Stratification of treatment intensity in relapsed pediatric Hodgkin lymphoma

Pediatric and Adolescent Hodgkin Lymphoma: Paving the Way for Standards of Care and Shared Decision Making

Hodgkin lymphoma (HL) is a treatable cancer with an incidence peak in adolescent and young adult years. Treatment strategies have been developed to balance the intensity of therapy needed to maintain disease-free survival while simultaneously preserving overall survival. Risk-based, response-adapted frontline therapy has long used a combination of chemotherapy and radiotherapy (RT). Successive clinical trials over the past three decades have safely reduced cumulative alkylator, anthracycline, and RT exposures for many patients. The advent of checkpoint inhibitors and the CD30-targeted antibody drug conjugate, brentuximab vedotin, has provided new options for de-escalation of conventional therapies associated with late effects in survivors treated at a young age. The ability to evaluate novel agents has been accelerated in collaborative trials inclusive of children and adolescents within the US National Clinical Trials Network and between the Children's Oncology Group and the EuroNet Pediatric Hodgkin Lymphoma Consortium. With numerous treatment options, patients with HL and their clinicians have an opportunity for shared decision making from diagnosis, through cancer treatment, and into survivorship. Given excellent survival outcomes, decisions about treatment in classic HL should be collaborative and attention to long-term survivorship needs should remain a high priority. Patient-reported outcomes remain an important tool to aid clinicians working with survivors to optimize health status and related quality of life for decades after HL therapy.

Children's Oncology Group's 2023 blueprint for research: Hodgkin lymphoma

The goal of therapy in pediatric Hodgkin lymphoma (HL) is to maximize overall survival while minimizing the morbidity of curative therapy. Key findings from recent Children's Oncology Group (COG) trials include: (i) superior event-free survival with the addition of brentuximab vedotin (Bv) in frontline regimens for high-risk disease, (ii) successful reduction in myeloablative regimens with demonstrated safety and efficacy of Bv and checkpoint inhibitor therapy in relapsed disease, and (ii) the potential to select a population that can be salvaged after relapse without receiving a stem cell transplant. The COG HL committee will lead a National cancer Institute National Clinical Trials Network phase 3 trial to evaluate the combination of Bv/nivolumab in early-stage disease. Ongoing advances in technology and blood biomarkers are increasing the ability to deliver biologically driven, personalized treatment for HL.

Nivolumab plus Brentuximab vedotin +/- bendamustine combination therapy: a safe and effective treatment in pediatric recurrent and refractory classical Hodgkin lymphoma

Introduction

Classical Hodgkin lymphoma (cHL) is the most common pediatric lymphoma. Approximately 10% of patients develop refractory or recurrent disease. These patients are treated with intensive chemotherapy followed by consolidation with radiotherapy or high-dose chemotherapy and autologous stem cell reinfusion. Although this treatment is effective, it comes at the cost of severe long-term adverse events, such as reduced fertility and an increased risk of secondary cancers. Recently, promising results of inducing remission with the immune checkpoint inhibitor nivolumab (targeting PD-1) and the anti-CD30 antibody-drug conjugate Brentuximab vedotin (BV) +/- bendamustine were published.

Methods

Here we describe a cohort of 10 relapsed and refractory pediatric cHL patients treated with nivolumab + BV +/- bendamustine to induce remission prior to consolidation with standard treatment.

Results and discussion

All patients achieved complete remission prior to consolidation treatment and are in ongoing complete remission with a median follow-up of 25 months (range: 12 to 42 months) after end-of-treatment. Only one adverse event of CTCAE grade 3 or higher due to nivolumab + BV was identified. Based on these results we conclude that immunotherapy with nivolumab + BV +/- bendamustine is an effective and safe treatment to induce remission in pediatric R/R cHL patients prior to standard consolidation treatment. We propose to evaluate this treatment further to study putative long-term toxicity and the possibility to reduce the intensity of consolidation treatment.

Outcome and toxicity of ifosfamide, carboplatin, and etoposide versus gemcitabine and vinorelbine regimen for pediatric patients with relapsed or refractory Hodgkin's lymphoma

Background

Pediatric classical Hodgkin lymphoma (CHL) is a curable disease; however, the optimal salvage regimen is unclear for relapsed/refractory (R/R) disease. This study aimed to compare response rates, toxicity, event-free survival (EFS), and overall survival (OS) of ifosfamide, carboplatin, and etoposide (ICE) with gemcitabine and vinorelbine (GV) regimen after first-line doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) in pediatric patients with R/R CHL.

Methods

This is a retrospective cohort study of 132 pediatric patients with R/R CHL treated from July 2012 to December 2020 with ICE (n = 82) or GV (n = 50).

