ANCHOR: melflufen plus dexamethasone and daratumumab or bortezomib in relapsed/refractory multiple myeloma: final results of a phase I/IIa study

Melphalan flufenamide (melflufen), a first-in-class, alkylating peptide-drug conjugate, demonstrated clinical benefit in combination with dexamethasone in triple-class refractory multiple myeloma (MM). The phase I/IIa ANCHOR study evaluated melflufen (30 or 40 mg) and dexamethasone (40 mg with daratumumab; 20 mg followed by 40 mg with bortezomib; dose reduced if aged ≥75 years) in triplet combination with daratumumab (16 mg/kg; daratumumab arm) or bortezomib (1.3 mg/m2; bortezomib arm) in patients with relapsed/refractory MM refractory to an immunomodulatory agent and/or a proteasome inhibitor and who had received one to four prior lines of therapy. Primary objectives were to determine the optimal dose of melflufen in triplet combination (phase I) and overall response rate (phase IIa). In total, 33 patients were treated in the daratumumab arm and 23 patients received therapy in the bortezomib arm. No dose-limiting toxicities were reported at either melflufen dose level with either combination. With both triplet regimens, the most common grade ≥3 treatment-emergent adverse events were thrombocytopenia and neutropenia; thrombocytopenia was the most common treatment-emergent adverse event leading to treatment discontinuation. In the daratumumab arm, patients receiving melflufen 30 mg remained on treatment longer than those receiving the 40-mg dose. In the daratumumab arm, the overall response rate was 73% and median progression-free survival was 12.9 months. Notably, in the bortezomib arm, the overall response rate was 78% and median progression-free survival was 14.7 months. Considering the totality of the data, melflufen 30 mg was established as the recommended dose for use with dexamethasone and daratumumab or bortezomib for future studies in relapsed/refractory MM.

Melflufen plus dexamethasone in relapsed/refractory multiple myeloma: long-term survival follow-up from the Phase II study O-12-M1

An updated survival analysis was conducted for the Phase II study O-12-M1 of melphalan flufenamide (melflufen) plus dexamethasone in patients with relapsed/refractory multiple myeloma (RRMM) with two or more prior lines of therapy (including bortezomib and lenalidomide). Partial response or better was seen in 31%. After a 46-month median overall survival (OS) follow-up, melflufen plus dexamethasone had a median OS of 20·7 months (75th percentile OS, 47·5 months). The median time-to-next treatment for melflufen plus dexamethasone was 7·9 months. In summary, melflufen plus dexamethasone resulted in sustained long-term clinical benefit in patients with RRMM.

ANCHOR (OP-104): Melflufen plus dexamethasone (dex) and bortezomib (BTZ) in relapsed/refractory multiple myeloma (RRMM)—Optimal dose, updated efficacy and safety results

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Background: Development of resistance to standard treatments for RRMM highlights the need for novel therapies. Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate (PDC) that leverages aminopeptidases and rapidly releases alkylating agents inside tumor cells. Melflufen + dex showed clinical activity and an acceptable safety profile in HORIZON (Richardson et al. J Clin Oncol. 2020 Dec 9 [Epub]). This is an update of the BTZ arm of the phase 1/2a ANCHOR study (NCT03481556). Methods: Patients (pts) with RRMM were intolerant or refractory to a prior IMiD, with 1-4 prior lines of therapy (LoTs). Prior treatment with a proteasome inhibitor (PI) was allowed, but pts could not be refractory to PIs in the last LoT. Melflufen (30, 40, or 20 mg intravenously; d 1 of each 28-d cycle) was administered with BTZ (1.3 mg/m2 subcutaneous) + oral dex (20 mg on d 1, 4, 8, and 11 and 40 mg on d 15 and 22; dex dose reduced if aged ≥ 75 y). The primary objective in phase 1 was to determine the optimal phase 2 dose of melflufen for this combination. Results: As of the data cutoff date (October 19, 2020), 13 pts received melflufen (30 mg, n = 6; 40 mg, n = 7) + dex and BTZ. In the 30 mg and 40 mg cohorts, respectively, median age was 78.5 y (range, 70-82) and 70.0 y (range, 61-76); median prior LoTs was 3.5 (range, 2-4) and 2.0 (range, 1-4); 33% and 50% of evaluable pts had high-risk cytogenetics; 83% and 71% were refractory to last LoT; 100% and 86% received a prior PI; 33% and 14% were refractory to PIs. In the 30 mg and 40 mg cohorts, respectively, median treatment duration was 6.5 mo (range, 1.4-29.0) and 8.7 mo (range, 2.1-19.6); 4 (67%) and 4 pts (57%) were still on treatment; 2 and 3 pts discontinued (30 mg: progressive disease [PD] and other [1 pt each]; 40 mg: adverse event [AE], lack of efficacy, and PD [1 pt each]). Confirmed overall response rate in the 30 mg and 40 mg cohorts, respectively, was 50% (1 very good partial response [VGPR] and 2 partial response [PR]) and 71% (1 complete response, 3 VGPR, and 1 PR). Most common grade 3/4 treatment-related AEs (TRAEs) were thrombocytopenia (30 mg: 50%; 40 mg: 100%) and neutropenia (30 mg: 33%; 40 mg: 71%); grade 3/4 nonhematologic TRAEs were infrequent; 3 pts discontinued study treatment due to treatment-emergent AEs (30 mg: cardiac failure chronic and osteolysis [1 pt each]; 40 mg: thrombocytopenia [1 pt]). Serious TRAEs occurred in 2 pts (33%) in the 30 mg cohort (neutropenia and pneumonia [1 pt], syncope [1 pt]) and 1 pt (14%) in the 40 mg cohort (thrombocytopenia and neutropenia). No dose-limiting toxicities occurred at either dose level. Fatal AEs occurred in 1 pt in the 30 mg cohort (cardiac failure chronic; unrelated to study treatment). Conclusions: ANCHOR determined that the optimal dose of melflufen is 30 mg + dex and BTZ; results showed clinical activity in heavily pretreated pts. Recruitment is ongoing; updated data will be presented. Clinical trial information: NCT03481556.

