A Phase II Study of Lenalidomide, Ixazomib, Dexamethasone, and Daratumumab in Transplant-Ineligible Patients with Newly Diagnosed Multiple Myeloma (AFT-41)

Background: Clinical data support the combination of an immunomodulatory drug, a proteasome inhibitor, and a glucocorticoid for the treatment of newly diagnosed multiple myeloma (NDMM). The combination of lenalidomide, bortezomib, and low-dose dexamethasone is a very active, well-tolerated standard of care in the transplant-ineligible NDMM population. Ixazomib, an oral proteasome inhibitor is approved by the US Food and Drug Administration in combination with lenalidomide and dexamethasone for the treatment of relapsed MM. Given that ixazomib has improved binding kinetics and pharmacologic profile compared with bortezomib, it is expected that these differences will translate into similar, if not improved, efficacy and safety profiles in the upfront setting. A phase l/ll study of lenalidomide, ixazomib, and dexamethasone in previously untreated patients with MM demonstrated that this combination was well-tolerated and active (NCT01217957). More recently, the GRIFFIN study evaluated the addition of the anti-CD38 monoclonal antibody, daratumumab to lenalidomide, bortezomib, and dexamethasone in transplant-eligible NDMM and demonstrated the ability of daratumumab to improve efficacy of the three-drug combination with an acceptable safety profile. Building upon these data, our study evaluates the addition of daratumumab to the all-oral regimen of lenalidomide, ixazomib, and dexamethasone in transplant-ineligible NDMM. The combination proposed in this study has been evaluated in NDMM irrespective of transplant eligibility and has demonstrated excellent efficacy and tolerability. Responses were rapid with 88% achieving a partial response (PR) or better after 2 cycles (33% very good partial response (VGPR) and 52% VGPR for 29 patients who had completed 4 cycles) with an overall response rate of 95%. 1 In our study, transplant-ineligible NDMM patients will be randomized to receive 12 cycles of induction with lenalidomide, ixazomib, dexamethasone, and daratumumab followed by lenalidomide alone versus lenalidomide, ixazomib, and daratumumab. Study Design and Methods: A randomized, phase II clinical trial (NCT04009109) is being conducted to assess the impact on progression-free survival (PFS) of the addition of ixazomib and daratumumab to lenalidomide as maintenance treatment following induction with lenalidomide, ixazomib, dexamethasone, and daratumumab. In this ongoing trial, eligible patients are randomized 1:1 to Arm A (12 cycles of lenalidomide, ixazomib, dexamethasone, and daratumumab followed by lenalidomide until disease progression or unacceptable toxicity or a maximum of 2 years of maintenance therapy) vs. Arm B (12 cycles of lenalidomide, ixazomib, dexamethasone, and daratumumab, followed by lenalidomide, ixazomib, and daratumumab until disease progression or unacceptable toxicity or a maximum of 2 years maintenance therapy). Eligible patients have NDMM requiring treatment, are ≥18 years, have ECOG PS of 0-2, and must have been deemed ineligible for stem cell transplantation. The primary endpoint is PFS. With a sample size of 188 patients (94 patients per arm) enrolled over a 36-month period and followed for a minimum of 24 months after the close of enrollment, a one-sided alpha=0.10 log rank test will have an 85% chance of detecting an increase in median PFS time from 30 months to 48 months (a hazard ratio of 0.625) with the addition of ixazomib and daratumumab to lenalidomide as a maintenance treatment following induction with ixazomib, lenalidomide, dexamethasone, and daratumumab. Secondary outcomes of interest include minimal residual disease, overall survival, changes in body composition, quality of life, psychosocial measures of functional status including social activity and support, psychological state, and nutrition using a geriatric assessment tool, and the association of these psychosocial measures with therapy-associated toxicities. 1Kapoor et al. Blood (2019) 134 (Supplement_1): 864. Support: Alliance Foundation Trials; Janssen, Takeda, Celgene; https://acknowledgments.alliancefound.org Figure 1 Figure 1. Disclosures O'Donnell: Bristol Myer Squibb: Consultancy; Janssen: Consultancy; Takeda: Consultancy; Oncopeptide: Consultancy; Adaptive: Consultancy; Karyopharm: Consultancy. Nadeem: GSK: Consultancy; Karyopharm: Consultancy; Adaptive: Consultancy; Takeda: Consultancy; Bristol Myer Squibb: Consultancy. Dinner: Kite/Gilead: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Yee: Takeda: Consultancy; Sanofi: Consultancy; Bristol Myers Squibb: Consultancy; Oncopeptides: Consultancy; Janssen: Consultancy; Karyopharm: Consultancy; Amgen: Consultancy; Adaptive: Consultancy; GSK: Consultancy. Mo: Karyopharm: Honoraria, Membership on an entity's Board of Directors or advisory committees; Epizyme: Consultancy; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Eli Lilly: Consultancy. Tuchman: Karyopharm: Research Funding; Shattuck Labs: Consultancy; Sanofi / Genzyme: Consultancy, Research Funding; Caelum: Consultancy, Research Funding; Oncopeptides: Consultancy. Raje: Caribou: Other; Janssen: Other; bluebird bio: Other; Amgen: Other; Celgene: Other; BMS: Other. Richardson: AstraZeneca: Consultancy; Regeneron: Consultancy; Janssen: Consultancy; Celgene/BMS: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; GlaxoSmithKline: Consultancy; Secura Bio: Consultancy; Sanofi: Consultancy; Protocol Intelligence: Consultancy; Karyopharm: Consultancy, Research Funding; AbbVie: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding.

