Introduction Multi-agent induction chemotherapy followed by autologous stem cell transplant (ASCT) is a standard of care for younger patients with multiple myeloma, aimed at maximising the depth and duration of first response (PFS1). However, the duration of PFS1 is variable between patients. Improved understanding of how to identify high risk patients who relapse early and the ability to design strategies applicable to their biology represents the central aim of personalized medicine approaches for MM. This landmarked analysis of the Myeloma XI trial was designed to identify the characteristics of patients with PFS1 of less than a year after ASCT. Patients and methods In MXI patients were randomised to induction therapy with CTD (cyclophosphamide, thalidomide and dexamethasone) or RCD (lenalidomide, cyclophosphamide and dexamethasone) and +/- CVD (bortezomib, cyclophosphamide, dexamethasone) intensification in patients with Patients who completed ASCT were identified with very early relapse (PFS1 Results Of 1274 patients receiving ASCT: 178 (14%) relapsed within 12m and 1096 (86%) thereafter. There were higher rates of ≥VGPR in the PFS1≥12m group (70% vs 59%) and in both groups most patients responded at ≥PR (PFS1 Inferior outcomes continued for the PFS1 As PFS1 Discussion Nearly three quarters of those with PFS1 Disclosures Bygrave:Amgen: Honoraria; Takeda: Honoraria, Other: Travel Support; Janssen: Honoraria, Other: Travel support; Celgene: Honoraria, Other: Travel support, Research Funding. Pawlyn:Amgen: Consultancy, Honoraria, Other: Travel Support; Celgene Corporation: Consultancy, Honoraria, Other: Travel support; Takeda Oncology: Consultancy, Other: Travel support; Janssen: Honoraria, Other: Travel support. Davies:Janssen: Consultancy, Honoraria; Takeda: Consultancy, Membership on an entity9s Board of Directors or advisory committees; MMRF: Honoraria; ASH: Honoraria; TRM Oncology: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity9s Board of Directors or advisory committees; Abbvie: Consultancy. Cairns:Merck Sharp and Dohme: Research Funding; Amgen: Research Funding; Celgene: Research Funding. Striha:MSD: Research Funding; Celgene: Research Funding; Abbvie: Research Funding; Janssen: Research Funding; Amgen: Research Funding. Hockaday:Millenium: Research Funding; MSD: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Amgen: Research Funding; Abbvie: Research Funding. Jones:Celgene: Honoraria, Other: Travel support, Research Funding. Kishore:Celgene: Honoraria; Takeda: Honoraria, Other: travel support. Garg:Amgen: Honoraria, Other: Travel Support; Takeda: Other: Travel Grant; Novartis: Other: travel support, Research Funding; Janssen: Honoraria. Williams:Janssen: Honoraria, Other: Travel support, Speakers Bureau; Celgene: Honoraria, Other: Travel Support, Speakers Bureau; Takeda: Honoraria, Other: Travel support; Amgen: Honoraria, Speakers Bureau. Karunanithi:Janssen: Other: Travel support, Research Funding; Celgene: Other: Travel support, Research Funding. Lindsay:Celgene: Honoraria, Other: Travel support; BMS: Consultancy, Other: Travel support; Takeda: Other: Travel support; Janssen: Consultancy; Novartis: Other: Travel support. Jenner:Novartis: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Chugai: Membership on an entity9s Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: travel support, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity9s Board of Directors or advisory committees, Other: Travel support, Research Funding, Speakers Bureau. Cook:Amgen, Bristol-Myers Squibb, GlycoMimetics, Celgene, Janssen and Takeda and Sanofi: Honoraria; Celgene, Janssen and Takeda: Research Funding. Drayson:Abingdon Health: Equity Ownership, Membership on an entity9s Board of Directors or advisory committees. Owen:Takeda: Honoraria, Other: Travel Support; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Other: Travel support. Gregory:Janssen: Honoraria; Amgen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Merck Sharp and Dohme: Research Funding. Morgan:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Jackson:Amgen: Honoraria; Celgene: Honoraria; Chugai: Honoraria; Janssen: Honoraria; Takeda: Honoraria. Kaiser:Chugai: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Other: Travel support; Takeda: Consultancy, Other: Travel Support; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding.