BASELINE METABOLIC TUMOR VOLUME IS AN INDEPENDENT PROGNOSTIC FACTOR FOR RELAPSED AND REFRACTORY HODGKIN LYMPHOMA PATIENTS RECEIVING PET-ADAPTED SALVAGE THERAPY WITH BRENTUXIMAB VEDOTIN AND AUGMENTED ICE

Update on the role of brentuximab vedotin in classical Hodgkin lymphoma

Brentuximab vedotin (BV) is an effective and well-tolerated treatment for patients with classical Hodgkin lymphoma (HL). It was initially approved by the US FDA for the treatment of HL after failure of autologous hematopoietic stem cell transplant (autoHSCT) or after failure of at least two prior lines of multiagent chemotherapy in patients who are not transplant candidates, and then subsequently, as consolidation therapy after autoHSCT in patients who are at high risk for relapse. However, the role of BV in the treatment of HL is evolving. BV has shown promising efficacy as a salvage treatment in the second-line setting prior to autoHSCT. Most recently, the ECHELON-1 trial demonstrated that BV combined with AVD for the treatment of newly diagnosed advanced stage HL improved modified progression-free survival (mPFS) compared with standard ABVD. Based on these results, the US FDA has approved BV as part of the initial treatment of advanced stage HL. With the approval of BV as front-line therapy, depending on how widely the use of BV plus AVD is adopted, the role of BV in the treatment of patients with relapsed or refractory (rel/ref) HL may need to be redefined. BV retreatment can be effective, and studies of rational BV-based combination regimens may help to improve response rates and overcome BV resistance. Furthermore, BV has been demonstrated to be effective in the initial treatment of elderly or unfit patients, and ongoing studies are evaluating the addition of BV to initial chemotherapy in patients with early stage HL.

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.

Optimizing therapy in advanced-stage Hodgkin lymphoma

The treatment of Hodgkin lymphoma has evolved continuously since the introduction of extended-field radiotherapy in the 1960s to involved-field and then involved-node radiotherapy, multiagent chemotherapy, combined chemoradiotherapy, risk-adapted and response-adapted modulation, and, most recently, introduction of antibody-drug conjugates and immune checkpoint-blocking antibodies. These changes have translated into progressively increasing cure rates, so that 10-year survival figures now exceed 80%, compared with <50% 40 years ago. The challenge now is how to improve upon success while maintaining, or if possible improving, the quality of life for survivors. Steering between undertreatment, with the risk of avoidable recurrences, and overtreatment, with the risk of unnecessary toxicity, remains complex because control of the lymphoma and the probability of survival are no longer closely linked. This requires trials with long follow-up and continuous reappraisal of the interaction between the illness; the method used to define risk, and the type of treatment involved. One important factor in this is age: outcomes in older patients have not improved at the same rate as those in the population under 60 years of age, reflecting the need for different approaches. Recently, treatment has moved from being primarily risk-based, using baseline characteristics such as anatomical stage and severity of the illness, to a more dynamic approach that takes account of the response to therapy, using functional imaging to make an early appraisal, with the option to modulate subsequent treatment. The results of several trials indicate that this has advantages, but a combination of risk- and response-adaptation is probably ideal.