Exagamglogene Autotemcel for Severe Sickle Cell Disease.

BACKGROUND: Exagamglogene autotemcel (exa-cel) is a nonviral cell therapy designed to reactivate fetal hemoglobin synthesis by means of ex vivo clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 gene editing of autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) at the erythroid-specific enhancer region of BCL11A. METHODS: We conducted a phase 3, single-group, open-label study of exa-cel in patients 12 to 35 years of age with sickle cell disease who had had at least two severe vaso-occlusive crises in each of the 2 years before screening. CD34+ HSPCs were edited with the use of CRISPR-Cas9. Before the exa-cel infusion, patients underwent myeloablative conditioning with pharmacokinetically dose-adjusted busulfan. The primary end point was freedom from severe vaso-occlusive crises for at least 12 consecutive months. A key secondary end point was freedom from inpatient hospitalization for severe vaso-occlusive crises for at least 12 consecutive months. The safety of exa-cel was also assessed. RESULTS: A total of 44 patients received exa-cel, and the median follow-up was 19.3 months (range, 0.8 to 48.1). Neutrophils and platelets engrafted in each patient. Of the 30 patients who had sufficient follow-up to be evaluated, 29 (97%; 95% confidence interval [CI], 83 to 100) were free from vaso-occlusive crises for at least 12 consecutive months, and all 30 (100%; 95% CI, 88 to 100) were free from hospitalizations for vaso-occlusive crises for at least 12 consecutive months (P<0.001 for both comparisons against the null hypothesis of a 50% response). The safety profile of exa-cel was generally consistent with that of myeloablative busulfan conditioning and autologous HSPC transplantation. No cancers occurred. CONCLUSIONS: Treatment with exa-cel eliminated vaso-occlusive crises in 97% of patients with sickle cell disease for a period of 12 months or more. (CLIMB SCD-121; ClinicalTrials.gov number, NCT03745287.).

CRISPR-Cas9 Gene Editing for Sickle Cell Disease and ß-Thalassemia.

Transfusion-dependent ß-thalassemia (TDT) and sickle cell disease (SCD) are severe monogenic diseases with severe and potentially life-threatening manifestations. BCL11A is a transcription factor that represses γ-globin expression and fetal hemoglobin in erythroid cells. We performed electroporation of CD34+ hematopoietic stem and progenitor cells obtained from healthy donors, with CRISPR-Cas9 targeting the BCL11A erythroid-specific enhancer. Approximately 80% of the alleles at this locus were modified, with no evidence of off-target editing. After undergoing myeloablation, two patients - one with TDT and the other with SCD - received autologous CD34+ cells edited with CRISPR-Cas9 targeting the same BCL11A enhancer. More than a year later, both patients had high levels of allelic editing in bone marrow and blood, increases in fetal hemoglobin that were distributed pancellularly, transfusion independence, and (in the patient with SCD) elimination of vaso-occlusive episodes. (Funded by CRISPR Therapeutics and Vertex Pharmaceuticals; ClinicalTrials.gov numbers, NCT03655678 for CLIMB THAL-111 and NCT03745287 for CLIMB SCD-121.).

A randomized phase 3 trial of interferon-α vs hydroxyurea in polycythemia vera and essential thrombocythemia.

The goal of therapy for patients with essential thrombocythemia (ET) and polycythemia vera (PV) is to reduce thrombotic events by normalizing blood counts. Hydroxyurea (HU) and interferon-α (IFN-α) are the most frequently used cytoreductive options for patients with ET and PV at high risk for vascular complications. Myeloproliferative Disorders Research Consortium 112 was an investigator-initiated, phase 3 trial comparing HU to pegylated IFN-α (PEG) in treatment-naïve, high-risk patients with ET/PV. The primary endpoint was complete response (CR) rate at 12 months. A total of 168 patients were treated for a median of 81.0 weeks. CR for HU was 37% and 35% for PEG (P = .80) at 12 months. At 24 to 36 months, CR was 20% to 17% for HU and 29% to 33% for PEG. PEG led to a greater reduction in JAK2V617F at 24 months, but histopathologic responses were more frequent with HU. Thrombotic events and disease progression were infrequent in both arms, whereas grade 3/4 adverse events were more frequent with PEG (46% vs 28%). At 12 months of treatment, there was no significant difference in CR rates between HU and PEG. This study indicates that PEG and HU are both effective treatments for PV and ET. With longer treatment, PEG was more effective in normalizing blood counts and reducing driver mutation burden, whereas HU produced more histopathologic responses. Despite these differences, both agents did not differ in limiting thrombotic events and disease progression in high-risk patients with ET/PV. This trial was registered at www.clinicaltrials.gov as #NCT01259856.

Continuous and differential improvement in worldwide access to hematopoietic cell transplantation: activity has doubled in a decade with a notable increase in unrelated and non-identical related donors.