CTIM-02. PHASE II STUDY OF IPILIMUMAB AND NIVOLUMAB IN LEPTOMENINGEAL CARCINOMATOSIS

Leptomeningeal disease (LMD) is an increasingly common complication from solid tumor malignancies with a poor prognosis and limited treatment options. We conducted a single arm Phase II study of combined ipilimumab and nivolumab in patients with LMD from solid tumor malignancies (NCT02939300). Patients received manufacturer-specific dosing regimens of combined ipilimumab and nivolumab based on primary-tumor histology until definitive progression or unacceptable toxicity. The primary end point was rate of overall survival at 3 months (OS3). A Simon two-stage design was used to compare a null hypothesis OS3 of 18% against an alternative of 44%. Eighteen patients with diverse primary tumor histologies were enrolled and all received at least one dose of combined ipilimumab and nivolumab. Median follow up based on patients still alive was 8.0 months (range: 0.5 to 15.9 months). The study met its primary endpoint as 8 of 18 (OS3 0.44; 90% CI: 0.24 to 0.66) patients were alive at three months after enrollment. One third of patients experienced one (or more) grade-3 or higher adverse events possibly related to treatment. Two patients discontinued protocol treatment due to unacceptable toxicity (hepatitis and colitis, respectively). The most frequent adverse events overall included fatigue (N=7), nausea (N=6), fever (N=6), anorexia (N=6) and rash (N=6). Combined ipilimumab and nivolumab has an acceptable safety profile and demonstrates promising activity in LMD patients; this therapeutic approach should be studied in larger, multicenter clinical trials to validate these results as well as better identify patients who will benefit.

Phase II study of ipilimumab and nivolumab in leptomeningeal carcinomatosis

Leptomeningeal disease (LMD) is a common complication from solid tumor malignancies with a poor prognosis and limited treatment options. We present a single arm Phase II study of 18 patients with LMD receiving combined ipilimumab and nivolumab until progression or unacceptable toxicity (NCT02939300). The primary end point is overall survival at 3 months (OS3). Secondary end points include toxicity, cumulative time-to-progression at 3 months, and progression-free survival. A Simon two-stage design is used to compare a null hypothesis OS3 of 18% against an alternative of 44%. Median follow up based on patients still alive is 8.0 months (range: 0.5 to 15.9 months). The study has met its primary endpoint as 8 of 18 (OS3 0.44; 90% CI: 0.24 to 0.66) patients are alive at three months. One third of patients have experienced one (or more) grade-3 or higher adverse events. Two patients have discontinued protocol treatment due to unacceptable toxicity (hepatitis and colitis, respectively). The most frequent adverse events include fatigue (N = 7), nausea (N = 6), fever (N = 6), anorexia (N = 6) and rash (N = 6). Combined ipilimumab and nivolumab has an acceptable safety profile and demonstrates promising activity in LMD patients. Larger, multicenter clinical trials are needed to validate these results.