Results

The median age at relapse was 13.9 years, and 68.2% were men. Rates of complete response, partial response, and progressive disease before consolidation were 50.6%, 3.7%, and 45.7% for ICE and 28.5%, 0%, and 71.5% for GV (P = 0.011). By multivariate analysis, regimen (P = 0.002), time to relapse (P = 0.0001), and B-symptoms (P = 0.002) were independent factors to lower response rates. Hematological toxicity, electrolyte disturbance, hemorrhagic cystitis, infectious complications, and hospital admission for fever neutropenia were statistically significant higher for the ICE regimen. Treatment-related mortalities were 2.4% for ICE and 2% for GV (P = 0.86). The 3-year EFS was 39.3% ± 11.4% for ICE and 24.9% ± 12.5% for GV (P = 0.0001), while 3-year OS was 69.3% ± 10.6% and 74% ± 12.9% (P = 0.3), respectively. By multivariate analysis, regimen (P = 0.0001), time to relapse (P = 0.011), B-symptoms (P = 0.001), and leukocytosis (P = 0.007) were significant for EFS, while anemia (P = 0.008), and progressive disease on early response evaluation (P = 0.022) were significant for OS.

Conclusions

The ICE regimen had a better overall response rate and EFS, but higher toxicity, than GV; however, OS and mortality were similar.

Therapy results in pediatric Hodgkin lymphoma - does less mean better? Experience from a single children's oncology center

Therapy results in pediatric Hodgkin lymphoma reflect remarkable progress in pediatric oncology. In the last decade, relevant development of new therapeutic options for children with refractory or relapsed disease has been made. In this study, we retrospectively analyzed therapy results and risk factors in children treated in a single oncology center according to five therapeutic protocols. Data from 114 children treated by a single institution between 1997 and 2022 were analyzed. Classic Hodgkin lymphoma therapy results were divided into four therapeutic periods: 1997-2009, 2009-2014, 2014-2019, and 2019-2022. For nodular lymphocyte-predominant Hodgkin lymphoma, data from one therapeutic protocol was analyzed. For the entire group, the 5-year probability of overall survival was 93.5%. There were no statistically significant differences between therapeutic periods. The occurrence of B symptoms at diagnosis and incidence of relapse were risk factors for death (p = 0.018 and p < 0.001). Relapse occurred in 5 cases. The 5-year probability of relapse-free survival for the entire group was 95.2%, without significant differences between groups. Patients treated between 1997 and 2009 had over a sixfold higher risk for events, defined as primary progression, relapse, death, or incidence of secondary malignancies (OR = 6.25, p = 0.086). The 5-year probability of event-free survival for all patients was 91.3%. Five patients died, and the most common cause of death was relapse. Modern therapeutic protocols in pediatric Hodgkin lymphoma are marked by excellent outcomes. Patients with disease relapses have a notably high risk of death, and the development of new therapeutic options for this group remains one of the main goals of current trials.

Durable remission for four pediatric patients with high-risk relapsed classical Hodgkin lymphoma treated with brentuximab vedotin plus gemcitabine but without autologous stem cell transplantation: A report from the Children's Oncology Group

Patients with therapy-refractory or high-risk relapsed classical Hodgkin lymphoma are typically treated with the high-dose chemotherapy and autologous stem cell transplantation (HDC/ASCT) to consolidate the response to salvage therapy. The combination of brentuximab vedotin with gemcitabine has recently been shown to be an effective and safe salvage regimen. While the majority of patients with complete responses to this regimen ultimately underwent HDC/ASCT consolidation, four subjects, reported herein, achieved durable complete remissions lasting more than 4 years after the study treatment but without ASCT consolidation. Further investigation of treatment strategies incorporating targeted agents may allow omission of HDC/ASCT for select patients.

Advances in Hodgkin Lymphoma: Including the Patient's Voice

Since the initial treatment with radiation therapy in the 1950s, the treatment of Hodgkin lymphoma has continued to evolve, balancing cure and toxicity. This approach has resulted in low rates of relapse and death and fewer short and late toxicities from the treatments used in pursuit of cure. To achieve this balance, the field has continued to progress into an exciting era where the advent of more targeted therapies such as brentuximab vedotin, immunotherapies such as PD-1 inhibitors, and chimeric antigen receptor T-cells (CAR-T) targeted at CD30 are changing the landscape. As in the past, cooperative group and international collaborations are key to continuing to drive the science forward. Increased focus on patient-reported outcomes can further contribute to the goal of improved outcomes by examining the impact on the individual patient in the acute phase of therapy and on long-term implications for survivors. The goals of this review are to summarize recent and current clinical trials including reduction or elimination of radiation, immunotherapies and biologically-targeted agents, and discuss the use of patient-reported outcomes to help discern directions for new therapeutic regimens and more individualized evaluation of the balance of cure and toxicity.

Rituximab as adjunctive therapy to BEAM conditioning for autologous stem cell transplantation in Hodgkin lymphoma

While high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) leads to improved disease-free survival (DFS) for children and adults with relapsed/refractory Hodgkin lymphoma (HL), relapse remains the most frequent cause of mortality post-transplant. Rituximab has been successfully incorporated into regimens for other B-cell lymphomas, yet there have been limited studies of rituximab in HL patients. We hypothesized that adding rituximab to BEAM (carmustine, etoposide, cytarabine, melphalan) conditioning would reduce relapse risk in HL patients post-transplant. Here, we retrospectively review the outcomes of patients with relapsed/refractory HL who received rituximab in addition to BEAM. The primary outcome was DFS. Our cohort included 96 patients with a median age of 28 years (range, 6-76). Majority of patients (57%) were diagnosed with advanced (Stage III-IV) disease, and 62% were PET negative pre-transplant. DFS was 91.5% at 1 year [95% CI 86-98%], and 78% at 3 years [95% CI 68-88%]. NRM was 0% and 3.5% at 1-year [95% CI 0-3%] and 3-years [95% CI 0-8.5%], respectively. 25% of patients developed delayed neutropenia, with 7% requiring infection-related hospitalizations, and one death. We have demonstrated excellent outcomes for patients receiving rituximab with BEAM conditioning for relapsed/refractory HL. Future comparative studies are needed to better determine whether rituximab augments outcomes post-transplant.

Combination Brentuximab Vedotin and Bendamustine for Pediatric Patients with Relapsed/Refractory Hodgkin Lymphoma

BVB was an effective and tolerable retrieval regimen for pediatric patients with R/R HL and resulted in minimal toxicity.

Stem cell mobilization and collection was successful in patients before autologous stem cell transplant.

In patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL), achieving a complete metabolic response (CMR) after salvage therapy is associated with superior outcomes, and optimal treatments must be identified. The combination of brentuximab vedotin and bendamustine (BVB), although highly active in adult patients, has not been extensively evaluated in pediatric patients with R/R HL. We performed a multicenter, retrospective review of pediatric patients <21 years of age with R/R HL treated with BVB from January 2016 through July 2019. Response was assessed by local radiologists according to Lugano classification criteria. Twenty-nine patients (17 relapsed, 12 refractory) with a median age of 16 years (range, 10-20) were treated with BVB and received a median of 3 cycles of therapy (range, 2-7). Patients received an infusion of 1.8 mg/kg of BV on day 1 with bendamustine 90 mg/m² on days 1 and 2 of 3-week cycles. Nineteen patients (66%) achieved a CMR (95% CI, 46-82). An objective response was observed in 23 patients (objective response rate, 79%; 95% CI, 60-92). The most common grade 3 and 4 toxicities were hematologic, and 3 patients (10%) experienced grade 3 infusion reactions. Seventeen of 18 patients underwent successful mobilization and collection of stem cells. Sixteen patients (13 autologous, 3 allogeneic) received a consolidative transplant after BVB. The 3-year post-BVB event-free and overall survival were 65% (95% CI, 46-85) and 89% (95% CI, 74-100), respectively. For pediatric patients with R/R HL, BVB was well tolerated and compared favorably with currently accepted salvage regimens.

Recent progress in the treatment of cancer in children

Although significant improvements have been made in the outcomes of children with cancer, the pace of improvement has slowed in recent years as the limits of therapy intensification may have been reached for many pediatric cancers. Furthermore, with increasing numbers of pediatric cancer survivors, the long-term side effects of treatment have become increasingly apparent. Therefore, attention has shifted to the use of molecularly targeted agents and immunotherapies to improve the outcomes of children who are not cured by traditional cytotoxic chemotherapies and to decrease exposure to cytotoxic chemotherapy and reduce late effects. This review describes the recent progress in the treatment of children with cancer, focusing in particular on diseases in which targeted and immunotherapeutic agents have made an impact.

