Real-world (RW) treatment patterns and comparative effectiveness of Bruton tyrosine kinase inhibitors (BTKi) in patients (pts) with mantle cell lymphoma (MCL)

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Background: BTKi therapies, approved for relapsed or refractory (R/R) MCL, have not been comprehensively evaluated in RW populations. This study aimed to assess patient characteristics, treatment patterns and associated outcomes in RW BTKi-treated MCL pts. Methods: The retrospective multicenter chart review was conducted in the Cardinal Health Oncology Provider Extended Network. EMR data were extracted for eligible pts diagnosed with MCL who initiated any of the approved BTKi (ibrutinib [ibr], acalabrutinib [acal], zanubrutinib [zanu]) from 2018 to 2021; pts enrolled in trials were excluded. Index date was defined as the use of any of the BTKis. Pts were followed 12-mo pre-index for medical history, and from index to last follow-up or death. Descriptive analyses were conducted to assess demographic/clinical characteristics, MCL baseline features, BTKi treatment patterns, adverse events (AE), and response rates by BTKi. Multivariable logistic regression was performed to assess factors associated with response and AE. Results: The study cohort consisted of 300 MCL pts (59% male; 69% white); most (64%) pts were covered by Medicare, 34% had commercial insurance. BTKis were given mainly as monotherapy (93%) and in R/R setting (86%). Pts in zanu group were significantly older (n = 100, median age = 71, range = 50-91) than pts in ibr (n = 100, median age = 69, range = 39-87) and acal (n = 100, median age = 70, range = 51-86) groups. Significantly fewer pts in the zanu group had baseline Ann Arbor stage I-II (4%) than ibr (10%) or acal (13%), while more zanu pts had presence of B symptoms (67%) than ibr (44%) or acal (57%). Pts in the zanu group also had significantly less with ECOG of 3+ (4%) compared to ibr (8%) or acal (6%). At BTKi initiation, significantly more pts in zanu group (18%) had history of atrial fibrillation than ibr (1%) or acal (5%). Multivariable regression reported a significant association of age, gender, extranodal/splenic involvement, and timing of BTKi initiation with response and AE (Table). Conclusions: This study provides the first RW evidence on comparative effectiveness of ibr, acal, zanu in MCL pts. While pts treated with zanu were older and had more complex MCL baseline features at initiation, multivariable regression suggested a trend favoring zanu over ibr or acal for both response and AE. Frontline initiation of BTKi therapy was also associated with improved tolerability. Future RW studies are needed to discern long-term outcomes.[Table: see text]

Randomized phase II trial of bortezomib, lenalidomide, dexamthasone with/without elotuzumab for newly diagnosed, high risk multiple myeloma (SWOG-1211)

8054

Background: The introduction of immunomodulatory agents, proteasome inhibitors, and autologous stem cell transplantation (ASCT) has improved outcomes for patients with multiple myeloma (MM), but those with high risk MM (HRMM) have a poor long-term prognosis. Herein we provide survival outcomes on the first randomized trial in newly diagnosed HRMM, S1211, to follow-up on the previously reported progression-free survival (PFS) (NCT01668719, Usmani SZ et al, Lancet Haem 2021). Methods: S1211 is a randomized phase II trial comparing 8 cycles of lenalidomide, bortezomib and dexamethasone (RVd) induction followed by dose-attenuated RVd maintenance until disease progression with or without elotuzumab (RVd-Elo). Stem cell collection was allowed, but ASCT was deferred until progression. HRMM was defined by one of the following: gene expression profiling high-risk (GEPhi), t(14;16), t(14;20), del(17p), amplification 1q21, primary plasma cell leukemia (pPCL), or elevated serum LDH (> 2X ULN). Median PFS was the primary endpoint, using a one-sided stratified log-rank test at a one-sided significance level of 0.1. Secondary endpoints included overall response rate (ORR), adverse events (AE), serious adverse events (SAE) and OS. Response was assessed using the IMWG 2009 criteria. Results: S1211 enrolled 103 evaluable patients, RVd n=54, RVd-Elo n=49. 74% had ISS II/III, 48% amp1q21, 38% del(17p), 11% t(14;16), 9% GEPhi, 7% pPCL, 5% t(14;20) and 4% elevated LDH (17% >1 feature). With median follow-up of 72 months (mos.), no difference in median PFS was observed [RVd-Elo=29 mos., RVd= 34 mos., HR = 1.11 (80% CI=0.82, 1.49, p=0.66]. No difference in OS was observed [RVd-Elo = median not reached (NR), RVd= 68 mos., HR = 0.85 (80% CI: 0.59, 1.23), p-value = 0.58]. 76% pts had >Grade 3 AEs, no differences in the safety profile were observed. Amongst patients with gain/amp 1q21, median PFS was [RVd-Elo=31 mos., RVd= 37 mos., HR = 1.48 (80% CI= 0.95, 2.31), p=0.25], median OS was [RVd-Elo = 61 mos., RVd= 68 mos., HR = 1.23 (80% CI: 0.72, 2.10), p-value = 0.63]. In patients with del(17p), median PFS was RVd-Elo=41 mos., RVd= 30 mos.[HR = 0.98 (80% CI= 0.60, 1.58), p=0.95], median OS RVd-Elo = NR, RVd= 72 mos., [HR = 0.77 (80% CI: 0.40, 1.48), p-value = 0.61]. Conclusions: In the first randomized HRMM study reported to date, the addition of Elo to RVd induction and maintenance did not improve PFS and OS with a median follow-up of 6 years. Although the median PFS for Del17p subgroup on RVd-Elo arm is higher than RVd, it did not achieve statistical significance. The PFS and OS observed for gain/amp 1q21 and del17p in the RVd control arm may serve as important benchmarks for future enrichment design HRMM clinical trials. The PFS and OS in both arms of the study exceeded the original statistical assumptions and support the role for PI/IMiD combination induction/maintenance therapy for this population. Clinical trial information: NCT01668719.

Indatuximab ravtansine plus dexamethasone with lenalidomide or pomalidomide in relapsed or refractory multiple myeloma: a multicentre, phase 1/2a study

BACKGROUND

Indatuximab ravtansine (BT062) is an antibody-drug conjugate that binds to CD138 and synergistically enhances the antitumor activity of lenalidomide in preclinical models of multiple myeloma. This phase 1/2a study was done to determine the safety, activity, and pharmacokinetics of indatuximab ravtansine in combination with immunomodulatory drugs in patients with relapsed or refractory multiple myeloma.