Phase I study of napabucasin in combination with FOLFIRI + bevacizumab in Japanese patients with metastatic colorectal cancer

Background Napabucasin is an oral NAD(P)H:quinone oxidoreductase 1 bioactivatable agent that generates reactive oxygen species, is hypothesised to affect multiple oncogenic cellular pathways, including STAT-3, and is expected to result in cancer cell death. This phase I study investigated the safety, tolerability, and pharmacokinetics of napabucasin co-administered with fluorouracil, l-leucovorin, and irinotecan (FOLFIRI) chemotherapy plus bevacizumab in Japanese patients with metastatic colorectal cancer (CRC). Methods Patients with histologically confirmed unresectable stage IV CRC received oral napabucasin 240 mg twice daily (BID). Intravenous FOLFIRI and bevacizumab therapy was initiated on day 3 at approved doses. Unacceptable toxicity was evaluated over the first 30 days of treatment, after which treatment continued in 14-day cycles until toxicity or disease progression. Endpoints included safety, pharmacokinetics, and tumour response based on RECIST v1.1. Results Four patients received treatment; three were evaluable during the unacceptable toxicity period. All four patients experienced diarrhoea and decreased appetite (considered napabucasin-related in four and two patients, respectively), and three patients experienced neutrophil count decreased. No unacceptable toxicity was reported during the 30-day evaluation period. No grade 4 events, deaths, or serious adverse events were reported. The addition of FOLFIRI and bevacizumab to napabucasin did not significantly change the pharmacokinetic profile of napabucasin; however, results were variable among patients. The best overall response was stable disease in two patients (50.0%). Conclusions Napabucasin 240 mg BID in combination with FOLFIRI and bevacizumab was tolerated, with a manageable safety profile in Japanese patients with metastatic CRC.

Feasibility of an adapted schedule of carboplatin plus paclitaxel in elderly women with advanced ovarian cancer: A retrospective cohort.

5546 Background: The EWOC-1 trial compared Carboplatin monotherapy (C mono) to two different Carboplatin + Paclitaxel (CP) regimens (weekly or 3-weekly) in vulnerable elderly patients treated for advanced ovarian cancers (OC). This study was closed prematurely because of a worse outcome in the C mono group. Both CP regimens were equivalent in terms of feasibility and efficacy with different toxicity profiles. Optimal CP regimen in elderly patient is still unknown. Here we propose a study of another adapted regimen of CP (aCP) performed in elderly patients in our institution. Methods: We retrospectively analyzed OC patients ≥ 70 years who received a Carboplatin AUC 4-5 d1q3week + Paclitaxel 80 mg/m² d1-d8 q3week regimen between 2015 and 2019. Primary endpoint was treatment feasibility according to the EWOC-1 standard: completion of 6 courses of chemotherapy without early stopping for disease progression, death or unacceptable toxicity (adverse event (AE) related to chemotherapy or treatment procedure leading either to early treatment stopping, to an unplanned hospital admission or to death or to a dose delay lasting more than 14 days or more than 2 dose reductions). Results: We identified 36 pts with a median age of 79 years (table). All patient but one had an ONCODAGE-G8 score ≤ 14, 30.6% of patients had a comorbidity Charlson’s index > 4 and 52.5% had an albumin rate < 35 g/L. The feasibility endpoint was met in 58.3% of patients (IC95% = [25.6; 57.8]). Main causes of treatment failure (TF) were early discontinuation because of toxicity in 6 patients (16.7%) and progressive disease in 3 patients (8.33%). Median PFS was 35.3 months (IC95% = [22.7; NR]) and median OS was 62.1 months (IC95% = [31.4.0; NR]). The most frequent AE were asthenia (all grades = 94.4%, grade 3-4 = 13.9%), anemia (all grades = 94.4%, grade 3-4 = 27.8%), neutropenia (all grades = 66.7%, grade 3-4 = 38.9%) and neuropathy sensory (all grades = 61.1%, no grade 3-4). Non high-grade-serous histological type and a poor Charlson’s score were associated with a higher rate of TF (100% and 63.6%, respectively). Conclusions: These results are consistent with the findings of the EWOC-1 trial in both CP regimens and suggest that aCP could be non-inferior with an acceptable toxicity profile. Further prospective and comparative studies are mandatory to confirm this trend and to better identify predictive factors of TF in OC elderly patients.[Table: see text]

Outcomes of BRAF mutant metastatic melanoma (MM) patients (pts) after cessation of targeted therapy (TT) with BRAF or BRAF/MEK inhibitor(i).