Autologous hematopoietic cell transplantation for the treatment of relapsed/refractory pediatric, adolescent, and young adult Hodgkin lymphoma: a single institutional experience

Pediatric, adolescent, and young adult patients with relapsed or refractory Hodgkin lymphoma receive multimodal therapy, including autologous hematopoietic cell transplantation (AutoHCT). Despite aggressive therapy, historical outcomes for this patient population have been poor. This paper describes a single institutional experience utilizing AutoHCT in 74 patients treated from 1988-2015. Our results demonstrate significantly improved outcomes over time. Compared with patients treated in the earlier era (1988-2001), 5-year overall survival improved from 62.5 ± 9.6% to 91.8 ± 4.4% (p < 0.001) and event free survival improved from 41.7 ± 9.6% to 87.7 ± 5.3% (I < 0.001) for patients treated in a later era (2002-2015). Improvements in survival are multifactorial, including reductions in both relapse and nonrelapse mortality. Further investigation is needed to determine the role of AutoHCT in a modern treatment cohort that includes frequent use of targeted immunotherapies. In addition, as the use and availability of effective novel therapeutics increases for this patient population there may be an opportunity for the reduction of standard cytotoxic therapies, including in AutoHCT preparative regimens, thereby mitigating late effects.

Risk and Response Adapted Treatment Guidelines for Managing First Relapsed and Refractory Classical Hodgkin Lymphoma in Children and Young People. Recommendations from the EuroNet Pediatric Hodgkin Lymphoma Group

The objective of this guideline is to aid clinicians in making individual salvage treatment plans for pediatric and adolescent patients with first relapse or refractory (R/R) classical Hodgkin lymphoma (cHL). While salvage with standard dose chemotherapy followed by high dose chemotherapy and autologous stem cell transplant is often considered the standard of care in adult practice, pediatric practice adopts a more individualized risk stratified and response adapted approach to salvage treatment with greater use of non-transplant salvage. Here, we present on behalf of the EuroNet Pediatric Hodgkin Lymphoma group, evidence and consensus-based guidelines for standardized diagnostic, prognostic and response procedures to allocate children and adolescents with R/R cHL to stratified salvage treatments.

Closing the survivorship gap in children and adolescents with Hodgkin lymphoma

The treatment of Hodgkin lymphoma (HL) is one of early success. However, disease-free survival (DFS) does not reflect latent organ injury and its impact on health status and well-being beyond 5 years. In fact, we are at a crossroads, in terms of needing individualized approaches to maintain DFS, while minimizing late effects and preserving health-related quality of life (HRQoL). Premature morbidity and mortality translate to a high societal cost associated with the potential number of productive life years ahead in this population who are young at diagnosis. The discordance between short-term lymphoma-free survival and long-term health and HRQoL creates a "survivorship gap" which can be characterized for individuals and for subgroups of patients. The current review delineates contributors to compromised outcomes and health status in child and adolescent (paediatric) HL and frames the survivorship gap in terms of primary and secondary prevention. Primary prevention aims to titrate therapy. Secondary prevention entails strategies to intervene against late effects. Bridging the survivorship gap will be attained with enhanced knowledge of and attention to biology of the tumour and microenvironment, host genetic factors, HRQoL and sub-populations with disparate outcomes.

Response-adapted therapy for the treatment of children with newly diagnosed high risk Hodgkin lymphoma (AHOD0831): a report from the Children's Oncology Group

The AHOD0831 study for paediatric patients with high risk Hodgkin lymphoma tested a response-based approach designed to limit cumulative alkylator exposure and reduce radiation volumes. Patients (Stage IIIB/IVB) received two cycles of ABVE-PC (doxorubicin, bleomycin, vincristine, etoposide, prednisone, cyclophosphamide). Rapid early responders [RER, no positron emission tomography (PET) activity above mediastinal blood pool] were consolidated with 2 cycles of ABVE-PC. Slow early responders (SER) received 2 cycles of ifosfamide/vinorelbine and 2 cycles of ABVE-PC. Radiotherapy was administered to sites of initial bulk and/or SER. By intent-to-treat analysis, 4-year second event-free survival (EFS; freedom from second relapse or malignancy) was 91·9% [95% confidence interval (CI): 86·1-95·3%], below the projected baseline of 95% (P = 0·038). Five-year first EFS and overall survival (OS) rates are 79·1% (95% CI: 71·5-84·8%) and 95% (95% CI: 88·8-97·8%). Eight of 11 SER patients with persistent PET positive lesions at the end of chemotherapy had clinical evidence of active disease (3 biopsy-proven, 5 with progressive disease or later relapses). Although this response-directed approach did not reach the ambitiously high pre-specified target for second EFS, EFS and OS rates are comparable with results of recent trials despite the reduction in radiotherapy volumes from historical involved fields. Persistent PET at end of chemotherapy identifies a cohort at an especially high risk for relapse/early progression.

Treatment patterns and disease outcomes for pediatric patients with refractory or recurrent Hodgkin lymphoma treated with curative-intent salvage radiotherapy

BACKGROUND AND PURPOSE

The use of radiotherapy (RT) for pediatric patients with Hodgkin lymphoma (HL) experiencing disease progression or recurrence (15%) is controversial. We report treatment patterns and outcomes for pediatric patients with refractory/recurrent HL (rrHL) treated with curative-intent RT.

MATERIALS AND METHODS

Forty-six patients with rrHL treated with salvage RT at our institution were identified. All received risk-adapted, response-based frontline therapy and were retrieved with cytoreductive regimens followed by RT to failure sites, with or without autologous hematopoietic cell transplantation (AHCT). Cumulative incidence (CIN) of local failure (LF) and survival were estimated after salvage RT and regression models determined predictors of LF after salvage RT.

RESULTS

RT was administered as part of frontline therapy in 70% of patients, omitted for early response assessment in 13%, or deferred for primary progression in 17%. AHCT was omitted in 20% of patients. Median initial and salvage dose/site were 25.5 Gy and 30.6 Gy, respectively. Eight patients experienced progression. Two died without progression (median follow-up from salvage RT = 3.8 years). The 5-year CIN of LF after salvage RT was 17.7% (95% confidence interval [CI], 8.2-30.2%). The 5-year freedom from subsequent treatment failure and overall survival (OS) was 80.1% (95% CI, 69.2-92.6%) and 88.5% (95% CI, 79.5-98.6%), respectively. Inadequate response to salvage systemic therapy (p = 0.048) and male sex (p = 0.049) were significantly associated with LF after salvage RT.

CONCLUSION

rrHL is responsive to salvage RT, with low LF rates after moderate doses. OS is excellent, despite refractory disease. Initial salvage therapy response predicts subsequent LF.

Brentuximab vedotin with gemcitabine for paediatric and young adult patients with relapsed or refractory Hodgkin's lymphoma (AHOD1221): a Children's Oncology Group, multicentre single-arm, phase 1-2 trial

BACKGROUND

Patients with primary refractory Hodgkin's lymphoma or early relapse have a poor prognosis. Although many salvage regimens have been developed, there is no standard of care. Brentuximab vedotin and gemcitabine have been shown to be active in patients with relapsed or refractory Hodgkin's lymphoma when used as monotherapy, and each has been successfully used in combination with other agents. Preclinical data suggest that brentuximab vedotin can sensitise lymphoma cells to gemcitabine, supporting the use of the combination. We aimed to define the safety and efficacy of brentuximab vedotin with gemcitabine in children and young adults with primary refractory Hodgkin's lymphoma or early relapse.

METHODS

In this Children's Oncology Group, multicentre, single-arm, phase 1-2 trial, we recruited patients with Hodgkin's lymphoma from hospitals across the USA and Canada. Eligible patients were aged younger than 30 years, had no previous brentuximab vedotin exposure, and had primary refractory disease or relapse of less than 1 year from completion of initial treatment. Each 21-day cycle consisted of 1000 mg/m2 intravenous gemcitabine on days 1 and 8 and intravenous brentuximab vedotin on day 1 at 1·4 mg/kg or 1·8 mg/kg. The primary objectives were to establish the recommended phase 2 dose of brentuximab vedotin in this combination, the safety of the combination, and the proportion of patients who achieved a complete response among those treated at the recommended phase 2 level, within four cycles of treatment. This trial is registered with ClinicalTrials.gov, number NCT01780662.

FINDINGS

Between Feb 5, 2013, and Aug 19, 2016, 46 patients were enrolled, including one who was found to be ineligible, in the two phases of the study. The recommended phase 2 dose of brentuximab vedotin was 1·8 mg/kg in combination with gemcitabine 1000 mg/m2. 24 (57%) of 42 evaluable patients (95% CI 41-72) given this dose level had a complete response within the first four cycles of treatment. Four (31%) of 13 patients with a partial response or stable disease had all target lesions with Deauville scores of 3 or less after cycle 4. By modern response criteria, these were also complete responses (total number with complete response 28 [67%] of 42 [95% CI 51-80]). The most common grade 3-4 adverse events in all 42 participants treated at the recommended phase 2 dose were neutropenia (15 [36%]), rash (15 [36%]), transaminitis (9 [21%]), and pruritus (4 [10%]). There were no treatment-related deaths.

INTERPRETATION

Brentuximab vedotin with gemcitabine is a safe combination treatment with a tolerable toxicity profile for patients with primary refractory Hodgkin's lymphoma or high-risk relapse. The preliminary activity of this combination shown in this trial warrants further investigation in randomised controlled trials.

FUNDING

National Institutes of Health and the St. Baldrick's Foundation.

