Lisocabtagene Maraleucel in Relapsed/Refractory Mantle Cell Lymphoma: Primary Analysis of the Mantle Cell Lymphoma Cohort From TRANSCEND NHL 001, a Phase I Multicenter Seamless Design Study

PURPOSE

To report the primary analysis results from the mantle cell lymphoma (MCL) cohort of the phase I seamless design TRANSCEND NHL 001 (ClinicalTrials.gov identifier: NCT02631044) study.

METHODS

Patients with relapsed/refractory (R/R) MCL after ≥two lines of previous therapy, including a Bruton tyrosine kinase inhibitor (BTKi), an alkylating agent, and a CD20-targeted agent, received lisocabtagene maraleucel (liso-cel) at a target dose level (DL) of 50 × 106 (DL1) or 100 × 106 (DL2) chimeric antigen receptor-positive T cells. Primary end points were adverse events (AEs), dose-limiting toxicities, and objective response rate (ORR) by independent review committee per Lugano criteria.

RESULTS

Of 104 leukapheresed patients, liso-cel was infused into 88. Median (range) number of previous lines of therapy was three (1-11) with 30% receiving ≥five previous lines of therapy, 73% of patients were age 65 years and older, 69% had refractory disease, 53% had BTKi refractory disease, 23% had TP53 mutation, and 8% had secondary CNS lymphoma. Median (range) on-study follow-up was 16.1 months (0.4-60.5). In the efficacy set (n = 83; DL1 + DL2), ORR was 83.1% (95% CI, 73.3 to 90.5) and complete response (CR) rate was 72.3% (95% CI, 61.4 to 81.6). Median duration of response was 15.7 months (95% CI, 6.2 to 24.0) and progression-free survival was 15.3 months (95% CI, 6.6 to 24.9). Most common grade ≥3 treatment-emergent AEs were neutropenia (56%), anemia (37.5%), and thrombocytopenia (25%). Cytokine release syndrome (CRS) was reported in 61% of patients (grade 3/4, 1%; grade 5, 0), neurologic events (NEs) in 31% (grade 3/4, 9%; grade 5, 0), grade ≥3 infections in 15%, and prolonged cytopenia in 40%.

CONCLUSION

Liso-cel demonstrated high CR rate and deep, durable responses with low incidence of grade ≥3 CRS, NE, and infections in patients with heavily pretreated R/R MCL, including those with high-risk, aggressive disease.

Health-related quality of life in patients with triple-class exposed relapsed and refractory multiple myeloma treated with idecabtagene vicleucel or standard regimens: patient-reported outcomes from the phase 3, randomised, open-label KarMMa-3 clinical trial

BACKGROUND

Chimeric antigen receptor T-cell therapy idecabtagene vicleucel (ide-cel) showed significantly improved progression-free survival compared with standard regimens in adults with relapsed and refractory multiple myeloma who had received two to four previous regimens in the ongoing phase 3 KarMMa-3 trial (NCT03651128). This study analysed patient-reported outcomes (PROs), a KarMMa-3 secondary endpoint.

METHODS

In the randomised, open-label, phase 3 KarMMa-3 trial, 386 patients in hospitals (≥18 years of age, with measurable disease and an Eastern Cooperative Oncology Group performance status score of 0 or 1, who had received two to four previous regimens-including an immunomodulatory agent, a proteasome inhibitor, and daratumumab-and had documented disease progression after receiving their last dose of the last therapy) were randomly assigned to ide-cel (n=254) or standard regimens (daratumumab, pomalidomide, and dexamethasone; daratumumab, bortezomib, and dexamethasone; ixazomib, lenalidomide, and dexamethasone; carfilzomib and dexamethasone; or elotuzumab, pomalidomide, and dexamethasone; n=132). Patients were expected to complete the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life C30 Questionnaire (QLQ-C30), Multiple Myeloma Module (QLQ-MY20), EQ 5 dimensions (EQ-5D), and EQ-5D visual analogue scale (VAS) at baseline and follow-up timepoints (data cutoff April 18, 2022). PROs included nine prespecified primary domains: EORTC QLQ-C30 GHS-quality of life (QoL), physical functioning, cognitive functioning, fatigue, and pain; QLQ-MY20 disease symptoms and side effects of treatment; and five-level EQ-5D (EQ-5D-5L) index score and EQ-5D visual VAS. Differences in overall least-squares mean changes from baseline to month 20 were analysed using post-hoc constrained longitudinal data analysis. Time to confirmed improvement or deterioration from baseline was analysed using Cox proportional hazard models.