9564 Background: Since their introduction into the clinic a decade ago, BRAF and BRAF/MEKi have dramatically changed the outcomes of pts with BRAF mutant MM. While typically, these agents are administered until progression (PD), other reasons for stopping TT include unacceptable toxicity, complete response to treatment, or pt/physician decision or preference. The outcomes for MM pts that stop TT for reasons other than PD are largely unknown. Here we report the clinical features and outcomes of the largest cohort of MM pts who stopped TT for reasons other than PD to date. Methods: Under an institutionally approved database, we identified MM pts treated at the MD Anderson Cancer Center with BRAF±MEK inhibitors, and their records were reviewed to identify pts that stopped TT for reasons other than PD. Pts demographics, treatment information and clinical outcomes were recorded. Overall survival (OS) time was computed from three start dates (initial diagnosis, initial unresectable stage III melanoma, 1st dose of TT) to last known vital sign. Pts alive at the last follow-up date were censored. Time to recurrence was computed from date of 1st dose of TT to recurrence. Pts who did not experience disease recurrence were censored The Kaplan-Meier method was used to estimate OS and time to recurrence. Results: A total of 58 pts were identified, 32 (55%) were male. Most pts had a BRAF V600E (n = 49) or V600K (n = 6) mutation. At TT initiation median age was 59.5 years (range 29- 95), LDH was within normal range in 46 (85%), median number of prior systemic therapies was 1 (range 0-5), with 50% of pts receiving prior systemic therapy. Most (n = 33; 57%) pts were treated with single agent BRAFi (12 with dabrafenib, 11 vemurafenib). Among pts treated with combination TT (n = 25), most received dabrafenib with trametinib (n = 21; 84%). Median TT treatment duration was 9.5 months (range 0.03-80.5 months). Reasons for TT discontinuation were unacceptable toxicity (n = 29; 50%) and pt or physician decision/preference in responding patients (n = 23; 40%). At time of TT discontinuation, 48% of pts had achieved a complete response (CR), 28% a partial response (PR), and 22% stable disease (SD), 1 patient had unknown disease status. With standard follow-up, after stopping TT, 40 pts (69%) have recurred or experienced PD, with a median time to recurrence of 14.9 months (95% CI:7.8-26.3 months). At PD, 32 (76%) of pts had new metastatic sites. After PD 26 pts (63%) pts received BRAF/MEKi, 11 (44%) achieved a CR and 6 (24%) a PR, and 5 (20%) for a response rate of 88%; while 3 (12%) pt had PD as best response and 1 was unknown. For the full cohort, the median OS from time of 1st dose of TT was 6.4 years. Conclusions: Among MM pts who stopped TT for reasons other than PD, the majority of pts recurred, but most responded to re-introduction of TT. This information can help to inform discussion with pts regarding cessation of, or re-challenge with, TT.

Olaparib treatment (Tx) in patients (pts) with platinum-sensitive relapsed ovarian cancer (PSR OC) by BRCA mutation (BRCAm) and homologous recombination deficiency (HRD) status: Overall survival (OS) results from the phase II LIGHT study.

5515 Background: LIGHT (NCT02983799) evaluated olaparib Tx in pts with PSR OC in cohorts with known BRCAm and HRD status. We report the final OS analyses. Methods: We conducted anopen-label, non-randomized, multicenter study of pts with PSR OC and ≥1 prior line of platinum-based chemotherapy (CTx). Pts were assigned to one of 4 cohorts: germline (g) BRCAm; somatic (s) BRCAm; HRD +ve (non-BRCAm); and HRD -ve. Genomic instability score (GIS) and gBRCAm status were determined by Myriad myChoice and BRACAnalysis CDx tests, respectively. HRD +ve tumors were defined by a GIS ≥42. Pts received olaparib Tx (starting dose 300 mg bid) until disease progression or unacceptable toxicity. OS was a secondary endpoint and was analyzed at 12 months (mo) after the primary analysis and 18 mo after the last pt was enrolled. Safety was assessed in pts who received ≥1 dose. Results: Data cut-off (DCO) was Aug 27, 2020. Of 272 enrolled pts, 271 received olaparib; of these, 270 had measurable disease at baseline and were included in efficacy analyses (Table). At DCO, 40% of pts had died (maturity) with a median follow-up in censored pts of 26.3 mo. Kaplan–Meier 18-mo OS rates were 86%, 88%, 79%, and 60% in the gBRCAm, sBRCAm, HRD +ve (non-BRCAm), and HRD -ve cohorts, respectively. Platinum-based CTx was the most common first subsequent Tx and was received by 39% pts after olaparib discontinuation. At DCO, the median duration of Tx was 7.4 mo and 244 pts had discontinued treatment, mainly due to disease progression (72%); 5% discontinued due to treatment-emergent adverse events (TEAEs). The only TEAE leading to discontinuation in >1 pt was nausea (2 pts). Serious TEAEs were reported in 25% of pts. The most common serious TEAE was small intestinal obstruction (6%). Three adverse events of special interest occurred, each in 1 pt (<1%): acute myeloid leukemia (post discontinuation), pneumonitis, and pulmonary fibrosis. Conclusions: In the final OS analysis, 18-mo OS ranged from 60–88% across the 4 cohorts. Consistent with the primary analysis, the 18-mo OS rate was highest in the BRCAm cohorts (similar OS in g and sBRCAm); among pts without a BRCAm, 18-mo OS was highest in the HRD +ve cohort. No new safety signals were observed compared with the primary analysis and with prior olaparib studies. Clinical trial information: NCT02983799. [Table: see text]

