LAUSR

Introduction: Doublet combinations including lenalidomide (len) and dexamethasone (dex; Ld) are increasingly used to treat frontline (FL) multiple myeloma (MM) patients (pts). Len has also been used as maintenance therapy where strategies increasing len dose with first relapse have been considered (Harousseau JL et al. Blood 2017). Triplet combinations are emerging as standard of care for relapsed/refractory (RR) MM and the treatment paradigm is shifting, with new agents like carfilzomib, ixazomib, elotuzumab, and daratumumab being added to Ld. Although these new combinations have shown improved clinical outcomes in RRMM, most pts ultimately relapse. Thus, treatment decision with each relapse becomes increasingly important to improve survival; the most critical decision may come at first relapse. With earlier len use, better understanding of treatment sequencing patterns of len and its use in clinical practice settings may help optimize treatment strategies in RRMM pts in later lines. We present real-world clinical practice data on treatment sequencing at relapse from len-based FL therapy. Methods: Pts aged ≥18 y with ≥1 diagnosis (International Classification of Diseases [ICD], 9th Revision, codes 203.0x or ICD-10 codes C90.0x), preceded by ≥12 mo (baseline) without a MM claim, were identified from January 1, 2010 in the Explorys electronic medical records US database and followed through the course of available follow-up. FL therapy included all anti-MM treatment received after 1st claim for an anti-MM prescription or administration of anti-MM therapy. The end of a line of therapy (LoT) was defined as the 1st day of a treatment gap of >90 d or initiation of a salvage regimen. LoT escalation was a surrogate for disease progression. Baseline characteristics plus Ld and len monotherapy (mono) patterns of use were summarized using descriptive statistics. Results: 766 FL pts were treated with Ld (466 [61%]) or len mono (300 [39%]). Pts in the 2 cohorts were similar in age and race; males and pts in the US Midwest region (Table) tended to receive Ld vs len mono. Pts on Ld generally had more comorbidities vs pts on len mono. Of 466 pts on Ld, 97% (n=452) had a recorded len dose, of whom 56% (n=253) started len at 25 mg/d and 44% (n=199) at Conclusions: In real-world clinical practice, about half of pts receiving Ld as FL therapy moved to len mono maintenance therapy; over one-third of these had their len dose reduced. Of pts with reduced len dose, ~50% relapsed and switched treatment in 2L. PI-based regimens and len re-treatment were the most common 2L therapy options after progression on len in FL. Pts on Ld were more likely to progress to 2L if they started treatment with low-dose len. Pts receiving low-dose len were less likely to have len dose increased. Findings suggest the increasing importance of optimizing treatment strategies in RRMM pts who receive len as FL therapy, including use of new triplets, especially for early relapse. Analysis of outcome data is currently ongoing. Study support: Bristol-Myers Squibb Disclosures Chen: Bristol-Myers Squibb: Employment. Potluri: SmartAnalyst Inc.: Employment; Janssen: Consultancy, Research Funding. Kanakamedala: SmartAnalyst Inc.: Employment. Papademetriou: SmartAnalyst Inc.: Employment. Yasenchak: Bristol-Myers Squibb: Consultancy; Seattle Genetics: Consultancy. Ranjan: SmartAnalyst India Pvt. Ltd: Employment. Bhandari: SmartAnalyst India Pvt. Ltd: Employment. Mann: SmartAnalyst India Pvt. Ltd: Employment. Davis: Bristol-Myers Squibb: Employment.