Results of the AHOD0431 trial of response adapted therapy and a salvage strategy for limited stage, classical Hodgkin lymphoma: A report from the Children's Oncology Group

BACKGROUND

The Children's Oncology Group AHOD0431 study evaluated a response-directed treatment paradigm in which minimal initial chemotherapy and low-dose radiation was received only by patients who did not achieve a complete remission, and a chemotherapy/low-dose radiation salvage regimen was received by those who had a protocol-defined, low-risk recurrence.

METHODS

Patients younger than 21 years who had stage IA or IIA nonbulky disease were eligible. The treatment strategy was evaluated by determining the proportion that received minimal chemotherapy alone, the proportion that had a first or second remission without the receipt of high-dose chemotherapy/stem cell rescue or higher dose involved-field radiation therapy (>21 grays), and overall survival.

RESULTS

In total, 278 patients were eligible. At 4 years, 49.0% had received minimal chemotherapy and no radiation, 88.8% were in remission without receiving high-dose chemotherapy with stem cell rescue or >21 grays of involved-field radiation therapy, and the overall survival rate was 99.6%. Patients who had mixed cellularity histology had a 4-year event-free survival (EFS) rate of 95.2%, which was significantly better than the 75.8% EFS for those who had nodular sclerosis histology (P = .008). A red blood cell sedimentation rate ≤20 mm/hour and a negative fluorodeoxyglucose-positron emission tomography scan after 1 cycle of chemotherapy (PET1) were associated with a favorable EFS outcome. The study was closed early when the receipt of radiation therapy exceeded the predefined monitoring boundary.

CONCLUSIONS

This limited chemotherapy response-based approach was successful in patients who had a negative PET1 result, had MC histology, or had a low red blood cell sedimentation rate. In this treatment paradigm, evaluation of increased chemotherapy intensity or the integration of active new agents is indicated for patients who have nodular sclerosis histology with a high ESR or who have a positive PET1 result. Cancer 2018. © 2018 American Cancer Society.

Targeting Hodgkin and Reed-Sternberg Cells with an Inhibitor of Heat-Shock Protein 90: Molecular Pathways of Response and Potential Mechanisms of Resistance

Classical Hodgkin lymphoma (cHL) cells overexpress heat-shock protein 90 (HSP90), an important intracellular signaling hub regulating cell survival, which is emerging as a promising therapeutic target. Here, we report the antitumor effect of celastrol, an anti-inflammatory compound and a recognized HSP90 inhibitor, in Hodgkin and Reed–Sternberg cell lines. Two disparate responses were recorded. In KM-H2 cells, celastrol inhibited cell proliferation, induced G0/G1 arrest, and triggered apoptosis through the activation of caspase-3/7. Conversely, L428 cells exhibited resistance to the compound. A proteomic screening identified a total of 262 differentially expressed proteins in sensitive KM-H2 cells and revealed that celastrol’s toxicity involved the suppression of the MAPK/ERK (extracellular signal regulated kinase/mitogen activated protein kinase) pathway. The apoptotic effects were preceded by a decrease in RAS (proto-oncogene protein Ras), p-ERK1/2 (phospho-extracellular signal-regulated Kinase-1/2), and c-Fos (proto-oncogene protein c-Fos) protein levels, as validated by immunoblot analysis. The L428 resistant cells exhibited a marked induction of HSP27 mRNA and protein after celastrol treatment. Our results provide the first evidence that celastrol has antitumor effects in cHL cells through the suppression of the MAPK/ERK pathway. Resistance to celastrol has rarely been described, and our results suggest that in cHL it may be mediated by the upregulation of HSP27. The antitumor properties of celastrol against cHL and whether the disparate responses observed in vitro have clinical correlates deserve further research.

Pharmacotherapeutic Management of Pediatric Lymphoma

Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) comprise approximately 15% of all childhood malignancies. Cure rates for both lymphoma entities have evolved tremendously during the last couple of decades, raising the 5-year survival rates to almost 100% for HL and to 85% for NHL. The mainstay therapy for both malignancies is still chemotherapy-with different regimens recommended for different types of disease. In HL, combined modality treatment, i.e., chemotherapy followed by radiotherapy, has long been the standard regimen. In order to reduce long-term side effects, such as second malignancies, most major pediatric HL consortia have studied response-based radiotherapy reduction strategies over the last 3 decades. For recurrent disease, high-dose chemotherapy followed by an autologous or an allogeneic hematopoietic stem-cell transplant is an option. No targeted agents have yet gained regulatory approval for use in pediatric patients with lymphoma. For adult lymphoma patients, the CD20 antibody rituximab and the CD30 antibody-drug conjugate brentuximab vedotin are targeted agents used regularly in first- and second-line treatment regimens. More recently, immune checkpoint inhibitors, phosphatidyl-inositol-3-kinase inhibitors, and Bruton's tyrosine kinase inhibitors appear to be very promising new treatment options in adult lymphoma. Here, we discuss the current experience with these types of agents in pediatric lymphoma patients.

