PS1401 PATIENT REPORTED EXPERIENCE FROM PART 2 OF THE FIRST TIME IN HUMAN STUDY OF THE BCMA ANTIBODY DRUG CONJUGATE GSK2857916 FOR ADVANCED RELAPSED REFRACTORY MULTIPLE MYELOMA (DREAMM‐1)

Abstract

Background:We assessed the safety, tolerability, and preliminary clinical activity of GSK2857916, a novel anti‐BCMA antibody conjugated to microtubule‐disrupting agent MMAF, in patients with relapsed and refractory multiple myeloma. Patient experience of clinical benefit and tolerability was evaluated as part of the BMA117159 study (NCT02064387) through optional patient‐reported outcome (PRO) diary and trial exit interviews.Aims:To evaluate the patient reported experience of GSK285791 based on daily diary and end of treatment (EOT) interviews.Methods:Details of the study design have been previously published. Patients were dosed every 3 weeks for up to 16 cycles (∼1 year). In the Part 2 expansion phase at the RP2D a subset of patients completed an optional bone pain and fatigue PRO diary at baseline and during treatment (Day 1–8 and 15 of each cycle), capturing severity of bone pain and fatigue over 24 hours. Patients were also invited to participate in qualitative exit interviews at EOT. Those who reported bone pain were asked to compare bone pain severity from study start to end on a scale of 0–10, describe changes in symptoms, and discuss treatment satisfaction. Similarly, patients were asked to describe fatigue symptoms, and any other symptoms they experienced related to treatment. Due to the implementation via an amendment, many patients were already off study and unavailable for participation. The reported results reflect an interim analysis of patient exit interviews. This study is ongoing but closed for recruitment.Results:Bone Pain and Fatigue Diaries: 9 out of 35 patients completed the diary at baseline. Overall mean scores for bone pain and fatigue severity decreased after baseline, ranging from 0 to 5 points across visits.Exit Interviews: A total of 13 patients participated in trial exit interviews (7 female [54%], mean age: 64, 51–76). Of the 13 patients, 10 completed their interviews within 3 weeks following EOT, and the remaining 3 patients were within 8 weeks. Nearly all interviewed patients (n = 12/13, 92%) experienced a partial response or greater by IMWG criteria. During the exit interview, patients reported an average improvement in bone pain from 6.4 to 4.0 (scale 0–10). Fatigue ratings decreased from 8.0 to 5.5. Among exit interview participants, the most commonly reported visual symptoms included blurred vision (n = 8) and photophobia (n = 7). Interview‐reported ratings (symptom at its worst) showed severity of visual symptoms reduced, with half of the patients reporting improvements after treatment end. Impacts on visual functioning included some difficultly driving (n = 10, 77%) and reading (n = 9, 70%). However, only 4 (31%) patients mentioned decreased independence while on treatment. On the scale from 0–10, overall treatment satisfaction was high (mean = 8.1, median = 9.0).Summary/Conclusion:The PRO diary data and the exit interview results suggest that patients experienced improvements in fatigue and bone pain during the study in keeping with high response rates. Although visual symptoms were frequent with treatment, they were manageable and improving post‐treatment. Overall patients had a high level of satisfaction with treatment. This study was limited by small sample sizes but provides valuable preliminary insight into the patient experience of GSK2857916. The impact on patient symptoms, functioning, and tolerability will be further explored in future studies.