FINDINGS

Patients were randomly assigned between May 6, 2019, and April 8, 2022. Overall, the median age was 63 years (IQR 55-68); 151 (39%) patients were female; and 250 (65%) patients were White, 36 (9%) Black or African American, 19 (5%) Hispanic or Latino, 12 (3%) Asian, and seven (2%) of other race. The median follow-up was 18·6 months (IQR 14·0-26·4). PRO compliance was higher than 75% throughout. Overall least-squares mean changes from baseline favoured ide-cel with Hedges' g effect sizes from 0·3 to 0·7 for most domains. Patients in the ide-cel group showed statistically significant and clinically meaningful improvements across the primary PRO domains of interest, with the exception of QLQ-MY20 disease symptoms, side effects of treatment, and EQ-5D-5L index score, which showed improvement across assessment visits but did not exceed the within-group minimally important difference thresholds. The ide-cel group had shorter times to clinically meaningful improvement than the standard regimens group in QLQ-C30 domains except in role functioning, diarrhoea, and financial difficulties; in QLQ-MY20 domains except body image; and in EQ-5D-VAS.

INTERPRETATION

Ide-cel offers improved health-related quality of life compared with standard regimens for patients with relapsed and refractory multiple myeloma after previous lines of therapy. The PRO data highlight the extended QoL benefits of a one-time infusion with ide-cel compared with continuous treatment with standard regimens in the treatment of triple-class exposed patients with relapsed and refractory multiple myeloma.

FUNDING

2seventy bio and Celgene, a Bristol Myers Squibb Company.

Patient-Reported Outcomes With Belantamab Mafodotin Treatment in Patients With Triple-Class Refractory Multiple Myeloma

In the randomized phase II DREAMM-2 study, single-agent belantamab mafodotin demonstrated deep and durable responses and a manageable safety profile in triple-class refractory relapsed/refractory multiple myeloma (RRMM). We present patient-reported outcomes (PROs) from this study for patients treated with the approved dose of belantamab mafodotin (2.5 mg/kg q3w). Disease and treatment-related symptoms, health-related quality of life (HRQOL), functioning, and patient-reported ocular changes were assessed using questionnaires (European Organisation for Research and Treatment of Cancer Quality of Life questionnaires EORTC-QLQ-C30 and EORTC-QLQ-MY20, Ocular Surface Disease Index [OSDI], and the National Eye Institute Visual Functioning Questionnaire 25 [NEI VFQ-25]) at baseline, during treatment (every 3 or 6 weeks), and at the end of treatment (EOT). Eye examinations were conducted at baseline, prior to each treatment cycle, and at EOT. Patients reported ocular symptoms in the OSDI and NEI VFQ-25 questionnaires, with the median time to worst severity of 45 to 64 days depending on symptoms considered. Some limitations in driving and reading were reported. Ocular symptoms were improved and median time to recovery was 23.5 to 44.0 days. EORTC-QLQ-C30 data suggest core MM symptoms (including fatigue and pain), overall HRQOL, and patient functioning were maintained while patients continued belantamab mafodotin treatment, even if meaningful worsening of vision-related symptoms occurred. These PRO results, together with the clinical efficacy of belantamab mafodotin, support its use in patients with RRMM and further evaluation of its use at earlier lines of therapy.

A toolbox of different approaches to analyze and present PRO-CTCAE data in oncology studies

BACKGROUND

The Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) is used to assess symptomatic adverse events in oncology trials. Currently, no standard for PRO-CTCAE analysis exists.

METHODS

Key methods of descriptive analysis and longitudinal modelling using PRO-CTCAE data from an oncology clinical trial, DREAMM-2, a Phase II trial of belantamab mafodotin in multiple myeloma (NCT03525678), were explored. Descriptive methods included maximum post-baseline ratings, mean change over time, ratings above a predefined cut-off, line graphs, and stacked bar charts to illustrate patient-reported adverse events at one timepoint or dynamics over time. Analysis methods involving modelling over time included toxicity over time (ToxT) (repeated measurement model, time-to-event, area under the curve analyses), generalized estimating equations (GEE), and ordinal log-linear models (OLLM).

