Key Information
Background:
Treatment options for patients (pts) with relapsed/refractory (RR) AL amyloidosis are limited. Daratumumab (dara) has been approved as monotherapy (DMT) or combination therapy (DCT) for multiple myeloma (MM). Data for dara-based therapy (DBT) in AL are sparse.
Methods:
We studied pts with RR AL without coexisting MM seen at Mayo Clinic from 11/2015 to 02/2018 & treated with DBT. Hematologic response (HR) & organ response (OR) were defined per Consensus criteria. All time to event analyses were done from the time of DBT initiation. Pts with dFLC 4 mg/dL at the time of start of DBT were considered non evaluable (NE) for HR other than disease progression. DCT included dara, pomalidomide & dexamethasone (dex) (35%), dara, lenalidomide & dex (26%), dara, bortezomib & dex (22%) & other DBT regimens (17%).
Results:
45 pts (DMT, n = 22; DCT, n = 23) received DBT; median age at DBT initiation was 64 years (range: 46-82). Data for HR assessment were available in 44 pts & 31 were evaluable for HR. HR & end points are outlined in Table 1. Among 13 NE pts, response improved to CR in 5 (38%) while remaining 8 continued to be NE. Of these 13 pts, 77% reached dFLC 1 mg/dL at last follow up (FU). Cardiac, renal & liver involvement was observed in 59%, 43% & 7% of pts. Cardiac, renal and liver OR was 46%, 32%, 0%, respectively. At last FU, 31 pts were on DBT. Three (7%) pts had disease progression. Hematologic toxicity (HT) from DBT included anemia _2 grade (Gr = ) 69%, 3 Gr 3%; thrombocytopenia 1 Gr 38%; neutropenia _2 Gr21% &> 2 Gr 7%. Non-HTs included fatigue (23%), infusion reactions (21%), & treatment-emergent neuropathy (14%).
Conclusions:
DBT is safe & effective in heavily pretreated pts with AL. HR is achieved rapidly with DBT, particularly with DCT.