METHODS

This open-label, phase 1/2a study took place at nine hospital sites in the USA. Eligible patients were aged 18 years or older, had relapsed or refractory multiple myeloma, and ECOG performance status or Zubrod score of 2 or below. Patients who received indatuximab ravtansine with lenalidomide and dexamethasone (indatuximab ravtansine plus lenalidomide) had failure of at least one previous therapy. Patients treated with indatuximab ravtansine with pomalidomide and dexamethasone (indatuximab ravtansine plus pomalidomide) had failure of at least two previous therapies (including lenalidomide and bortezomib) and had progressive disease on or within 60 days of completion of their last treatment. In phase 1, patients received indatuximab ravtansine intravenously on days 1, 8, and 15 of each 28-day cycle in escalating dose levels of 80 mg/m², 100 mg/m², and 120 mg/m², with lenalidomide (25 mg; days 1 to 21 every 28 days orally) and dexamethasone (20-40 mg; days 1, 8, 15, and 22 every 28 days). In phase 2, the recommended phase 2 dose of indatuximab ravtansine was given to an expanded cohort of patients in combination with lenalidomide and dexamethasone. The protocol was amended to allow additional patients to be treated with indatuximab ravtansine plus pomalidomide (4 mg; days 1 to 21 every 28 days orally) and dexamethasone, in a more heavily pretreated patient population than in the indatuximab ravtansine plus lenalidomide group. The phase 1 primary endpoint was to determine the dose-limiting toxicities and the maximum tolerated dose (recommended phase 2 dose) of indatuximab ravtansine, and the phase 2 primary endpoint was to describe the objective response rate (ORR; partial response or better) and clinical benefit response (ORR plus minor response). All patients were analysed for safety and all patients with post-treatment response assessments were analysed for activity. This study is registered with ClinicalTrials.gov, number NCT01638936, and is complete.

FINDINGS

64 (86%) of 74 screened patients were enrolled between July 3, 2012, and June 30, 2015. 47 (73%) patients received indatuximab ravtansine plus lenalidomide (median follow-up 24·2 months [IQR 19·9-45·4]) and 17 (27%) received indatuximab ravtansine plus pomalidomide (24·1 months [17·7-36·7]). The maximum tolerated dose of indatuximab ravtansine plus lenalidomide was 100 mg/m², and defined as the recommended phase 2 dose for indatuximab ravtansine plus pomalidomide. An objective response for indatuximab ravtansine plus lenalidomide was observed in 33 (71·7%) of 46 patients and in 12 (70·6%) of 17 patients in the indatuximab ravtansine plus pomalidomide group. The clinical benefit response for indatuximab ravtansine plus lenalidomide was 85% (39 of 46 patients) and for indatuximab ravtansine plus pomalidomide it was 88% (15 of 17 patients). The most common grade 3-4 adverse events in both groups were neutropenia (14 [22%] of 64 patients), anaemia (10 [16%]), and thrombocytopenia (seven [11%]). Treatment-emergent adverse events (TEAEs) that led to discontinuation occurred in 35 (55%) of the 64 patients. Five (8%) patients with a TEAE had a fatal outcome; none was reported as related to indatuximab ravtansine.

INTERPRETATION

Indatuximab ravtansine in combination with immunomodulatory drugs shows preliminary antitumor activity, is tolerated, and could be further evaluated in patients with relapsed or refractory multiple myeloma.

FUNDING

Biotest AG.

Regulatory T-cell depletion in the setting of autologous stem cell transplantation for multiple myeloma: pilot study

BACKGROUND

Progression after high-dose melphalan with autologous stem cell transplantation (ASCT) in multiple myeloma (MM) may be due in part to immune dysfunction. Regulatory T (Treg) cells reconstitute rapidly after ASCT and inhibit immune responses against myeloma cells.

METHODS

We performed a randomized study to evaluate two methods of Treg depletion in patients with MM undergoing ASCT. No Treg depletion was performed in the control ASCT arm. An anti-CD25 monoclonal antibody (basiliximab 20 mg IV) was administered on day +1 post-ASCT in the in vivo Treg depletion (IVTRD) arm. Tregs were depleted from autologous stem cell (ASC) grafts with anti-CD25 microbeads and the CliniMACS device in the ex vivo Treg depletion (EVTRD) arm.

RESULTS

Fifteen patients were enrolled, five in each arm. The conditioning regimen was melphalan 200 mg/m². Primary objectives included assessments of efficiency of IVTRD/EVTRD, kinetics of Treg depletion and recovery following ASCT, and safety. EVTRD removed 90% of CD4⁺CD25⁺ cells from ASC grafts. IVTRD and EVTRD led to reductions in Treg frequency between days +7 and +90 post-transplant compared with the control (p=0.007 and p<0.001, respectively).

CONCLUSIONS

IVTRD and EVTRD are feasible and significantly reduce and delay Treg recovery post-ASCT for MM, and serve as a platform for using post-transplant immunotherapies to improve post-ASCT outcomes.

TRIAL REGISTRATION NUMBER

NCT01526096.

Cost-effectiveness of zanubrutinib versus ibrutinib in adult patients with Waldenström macroglobulinemia in the United States

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Background: The efficacy of zanubrutinib and ibrutinib was examined in the randomized ASPEN trial (NCT03053440) in adult patients with Waldenström macroglobulinemia (WM). This analysis assessed the cost-effectiveness (CE) of zanubrutinib vs ibrutinib in this population from a US payer perspective. Methods: A 3-state (pre-progression, post-progression, and death) partitioned survival model was used to estimate the life years (LYs), quality-adjusted life years (QALYs), and costs for each treatment over a 30-year lifetime horizon. Overall survival (OS), progression-free survival (PFS), and time-to-discontinuation (TTD) curves were fitted using parametric distributions to extrapolate long-term outcomes. Selection of the parametric models for each outcome and treatment was based on assessments of 1) the proportional hazard assumption, 2) goodness-of-fit, and 3) clinical plausibility of extrapolated mean OS and associated hazard patterns (based on literature and US clinical expert input) and the alignment between PFS and TTD. Background US mortality was accounted for in the model. Utilities were based on the ASPEN EQ-5D data and literature. Costs (2020 US$) included drug (wholesale acquisition cost from RED BOOK) and adverse event management (Healthcare Cost and Utilization Project) for zanubrutinib and ibrutinib, routine care, and terminal care. Sensitivity analyses were conducted to evaluate the impact of parameter uncertainty. All outcomes were discounted at 3% annually. Results: In the base case analyses using the dependent exponential model for all outcomes over a 30-year time horizon, zanubrutinib led to 0.94 LY and 0.84 QALY gained with an additional total drug cost of $11,132. This additional cost was primarily driven by patients staying on zanubrutinib treatment longer as zanubrutinib has longer time to treatment failure. However, this is partially offset by zanubrutinib’s lower monthly drug acquisition, reduced cost of routine care (–$2,935) and terminal care (–$2,964) than ibrutinib. The incremental cost-effectiveness ratio (ICER) of zanubrutinib is $13,205 per QALY gained. The deterministic sensitivity analyses showed that ICER was most sensitive to the monthly costs of routine care. The probabilistic sensitivity analyses showed that the mean probabilistic ICER was $16,804, and that the probability of zanubrutinib being cost-effective was 61% at a willingness-to-pay threshold of $100,000 per QALY gained. Varying the time horizon to 5, 10, or 15 years consistently led to zanubrutinib being dominant (i.e., greater QALYs but lower costs). Conclusions: Zanubrutinib appears to be cost-effective compared with ibrutinib for the treatment of patients with WM in the US.[Table: see text]

Efficacy and safety of zanubrutinib versus rituximab-based chemoimmunotherapy in Waldenström macroglobulinemia (WM): Matching-adjusted indirect comparisons

