BACKGROUND: Real-world data can provide important information on the safety profile for recommended treatment options, but these data are collected infrequently. The ongoing post-authorization safety study (PASS) MM-034 (NCT03106324) is a prospective non-interventional study in patients (pts) with newly diagnosed multiple myeloma (NDMM) who are transplant ineligible. This study allows for the collection of robust safety data for currently recommended regimens for the management of these pts. Global guidelines recommend lenalidomide (LEN) regimens, such as LEN plus dexamethasone (DEX; Rd) and LEN plus bortezomib (BORT) plus DEX (Vd), and BORT regimens, including BORT plus melphalan plus prednisone (VMP). METHODS: Transplant-ineligible adult pts with NDMM initiating therapy in centers throughout Europe are being enrolled in the ongoing MM-034 trial. Pts receiving any first-line regimen are eligible, but the decision for which treatment regimen will be used must be made prior to study inclusion. The primary endpoint is the incidence of cardiovascular events. Secondary endpoints include the incidence of renal impairment, infections, and second primary malignancies. In this analysis, the safety profiles of Rd, Vd, and VMP were compared. RESULTS: As of April 12, 2019, 145 Rd, 53 Vd, and 83 VMP pts were enrolled in the study (evaluable cohort). At the time of data cutoff, treatment was ongoing in 64.8% of Rd pts, 41.5% of Vd pts, and 61.4% of VMP pts. Median age was 79 years in Rd pts and 75 years in both Vd and VMP pts. The proportion of pts with ISS stage III disease was higher in the Vd group (24.8% Rd vs 32.1% Vd vs 24.1% VMP), and more pts in the VMP group were male (49.7% Rd vs 58.5% Vd vs 65.1% VMP). Adverse events (AEs) of all grades confirmed the expected side effects. Any-grade neutropenia occurred in 7.6%, 11.3%, and 13.3% of Rd, Vd, and VMP pts, respectively, and thrombocytopenia occurred in 6.2%, 5.7%, and 12.0%, respectively. However, any-grade febrile neutropenia was seen only in the VMP group, at 2.4%, but not in the other 2 groups. Any-grade polyneuropathy was reported in 1.4% of Rd pts, but in 18.9% of Vd pts and 19.3% of VMP pts. Any-grade infections of all kinds occurred in 28.3% of Rd pts, 41.5% of Vd pts, and 20.5% of VMP pts, with pneumonia in 3.4%, 11.3%, and 2.4% of Rd, Vd, and VMP pts, respectively. Any-grade thrombosis was reported in 4.8% of Rd pts and 3.8% of Vd pts and in no VMP pts. Grade 3/4 AEs occurred in 42.8% of Rd pts, 52.8% of Vd pts, and 43.4% of VMP pts. Grade 3/4 neutropenia was reported in 4.8%, 9.4%, and 8.4% of Rd, Vd, and VMP pts, respectively, and thrombocytopenia in 2.8%, 0%, and 8.4%, respectively. Grade 3/4 infections were lower in Rd pts (6.9% vs 24.5% Vd and 12.0% VMP); pneumonia, the most important of these, was reported in 0.7%, 5.7%, and 2.4% of Rd, Vd, and VMP pts, respectively. Grade 3/4 peripheral neuropathy was not seen in the Rd group; however, it was reported in 3.8% of Vd pts and 2.4% of VMP pts. Grade 3/4 venous thrombosis was reported in only 0.7% of Rd pts, with no events reported in the Vd and VMP groups. CONCLUSIONS: The results from this analysis, along with those from a previous analysis of cardiovascular events in the LEN-treated and non-LEN treated cohorts of pts from the European PASS MM-034 study (De Stefano, EHA 2019), provide real-world evidence for the safety profile of Rd as first-line therapy and support the role of Rd in the treatment of pts with NDMM who are transplant ineligible. Disclosures Cavo: celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Tromp:Janssen: Other: Grant. Dhanasiri:Celgene Corporation: Employment, Equity Ownership. Kueenburg:Celgene: Consultancy. Rosettani:Celgene International: Employment. Martin:Celgene: Employment. Pozzi:Celgene: Consultancy. Bacon:Celgene: Employment, Equity Ownership. Gamberi:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Front-line treatment (of any type) was at the discretion of the investigator.