RESULTS

Visualizations of PRO-CTCAE data highlighted different aspects of the data. Selection of the appropriate visualization will depend on the audience and message to be conveyed. Consistent results were obtained by all modelling approaches; no difference was found between dose groups of the DREAMM-2 study in any PRO-CTCAE item by the ToxT approach or the more sophisticated GEE and OLLM methods. Interpretation of GEE results was the most challenging. OLLM supported the interval nature of the PRO-CTCAE response scale in the DREAMM-2 study. All modelling approaches account for multiple testing (driven by the number of items).

CONCLUSIONS

Descriptive analyses and longitudinal modelling approaches are complementary approaches to presenting PRO-CTCAE data. In modelling, the ToxT approach may be a good compromise compared with more sophisticated analyses.

Exploring alternative dosing regimens of single-agent belantamab mafodotin on safety and efficacy in patients with relapsed or refractory multiple myeloma: DREAMM-14

TPS8073

Background: Belantamab mafodotin (belamaf: BLENREP) is a first-in-class, monomethyl auristatin F (MMAF)-containing, B-cell maturation antigen (BCMA)-directed antibody–drug conjugate (ADC). In the DREAMM-2 study, belamaf showed deep responses with a manageable safety profile in patients with relapsed/refractory multiple myeloma (RRMM). At 13 months of follow-up, the median duration of response was 11 months and overall survival was 13.7 months at the 2.5 mg/kg Q3W dose. Corneal events are common and expected with belamaf and other MMAF-containing ADCs. In DREAMM-2, corneal events were managed with dose modifications. Clinical responses were observed even with prolonged dose holds, suggesting alternative dosing regimens may lower corneal event rates without compromising efficacy. The DREAMM-14 study (NCT05064358) will investigate if an improved benefit/risk profile of single-agent belamaf can be achieved by modifying the dose, schedule, or both, relative to the approved dosing regimen (2.5 mg/kg Q3W). Methods: This Phase II, randomized, open-label study will include adults with RRMM who had ≥3 prior lines of therapy (LOT), including an anti-CD38 monoclonal antibody, an immunomodulatory agent, and a proteasome inhibitor. Patients with corneal epithelial disease (except nonconfluent superficial punctate keratitis) or with prior exposure to BCMA-targeted therapies, or ADCs will be excluded. Patients will be randomized into Arms A–D (n=40 each) and Arm E (n=20) in parallel and stratified by the International Staging System (I vs II vs III) and prior LOT (3 vs ≥4). Belamaf will be administered as follows—Arm A: 2.5 mg/kg Q3W; Arm B: 1.9 mg/kg Q3W; Arm C: 2.5 mg/kg Q6W; Arm D: 1.9 mg/kg Q6W; Arm E: 1.9 mg/kg Q6W with ocular event-related dose modifications based on oncology staff assessment of ocular symptoms (patient-reported symptoms using the Ocular Surface Disease Index), and visual acuity (Snellen chart or equivalent) in addition to corneal findings assessed by an eye care specialist. Patients in all Arms will have response assessments, safety assessments, and ophthalmic exams performed by an eye care specialist Q3W regardless of dosing schedule. Ocular event-related dose modifications (except in Arm E) will be guided by a modified Keratopathy and Visual Acuity scale. The primary endpoint will be incidence of ocular events. Key secondary endpoints include ocular safety and tolerability, overall safety and tolerability, pharmacokinetics, and efficacy outcomes. Follow-up for progression-free survival will be Q3W until progressive disease, start of new anticancer therapy, withdrawal of consent, end of study, or death. Status: Recruitment is ongoing. Funding: GSK (Study 209628); drug linker technology licensed from Seagen Inc.; mAb produced using POTELLIGENT Technology licensed from BioWa. Clinical trial information: NCT05064358.

Qualitative study to characterize patient experience and relevance of patient-reported outcome measures for patients with metastatic synovial sarcoma

Background

The outlook for patients with metastatic synovial sarcoma (mSS) is poor. Better understanding of patient experience in this setting, beyond clinical measures, may guide improvements in management. Validated patient-reported outcome (PRO) instruments specific to many types of cancer exist, but for rare cancers this is often not the case.