7559

Background: Given a lack of WM randomized trials directly comparing zanubrutinib with chemoimmunotherapy, this study aimed to indirectly compare zanubrutinib with bendamustine-rituximab (BR) and with dexamethasone-rituximab-cyclophosphamide (DRC) separately through matching-adjusted indirect comparisons (MAIC). Methods: MAIC were conducted to re-weight the individual data of 102 WM patients (83 relapsed/refractory [R/R] and 19 treatment-naïve [TN]) treated with zanubrutinib in the ASPEN trial (NCT03053440) so that the weighted average baseline characteristics of patients treated with zanubrutinib matched those of 71 R/R patients treated with BR, and 72 TN patients treated with DRC separately. Matching variables for MAIC with BR included age, prior lines of therapy, IgM concentration, International Prognostic Scoring System for WM score, and extramedullary disease (EMD); and for MAIC with DRC included age, platelet count, hemoglobin concentration, and EMD. Kaplan-Meier curves of progression-free survival (PFS) and overall survival (OS) of comparators were digitized to re-create patient-level data. Comparisons of survival and adverse event incidence between treatments were conducted using Cox proportional hazards models and modified Poisson models. Results: Compared to DRC, zanubrutinib was associated with longer PFS (hazard ratio [HR]: 0.39 [95% confidence interval 0.18-0.82] and 0.35 [0.14-0.86] pre- and post-matching, respectively) and longer OS (HR: 0.56 [0.20-1.53] and 0.47 [0.14-1.62] pre- and post-matching, respectively), and insignificantly higher incidences of neutropenia (risk ratio [RR]: 1.63 [0.71-3.77] and 1.47 [0.58-3.74] pre- and post-matching, respectively). Compared to BR, zanubrutinib was associated with longer PFS (HR: 0.32 [0.15-0.69] and 0.37 [0.15-0.91] pre- and post-matching, respectively), longer OS (HR: 0.31 [0.12, 0.80] and 0.29 [0.10-0.85] pre- and post-matching, respectively), lower incidences of neutropenia (RR: 0.45 [0.26-0.78] and 0.50 [0.27-0.91] pre- and post-matching, respectively) and lower incidences of pneumonia (RR: 0.18 [0.02-1.55] and 0.26 [0.03-2.28] pre- and post-matching, respectively). Conclusions: Zanubrutinib demonstrated longer PFS than DRC, and longer PFS and OS than BR in WM, before and after matching adjustment based on patient characteristics. [Table: see text]

Carfilzomib, lenalidomide, and dexamethasone plus transplant in newly diagnosed multiple myeloma

In this phase 2 multicenter study, we evaluated the incorporation of autologous stem cell transplantation (ASCT) into a carfilzomib-lenalidomide-dexamethasone (KRd) regimen for patients with newly diagnosed multiple myeloma (NDMM). Transplant-eligible patients with NDMM received 4 cycles of KRd induction, ASCT, 4 cycles of KRd consolidation, and 10 cycles of KRd maintenance. The primary end point was rate of stringent complete response (sCR) after 8 cycles of KRd with a predefined threshold of ≥50% to support further study. Seventy-six patients were enrolled with a median age of 59 years (range, 40-76 years), and 35.5% had high-risk cytogenetics. The primary end point was met, with an sCR rate of 60% after 8 cycles. Depth of response improved over time. On intent-to-treat (ITT), the sCR rate reached 76%. The rate of minimal residual disease (MRD) negativity using modified ITT was 70% according to next-generation sequencing (<10-5 sensitivity). After median follow-up of 56 months, 5-year progression-free survival (PFS) and overall survival (OS) rates were 72% and 84% for ITT, 85% and 91% for MRD-negative patients, and 57% and 72% for patients with high-risk cytogenetics. For high-risk patients who were MRD negative, 5-year rates were 77% and 81%. Grade 3 to 4 adverse events included neutropenia (34%), lymphopenia (32%), infection (22%), and cardiac events (3%). There was no grade 3 to 4 peripheral neuropathy. Patients with NDMM treated with KRd with ASCT achieved high rates of sCR and MRD-negative disease at the end of KRd consolidation. Extended KRd maintenance after consolidation contributed to deepening of responses and likely to prolonged PFS and OS. Safety and tolerability were manageable. This trial was registered at www.clinicaltrials.gov as #NCT01816971.

Phase 1 study of selinexor plus carfilzomib and dexamethasone for the treatment of relapsed/refractory multiple myeloma

Selinexor, an oral Selective Inhibitor of Nuclear Export, targets Exportin 1 (XPO1, also termed CRM1). Non-clinical studies support combining selinexor with proteasome inhibitors (PIs) and corticosteroids to overcome resistance in relapsed/refractory multiple myeloma (RRMM). We conducted a phase I dose-escalation trial of twice-weekly selinexor in combination with carfilzomib and dexamethasone (SKd) to determine maximum tolerated dose in patients with RRMM (N = 21), with an expansion cohort to assess activity in carfilzomib-refractory disease and identify a recommended phase II dose (RP2D). During dose escalation, there was one dose-limiting toxicity (cardiac failure). The RP2D of twice-weekly SKd was selinexor 60 mg, carfilzomib 20/27 mg/m2 and dexamethasone 20 mg. The most common grade 3/4 treatment-emergent adverse events included thrombocytopenia (71%), anaemia (33%), lymphopenia (33%), neutropenia (33%) and infections (24%). Rates of ≥minimal response, ≥partial response and very good partial response were 71%, 48% and 14%, respectively; similar response outcomes were observed for dual-class refractory (PI and immunomodulatory drug)/quad-exposed (carfilzomib, bortezomib, lenalidomide and pomalidomide) patients (n = 17), and patients refractory to carfilzomib in last line of therapy (n = 13). Median progression-free survival was 3·7 months, and overall survival was 22·4 months in the overall population. SKd was tolerable and re-established disease control in RRMM patients, including carfilzomib-refractory patients. Registered at ClinicalTrials.gov (NCT02199665).

Phase 1 study of marizomib in relapsed or relapsed and refractory multiple myeloma: NPI-0052-101 Part 1

Marizomib (MRZ) is a novel, irreversible proteasome inhibitor in clinical development for the treatment of relapsed or relapsed and refractory multiple myeloma (RRMM). MRZ inhibits the 3 proteolytic activities of the 20S proteasome with specificity distinct from bortezomib and carfilzomib. Study NPI-0052-101 Part 1 enrolled relapsed or RRMM patients into an open-label, dose-escalation design to determine the maximum tolerated dose and recommended phase 2 dose (RP2D) of MRZ administered intravenously on 2 different schedules: schedule A (0.025-0.7 mg/m(2) once weekly on days 1, 8, and 15 of 4-week cycles) and schedule B (0.15-0.6 mg/m(2) twice weekly on days 1, 4, 8, and 11 of 3-week cycles; concomitant dexamethasone was allowed with schedule B). Patients had received an average of 4.9 and 7.3 prior treatment regimens (schedules A and B, respectively). MRZ schedule A was administered to 32 patients, and the RP2D was established as 0.7 mg/m(2) infused over 10 minutes. Schedule B was administered to 36 patients, and the RP2D was determined to be 0.5 mg/m(2) infused over 2 hours. The most common (>20% of patients) related adverse events were fatigue, headache, nausea, diarrhea, dizziness, and vomiting. Six patients achieved clinical benefit responses (defined as minimal response or better), including 5 partial responses (1 patient on schedule A and 4 on schedule B; 3 of these 4 patients received concomitant dexamethasone). MRZ was generally well tolerated, and results suggest activity in previously treated RRMM patients. Combination studies using pomalidomide and dexamethasone are now underway. The trial was registered at www.clinicaltrials.gov as #NCT00461045.

