Long-term outcomes of IMiD-based trials in patients with immunoglobulin light-chain amyloidosis: a pooled analysis

Rarity of light-chain amyloidosis (AL) makes randomized studies challenging. We pooled three phase II studies of immunomodulatory drugs (IMiDs) to update survival, toxicity, and assess new response/progression criteria. Studies included were lenalidomide-dexamethasone (Len-Dex) (n = 37; years: 2004–2006), cyclophosphamide-Len-Dex (n = 35; years: 2007–2008), and pomalidomide-Dex (n = 29; years: 2008–2010) trial. Primary endpoint was hematologic response. Overall survival (OS) was calculated from registration to death and progression-free survival (PFS) was calculated from registration to progression or death. Hematologic, cardiac, and renal response/progression was assessed using the modern criteria. Analysis included 101 patients, with a median age of 65 years, 61% male, 37 newly diagnosed (ND), and 64 relapsed/refractory (RR). Median follow-up was 101 months (range 17–150) and 78% of patients died. OS and PFS for pooled cohort were 31 and 15 months, respectively. Forty-eight patients achieved a hematologic response; for ND, 10 patients (28%) achieved ≥VGPR (very good partial response) and 8 (14%) among the RR. Only cardiac stage was prognostic for OS. Common grade ≥3 toxicities were hematologic, fatigue, and rash, and were similar among studies. Hematologic and renal responses occurred more frequently and rapidly using modern response criteria; cardiac response was less frequent but occurred quickly. IMiDs can result in long progression-free intervals/survival with tolerable toxicities. The new response/progression criteria were rapid and allows for tailoring therapy.