Updated results from DIAMOND-01 (CLI24-001) trial: A phase I/II study of SEL24/MEN1703, a first-in-class dual PIM/FLT3 kinase inhibitor, in acute myeloid leukemia.

7023 Background: SEL24/MEN1703, a dual PIM/FLT3 kinase inhibitor, in the dose escalation (DE) DIAMOND-01 trial (CLI24-001, NCT03008187), showed an acceptable safety profile up to the recommended dose (RD) of 125 mg along with initial evidence of single agent activity and meaningful target engagement in heavily pre-treated patients (pts) with AML (Solomon et al, EHA 2020; Tomirotti et al, ASH 2020). Here we present updated data including pts enrolled in the Phase II, cohort expansion (CE) of the study. Methods: DIAMOND-01 trial enrolled pts unsuitable for chemotherapy having relapsed or refractory (R/R) (DE and CE) or previously untreated (DE) AML. Previous targeted therapies – except PIM inhibitors – were allowed. SEL24/MEN1703 was given orally, QD, 14 days ON / 7 days OFF until progression/unacceptable toxicity. The DE tested MEN1703 escalating doses from 25 to 150 mg, whereas in the CE the RP2D (125 mg) was administered. The key objectives of the CE were the confirmation of the safety profile determined in the DE along with further investigation of single agent activity. Adverse events (AEs) were graded according to NCI-CTCAE v.4.03; responses assessed as per ELN 2017 criteria. Results: As of January 21, 2021 (cut-off date), n = 48 pts were treated across DE (n = 25) and CE (n = 23). Median age was 69 (25-84) years. Overall, 20 (43%) and 15 (32%) pts had non de novo AML and primary refractory AML, respectively. Adverse karyotype was reported in 7 (15%) pts. Most frequently reported mutations were FLT3/ITD (23%, n = 11), DNMT3A (15% n = 7), NPM1 (15%, n = 7), IDH1 (13%, n = 6) and IDH2 (4%, n = 2), CEBPA (4%, n = 2), FLT3/TKD (2%, n = 1). Median number of cycles was 2 (1-8). At the RD (n = 30), most frequent serious treatment-emergent AEs (serious TEAEs) were pneumonia (23%), sepsis and febrile neutropenia (13%) and pulmonary mycosis (10%) whereas most frequent G≥3 TEAEs were febrile neutropenia and pneumonia (23%), leukocytosis (20%) and neutrophil count decrease, platelet count decrease, lymphocyte count decrease and sepsis (13%). Responses occurred in 2 pts in the CE, both with IDH1 mutant disease (naïve to IDH inhibitors) who achieved complete remission with incomplete hematologic recovery (CRi). Both responses occurred by Cycle 3, with a duration of 79 (ongoing at cut-off date) and 43 days, respectively. Across DE and CE, 4 CR/CRi occurred, three of which in pts with IDH mutations. A total of 3 out of 6 pts with IDH mutations treated at doses ≥75 mg achieved CR/CRi, including a CR in a patient with IDH2 mutant AML relapsed on Enasidenib. Conclusions: SEL24/MEN1703 confirmed a manageable safety profile at RD and showed preliminary single agent efficacy in R/R AML, particularly clustering in pts with IDH mutant disease either naïve or previously exposed to IDH inhibitors. These results warrant further investigation of SEL24/MEN1703 in AML, with potential focus in the IDH mutated subset. Clinical trial information: NCT03008187.