Evaluation of the QTc prolongation potential of a monoclonal antibody, siltuximab, in patients with monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, or low-volume multiple myeloma

PURPOSE

A phase 1 study evaluated the QTc prolongation potential of siltuximab, a chimeric, anti-interleukin-6 mAb, in patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), or low-volume MM.

METHODS

Patients with baseline QTcF and QTcB ≤ 500 ms, QRS < 100 ms, PR < 200 ms and no significant cardiac disease received siltuximab 15 mg/kg q3w, the highest dosage used in clinical studies, for 4 cycles. Twelve-lead ECGs obtained at multiple time points pre- and post-infusion at cycles 1 and 4 were evaluated by central cardiology laboratory. No effect on QTc interval was concluded if the upper limit of least square (LS) mean 90 % CI for QTc change from baseline at each time point was <20 ms.

RESULTS

An effect on QTc prolongation was ruled out, as the upper bound of 90 % CI was <10 ms at each time point in 27 evaluable patients (13 MGUS, 13 SMM, 1 low-volume MM) with no differences between disease types. Maximum mean QTc increase from baseline occurred 3 h after cycle 1 infusion (QTcF = 3.2 [LS mean 90 % CI -0.01, 6.45] ms; QTcB = 2.7 [-0.69, 6.14] ms). At all other time points, mean QTcF and QTcB increase from baseline was ≤1.5 ms and upper bound 90 % CI was ≤5.1 ms. Twenty patients had mostly low-grade AEs, including nausea, fatigue (20 % each); thrombocytopenia, headache (each 13 %); dyspnea, leukopenia, neutropenia, paresthesia, abnormal hepatic function, URTI (each 10 %). Three MGUS patients achieved 50 % M-protein reduction. There was no association between siltuximab pharmacokinetics and QTc interval.

CONCLUSIONS

Siltuximab did not affect the QTc interval. Overall safety was similar to other single-agent siltuximab studies.

Weekly MLN9708, an investigational oral proteasome inhibitor (PI), in relapsed/refractory multiple myeloma (MM): Results from a phase I study after full enrollment

8514

Background: MLN9708 is an investigational, orally bioavailable, potent, reversible, specific inhibitor of the 20S proteasome that has demonstrated antitumor activity in in vivo models of MM. We report safety, activity and pharmacokinetics (PK) of weekly oral MLN9708 in a phase 1 trial in patients (pts) with relapsed and/or refractory MM after full enrollment (NCT00963820). Methods: Pts received MLN9708 (days 1, 8, 15; 28-day cycles) at 0.24–3.95 mg/m2 (dose-escalation phase) and at the MTD, 2.97 mg/m2, in relapsed and refractory (RR), bortezomib (btz)-relapsed, PI-naïve, and prior carfilzomib (CZ) expansion cohorts. Adverse events (AEs) were graded by NCI-CTCAE v3.0. Response was assessed by IMWG uniform criteria. Results: 60 pts (33 male, median age 64 yrs [40–79]) were enrolled, 32 in the dose-escalation phase and 31 to the expansion cohorts (11 RR, 10 btz-relapsed, 6 PI-naïve, 4 CZ; 2 RR and 1 btz-relapsed pts included from MTD dose-escalation cohort). Median time from MM diagnosis was 4.9 yrs (1.5–18.8). Median number of prior regimens was 6 (2–18), including btz, lenalidomide, thalidomide, and CZ in 83%, 95%, 52%, and 13%, respectively; 76% were refractory to last therapy (17% btz-refractory). At data cut-off (Nov 29, 2012) pts had received a median of 2 cycles (1–11); 5 pts remained on treatment. All-grade/grade ≥3 drug-related AEs were seen in 83%/52% of pts; common drug-related grade ≥3 AEs were thrombocytopenia (33%), diarrhea, neutropenia (17%), decreased appetite, fatigue, and lymphopenia (8%). 6 pts (10%) had drug-related PN (no grade ≥3). 5 pts discontinued due to drug-related AEs; 1 pt died on study due to an unrelated AE. By investigator assessment in 41 evaluable pts, responses included1 VGPR, 5 PR, 1 MR, and 15 with SD. MLN9708 was rapidly absorbed, with a terminal half-life of 4–12 days (supporting weekly dosing) and a proportional increase in plasma AUC with dose (0.8–3.95 mg/m2). PK data were similar across expansion cohorts. Conclusions: Current data suggest weekly oral MLN9708 is generally well tolerated with infrequent PN, and shows activity in this heavily pretreated population with prior exposure to immunomodulatory drugs and btz. Clinical trial information: NCT00963820.

Weekly dosing of the investigational oral proteasome inhibitor MLN9708 in patients (pts) with relapsed/refractory multiple myeloma (MM): A phase I study

8034

Background: Phase 1 studies are evaluating IV and oral dosing of the reversible proteasome inhibitor MLN9708 in multiple tumor types. We report the safety, MTD, pharmacokinetics (PK), pharmacodynamics, and preliminary responses with weekly oral MLN9708 in pts with relapsed/refractory MM (NCT00963820). Methods: Pts aged ≥18 yrs received MLN9708 on d 1, 8, and 15 of 28-d cycles. In the dose-escalation phase, pts required ≥2 prior therapies (including bortezomib, thalidomide/lenalidomide, and corticosteroids). At the MTD, pts were to be enrolled to relapsed and refractory (RR), bortezomib-relapsed (VR), proteasome inhibitor (PI) naïve, and carfilzomib (CZ) expansion cohorts. Results: 36 pts have been enrolled to date (data cut-off: Dec 1, 2011), 32 in the dose-escalation phase (0.24–3.95 mg/m2) and 8 to expansion cohorts (2 RR, 5 VR, 1 PI naïve; RR and VR cohorts each include 2 pts from MTD dose-escalation cohort). Median age was 64.5 yrs (range 40–79), 53% were male, and median number of prior lines of therapy was 3.5 (range 1-13), including 92%, 92%, 56%, and 8% who had prior bortezomib, lenalidomide, thalidomide, and carfilzomib, respectively. Pts have received a median of 2 cycles (range 1–11); 5 pts remain on treatment. Among 24 DLT-evaluable pts, 3 DLTs were seen: 2 at 3.95 mg/m2 (1 grade 3 rash, 1 grade 3 GI AEs) and 1 at 2.97 mg/m2 (grade 3 GI AEs). The MTD was determined as 2.97 mg/m2. Overall, 69% of pts had drug-related AEs, and 28% had related grade ≥3 AEs, including thrombocytopenia (17%), diarrhea (11%), nausea, neutropenia, and fatigue (each 8%). Only 3 (8%) pts had drug-related peripheral neuropathy (PN; no grade ≥3). 2 pts discontinued due to AEs. In 18 response-evaluable pts, 1 had a VGPR at 3.95 mg/m2, 1 had a PR at 2.97 mg/m2, and 8 have achieved SD durable for up to 9.5 mos. PK analyses showed linear plasma PK (0.8–3.95 mg/m2), Tmax of 0.5-2 hr, and terminal half-life of 7 d for MLN2238 (biologically active hydrolysis product). There was a trend for a dose-dependent increase in whole blood 20S proteasome inhibition. Conclusions: Current data suggest weekly oral MLN9708 is generally well tolerated with infrequent PN, and shows early signs of antitumor activity.

