than R-CVP but it is necessary to point out higher age of patients in the R-CVP arm. The 5- year overall survival rate in patients using R-CHOP ± RM and R-CVP ± RM was 84.9% (95% CI 77.5-90%), and 65.0% (95% CI 50.1-76.4%), respectively, p = 0.0008. The patients who achieved CR + uCR after having received first-line therapy had better outcomes compared to patients in PR. The 5- year overall survival rate in uCR + CR patients treated with R-CHEMO + RM1 and PR patients treated with R-CHEMO + RM1 was 90.6% and 68.3%, respectively, p = 0.0019. Rituximab maintenance treatment in patients 65 years and older yielded improved survival rates in a real world clinical setting. The R-CHOP regimen seems to be a more effective induction agent than R-CVP but the outcome of less intensively treated patients with R-CVP + RM is also acceptable. The achievement of uCR + CR after first-line therapy is associated with a better outcome.

Potential loss of prognostic significance of minimal residual disease assessment after R-CHOP-based induction in elderly patients with mantle cell lymphoma in the era of rituximab maintenance.

Rituximab maintenance (RM) prolongs survival of elderly patients with mantle cell lymphoma (MCL). Persistent minimal residual disease (MRD) after induction repeatedly correlated with shorter progression-free survival (PFS). However, none of the published studies analyzed patients treated with RM. The main purpose was to analyze prognostic significance of MRD in the elderly patients with newly diagnosed MCL treated according to the recently published observational trial protocol (alternation of R-CHOP and R-cytarabine, 3 + 3 cycles, GovTrial number NCT03054883) at the centers that implemented RM. Minimal residual disease was evaluated by a EuroMRD standardized real-time PCR approach after 3 and 6 cycles of the induction therapy. Prognostic significance of MRD was analyzed in a subcohort of patients treated at the centers that implemented RM as a standard approach. Bone marrow proved to be a significantly more sensitive source for MRD detection than peripheral blood. In either compartment MRD (positive versus negative) after 3 or 6 cycles of the induction therapy did not correlate with PFS. The observed loss of prognostic significance of MRD after the R-CHOP-based induction appears to be a consequence of RM immune control over the residual lymphoma.

TP53 Mutation and Complex Karyotype Portends a Dismal Prognosis in Patients With Mantle Cell Lymphoma.

BACKGROUND: TP53 mutation (TP53mut) and a complex karyotype (CK) were shown to be predictors of poor outcome in mantle-cell lymphoma (MCL). In this study we examined the combined effect of both of these risk factors. PATIENTS AND METHODS: Patients diagnosed with MCL between January 2000 and December 2014 (n = 74) were evaluated. Forty-eight of them had available material for TP53 and cytogenetic examination. We analyzed the prognostic effect of combined TP53mut and CK in the cohort of patients treated with rituximab-containing therapy. RESULTS: Three-year (3-y) overall survival (OS) and 3-y progression-free survival (PFS) in CK patients were shorter compared with non-CK (P = .001 for OS; P = .02 for PFS). TP53mut was a predictor of shorter survival compared with TP53 wild type (OS and PFS; P < .001). The incidence of TP53mut was not significantly associated with CK (P = .240). CK and TP53mut were predictors of inferior PFS and OS independent of age and Mantle-Cell Lymphoma International Prognostic Index, with hazard ratios of 2.35 (P = .024), 4.50 (P < .001) for PFS and 4.31 (P < .001), 5.46 (P < .001) for OS analysis in the CK and TP53mut groups, respectively. The combination of TP53mut and CK status stratified the patients into 3 prognostic groups (P < .001) with the worst outcome in patients with CK and TP53mut. CONCLUSION: TP53 mutation and CK occurred independently and patients harboring both had a dismal prognosis. The study suggests the importance of molecular cytogenetics and examination of the TP53mut status to be performed simultaneously before treatment.

The incidence of biopsy-proven transformation in follicular lymphoma in the rituximab era. A retrospective analysis from the Czech Lymphoma Study Group (CLSG) database.

The aim of this study is to assess the incidence, risk factors, and outcome of biopsy-proven transformation in follicular lymphoma (FL) patients in the rituximab era. Transformation was analyzed in 1233 patients with initially diagnosed FL grades 1-3A, identified between 2002 and 2012 in the prospectively maintained Czech Lymphoma Study Group database. Only patients with histologically proven transformation (HT) were included. HT occurred in 58 cases at a median of 3.0 years from the initial FL diagnosis; the HT rate was 4% at 5 years. Transformation occurred most frequently at the first relapse (84% patients). Median OS from the HT was 2.5 years (95% CI 0.4-4.6) and 6-year OS with HT was shorter compared to all FLs (60 vs. 83.9%; 95% CI). A bulky tumor (≥ 10 cm), increased lactate dehydrogenase, age ≥ 60 years, and International Prognostic Index (intermediate/high risk), but not Follicular Lymphoma International Prognostic Index, were associated with transformation (p < 0.05). In the first line, 70% of patients received rituximab (including 36% rituximab maintenance), 57% CHOP-like regimens, and 2.6% of patients were treated with fludarabine-based therapy, whereas 11% of patients were watched only. The patients treated with R-CHOP in the first line (n = 591) showed the transformation rate at 5 years of 4.23% (95% CI 2.52-5.93); subsequent rituximab maintenance (n = 276) vs. observation (n = 153) was associated with a lower transformation rate (p.033; HR 3.29; CI 1.10-9.82). The transformation rate seems to be lower than in previous series, which may be influenced by broad use of rituximab, but prognosis of HT developed during therapy continues to be poor.