ALBERT

Description: Background: The International Society of Amyloidosis validated the criteria of hematologic response to therapy in AL amyloidosis, based on the reduction of free light chain (FLC) concentration and serum and urine immunofixation. Complete response (CR) predicted the longest survival and was defined by negative serum and urine immunofixation (s&u-IFE) with a normal FLC ratio (FLCR). Subsequently, we and others showed that, in patients with a difference between involved and uninvolved FLC (dFLC) between 20 and 49 mg/L, achieving a dFLC

Description: Background: AL amyloidosis is a rare life-threatening disease arising from a disorder of plasma cells resulting in excessive immunoglobulin free light chains (FLC) that are misfolded, aggregate, and form toxic deposits in vital organs including the heart, kidneys, and liver (Merlini G, et al. Nat Rev Dis Primers. 2018). The primary goal of therapy is to reduce or eliminate the FLC and halt the progression of organ damage and improve function. Measures that can improve hematologic responses may improve organ responses and impact survival. Treatments used in other plasma cell disorders, like multiple myeloma (MM), including autologous stem cell transplantation (ASCT), are commonly used to treat AL amyloidosis. However, there are no approved therapies for AL amyloidosis. Effective treatment, especially for patients with advanced cardiac involvement, remains a high unmet medical need (Merlini G, et al. Nat Rev Dis Primers. 2018; Milani P, et al. Expert Rev Hematol. 2018). Melflufen, a lipophilic peptide-conjugated alkylator that rapidly delivers a highly cytotoxic payload into cells through peptidase activity, is currently under investigation for the treatment of relapsed/refractory MM (RRMM). In the phase 1/2 study, O-12-M1, of patients with RRMM and ≥2 prior lines of therapy, including lenalidomide and bortezomib, melflufen plus dexamethasone showed an overall response rate of 31%, median progression-free survival of 5.7 months, and median overall survival of 20.7 months, with manageable hematologic toxicity (Richardson PG, et al. Blood. 2017; Abstract 3150). The activity of melflufen in RRMM suggests that it may have potential therapeutic applications for patients with AL amyloidosis. OP201 is a planned, phase 1/2, open-label study evaluating the safety and efficacy of melflufen and dexamethasone in patients who have AL amyloidosis and have received ≥1 prior therapy. Study Design: The planned enrollment for OP201 is approximately 46 patients. Patients must have AL amyloidosis and ≥1 prior therapy, which can include 1 prior nontransplant regimen, a prior ASCT, or 1 prior induction regimen followed by a single ASCT (without hematologic progression between induction and ASCT). Other key inclusion criteria include measurable hematologic and organ involvement (cardiac and/or renal and/or liver), Eastern Cooperative Oncology Group performance status ≤2, adequate baseline hematologic and organ function, ≤30% bone marrow plasma cells, echocardiogram with left ventricular ejection fraction ≥45% and electrocardiogram with QTcF interval of ≤470 ms. Key exclusion criteria include evidence of gastrointestinal bleeding, cardiac risk stage 3 with N-terminal pro-brain natriuretic peptide 〉5000 pg/mL, active infection, concurrent symptomatic MM, significant ventricular arrhythmias, and severe orthostatic hypotension. Phase 1 dose escalation will follow a standard 3+3 design, with 3 to 6 patients evaluable for dose-limiting toxicity at each dose level. Patients will receive melflufen intravenously at 1 of 3 dose levels (20 mg, 30 mg, or 40 mg) on day 1 and oral dexamethasone 40 mg (20 mg at investigator's discretion) on days 1 and 2 of each 28-day cycle. Treatment will continue for up to 8 cycles until stable hematologic partial response or better after cycle 4, less than hematologic partial response after cycle 2, nonhematologic or hematologic disease progression, unacceptable toxicity, or physician's determination that it is not in patient's best interest to continue treatment. The primary endpoints for the phase 1 study are safety and identifying the recommended phase 2 dose (RP2D) of melflufen. Phase 2 will include 26 patients (20 phase 2 + 6 phase 1) treated at the RP2D. The primary endpoint for phase 2 is the hematologic overall response rate after 4 cycles of treatment. Key secondary endpoints include pharmacokinetics (phase 1), best hematologic response, duration of hematologic response, organ system-specific response, duration of organ system-specific responses, time to next AL amyloidosis treatment, and overall survival. Disclosures Palladini: Sebia: Honoraria; Celgene: Other: Travel grant; Janssen-Cilag: Honoraria; Janssen-Cilag: Other: Travel grant. Schönland:Prothena: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Medac: Other: Travel Grant; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Lentzsch:Abbvie: Consultancy; Crossfires in hematologic Malignancies: Honoraria; BMS: Consultancy; Takeda: Consultancy; Clinical Care Options: Speakers Bureau; Columbia University: Patents & Royalties: 11-1F4mAb as Anti-Amyloid Strategy; Janssen: Consultancy; Multiple Myelopma Research Foundation: Honoraria; Bayer: Consultancy; Sanofi: Consultancy, Research Funding; Proclara: Consultancy; Caelum Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Research Funding; International Myeloma Foundation: Honoraria. Cibeira:Amgen: Honoraria; Celgene: Honoraria; Janssen: Consultancy, Honoraria. Hajek:PharmaMar: Honoraria, Other: Consultant or advisory relationship; Novartis: Other: Consultant or advisory relationship, Research Funding; Janssen: Honoraria, Other: Consultant or advisory relationship, Research Funding; Amgen: Honoraria, Other: Consultant or advisory relationship, Research Funding; Bristol-Myers Squibb: Honoraria, Other: Consultant or advisory relationship, Research Funding; AbbVie: Other: Consultant or advisory relationship; Celgene: Honoraria, Other: Consultant or advisory relationship, Research Funding; Takeda: Honoraria, Other: Consultant or advisory relationship, Research Funding. Jaccard:Celgene: Honoraria, Research Funding; Abbvie: Honoraria; Janssen: Honoraria, Research Funding; Pfizer: Honoraria. Jamroziak:Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. Kastritis:Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Honoraria; Prothena: Honoraria; Genesis: Honoraria. Sanchorawala:Proclara: Consultancy, Honoraria; Caelum: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Research Funding; Celgene: Research Funding; Takeda: Research Funding; Prothena: Research Funding. Schjesvold:SkyliteDX: Honoraria; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Wechalekar:Celgene: Honoraria; GSK: Honoraria; Amgen: Research Funding; Janssen-Cilag: Honoraria; Takeda: Honoraria. Thuresson:Oncopeptides: Employment, Equity Ownership. Harmenberg:Oncopeptides: Consultancy, Equity Ownership. Byrne:Takeda: Consultancy; Oncopeptides: Consultancy. Merlini:University of Pavia: Employment.