Phase I trial of anti-CS1 monoclonal antibody elotuzumab in combination with bortezomib in the treatment of relapsed/refractory multiple myeloma

PURPOSE

To evaluate the maximum-tolerated dose (MTD), safety, and efficacy of elotuzumab in combination with bortezomib in patients with relapsed or relapsed and refractory multiple myeloma (MM).

PATIENTS AND METHODS

Elotuzumab (2.5, 5.0, 10, or 20 mg/kg intravenously [IV]) and bortezomib (1.3 mg/m(2) IV) were administered on days 1 and 11 and days 1, 4, 8, and 11, respectively, in 21-day cycles by using a 3 + 3 dose-escalation design. Patients with stable disease or better after four cycles could continue treatment until disease progression or unexpected toxicity. Responses were assessed during each cycle by using European Group for Blood and Marrow Transplantation (EBMT) criteria.

RESULTS

Twenty-eight patients with a median of two prior therapies were enrolled; three patients each received 2.5, 5.0, and 10 mg/kg of elotuzumab and 19 received 20 mg/kg (six during dose escalation and 13 during an expansion phase). No dose-limiting toxicities were observed during cycle 1 of the dose-escalation phase, and the MTD was not reached up to the maximum planned dose of 20 mg/kg. The most frequent grade 3 to 4 adverse events (AEs) were lymphopenia (25%) and fatigue (14%). Two elotuzumab-related serious AEs of chest pain and gastroenteritis occurred in one patient. An objective response (a partial response or better) was observed in 13 (48%) of 27 evaluable patients and in two (67%) of three patients refractory to bortezomib. Median time to progression was 9.46 months.

CONCLUSION

The combination of elotuzumab and bortezomib was generally well-tolerated and showed encouraging activity in patients with relapsed/refractory MM.

Lenalidomide, bortezomib, pegylated liposomal doxorubicin, and dexamethasone in newly diagnosed multiple myeloma: a phase 1/2 Multiple Myeloma Research Consortium trial

This phase 1/2 trial evaluated combination lenalidomide, bortezomib, pegylated liposomal doxorubicin, and dexamethasone (RVDD) in newly diagnosed multiple myeloma (MM) patients. Patients received RVDD at 4 dose levels, including the maximum tolerated dose (MTD). Patients with a very good partial response or better (≥ VGPR) after cycle 4 proceeded to autologous stem cell transplantation or continued treatment. The primary objectives were MTD evaluation and response to RVDD after 4 and 8 cycles. Seventy-two patients received a median of 4.5 cycles. The MTDs were lenalidomide 25 mg, bortezomib 1.3 mg/m(2), pegylated liposomal doxorubicin 30 mg/m(2), and dexamethasone 20/10 mg, as established with 3-week cycles. The most common adverse events were fatigue, constipation, sensory neuropathy, and infection; there was no treatment-related mortality. Response rates after 4 and 8 cycles were 96% and 95% partial response or better, 57% and 65% ≥ VGPR, and 29% and 35% complete or near-complete response, respectively. After a median follow-up of 15.5 months, median progression-free survival (PFS) and overall survival (OS) were not reached. The estimated 18-month PFS and OS were 80.8% and 98.6%, respectively. RVDD was generally well tolerated and highly active, warranting further study in newly diagnosed MM patients. This trial was registered at www.clinicaltrials.gov as NCT00724568.

Phase III randomised study of dexamethasone with or without oblimersen sodium for patients with advanced multiple myeloma

Upregulation of the Bcl-2 antiapoptotic protein is reported to be associated with aggressive clinical course in multiple myeloma. Oblimersen sodium is a bcl-2 antisense oligonucleotide complementary to the first six codons of the open-reading frame of bcl-2 mRNA that can decrease transcription of Bcl-2 protein and increase myeloma cell susceptibility to cytotoxic agents. In this phase III randomised trial, we investigated in patients with relapsed/refractory myeloma whether addition of oblimersen to dexamethasone improved clinical outcomes vs. dexamethasone alone. Two hundred and twenty-four patients were randomised to receive either oblimersen/dexamethasone (N = 110) or dexamethasone alone (N = 114). The primary endpoint was time to tumor progression (TTP). Final results of this study demonstrated no significant differences between the two groups in TTP or objective response rate. The oblimersen/dexamethasone regimen was generally well tolerated with fatigue, fever and nausea, the most common adverse events reported.

Dose-Ranging Pharmacodynamic Study of Tipifarnib (R115777) in Patients With Relapsed and Refractory Hematologic Malignancies

Purpose

Tipifarnib, an orally bioavailable inhibitor of farnesyl transferase, has activity in hematologic malignancies, but the dose required to achieve the proposed biologic end point, inhibition of farnesylation, is unknown.

Patients and Methods

The impact on post-translational farnesylation was assessed in 42 patients with refractory hematologic malignancies and bone marrow involvement. Tipifarnib was taken orally for 21 days of a 28-day cycle. For cycle 1, patients were randomly assigned to one of four dose levels: 100 mg bid, 200 mg bid, 300 mg bid, and 600 mg bid. In cycle 1, peripheral blood and bone marrow mononuclear cells were analyzed for inhibition of HDJ2 prenylation by Western blot analysis at baseline and on day 21.

Results

Twenty-three patients were assessable for analysis of HDJ2 prenylation before and after therapy. Inhibition of farnesylation was noted at all dose levels, although the highest level of inhibition was noted at the 300-mg-bid dose. The inhibition of farnesylation in the peripheral blood correlated with the inhibition in the bone marrow (r = 0.62). Of the 26 patients assessable for clinical activity after cycle 1, three patients had a significant decrease in total blasts count (acute myeloid leukemia in two patients, and chronic myelogenous leukemia in one patient). The inhibition of farnesylation was greater in the three responders than the nonresponders (P = .03).

Conclusion

Farnesylation as measured by HDJ2 analysis was inhibited at all dose levels administered. Clinical activity may correlate with the degree of farnesylation inhibition, rather than dose of tipifarnib, and escalation beyond 300 mg bid might not result in additional clinical activity.

A phase I trial of gemcitabine plus cladribine in patients with advanced hematologic malignant diseases

PURPOSE

Gemcitabine and cladribine (2CdA) are nucleoside analogues that decrease DNA synthesis via inhibition of ribonucleotide reductase; the combination could be additive or synergistic. We conducted a dose escalation study to establish the maximum tolerable doses (MTD) of gemcitabine and 2CdA when given in combination in patients with advanced hematologic malignancies and to describe the toxicity profile of this combination.