Promoting access to and excellence in hematopoietic cell transplantation (HCT) by collecting and disseminating data on global HCT activities is one of the principal activities of the Worldwide Network for Blood and Marrow Transplantation, a non-Governmental organization in working relations with the World Health Organization. HCT activities are recorded annually by member societies, national registries and individual centers including indication, donor type (allogeneic/autologous), donor match and stem cell source (bone marrow/peripheral blood stem cells/cord blood). In 2018, 1,768 HCT teams in 89 countries (six WHO regions) reported 93,105 (48,680 autologous and 44,425 allogeneic) HCT. Major indications were plasma cell disorders and lymphoma for autologous, and acute leukemias and MDS/MPN for allogeneic HCT. HCT number increased from 48,709 in 2007. Notable increases were seen for autoimmune diseases in autologous and hemoglobinopathies in allogeneic HCT. The number of allogeneic HCT more than doubled with significant changes in donor match. While HCT from HLA identical siblings has seen only limited growth, HCT from non-identical related donors showed significant increase worldwide. Strongest correlation between economic growth indicator of gross national income/capita and HCT activity/ten million population was observed for autologous HCT (r=0.79). HCT from unrelated donors showed strong correlation (r=0.68), but only moderate correlation (r=0.51) was detected from related donors. The use of HCT doubled in about a decade worldwide at different speed and with significant changes regarding donor match as a sign of improved access to HCT worldwide. Although narrowing, significant gaps remain between developing and non-developing countries.

High dose total marrow irradiation (TMI) does not increase long-term toxicity of myeloablative fludarabine/busulfan (FluBu4) conditioning regimen in allogeneic hematopoietic stem cell transplantation (HSCT).

OBJECTIVES: Based on a previous phase 1 study, total marrow irradiation (TMI) at 9Gy was added to a myeloablative FluBu4 conditioning regimen in allogeneic hematopoietic stem cell transplantation (HSCT) for myeloid malignancies. Here, we report on the long-term toxicity of TMI combined with FluBu4 and compare it to patients who received only FluBu4. METHODS: We retrospectively analyzed 38 consecutive patients conditioned with FluBu4/TMI (n = 15) or FluBu4 (n = 23, control group) who had at least 1 year follow-up post-transplant. The rate of long-term adverse events that have been previously associated with total body irradiation (TBI) was analyzed in the two groups. RESULTS: The baseline characteristics did not differ between the two groups. The control group had a longer median follow-up (71.2 mo) than the TMI group (38.5 mo) (p = .004). The most common adverse events were xerostomia, dental complications, cataracts, or osteopenia and did not differ between the two groups. Cognitive dysfunction or noninfectious pneumonitis, often detected after high dose TBI, were also not different in the two groups (p = .12 and p = .7, respectively). There was no grade 4 adverse event. CONCLUSION: Our results suggest that a conditioning regimen with TMI 9Gy and FluBu4 does not increase long-term adverse events after allogeneic HSCT.

"Window of Opportunity" in Ocular Graft-Versus-Host Disease Treatment: Results of a Longitudinal Study and Case Reports.

OBJECTIVE: To perform a longitudinal study for determining the development of ocular graft-versus-host disease (oGVHD) after allogeneic hematopoietic stem cell transplant (HSCT) and report cases that illustrate the "window of opportunity" concept in oGVHD treatment. METHODS: Patients (n=61) were examined at prescheduled clinic visits before HSCT and three-month intervals after HSCT for 2 years. The presence or absence of oGVHD was determined using the international chronic oGVHD consensus group diagnostic criteria. Ocular surface washings (OSW) were obtained at each visit and analyzed for cytokine levels. RESULTS: In the longitudinal study, 26.2% (n=16; progressed group) developed either probable (11.5%, n=7) or definite oGVHD (14.8%, n=9). In the progressed group, clinically significant changes in signs (corneal staining and Schirmer I test) and symptoms at the post-HSCT visit as compared with the pre-HSCT visit occurred at 9 months. Significant differences in clinical signs and symptoms (whether average post-HSCT values or changes in values over pre-HSCT levels) between the progressed and nonprogressed groups occurred at a 9-month visit or later. In the progressed group, 55.6% of eyes that had negative matrix metalloproteinase 9 (MMP-9) test at pre-HSCT turned MMP-9 positive at 3 to 6 months post-HSCT. In the progressed group, interleukin 8 levels in OSW were significantly increased at 6 months post-HSCT. In the case reports, the "window of opportunity" was detected by MMP-9 turning positive, early corneal staining, interleukin 8 increase in OSW, and peripheral corneal epithelial thinning, which resolved with treatment initiation. CONCLUSIONS: A "window of opportunity" exists before patients developing symptomatic tear-deficient dry eye after HSCT for initiating treatment that may preempt oGVHD development; however, larger-scale longitudinal studies are needed for definitive recommendations.