Outcome of children and adolescents with relapsed Hodgkin lymphoma treated with high-dose therapy and autologous stem cell transplantation: the Memorial Sloan Kettering Cancer Center experience

To evaluate outcomes and prognostic markers among children with relapsed Hodgkin lymphoma (HL) treated with autologous stem cell transplant (ASCT), we conducted a retrospective analysis of 36 consecutive pediatric patients treated at Memorial Sloan Kettering Cancer Center from 1989 to 2013. With a median follow-up of 9.6 years, the 10-year overall survival (OS) and event-free survival (EFS) were 74.1 and 67.1% respectively. Absence of B-symptoms, chemotherapy-sensitive disease, and transplant date after 1997 were each associated with superior EFS [HR 0.12 (p = .0015), 0.18 (p = .0039), and 0.17 (p = .0208), respectively]. Childhood Hodgkin International Prognostic Score at relapse (R-CHIPS) was calculated in a subset of patients (n = 22) and a lower score was associated with improved OS (HR 0.29, p = .0352) and a trend toward improved EFS (HR 0.38, p = .0527). In summary, ASCT results in durable remission for the majority of pediatric patients with relapsed HL. R-CHIPS should be evaluated in larger cohorts as a potential predictive tool.

Hodgkin lymphoma in children and adolescents: improving the therapeutic index

Hodgkin lymphoma (HL) is a highly curable form of childhood cancer, with estimated 5 year survival rates exceeding 98%. However, the establishment of a “standard of care” approach to its management is complicated by the recognition that long-term overall survival declines in part from delayed effects of therapy and that there continue to be subgroups of patients at risk for relapse for which prognostic criteria cannot adequately define. This challenge has resulted in the development of various strategies aimed at identifying the optimal balance between maintaining overall survival and avoidance of long-term morbidity of therapy, often representing strategies quite different from those used for adults with HL. More precise risk stratification and methods for assessing the chemosensitivity of HL through imaging studies and biomarkers are in evolution. Recent advances in the understanding of the biology of HL have led to the introduction of targeted therapies in both the frontline and relapsed settings. However, significant barriers exist in the development of new combination therapies, necessitating collaborative studies across pediatric HL research consortia and in conjunction with adult groups for the adolescent and young adult (AYA) population with HL.

Hodgkin lymphoma in children and adolescents: improving the therapeutic index

Hodgkin lymphoma (HL) is a highly curable form of childhood cancer, with estimated 5 year survival rates exceeding 98%. However, the establishment of a “standard of care” approach to its management is complicated by the recognition that long-term overall survival declines in part from delayed effects of therapy and that there continue to be subgroups of patients at risk for relapse for which prognostic criteria cannot adequately define. This challenge has resulted in the development of various strategies aimed at identifying the optimal balance between maintaining overall survival and avoidance of long-term morbidity of therapy, often representing strategies quite different from those used for adults with HL. More precise risk stratification and methods for assessing the chemosensitivity of HL through imaging studies and biomarkers are in evolution. Recent advances in the understanding of the biology of HL have led to the introduction of targeted therapies in both the frontline and relapsed settings. However, significant barriers exist in the development of new combination therapies, necessitating collaborative studies across pediatric HL research consortia and in conjunction with adult groups for the adolescent and young adult (AYA) population with HL.

A prognostic model predicting autologous transplantation outcomes in children, adolescents and young adults with Hodgkin lymphoma

Autologous hematopoietic cell transplantation (AutoHCT) is a potentially curative treatment modality for relapsed/refractory Hodgkin lymphoma (HL). However, no large studies have evaluated pre-transplant factors predictive of outcomes of AutoHCT in children, adolescents and young adults (CAYA, age <30 years). In a retrospective study, we analyzed 606 CAYA patients (median age 23 years) with relapsed/refractory HL who underwent AutoHCT between 1995–2010. The probabilities of progression free survival (PFS) at 1, 5 and 10 years were 66% (95% CI: 62–70), 52% (95% CI: 48–57) and 47% (95% CI: 42–51), respectively. Multivariate analysis for PFS demonstrated that at the time of AutoHCT patients with Karnofsky/Lansky score ≥90, no extranodal involvement and chemosensitive disease had significantly improved PFS. Patients with time from diagnosis to first relapse of <1 year had a significantly inferior PFS. A prognostic model for PFS was developed that stratified patients into low, intermediate and high-risk groups, predicting for 5-year PFS probabilities of 72% (95% CI: 64–80), 53% (95% CI: 47–59) and 23% (95% CI: 9–36), respectively. This large study identifies a group of CAYA patients with relapsed/refractory HL who are at high risk for progression after AutoHCT. Such patients should be targeted for novel therapeutic and/or maintenance approaches post-AutoHCT.