PATIENTS AND METHODS

A total of 45 patients with advanced hematologic diseases were enrolled into two groups. Group A had adequate baseline hematopoiesis, defined as absolute neutrophil count (ANC) >1 x 10(9)/l and platelet count >50 x 10(9)/l. Group B did not meet these criteria. Hematologic dose-limiting toxicity (DLT) for group A was defined as grade 4 neutropenia or thrombocytopenia lasting >28 days; group B was not evaluated for hematologic toxicity. Nonhematologic DLT was defined similarly for both groups. Death occurring during the first cycle of treatment was considered a DLT event only if it was related to drug toxicity. Gemcitabine was administered as a 4-h intravenous infusion once every 28 days. 2CdA was administered over 1 h daily for the first 3 days of each 28-day cycle.

RESULTS

The MTD was not reached in either group. Myelosuppression was common, but not dose-limiting. Febrile neutropenia and infections were also common, particularly in group B, and judged in most cases to be due to bone marrow failure at baseline. Nonhematologic toxicities were generally mild, and skin rash, the most frequently observed, was dose-limiting in one patient enrolled in each group. Four deaths (three during the first cycle of treatment) occurred at the highest dose level tested in group B (gemcitabine 5000 mg/m2 and 2CdA 16 mg/m2). Although only one of these deaths was dose-limiting by stated criteria, this dose level did not appear to be safely tolerated in this patient population. Several responses were observed in patients with Hodgkin's disease.

CONCLUSIONS

The combination of gemcitabine and 2CdA is feasible in patients with hematologic malignancies. Phase II studies of this combination should be considered, particularly in patients with Hodgkin's disease.

Prognostic Factors for Survival With Gemcitabine Plus 5-fluorouracil Based Regimens for Metastatic Renal Cancer

PURPOSE

Combination gemcitabine and 5-fluorouracil (5-FU) may have activity in metastatic renal cell cancer. To identify patient subgroups most likely to benefit and compare survival to that in previously described patient series long-term survival as a function of known and suspected prognostic variables was determined.

MATERIALS AND METHODS

The survival status of 153 patients with metastatic renal cell cancer treated on 1 phase I and 4 phase II trials of gemcitabine/5-FU based regimens was updated. Univariate and multivariate Cox proportional hazards models were constructed using multiple imputation for missing values.

RESULTS

Performance status, prior nephrectomy, number of metastatic sites, decreased albumin and elevated alkaline phosphatase were highly prognostic for survival. Sarcomatoid differentiation and hypercalcemia had borderline prognostic significance. Using a previous described prognostic model that divided patients into 3 risk groups survival in those treated with gemcitabine/5-FU in this series was consistently better than survival in similar patients treated in the Motzer series.

CONCLUSIONS

Previously described prognostic factors for survival in metastatic renal cancer were confirmed. There is no clearly identifiable group that is most likely to benefit from a gemcitabine/5-FU regimen but there is a continued suggestion that this regimen provides a modest improvement over historical chemotherapy approaches.

Transplantation with low-density autologous PBSC prepared with BDS60 for women with Stage II, III and IV breast cancer

BACKGROUND

DS60 is a novel buoyant density solution, whose density has been adjusted to enrich PBSC from subjects who have been mobilized with cytokines alone, or cytokines plus chemotherapy. This report describes the use of BDS60 to enrich autologous PBSC that were used for hematological reconstitution after myeloablative chemotherapy in women with breast cancer.

METHODS

Fifty-one consecutive patients with high-risk Stage II or III breast cancer or chemotherapy-sensitive Stage IV breast cancer were enrolled. Forty-seven completed treatment and were evaluable. After mobilization with cyclophosphamide (4.0 g/m(2) i.v. once) and filgrastim (10 microg/kg/day), the patients underwent leukapheresis and the products were enriched with BDS60 using the DACS300 Kit. Myeloablative chemotherapy, given on Day -5 through Day -2, consisted of cyclophosphamide (1.5 g/m(2)/day), thiotepa (150 mg/m(2)/day) and carboplatin (200 mg/m(2)/day).

RESULTS

Forty-one patients underwent a single leukapheresis procedure to achieve the target number of BDS60-enriched CD34+ cells for transplantation (> or = 2 x 10(6)/kg). Five of the other six patients had less than the target number of cells in the leukapheresis product and thus required 2-4 leukapheresis procedures. Median cell recovery was 76.8% for CD34+ cells, 39.1% for nucleated cells, and 17.7% for platelets. Erythrocyte contamination of the final product was negligible. The median time to sustained neutrophil count > 500/mm(3) was 9 days (range: 8-12) and the median time to platelet count > 20 000/mm(3), without transfusion support, was also 9 days (range: 6-15). There were no late graft failures. Infusion-related adverse events were mild and no adverse events were attributed to the use of BDS60 to enrich CD34+ cells.

DISCUSSION

BDS60 is an effective, rapid method for enrichment of CD34+ cells by buoyant density centrifugation and the resulting cell product is safe and effective for engraftment after myeloablative therapy.

A phase II trial of docetaxel for peripheral blood stem cell mobilization for patients with breast cancer and ovarian cancer

As docetaxel is known to have significant antineoplastic activity against breast and ovarian cancer, we explored its application as a peripheral blood stem cell mobilizing agent in 33 women with stage lll-IV ovarian carcinoma (n = 10) or stage ll-lV breast cancer (n = 23) who were in preparation for high-dose chemotherapy. Eleven patients had bone and/or bone marrow involvement with their disease. The median number of prior regimens received before mobilization was two (range 1-3). The three dose levels administered were 100 mg/m(2), 110 mg/m(2) and 120 mg/m(2). Patients received one dose of docetaxel in the outpatient setting followed by G-CSF (10 microg/kg/day) starting 4 days after docetaxel administration. Leukapheresis commenced when WBC >1.0 x 10(9)/l or when the WBC began to rise after reaching a nadir. Ninety-seven percent of patients began leukapheresis within 7-9 days after receiving docetaxel (range 7-10 days). The collection goal was >/=2 x 10(6) CD34(+) cells/kg. Twenty-seven (82%) patients reached this goal in a median of 2 leukapheresis days (range 1-3). No grade 2-4 nonhematologic toxicities were noted. Thirteen patients (55%) showed a WBC nadir >1.0 x 10(9)/l. None of the patients experienced neutropenic fever or required blood or platelet transfusion support. In conclusion, docetaxel + G-CSF is an effective, well-tolerated regimen for PBPC mobilization which can be safely administered in the outpatient setting with minimal toxicity.