Description: Introduction: The monoclonal antibody daratumumab showed high response rates and a good safety profile in multiple myeloma and is being evaluated in clinical trials in AL amyloidosis. Light chain deposition disease (LCDD) is a rare monoclonal gammopathy of renal significance. Treatment directed against the underlying plasma cell clone can prevent renal progression. Bortezomib is commonly used upfront in these patients and daratumumab may represent a powerful novel option. Methods: We report the outcome of six patients with refractory light chain deposition disease (LCDD) treated with daratumumab at the Amyloidosis Research and Treatment Center of Pavia. All patients gave written informed consent. Hematologic response was assessed according to the International Society of Amyloidosis criteria. Results: Six patients (5 males and 1 female) received daratumumab intravenously at 16 mg/kg weekly for 8 weeks, followed by every other week infusions for 8 doses and then monthly infusions. Patients' clinical characteristics are reported in Table 1. All patients received daratumumab single agent except one who was treated with daratumumb and bortezomib combination (this patient received only 1 prior line of therapy). All patients were refractory to the last line of therapy. All patients received at least two months of therapy. All patients were previously treated with bortezomib, pomalidomide was used in 4 cases, lenalidomide, thalidomide and bendamustine in 2 cases each, and autologous stem cell transplant was performed in 4 subjects. The median time from LCDD diagnosis to daratumumab initiation was 8.3 years (range 8 - 147 months). Five of the 6 patients obtained hematologic response with at least a reduction of 50% of the dFLC value (partial response). Three patients obtained a very good partial response (dFLC

