Symptoms, Health-Related Quality of Life, and Tolerability of Loncastuximab Tesirine in Patients with Relapsed or Refractory Diffuse Large B Cell Lymphoma

Introduction

In the ongoing single-arm, open-label phase 2 ADCT-402-201 study (LOTIS 2, NCT03589469), loncastuximab tesirine has shown substantial antitumor activity with a manageable toxicity profile in patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) who had failed ≥ 2 prior therapies, including activity in patients with high-risk disease characteristics. The overall response rate was 48.3% (based on positron emission tomography-computed tomography [PET-CT] assessed by independent review according to Lugano response criteria), and the median duration of response was 10.25 months. This analysis examined symptoms, health-related quality of life (HRQoL), and tolerability using validated patient-reported outcome instruments.

Methods

Enrolled patients aged ≥18 years received loncastuximab tesirine as an intravenous infusion on day 1 of each 3-week treatment cycle. Responders were defined as patients with a best overall response of complete or partial response. Patient-reported symptoms and HRQoL were measured using the Functional Assessment of Cancer Treatment-Lymphoma (FACT-Lym) and EQ-5D 5 Levels (EQ-5D-5L) instruments at baseline, day 1 of each cycle while patients were treated, and at the end-of-treatment visit. Descriptive statistics for change from baseline scores and percentages of patients with improved, stable, or worsened symptoms were summarized by visit and clinical response. Analysis was conducted using data collected from study initiation (1 August 2018) through 6 April 2020.

Results

The 145 patients enrolled in this study had a median age of 66 years (range, 23-94). Patients were heavily pretreated, with a median of 3 (range, 2-7) prior systemic therapies. A baseline patient-reported outcome score and at least one post-baseline score were available for 130 patients. Completion rates among patients treated at each visit were ≥ 92% for EQ-5D-5L and ≥ 88% for FACT-Lym up to cycle 9, day 1 (24 weeks). After cycle 9, fewer than 20 patients had patient-reported outcome scores available for analysis.

For symptoms assessed in the FACT-Lym lymphoma subscale, pain in certain parts of the body, lumps/swelling, trouble sleeping at night, and fatigue were the most frequently reported symptoms at baseline (34%-59% reported "somewhat" to "very much"). Most patients (≥ 80%) reported "not at all" or "a little bit" at baseline for fever, night sweats, losing weight, itching, and loss of appetite. During the course of treatment, higher percentages of patients reported improvement than worsening for pain and lumps/swelling for the majority of visits. Fever, night sweats, and losing weight did not change for most patients. Itching was the only symptom for which more patients experienced worsening than improvement. For other symptoms, similar percentages of patients reported improvement and worsening.

The mean change from baseline in EQ-5D Visual Analog Scale (VAS) score showed a trend of improvement in overall health over time (see figure). The mean VAS change reached the minimally important difference of 7 points at cycle 8, day 1. This improvement was associated with clinical response.

When patients were asked how much they were bothered by side effects of treatment, most patients (> 60%) reported "not at all" or "a little bit" for all visits throughout the treatment.

Conclusions

Results of this analysis suggest that patients who responded to treatment with loncastuximab tesirine generally had stable or improved symptoms and overall HRQoL. The treatment was well tolerated by patients. These findings further support the clinical use of loncastuximab tesirine for the treatment of relapsed or refractory DLBCL.

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