Advances in the pathophysiology and treatment of relapsed/refractory Hodgkin's lymphoma with an emphasis on targeted therapies and transplantation strategies

Methodological framework for radiomics applications in Hodgkin's lymphoma

BACKGROUND

According to published data, radiomics features differ between lesions of refractory/relapsing HL patients from those of long-term responders. However, several methodological aspects have not been elucidated yet.

PURPOSE

The study aimed at setting up a methodological framework in radiomics applications in Hodgkin's lymphoma (HL), especially at (a) developing a novel feature selection approach, (b) evaluating radiomic intra-patient lesions' similarity, and (c) classifying relapsing refractory (R/R) vs non-(R/R) patients.

METHODS

We retrospectively included 85 patients (male:female = 52:33; median age 35 years, range 19-74). LIFEx (www.lifexsoft.org) was used for [18F]FDG-PET/CT segmentation and feature extraction. Features were a-priori selected if they were highly correlated or uncorrelated to the volume. Principal component analysis-transformed features were used to build the fingerprints that were tested to assess lesions' similarity, using the silhouette. For intra-patient similarity analysis, we used patients having multiple lesions only. To classify patients as non-R/R and R/R, the fingerprint considering one single lesion (fingerprint_One) and all lesions (fingerprint_All) was tested using Random Undersampling Boosting of Tree Ensemble (RUBTE).

RESULTS

HL fingerprints included up to 15 features. Intra-patient lesion similarity analysis resulted in mean/median silhouette values below 0.5 (low similarity especially in the non-R/R group). In the test set, the fingerprint_One classification accuracy was 62% (78% sensitivity and 53% specificity); the classification by RUBTE using fingerprint_All resulted in 82% accuracy (70% sensitivity and 88% specificity).

CONCLUSIONS

Lesion similarity analysis was developed, and it allowed to demonstrate that HL lesions were not homogeneous within patients in terms of radiomics signature. Therefore, a random target lesion selection should not be adopted for radiomics applications. Moreover, the classifier to predict R/R vs non-R/R performed the best when all the lesions were used.

Genomics-Guided Immunotherapy for Precision Medicine in Cancer

Next-generation sequencing (NGS) data have been central to the development of targeted therapy and immunotherapy for precision oncology. In targeted therapy, drugs directly attack cancer, by altering the expression of critical cancer genes identified with cancer genome profiling. Immunotherapy drugs indirectly attack cancer, by inducing the immune system to attack and treat cancer. Harnessing genomic data for deployment and development of immunotherapy comprises the field of immunogenomics. The discovery of a link between cancer cells escaping immune destruction and cancer progression, led to extensive research into this mechanism and drug development. In the past few years, FDA has granted accelerated approval to several immunotherapy cancer treatment drugs, pembrolizumab, nivolumab, and atezolizumab, belonging to the class of checkpoint inhibitors. Utilization of pretreatment genomic cancer screening to identify patients most likely to respond to immunotherapy and to customize immunotherapy for a given patient, promises to improve cancer treatment outcomes. Recent advances in molecular profiling, high-throughput sequencing, and computational efficiency has made immunogenomics the major tenet of precision medicine in cancer treatment. This review provides a brief overview on the state of art of immunogenomics in precision cancer medicine.

A role for surgery in the treatment of relapsed Hodgkin lymphoma

Treatment of Hodgkin lymphoma (HL) has advanced over time, rendering a fatal disease now largely curable. Multiagent chemotherapy regimens, hematopoietic stem cell transplantation, and radiotherapy are the mainstays of care. Surgical intervention is rarely indicated other than for biopsy at diagnosis. However, for patients with recurrent relapsed HL isolated to one anatomical location, refractory to all other therapy, there may be a beneficial role for surgical excision. Herein, we report the surgical management of three relapsed patients with stage IVB HL who were refractory to multiple other therapeutic approaches, who all achieved good event-free survival after operative management.

Transplant strategies in relapsed/refractory Hodgkin lymphoma

The majority of patients with Hodgkin lymphoma (HL) are cured with initial therapy. However, high-dose therapy with autologous hematopoietic cell transplant (AHCT) allows for the cure of an additional portion of patients with relapsed or primary refractory disease. Positron emission tomography-negative complete remission before AHCT is critical for long-term disease control. Several salvage options are available with comparable response rates, and the choice can be dependent of comorbidities and logistics. Radiation therapy can also improve the remission rate and is an important therapeutic option for selected patients. Brentuximab vedotin (BV) maintenance after AHCT is beneficial in patients at high risk for relapse, especially those with more than 1 risk factor, but can have the possibility of significant side effects, primarily neuropathy. Newer agents with novel mechanisms of action are under investigation to improve response rates for patients with subsequent relapse, although are not curative alone. BV and the checkpoint inhibitors nivolumab and pembrolizumab are very effective with limited side effects and can bridge patients to curative allogeneic transplants (allo-HCT). Consideration for immune-mediated toxicities, timing of allogeneic hematopoietic cell transplant based on response, and the potential for increased graft-versus-host disease remain important. Overall, prospective investigations continue to improve outcomes and minimize toxicity for relapsed or primary refractory HL patients.

Stop and go: hematopoietic cell transplantation in the era of chimeric antigen receptor T cells and checkpoint inhibitors

PURPOSE OF REVIEW

For several decades, hematopoietic cell transplantation (HCT) has been considered the standard curative therapy for many patients with hematological malignancies. In addition to the cytotoxic effects of the chemotherapy and radiation used in the conditioning regimen, the benefits of HCT are derived from a reset of the immune system and harnessing the ability of donor T cells to eliminate malignant cells. With the dawn of the era of immunotherapies in the form of checkpoint inhibitors and chimeric antigen receptor (CAR) T cells, the role of HCT has evolved.

RECENT FINDINGS

Immunotherapy with checkpoint inhibitors is increasingly being used for relapsed Hodgkin and non-Hodgkin lymphoma after autologous HCT. Checkpoint inhibitors are also being tested after allogeneic HCT with observable benefits in treating hematological malignancies, but with a potential risk of increased graft versus host disease and transplant-related mortality. Immunotherapy with Cluster of differentiation 19 CAR T cells are powerful options with aggressive B-cell malignancies both for therapy and as induction leading to allogeneic HCT.

SUMMARY

Although immunotherapies with checkpoint inhibition and CAR T cells are increasingly being used to treat hematological malignancies, HCT remains a standard of care for most of the diseases with the best chance of cure. Combination of these therapies with HCT has the potential to more effectively treat hematological malignancies.