Description: Proteasome inhibitors (PIs) are effective against multiple myeloma (MM), but the mechanisms of action and bases of individual susceptibility remain unclear. Recent work linked PI sensitivity to protein synthesis and proteasome activity, raising the question whether different levels of proteasome expression and workload underlie PI sensitivity in MM cells (MMCs). Exploiting human MM lines characterized by differential PI sensitivity, we report that highly sensitive MMCs express lower proteasome levels and higher proteasomal workload than relatively PI-resistant MMCs, resulting in the accumulation of polyubiquitinated proteins at the expense of free ubiquitin (proteasome stress). Manipulating proteasome expression or workload alters apoptotic sensitivity to PI, demonstrating a cause-effect relationship between proteasome stress and apoptotic responses in MMCs. Intracellular immunostaining in primary, patient-derived MMCs reveals that polyubiquitinated proteins hallmark neoplastic plasma cells, in positive correlation with immunoglobulin (Ig) content, both intra- and interpatient. Moreover, overall proteasome activity of primary MMCs inversely correlates with apoptotic sensitivity to PI. Altogether, our data indicate that the balance between proteasome workload and degradative capacity represents a critical determinant of apoptotic sensitivity of MMCs to PI, potentially providing a framework for identifying indicators of responsiveness and designing novel combination therapies.

Description: We report the use of NT-ProBNP (N-terminal fragment of brain natriuretic peptide) as an independent marker to identify patients with AL amyloidosis whose clonal response to chemotherapy is inadequate. The aim of chemotherapy is to allow improvement in amyloidotic organ function but the significant time lag often means that patients are either over or under treated. Use of biomarkers (such as BNP and NT-ProBNP) for risk stratification is an area of increasing interest. 200 patients with AL amyloidosis diagnosed between 2004–2007, who had completed one line of treatment and had a complete results available prior to and six month from the start of treatment, were identified from the databases of the Amyloidosis centres in Pavia, Italy and London, UK. Organ involvement and response was assessed according to the international consensus criteria (Gertz et al 2005). NT-ProBNP change was deemed significant if there was a rise or fall of both 30% and 〉300 ng/L over the starting value. Kaplan-Meier and Cox regression were used for survival analysis as appropriate. The median age was 63 yrs (range 38–83) and the median number of organs involved was 2. 132 (66%) had cardiac involvement, 150 (75%) had renal and 42 (21%) had liver involvement at presentation. 115 (56%) responded to chemotherapy with a complete response (CR) in 34 (17%) and a partial response in 81 (40%). At baseline, median NT-ProBNP was 1865 ng/L (range 50–70144) and was 〉332 ng/L (the cut-off reported as significant by Dispenzieri et al, J Clin Oncol 2004) in 159 patients (80%). The median follow-up was 23 months. The median overall survival (OS) has not been reached with an estimated 2 yr survival of 71%. Patients with cardiac involvement had worse outcomes (OS 29 mo vs. not reached; p =0.001) whereas renal, liver, neuropathy, soft tissue involvement, the light chain type or presence of a measurable M protein did not significantly impact survival. Haematologic responders had a significantly better overall survival (median not reached) than non-responders (median 22 months; p

Description: Abstract 3889 Poster Board III-825 Oral melphalan and dexamethasone (MDex) has been adopted in many referral centers as standard therapy for AL amyloidosis, particularly in patients who are not eligible for high dose melphalan (M) and autologous stem cell transplant (ASCT). A randomized trial failed to demonstrate the superiority of ASCT over MDex, and phase III trials are being designed to compare MDex with regimens including new drugs. However, only few small series of patients treated with MDex have been published so far. We report the outcome of 126 consecutive patients with AL amyloidosis who received first line MDex between January 2004 and December 2007. All the patients who were not eligible for ASCT with high dose M, due to any of the following conditions: age 〉60 years, N terminal natriuretic peptide type B (NT-proBNP) 〉332 ng/L, troponin I (cTnI) 〉0.1 ng/mL, glomerular filtration rate (eGFR) ≤50 mL/min, were included. Patients were given M (0.22 mg/Kg, or 0.16 mg/Kg if eGFR was 3% of body weight or complex ventricular arrhythmias at 24 h Holter ECG) on days 1-4 q28 days for up to 9 cycles. Treatment was discontinued if complete remission (CR) or partial hematologic response (PR) plus organ response (OR) was reached after 6 cycles, or in case of lack of response after 3 cycles. The International Society for Amyloidosis (ISA) consensus criteria for hematologic and organ response and progression were used. Progression free survival (PFS) was defined as the time to death or hematologic or organ progression according to the ISA criteria. Response and progression of NT-proBNP were defined as 3300 ng/L and 330% modifications. The median number of organs involved was 2 (range 1-5), 92 patients (73%) had heart involvement, with New York Heart Association (NYHA) class ≥2 heart failure in 66 cases (60%) and 93 patients (74%) had renal involvement, with eGFR 0.1 ng/mL in 27 patients (22%) and NT-proBNP was 〉332 ng/L in 99 (79%). Twenty-four patients (19%) experienced severe, though non fatal, adverse events. The most common was fluid retention (12%), that was significantly associated with NYHA class (p=0.02) and cTnI concentration (p