Methods

This study aimed to characterize patient experiences of symptoms and impacts of mSS and evaluate the content validity and relevance of the novel European Organization for Research and Treatment of Cancer Item Library 31 (EORTC IL31) Disease Symptoms PRO tool assessing synovial sarcoma symptoms. This tool comprises items from preexisting, validated cancer-specific PRO instruments from the EORTC Item Library. It was developed as an mSS-specific add-on to the EORTC Quality of Life Questionnaire Core 30 (QLQ-C30), which evaluates general cancer and treatment-related symptoms and functioning. This was a non-interventional, qualitative interview study involving semi-structured, concept elicitation (CE) and cognitive debriefing (CD) telephone interviews in adults with mSS. CE explored symptoms and their impact on functioning and quality of life; CD assessed participant understanding and relevance of the PRO tools.

Results

Among the 8 participants, the most common disease-related symptoms reported during CE were fatigue and pain, while shortness of breath was one of the most bothersome. The greatest negative impacts of mSS occurred in domains of physical functioning and sleep. Key treatment priorities for patients were to improve disrupted sleep and ability to undertake strenuous activities.

Conclusions

The interviews showed that, when used together, the EORTC IL31 and EORTC QLQ-C30 covered symptoms and impacts of most relevance and importance to patients with mSS, with no notable gaps and good conceptual coverage. This study therefore supports the content validity of 2 tools in mSS, advocating their use in clinical trials to assess treatment impact on PRO measures of importance to these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00450-1.

Landscape review of the patient-reported outcomes version of the common terminology criteria for adverse events (PRO-CTCAE) in oncology: Adoption and recent learnings

e18587

Background: The PRO-CTCAE is a patient-reported outcome measure of symptomatic toxicity in oncology trials designed to complement CTCAE criteria (clinician’s measure of adverse events [AEs]). Items for evaluation are selected from 78 symptomatic toxicities in the CTCAE. PRO-CTCAE uptake and use has not been uniformly assessed; understanding how to best analyze and present PRO-CTCAE data is important. We reviewed literature on clinical trials reporting the PRO-CTCAE to ascertain its use and current analytical methods to inform future analyses. Methods: A review of the literature and ongoing oncology trials using PubMed, oncology and outcomes research conferences (ASCO, ASH, ISOQOL, ISPOR), and ClinicalTrials.gov was completed August 2019; updated November 2020. Selected literature included guidance on: item selection; analytical methods; PRO-CTCAE data/endpoint use in clinical trials. Analytical and visualization methods from the literature were used to inform the specification of PRO-CTCAE analyses conducted on data from the DREAMM-2 (NCT03525678) trial of single-agent belantamab mafodotin (belamaf; BLENREP), a B-cell maturation antigen–binding antibody–drug conjugate, in relapsed/refractory multiple myeloma. Results: After screening (n = 197), 45 articles were reviewed: 13 related to recommendations for use/analysis, 7 to item selection, and 25 to examples of PRO-CTCAE use. 118 completed/ongoing trials reported PRO-CTCAE use (17 [14%] Phase I or I/II; 73 [62%] Phase II, II/III, or III; 3 [3%] Phase IV; 25 had no phase reported). Most (92/118, 78%) trials included the PRO-CTCAE as a secondary endpoint. The number of trials using the PRO-CTCAE increased from 3 in 2015 to 30 in 2020. PRO-CTCAE data in the literature were reported descriptively using tables (maximum post-baseline ratings; mean change over time; ratings higher than a predefined cutoff) and graphs (line graphs; stacked bar charts; heatmaps). These and more sophisticated analyses were applied to DREAMM-2 data to best capture the dynamics of patient-reported AEs over time, or control for baseline PRO-CTCAE ratings (eg, Toxicity over Time approach; ordinal log-linear models). Conclusions: The importance of tolerability and symptomatic AEs for patients is increasingly recognized, particularly for new therapies. This landscape review demonstrates recent growth in interest and adoption of PRO-CTCAE. There are few existing standards for analysis; this research increases understanding of existing methods and further evaluates ways of analyzing and presenting PRO-CTCAE data over time. Additional research exploring innovative methods to analyze PRO-CTCAE data and address its challenges is needed. Funding Source: GlaxoSmithKline (212225). Drug linker technology licensed from Seagen Inc.; mAb produced using POTELLIGENT Technology licensed from BioWa.