Clinical impact of ex vivo differentiated myeloid precursors after high-dose chemotherapy and peripheral blood progenitor cell rescue

The infusion of ex vivo differentiated myeloid precursors may be able to shorten the period of obligatory neutropenia after high-dose chemotherapy and peripheral blood progenitor cell rescue by providing cells capable of differentiating to mature neutrophils within days of infusion. To test this hypothesis, 21 female patients with metastatic breast cancer underwent progenitor cell mobilization with cyclophosphamide, etoposide and G-CSF. CD34+ cells from one to two leukapheresis products were isolated and placed in suspension culture with a serum-free growth medium supplemented with PIXY321. The cultures were maintained for 12 days with subcultures initiated on day 7. The remaining leukapheresis products were cryopreserved in an unmanipulated state. Forty-eight hours after completing high-dose cyclophosphamide, thiotepa and carboplatin, the cryopreserved progenitors were infused, followed 1 to 24 h later by infusion of the differentiated myeloid precursors. In one patient, the cultured cells were labeled with Indium-111 with nuclear imaging performed up to 48 h post infusion. The differentiated myeloid precursors were suitable for infusion in 17 of the patients with a median 13-fold expansion of total nucleated cells. A range of 5.6 to 1066 x 10(7) nucleated cells were infused. Morphologically the cells were predominantly of myeloid lineage (63%) with a median 41% of the cells expressing CD15. No untoward effects were noted with the infusion of the cultured cells. The median days to neutrophil and platelet recovery were 8 and 10 days, respectively. There was a significant relationship (r = 0.67, P = 0.007) between the dose of differentiated myeloid precursors (CD15+ cells) and the depth and duration of neutropenia; a similar relationship, however, was also observed with the dose of cryopreserved CD34+ cells. After infusion of the radiolabeled myeloid precursors, a pattern of distribution similar to radio-labeled granulocytes was noted with uptake detected initially in the lungs and subsequently the reticulo-endothelial system. The impact of differentiated myeloid precursors on neutropenia as an adjunct to high-dose chemotherapy and peripheral blood progenitor cell rescue remains unclear from this study. Further study with controlled doses of cryopreserved progenitors and escalating doses of differentiated myeloid precursors is required.

Timing of platelet recovery is associated with adequacy of leukapheresis product yield after cyclophosphamide and G-CSF in patients with lymphoma

A subgroup of patients with refractory Hodgkin's (HD) or non-Hodgkin's (NHL) lymphoma may be cured with high-dose chemotherapy and peripheral blood progenitor cell rescue. To investigate the relationship of adequate leukapheresis yield and time course of platelet recovery after mobilization chemotherapy, we retrospectively analyzed the leukapheresis yields in seven patients with Hodgkin's disease and fifteen patients with non-Hodgkin's lymphoma undergoing high-dose chemotherapy. Our goal was to develop a rule to determine when to initiate leukapheresis and then to prospectively validate this rule. All patients were mobilized with cyclophosphamide and G-CSF (granulocyte-colony stimulating factor). A total of 144 leukaphereses were completed and analyzed. Based on the CD34 content in the initial harvest product, fifteen patients were defined as poor mobilizers (CD34 < 0.15 x 10(6)/kg) and seven were good mobilizers. The platelet count on the first day of harvesting was significantly associated with the poor mobilizers (P = .03). Age, sex, marrow involvement, disease (HD vs. NHL), prior radiation, time since last chemotherapy, and total number of cycles of prior chemotherapy were not predictive of poor mobilizers. By using a platelet count cut off of 35 x 10(9)/L, we retrospectively analyzed 144 individual leukapheresis products, to test whether CD34 yield was predicted by the peripheral blood platelet count on the day of leukapheresis. This rule had an excellent sensitivity, 91%, and a specificity of 67%. Subsequently, we validated this rule with the next twenty-four patients undergoing leukapheresis of which there were 143 leukaphereses. The prediction rule exhibited a sensitivity of 72% and a specificity of 68% in the validation set. There does appear to be utility in using the platelet count to guide the initiation of leukapheresis after chemotherapy and G-CSF mobilization.

Clinical applications of ex vivo cultured CD34+ cells and myeloid progenitors

After extensive preclinical work, hematopoietic cellular therapy has recently entered a new era of clinical trials involving ex vivo cultured cells. The evolution of hematopoietic cell culture from clonogenic assays to large-scale static culture systems and bioreactors, and the identification and production of hematopoietic growth factors, have in part made this possible. In addition, murine models have demonstrated encouraging results with regard to the feasibility of infusing cultured cells, as well as to the potential efficacy. Several trials have recently been published utilizing ex vivo generated hematopoietic progenitors and myeloid progenitors, and are reviewed here. The field of clinical hematopoietic cellular therapy, while still in its infancy, is progressing rapidly, and promises to offer improved therapeutic options.

A Phase I dose escalation trial of continuous infusion paclitaxel to augment high dose cyclophosphamide and thiotepa plus stem cell rescue for the treatment of patients with advanced breast carcinoma

BACKGROUND

Paclitaxel, an effective chemotherapeutic agent in the management of breast carcinoma, may have activity in women whose disease has recurred after high dose chemotherapy. With this is mind the authors explored the addition of a 120-hour continuous infusion of paclitaxel to a previously reported regimen comprised of high dose cyclophosphamide and thiotepa.

METHODS

Thirty-one women with advanced breast carcinoma (30 patients with Stage IV disease and 1 patient with Stage IIIB disease) underwent harvest and cryopreservation of bone marrow and/or peripheral blood progenitor cells. High dose cyclophosphamide (2.5 g/m2) and thiotepa (225 mg/m2) were administered intravenously on Days -7, -5, and -3. Paclitaxel was administered as a 120-hour continuous infusion starting on Day -7.

RESULTS

Three patients were treated at the initial cohort dose of 50 mg/m2 (over 120 hours), 6 patients at 100 mg/m2, 6 patients at 125 mg/m2, 6 patients at 150 mg/m2, 6 patients at 180 mg/m2, and 4 patients at 210 mg/m2. All patients completed the treatment protocol as planned with no associated transplant-related deaths. Mucositis as evidenced by either stomatitis or noninfectious diarrhea was experienced by all patients and was determined to be the dose-limiting toxicity at the 210 mg/m2 dose level. One patient with dose-limiting mucositis required intubation for airway protection and also experienced Grade 3 (according to the Cancer and Leukemia Group B common toxicity grading scale) pulmonary and neurologic toxicity. Only one Grade 3 toxicity was encountered below the maximum tolerated dose in a patient who developed diffuse alveolar hemorrhage at a dose of 125 mg/m2. No allergic reactions or clinical evidence of peripheral neuropathies were encountered. Cardiac, hepatic, and renal toxicities were minimal. Response rates in this previously treated patient population were difficult to assess in light of the high incidence of bone metastases; an overall response rate of 24% was obtained.

CONCLUSIONS

Paclitaxel at a dose of 180 mg/m2 as a 120-hour continuous infusion may be added safely to high dose cyclophosphamide and thiotepa with autologous stem cell rescue. Further studies are ongoing to evaluate the efficacy and further define the toxicity of this recommended Phase II dose.