Description: Proteasome inhibitors (PI) proved to be extremely effective against different types of cancer, particularly against Multiple Myeloma (MM), a frequent and still incurable plasma cell malignancy. Phase II clinical trials showed that more than 50% of MM patients fail to respond to bortezomib, the only PI currently approved for clinical use. However, the mechanisms of action and bases of individual susceptibility to PI remain largely unclear, with no reliable predictor of response identified so far. Recent evidences linking proteasome activity and Ig synthesis to susceptibility to PI suggest that the exquisite sensitivity of MM cells (MMC) to PI might be explained by an imbalance between the efficiency of the ubiquitin (Ub)-proteasome pathway and the demand for proteasome-mediated degradation. We set out to explore this hypothesis both in vitro and ex vivo. To achieve this aim, we employed human MM cell lines characterized by differential apoptotic sensitivity to PI (U266 and RPMI8226, fairly resistant cell lines, versus MM.1S, an extremely sensitive one) and primary, patient derived MMC. In MM cell lines, we found that high apoptotic sensitivity to PI is associated with lower expression of active proteasomes (as assessed by decreased expression of cleaved catalytic subunits and enzymatic assays with fluorogenic substrates in cell extracts), together with higher proteasomal workload (demonstrated by higher proteasome-dependent loss of TCA-insoluble radioactivity in pulse-chase assays). Indeed, MM.1S cells displayed 2–3 times lower proteasomal activity as compared to the more resistant U266 and RPMI8226 cells, both on a per cell basis and upon normalization by protein content. Together with the reduced proteasome capacity, MM.1S cells showed a consistently higher production of client proteins for the Ub-proteasome pathway. Such an increased load appears to be the consequence of a higher production of Rapidly Degraded Polypeptides (RDP). These are newly synthesized proteins which are quickly redirected to proteasome-mediated degradation. The imbalance between proteasomal load and capacity results in remarkable accumulation of poly-Ub proteins at the expense of free Ub (as established by both western blotting and immunofluorescence), unveiling basal proteasome stress in PI-sensitive MMC. In order to establish a causal link between proteasome stress and sensitivity to PI, we pharmacologically modulated either proteasome expression or workload and successfully altered PI-induced apoptosis. As predicted, increasing proteasome workload by means of ER stressors (e.g. tunicamycin, thapsigargin, brefeldin A) dramatically enhances susceptibility to PI, while a raise in proteasomal activity (achieved by exploiting the proteasome stress response, an adaptive mechanism by which mammalian cells induce proteasome biogenesis in response to either decreased proteasome function or increased proteasomal demand), confers marked resistance to PI-induced apoptosis. Having established cause-effect relationships between determinants of proteasome stress and vulnerability to PI in vitro, we then asked if our model could be used to predict responsiveness to PI in MM patients. In keeping with this hypothesis, intracellular immunostaining in primary, patient-derived MMC reveals that accumulation of poly-Ub proteins specifically hallmarks neoplastic plasma cells, indicating that the cancer compartment in MM patients suffers from proteasome stress. Moreover, poly-Ub levels positively correlate with Ig content, both intra- and inter-patient, suggesting a direct effect of Ig synthesis and/or retention on proteasome functional load. Finally, overall proteasome activity of primary MMC inversely correlates with the intrinsic apoptotic sensitivity to PI as assessed ex vivo, providing a rationale for the assessment of this parameter as a potential predictor of the in vivo response to bortezomib or other PI. Altogether, our data indicate that the balance between proteasome workload and degradative capacity represents a critical determinant of apoptotic sensitivity of MMC to PI, providing both a novel predictive tool of potential prognostic value and the framework for novel combination therapies aimed at exacerbating proteasome stress in MM.