Analysis of time to next treatment (TTNT) in melflufen and dexamethasone-treated patients (pts) with relapsed/refractory multiple myeloma (RRMM)

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Background: Melflufen is a novel peptide-conjugated alkylator potentiated by intracellular aminopeptidases, which are markedly overexpressed in MM. Melflufen + dex had encouraging activity in pts with RRMM and ≥2 prior lines of therapy in the phase 1/2 O-12-M1 study (overall response rate 31%; median overall survival of 20.7 mo; Richardson et al. ASH 2017. Abs. 3150). TTNT is used in Real World Evidence (RWE) to assist treatment decisions and support economic reimbursement modeling. We report TTNT after melflufen + dex in O-12-M1. Methods: Pts with RRMM and ≥2 prior lines of therapy, including bortezomib and lenalidomide (len) received 40 mg IV melflufen on d 1 of each 28-d cycle + 40 mg weekly dex until progressive disease (PD)/unacceptable toxicity. Pts were followed up for 2 y after PD, and TTNT was retrospectively reviewed for subsequent therapy. Results: As of 9 Nov 2017, 45 pts were treated: median age, 66 y (47-78); ISS stage II/III, 60%; high-risk cytogenetics, 44%. Pts had 4 median prior lines of therapy; 87% were refractory to last line of therapy including alkylators (24%), proteasome inhibitors (PIs; 27%), IMiDs (56%), and monoclonal antibodies (mAbs, 9%); 11% were last-line double refractory. At data cutoff, 44 pts (98%) discontinued melflufen + dex, mainly due to adverse events (40%) and PD (29%). 26 pts received subsequent therapy. Median time from start of melflufen + dex to first subsequent therapy or death, whichever occurred first, (TTNT) was 7.9 mo (95% CI: 5.7-11.0); next therapy included alkylators (27%), PIs (38%), IMiDs (58%), and mAbs (8%). Conclusions: Types of subsequent salvage therapy used after melflufen + dex were similar to studies of approved agents in RRMM; TTNT was also similar (Table). Further trials are ongoing, including melflufen + dex vs pomalidomide (pom) + dex in pts with RRMM refractory to len (Phase 3 OCEAN study; NCT03151811). Clinical trial information: NCT01897714. [Table: see text]

[Nuclear magnetic resonance tomography of the spine and spinal cord compared with computed tomography and myelography]

In cases of syringomyelia MR is superior to CT and myelography in visualisation and delineation of the extent of the process. In diagnosing spinal tumours MR is a more sensitive method than CT and myelography. MR provides additional information on sagittal and frontal planes regarding the extent of the tumour. In diagnosis of disc prolapse MR seems to be as accurate as CT or myelography. We obtained additional information in diagnosis of degenerated disc tissue. Spinal stenosis is easily recognisable. CT was superior in differentiation of bony and disc protrusion. The results show that MR has opened up new possibilities in the diagnosis of spinal diseases and will result in a reorientation of the diagnostic approach.