Patient-reported outcomes (PRO) in patients (pts) with advanced or recurrent dMMR/MSI-H endometrial cancer (EC) treated with dostarlimab in the GARNET trial

275

Background: PRO enable direct measurement of the experiences of patients with cancer. Anti-programmed death 1 (PD-1) therapies have shown favorable PRO in lung cancer but a data gap remains in EC. Dostarlimab is an investigational anti-PD-1 monoclonal antibody which has shown promising activity in GARNET in advanced mismatch repair deficient (dMMR) EC pts and a low incidence of symptomatic grade ≥3 treatment-related adverse events. Here, we report on PRO measures collected from pts with dMMR/microsatellite instability high (MSI-H) EC in the single-arm GARNET trial. Methods: Pts with dMMR/MSI-H EC confirmed by local tests, with recurrent or advanced disease that progressed on a platinum regimen were enrolled. Pts received 500 mg Q3W of dostarlimab for 4 cycles, then 1000 mg Q6W until disease progression or discontinuation. PRO assessment was an exploratory endpoint and was measured by the EORTC Quality of Life Questionnaire (QLQ-C30), a validated instrument used evaluate quality of life (QOL), functioning, disease symptoms, and treatment-related side effects. PRO were collected at each dose administration, end of treatment, and follow-up. A mixed-model for repeated measures was used to assess change from baseline, accounting for time and baseline ECOG scores. The threshold to determine clinically meaningful group-level change was ±10 points. Results: PRO data were available for 43 pts. Compliance rates were 98%. Relative to baseline, pts reported meaningful improvements in pain, insomnia, and social and emotional functioning over the trial duration. Appetite, nausea, vomiting, constipation, diarrhea, and physical and role functioning were stable over the trial duration. QOL and global health status were also maintained. Conclusions: PRO from 43 pts enrolled in the GARNET trial show that disease- and treatment-related symptoms and QOL are improved or maintained while receiving treatment. These data, along with the efficacy and safety profile of dostarlimab, strongly support the use of dostarlimab in dMMR/MSI-H advanced EC. Funding: GlaxoSmithKline, Waltham, MA, USA. Clinical trial information: NCT02715284 .

Patient-reported outcomes (PRO) in the GARNET trial in patients (pts) with advanced or recurrent dMMR/MSI-H endometrial cancer (EC) treated with dostarlimab

e18032

Background: PRO enable direct measurement of the experiences of patients with cancer. Anti-programmed death 1 (PD-1) therapies have shown favorable PRO in lung cancer but a data gap remains in EC. Dostarlimab is an investigational anti-PD-1 monoclonal antibody which has shown promising activity in GARNET in advanced mismatch repair deficient (dMMR) EC pts (with an ORR of 42.9% and a disease control rate of 58.6%), and a low incidence of symptomatic grade ≥3 treatment-related adverse events (anemia [2·9%], colitis [1·9%], and diarrhea [1·9%]). Here, we report on PRO measures collected from pts with dMMR/microsattelite instability high (MSI-H) EC in the single-arm GARNET trial. Methods: Pts with dMMR/MSI-H EC confirmed by local tests, with recurrent or advanced disease that progressed on a platinum regimen were enrolled. Pts received 500 mg Q3W of dostarlimab for 4 cycles, then 1000 mg Q6W until disease progression or discontinuation. PRO assessment was an exploratory endpoint and was measured by the EORTC Quality of Life Questionnaire (QLQ-C30), a validated instrument used to evaluate quality of life, functioning, disease symptoms, and treatment-related side effects. PRO were collected at each dose administration, end of treatment, and follow-up. A mixed-model for repeated measures was used to assess change from baseline, accounting for time and baseline ECOG scores. The threshold to determine clinically meaningful group-level change was ±10 points. Results: PRO data were available for 43 pts. Compliance rates were high at 98%. Relative to baseline, pts reported meaningful improvements in pain, insomnia, and social and emotional functioning over the trial duration. Appetite, nausea, vomiting, constipation, diarrhea, and physical and role functioning were stable over the trial duration. Quality of life and global health status were also maintained. Conclusions: PRO from 43 pts enrolled in the GARNET trial show that disease- and treatment-related symptoms and quality of life are improved or maintained while receiving treatment. These data, along with with the efficacy and safety profile of dostarlimab, strongly support the use of dostarlimab in dMMR/MSI-H advanced EC. Clinical trial information: NCT02715284.

