Melphalan and Dexamethasone Plus Bortezomib Induces Hematologic and Organ Responses in AL-Amyloidosis with Tolerable Neurotoxicity.
Authors: Zonder Jeffrey A , Sanchorawala Vaishali , Snyder Rachel M. , Matous Jeffrey , Terebelo Howard , Janakiraman Nalini , Mapara Markus Y , Lalo Silvana , Tageja Nishant , Webb Craig , Monsma David , Sellers Catherine , Abrams Judith , Gasparetto Cristina 
Published: October 2019

Abstract
Abstract 746

Introduction:
Primary systemic amyloidosis (AL) is a monoclonal plasma cell disorder associated with progressive organ dysfunction and short survival. Standard therapy for patients (pts) not eligible for autologous stem cell transplant (ASCT) is melphalan (Mel; M) + dexamethasone (Dex; D). With non-ASCT therapy, the median overall survival (OS) of high-risk AL pts remains < 1 yr. After the VISTA study showed the addition of bortezomib (Bz) to Mel + Prednisone improved response rate, complete response rate, response duration, and OS in pts with myeloma, we designed this study to determine if adding Bz to MD improves outcomes in AL.

Key eligibility criteria:
ECOG PS ≤ 3, Cr ≤ 5 mg/dL, T.Bili ≤ 2.5 x IULN, ALT/AST ≤ 3 x IULN, ANC ≥ 1.0 K/mm3, PLT ≥ 80 K/mm3, peripheral neuropathy (PN) ≤ Gr 2 (≤ 1 if painful), no lower limit for LVEF.

Study design:
Two-stage Phase II study. Stage I: 16 pts with biopsy-proven AL or light chain deposition disease (LCDD). 1° endpoint: complete hematologic responses (cHR). If ≥5 cHRs observed, then 2nd stage with 17 more pts to be opened. The study has a 90% power to detect a true cHR rate of 50%. 2° endpoints include overall HR (cHR + Partial Responses (PR)), organ response (OrR), and OS.

Treatment:
M (9 mg/m2 PO days 1-4; 6 mg/m2 if Cr > 2.5 mg/dL), Bz (1.3 mg/m2 IV days 1, 8, 15, 22; 1.0 mg/m2 if pt has PN at baseline) and D (40 mg PO/IV days of & days after Bz; 20 mg if ≥ 70 yrs, peripheral edema, or CHF) in 4-6 wk cycles, max of 20 cycles. PN was assessed serially with the FACT/GOG-Ntx survey.

Results:
To date, 23 pts have been enrolled: 21 with AL; 2 with LCDD. Med age 64 (range: 47-76). Med # prior Rx: 1 (range: 0-2; 7 with ≥1 prior ASCT). Med # organs involved: 4 (range 1-6; 8 pts with ≥ 3). PS 0-1/2-3: 18/1. Response data for the 16 pts comprising stage 1 of this two-stage study are reported here; accrual of all 33 pts is expected to be complete by ASH, and results will be updated. One pt who was not response-evaluable (RE) for HR is included in toxicity data (n=17). Med # cycles MD-Bz: 4+ (range: 2-12+; 9 pts still on treatment). 15 of 16 pts had heme responses: 6 cHRs & 9 PRs. Ten RE pts had OrR (2 cardiac, 3 renal, 6 nerve, 1 lung; total >10 because some pts improved in > 1 organ). Nerve symptom improvement occurred exclusively in pts with cHR. Two pts had progressive disease (PD). Two pts died (4.5 and 9 mos from enrollment, from pneumonia and PD, respectively). Despite baseline dose adjustment for co-morbidities, 12 pts needed subsequent dose-reduction of ≥ 1 of the study meds during therapy (10 Bz, for thrombocytopenia and/or PN in almost all cases). Five pts developed neutropenia (Gr 3-4: 1), 15 pts developed thrombocytopenia (Gr 3-4: 11). Nine pts developed peripheral neuropathy (Gr 3: 2). Other grade 3-4 non-hematologic AEs seen in ≥ 2 pts included edema (5), syncope (3), SVT (2), dehydration (2), fatigue (2), and renal failure (2). One pt developed reversible cardiomyopathy (cycle 8) attributed to Bz. Calculated sensory/dysfunction (S/D) composite scores based on patient responses from the FACT/GOG-Ntx survey improved in 7 of 14 pts between cycles 1 and 4, were stable in 4 pts and worsened in only 3. On average, the S/D score accounted for 43% of each pt's total Ntx score at baseline, whereas it only accounted for 39% of the score after 4 cycles, and 45% after 8 cycles, indicating progressive disability from Bz-related PN was uncommon. As results of nerve conduction studies did not correlate well with reported symptoms or FACT/GOG-Ntx scores in stage 1 of the study, mandatory EMGs were discontinued in stage 2.

Conclusions:
MD-Bz shows promising activity in the treatment of AL, with 94% of pts in the first stage of this trial achieving HR (38% cHR) and evidence of OrR observed in 63%. Toxicity is manageable, but meds often require baseline or subsequent dose adjustment. A randomized study of MD +/- Bz in AL is planned.

Disclosures:
Zonder: Cephalon: Consultancy; Pfizer: Consultancy; Amgen: Consultancy; Millennium: Consultancy, Research Funding, Speaking CME Only, No PromotionalTalks; Celgene: Speaking CME only; no Promotional Talks. Off Label Use: Bortezomib is being used in the treatment of AL amyloidosis in this trial; it is currently approved for use as treatment of multiple myeloma.. Matous:Celgene: Honoraria, Speakers Bureau; Cephalon: Speakers Bureau. Janakiraman:Millennium: Honoraria, Research Funding. Mapara:Resolyx: Membership on an entity's Board of Directors or advisory committees, Research Funding; Cephalon: Membership on an entity's Board of Directors or advisory committees, My Wife: Suzanne Lentzsch, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, My wife: Suzanne Lentzsch, Research Funding; Sentium: Stocks. Gasparetto:Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.