Neutrophil maturation of CD34+ cells from peripheral blood and bone marrow in serum-free culture medium with PIXY321 and granulocyte-colony stimulating factor (G-CSF)

Bone marrow (BM) or peripheral blood (PB) CD34+ cells were cultured for 12 days in serum-free culture medium containing PIXY321 (IL-3/ GM-CSF fusion protein) with or without periodic supplements of granulocyte-colony stimulating factor (G-CSF). The cultures were evaluated at day 12 for total cell proliferation (fold increase from day 0), neutrophil differentiation by flow cytometry, using dual staining with CD15-FITC and CD11b-PE, and morphology using Wright-Giemsa and granule staining. In cultures containing PIXY321 where 6000 U/ml of G-CSF was added days 0 and 6, there was no significant difference (p > or = 0.05) in cell proliferation or the percent of CD15+/CD11b+ cells when compared with cultures with PIXY321 alone. ELISA analysis showed G-CSF levels had declined by 90% after 3 days of culture. Further studies were performed to assess the benefit of supplementing lower concentrations of G-CSF (600 U/ml) at more frequent intervals. A significant increase (p < or = 0.05) in cell proliferation and percent CD15+/CD11b+ was observed when G-CSF was added on days 0, 3, 6, and 9 (every 3 days) as compared with those cultures with PIXY321 alone. CD34+ cell proliferation without G-CSF was 19.6 +/- 4.8-fold, with G-CSF added on days 0 and 6 was 28.7 +/- 6.4-fold, and with G-CSF added on days 0, 3, 6, and 9 was 45.9 +/- 10.6-fold. Percent of CD15+/CD11b+ cells was 19.0 +/- 4.6%, 38.2 +/- 7.2%, and 58.5 +/- 6.5%, respectively, in these cultures. We observed more CD15+/CD11b+ cells, myelocytes/metamyelocytes, and secondary granule staining in cultures with G-CSF added on day, 0, 3, 6, and 9 as compared with cultures with G-CSF added on days 0 and 6 or no G-CSF added. We conclude that PIXY321 and G-CSF act synergistically on the in vitro proliferation and neutrophil differentiation of BM and PB CD34+ cells and that frequent supplements of G-CSF facilitate neutrophil differentiation.

Large-scale selection of CD34+ peripheral blood progenitors and expansion of neutrophil precursors for clinical applications

Hematopoietic recovery after high-dose chemotherapy is characterized by an obligate period of neutropenia of approximately 8-10 days. It is postulated that if a pool of neutrophil precursors and progenitors were expanded in vitro and reinfused, the duration of neutropenia may be substantially shortened by these cells capable of providing mature neutrophils within days of reinfusion. In this study, peripheral blood progenitor cell products were obtained from six normal donors mobilized with rhG-CSF and two patients mobilized with cyclophosphamide and rhG-CSF. CD34+ cells were isolated using the Isolex immunomagnetic bead method. A mean of 8.26 x 10(7) CD34+ cells with a mean purity of 74.5% were seeded at a concentration of 1 x 10(5)/ml into a 12 day stroma-free liquid culture using gas-permeable bags. A serum-free growth medium supplemented with PIXY321 was used. On day 7, there was a mean cellular expansion of fourfold, at which time the cells were resuspended at the initial concentration, yielding a mean culture volume of 3L (1-6 L). On day 12, there was an additional mean fold cellular expansion of 10 x, achieving an overall mean fold expansion of 41 +/- 16. Cellular characterization of the expanded cells revealed predominantly neutrophil precursors by morphology (mean 70.1%) and flow cytometric analysis. A mean of 52.3% of the expanded cells expressed CD15. Immunohistochemical staining revealed a mean of 7.1% CD41a+ megakaryocytic progenitors in the final cultured cell product. Detectable CD34+ cells were maintained only in those cultures initiated with greater than 90% CD34+ cells. Colony-forming units-granulocyte-macrophage (CFU-GM) were maintained in the 12 day culture at a level similar to the preculture number, whereas CFU mixed were depleted in all samples. On day 0, there were few CFU clusters (colonies containing fewer than 50 cells) identified, but by day 12, a mean total of 8.3 x 10(6) CFU clusters were identified. On day 12, the expanded cells were harvested and pooled using the Fenwal CS3000 Plus blood cell separator and resuspended in Plasma-Lyte-A with 1% human serum albumin. The mean harvest recovery of expanded progenitors was 91%, with a mean viability of 86%.

Clinical use of selected and expanded peripheral blood CD34+ cells: a preliminary report of feasibility and safety

In this report, we describe the preliminary results from a feasibility and safety study on the clinical use of CD34-positive cells cultured from mobilized peripheral blood. Separation and cell expansion were successfully performed, and the patients tolerated the infusions without problems and achieved engraftment.

Source of stem cells impacts on hematopoietic recovery after high-dose chemotherapy

The restoration of hematopoiesis after high-dose chemotherapy may be accelerated by the use of stem cells from the bone marrow (BM) or peripheral blood. Numerous reports utilizing mobilized peripheral blood progenitor cells (PBPC) for stem cell rescue have shown that PBPC are sufficient to restore hematopoiesis, but there are little data comparing the recovery among patients treated with various stem cell sources. We reviewed the clinical outcomes of 69 women at our institution who were treated for locally advanced or metastatic breast cancer with high-dose cyclophosphamide (CY) and thiotepa and autologous stem cell and growth factor support. Of the 43 patients with normal BM, 19 received BM alone and 24 received BM plus G-CSF mobilized PBPC. Of the 26 patients with evidence of metastatic disease in the BM, or evidence of fibrosis and hypocellularity, 15 received CY-mobilized PBPC and 11 received CY/G-CSF-mobilized PBPC. Of the marrow-negative patients, those receiving BM alone had significantly longer (P < 0.001) granulocyte recovery (absolute neutrophil count > 500 x 10(6)/l) and platelet recovery (platelets > 50 x 10(9)/l) compared with BM + G-CSF-mobilized PBPC. They also had significantly longer (P < 0.001) durations of antibiotic and amphotericin usage, increased transfusion requirements and longer hospitalizations. Of the marrow-positive patients, there was a slightly shortened granulocyte recovery, shortened hospital stays and lessened amphotericin usage in the patients who received CY/G-CSF-mobilized PBPC compared with the CY-mobilized patients. Although the number of harvested mononuclear cells differed significantly between the groups, this did not correlate with the time to hematopoietic recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative CD34 analysis may be used to guide peripheral blood stem cell harvests

The duration of neutropenia and thrombocytopenia after high-dose chemotherapy has improved since the introduction of myeloid growth factors and peripheral blood progenitor cells (PBPC), yet there remains a subset of patients who have delayed hematopoietic recovery. Currently, there ar no established, reliable parameters which may be used to guide stem cell harvests. We investigated the utility of measuring harvested CD34 positive cell populations by flow cytometry. From March 1990 to July 1993, 30 women with advanced breast cancer underwent therapy with high-dose cyclophosphamide and thiotepa and stem cell rescue. Patients received either cyclophosphamide (CY) mobilized PBPC or CY/G-CSF mobilized PBPC. The number of harvested CD34+ cell and CFU-GM (colony forming units-granulocyte macrophage) were quantitated for each stem cell produce. There ar complete CD34 data for 21 patients and complete CFU-GM data for 20 patients. There was a significantly delayed neutrophil recovery in those patients reinfused with < 0.75 x 10(6) CD34+ cells/kg body weight (median days 22) compared with patients reinfused with > 0.75 x 10(6)/kg (median days 12, P = 0.0004); a similar trend was seen with platelet recovery (median 135 days vs 18 days, respectively, P = 0.002). With neutrophil recovery, there was no improvement in time to engraftment with a large number of reinfused CD34+ cells, but there was a trend towards shortened platelet recovery when the number of reinfused CD34+ cells exceeded 2.0 x 10(6)/kg (median 15 days) compared with CD34+ < 2.0 x 10(6)/kg (median 75 days, P = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)