Final survival results from a multicenter, randomized phase II trial of intravenous paclitaxel plus FOLFOX (ivPOF) and/or intraperitoneal paclitaxel plus FOLFOX (ipPOF) versus mFOLFOX6 as first-line treatment of advanced gastric cancer (AGC): SYLT/FNF 004.

4041 Background: Progression-free (PFS) and overall (OS) survival for SYLT/FNF 004 were previously reported in ASCO and ASCO-GI 2019. At that time, PFS was statistically significantly improved with ivPOF or ipPOF compared to mFOLFOX6 as first-line treatment of AGC; however, there were no significant between-treatment differences in OS. Herein, we report final survival results for this trial. Methods: Subjects were randomly assigned to one of three treatments: intravenous paclitaxel 135 mg/m2 + mFOLFOX6 omitting the 5-FU bolus (ivPOF); intraperitoneal paclitaxel 80 mg/m2 + mFOLFOX6 omitting the 5-FU bolus (ipPOF); or mFOLFOX6 (oxaliplatin 85 mg/m2, leucovorin 400 mg/m2 followed by 5-FU 400 mg/m2 bolus and 5-FU 2400 mg/m2 as a 46-hour continuous infusion). Treatment cycles were repeated every 14 days for up to 9 cycles. Thereafter, maintenance treatment with S-1 80 mg/m2/day for 14 days every 3 weeks until disease progression, unacceptable toxicity, patient refusal, or physician decision. The original study objective was to compare ivPOF or ipPOF vs. mFOLFOX6 for PFS. Due to slow accrual, the protocol was later amended to compare POF (ivPOF and ipPOF) with mFOLFOX6 for PFS. Results: Between Nov 2015 and May 2018, 89 subjects (30 ivPOF, 29 ipPOF, 30 mFOLFOX6) were enrolled. As of the data cutoff on Dec 31, 2020, median follow-up was 41 (IQR: 37-43) months. The median number of cycles administered was 7 (IQR: 4-9) for POF; 6 (IQR: 4-9) for ivPOF; 9 (IQR: 4-9) for ipPOF; and 4 (IQR: 3-9) for mFOLFOX6. Median PFS and OS, respectively, were 6.23 (95% CI: 4.90 to 9.07) and 10.17 (95% CI: 8.97 to 16.4) months for POF and 4.55 (95% CI: 2.73 to 6.87) and 6.87 (95% CI: 5.83 to 13.6) months for mFOLFOX6. Both PFS and OS were statistically significantly better with POF, ivPOF or ipPOF versus mFOLFOX6 (Table). Safety was consistent with previous reports. Conclusions: POF, ivPOF or ipPOF improved both PFS and OS compared with mFOLFOX6, with similarly manageable adverse effects. Clinical trial information: NCT02845908. [Table: see text]

Lenalidomide and dexamethasone with or without clarithromycin in patients with multiple myeloma ineligible for autologous transplant: a randomized trial

Although case-control analyses have suggested an additive value with the association of clarithromycin to continuous lenalidomide and dexamethasone (Rd), there are not phase III trials confirming these results. In this phase III trial, 286 patients with MM ineligible for ASCT received Rd with or without clarithromycin until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). With a median follow-up of 19 months (range, 0–54), no significant differences in the median PFS were observed between the two arms (C-Rd 23 months, Rd 29 months; HR 0.783, p = 0.14), despite a higher rate of complete response (CR) or better in the C-Rd group (22.6% vs 14.4%, p = 0.048). The most common G3–4 adverse events were neutropenia [12% vs 19%] and infections [30% vs 25%], similar between the two arms; however, the percentage of toxic deaths was higher in the C-Rd group (36/50 [72%] vs 22/40 [55%], p = 0.09). The addition of clarithromycin to Rd in untreated transplant ineligible MM patients does not improve PFS despite increasing the ≥CR rate due to the higher number of toxic deaths in the C-Rd arm. Side effects related to overexposure to steroids due to its delayed clearance induced by clarithromycin in this elderly population could explain these results. The trial was registered in clinicaltrials.gov with the name GEM-CLARIDEX: Ld vs BiRd and with the following identifier NCT02575144. The full trial protocol can be accessed from ClinicalTrials.gov. This study received financial support from BMS/Celgene.