Current approaches in the management of low risk Hodgkin lymphoma in children and adolescents

The outcome for children and adolescents with low risk Hodgkin lymphoma (HL) is excellent, with event-free survival >85% and overall survival >95%. Historically, however, treatment has come at the cost of significant long-term toxicity from chemotherapy, radiation or a combination of these. Recent treatment strategies have focused on maintaining high event-free and overall survival while minimizing the use of therapy associated with late effects. The strategies used to achieve this vary greatly among paediatric cooperative groups and there is no one standard treatment for children with low risk HL. This review summaries recent clinical trials in paediatric low risk HL and addresses some of the important considerations when comparing trials, including differences in the definition of low risk HL, differences in outcome among histological subtypes and varying approaches to reduce or eliminate radiation therapy. Recommendations are provided for the treatment of children with low risk HL outside the setting of a clinical trial.

Role of cytotoxic therapy with hematopoietic cell transplantation in the treatment of Hodgkin lymphoma: guidelines from the American Society for Blood and Marrow Transplantation

The role of hematopoietic cell transplantation (HCT) in the therapy of Hodgkin lymphoma (HL) in pediatric and adult patients is reviewed and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are included and were reached unanimously by a panel of HL experts. Both autologous and allogeneic HCT offer a survival benefit in selected patients with advanced or relapsed HL and are currently part of standard clinical care. Relapse remains a significant cause of failure after both transplant approaches, and strategies to decrease the risk of relapse remain an important area of investigation.

Pediatric lymphomas and histiocytic disorders of childhood

Although there have been dramatic improvements in the treatment of children with non-hodgkin lymphoma, hodgkin lymphoma and histiocytic disorders over the past 3 decades, many still relapse or are refractory to primary therapy. In addition, late effects such as 2nd malignancies, cardiomyopathy and infertility remain a major concern. Thus, this review focuses on the current state of the science and, in particular, novel treatment strategies that are aimed at improving outcomes for all pediatric patients with lymphoma and histiocytic disorders while reducing treatment related morbidity.

Hodgkin lymphoma in children and adolescents: improving the therapeutic index

Hodgkin lymphoma (HL) is a highly curable form of childhood cancer, with estimated 5 year survival rates exceeding 98%. However, the establishment of a "standard of care" approach to its management is complicated by the recognition that long-term overall survival declines in part from delayed effects of therapy and that there continue to be subgroups of patients at risk for relapse for which prognostic criteria cannot adequately define. This challenge has resulted in the development of various strategies aimed at identifying the optimal balance between maintaining overall survival and avoidance of long-term morbidity of therapy, often representing strategies quite different from those used for adults with HL. More precise risk stratification and methods for assessing the chemosensitivity of HL through imaging studies and biomarkers are in evolution. Recent advances in the understanding of the biology of HL have led to the introduction of targeted therapies in both the frontline and relapsed settings. However, significant barriers exist in the development of new combination therapies, necessitating collaborative studies across pediatric HL research consortia and in conjunction with adult groups for the adolescent and young adult (AYA) population with HL.

Outcome of pediatric patients with lymphoma following stem cell transplant: a single institution report

Hematopoietic stem cell transplant (HSCT) is recommended for pediatric patients with relapsed/refractory lymphoma even though the evidence for this is limited. We retrospectively reviewed records of 57 patients (29 Hodgkin lymphoma [HL], 28 non-Hodgkin lymphoma [NHL]) who underwent HSCT between 1995 and 2012. All demonstrated chemoresponsiveness prior to HSCT and 44 patients had a complete response. All underwent myeloablative conditioning, 38 chemotherapy-based and 19 total body irradiation-based. Forty-one patients received autologous and 16 allogeneic HSCT. Twelve (21%) died within 100 days post-HSCT, and 25 patients relapsed at a median of 1.6 months post-HSCT. Three patients developed second malignant neoplasms. Five-year overall survival (OS) was 50.5% and event-free survival (EFS) was 43.4%. Outcomes for HL were significantly better than those for NHL (OS 61.9% vs. 38.7% [p = 0.005] and EFS 60.4% vs. 26% [p = 0.008]). In summary, approximately half of all pediatric patients with lymphoma who failed first-line therapy and demonstrated chemosensitivity to second-line therapy can be salvaged with HSCT.