Qualitative patient interviews on symptoms and impacts in metastatic synovial sarcoma (mSS)

e23576

Background: Synovial sarcoma (SS), a soft tissue sarcoma, is a rare and aggressive malignancy, with significant morbidity and mortality associated with mSS. There are currently no patient-reported outcome (PRO) instruments specific to mSS patients and little qualitative research to understand impacts on mSS patients’ health-related quality of life (QoL). The objective of this study was to characterize the symptoms and impacts experienced by mSS patients to inform the selection of content-valid PRO instruments for use in investigational trials in mSS patients. Methods: This was a non-interventional, qualitative interview study of adult participants in the United States (US) with physician-confirmed mSS. Participants were consented from a large private practice in the US. Six semistructured concept elicitation interviews (60–90m by telephone) were conducted by trained interviewers. Participants were asked to describe their mSS symptoms and their impact on functioning in an open-ended fashion with follow-up probes. Verbatim transcripts were analyzed using thematic analysis methods and Atlas.Ti software. Socio-demographics and clinical characteristics were collected by the site. The study received Institutional Review Board (IRB) approval from Western IRB. Results: Among the 6 participants, average age was 45y (range 21–61y) and 2 were female. All 6 participants had pulmonary metastasis, 1 participant had a liver metastasis, and 1 participant had a mediastinal mass. The most common symptoms participants spontaneously identified were pain (n = 6), fatigue (n = 6), coughing (n = 5, with 2 upon probing), shortness of breath (n = 4), phlegm/mucus in the lungs (n = 3), coughing up blood (n = 2), and gastrointestinal complications (n = 2). Nerve/shooting/burning pain (n = 5) was mentioned upon probing. Participants also reported impacts of their disease on sleep (quantity and quality) (n = 6), physical activity (n = 6), social life (n = 6), daily activities (n = 5), emotions (n = 5), loss of appetite (n = 3), and finances (n = 1). Although not spontaneously reported, global ratings of overall health and QoL were considered relevant by all participants. Conclusions: This is the first study to identify patient-relevant symptoms and impacts associated with mSS. Further interviews with additional participants are ongoing, and we will analyze these data to identify appropriate PRO instruments for use in investigational trials in mSS patients. Funding: GlaxoSmithKline (209386).

DREAMM-1 Patient perspectives from the first-in-human study of single-agent belantamab mafodotin for relapsed and refractory multiple myeloma (RRMM)

e20531

Background: Patient-reported outcomes in RRMM remain poor, particularly for those refractory to immunomodulatory agents, proteasome inhibitors, and anti-CD38 antibodies, and there is an increased risk of cumulative toxicities in these patients. Single-agent belantamab mafodotin (GSK2857916), a first-in-class, B-cell maturation antigen–binding immunoconjugate, has demonstrated deep and durable responses with a manageable safety profile in heavily pretreated patients with RRMM (DREAMM-1, NCT02064387). Here, we present patient-reported clinical benefit/tolerability of belantamab mafodotin evaluated by trial-embedded end-of-treatment (EOT) and follow-up interviews. Methods: DREAMM-1 study design and results have been reported ( Blood Cancer J 2019). Patients in the Part 2 expansion phase were administered single-agent belantamab mafodotin 3.4 mg/kg IV once every 3 weeks for 16 cycles and invited to participate in interviews at EOT and 6-month follow-up. Patients discussed symptoms, treatment-related adverse events (AEs), treatment burden, and overall treatment satisfaction, rated 0–10 (0 = not severe to 10 = most severe/0 = not at all satisfied to 10 = extremely satisfied). Results: A total of 17/35 patients (9 female [53%]) were interviewed; 4/17 patients completed both interviews. Most patients (94%; 16/17) achieved a partial response or better. At EOT, patients reported an improvement from the worst point in symptoms of bone pain (mean change in score from 6.4 to 4.0) and fatigue (8.0 to 5.5). The most commonly reported treatment-related AE was blurred vision (76%; 13/17). Among those reporting this AE, 62% (8/13) reported resolution or steady improvement in vision after EOT; with a reduction in severity rating from 7.3 at worst to 5.3 at EOT for this event. Most patients (93%; 13/14) never considered stopping treatment owing to AEs, including ocular events. Overall treatment satisfaction was high (mean score 7.9; median 9.0). Conclusions: Despite small sample sizes, trial-embedded interviews provide valuable insight into patient experience with belantamab mafodotin. Patients treated with single-agent belantamab mafodotin reported high treatment satisfaction and improvements in symptoms. Visual symptoms were frequent but manageable, and improved or resolved after treatment. Funding: GlaxoSmithKline (117159). Drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Clinical trial information: NCT02064387.