Risk score to predict event-free survival after hematopoietic cell transplant for sickle cell disease.

We developed a risk score to predict event-free survival (EFS) after allogeneic hematopoietic cell transplantation for sickle cell disease. The study population (n = 1425) was randomly split into training (n = 1070) and validation (n = 355) cohorts. Risk factors were identified and validated via Cox regression models. Two risk factors of 9 evaluated were predictive for EFS: age at transplantation and donor type. On the basis of the training cohort, patients age 12 years or younger with an HLA-matched sibling donor were at the lowest risk with a 3-year EFS of 92% (score, 0). Patients age 13 years or older with an HLA-matched sibling donor or age 12 years or younger with an HLA-matched unrelated donor were at intermediate risk (3-year EFS, 87%; score, 1). All other groups, including patients of any age with a haploidentical relative or HLA-mismatched unrelated donor and patients age 13 years or older with an HLA-matched unrelated donor were high risk (3-year EFS, 57%; score, 2 or 3). These findings were confirmed in the validation cohort. This simple risk score may guide patients with sickle cell disease and hematologists who are considering allogeneic transplantation as a curative treatment relative to other available contemporary treatments.

A comparison of four leukapheresis methods to harvest an optimal dose of CD34+ cells: A single center experience.

BACKGROUND: Chemokine receptor CXCR4 antagonist plerixafor (Px) as well as high volume (HV) leukapheresis have been shown to reduce hematopoietic stem progenitor cell (HSPC) mobilization failure rates. However, no direct comparisons of such methods currently exists. METHODS AND MATERIALS: We compared the HSPC collection yield based on basal peripheral blood CD34+ cell numbers in patients diagnosed with multiple myeloma or non-Hodgkin's lymphoma undergoing autologous stem cell transplantation in a retrospective chart review. The leukapheresis methods used included HV versus regular volume (RV) with or without Px. There were 116 patients in the study group while the historical control group had 34 patients. RESULTS AND CONCLUSIONS: Control group underwent RV leukapheresis without Px. Addition of Px or HV in the study group failed to display significant improvement in CD34+ cell collection yield; however, when basal CD34+ cell numbers were taken into account, both Px + RV and HV without Px increased CD34+ cell collection yield. The collection failure rates of HV without Px group were comparable to Px + RV when the basal CD34+ cell numbers were over 20/µl. Of interest, multivariate linear regression analysis did not detect any significant difference between HV versus Px + RV or other leukapheresis methods in CD34 yields or collection failure rates from a single collection after controlling for other factors (sex, age, or underlying disease). In multivariate analysis, pre apheresis CD34+ cell number was significantly and positively associated with the CD34+ cell yields from a single apheresis. In our studies, the majority of patients can be rescued without Px by HV alone as a potential cost saving approach. In summary, trend in our studies reflects that both Px and HV are capable of reducing the mobilization failure rates except the poorest mobilizers, which will need to be validated in larger studies.

Non-myeloablative human leukocyte antigen-matched related donor transplantation in sickle cell disease: outcomes from three independent centres.

Non-myeloablative haematopoietic progenitor cell transplantation (HPCT) from matched related donors (MRD) has been increasingly utilized in sickle cell disease (SCD). A total of 122 patients received 300 cGy of total body irradiation (TBI), alemtuzumab, unmanipulated filgrastim-mobilized peripheral blood HPC and sirolimus. The median follow-up was four years; median age at HPCT was 29 years. Median neutrophil and platelet engraftment occurred on day 22 and 19 respectively; 41 patients required no platelet transfusions. Overall and sickle-free survival at one and five years were 93% and 85% respectively. Age, sex, pre-HPCT sickle complications, ferritin and infused HPC numbers were similar between graft failure and engrafted patients. Mean donor myeloid chimaerism at one and five years post HPCT were 84% and 88%, and CD3 was 48% and 53% respectively. Two patients developed grade 1 and 2 skin graft-versus-host disease (GVHD) with no chronic GVHD. Median days of recipients taking immunosuppression were 489; 83% of engrafted patients have discontinued immunosuppression. Haemoglobin, haemolytic parameters and hepatic iron levels improved post HPCT. Pulmonary function testing, hepatic histology and neurovascular imaging remained stable, suggesting cessation of further sickle-related injury. Fourteen patients had children. In this largest group of adult SCD patients, this regimen was highly efficacious, well-tolerated despite compromised organ functions pre HPCT, and without clinically significant GVHD.

Pegylated interferon alfa-2a for polycythemia vera or essential thrombocythemia resistant or intolerant to hydroxyurea.

Prior studies have reported high response rates with recombinant interferon-α (rIFN-α) therapy in patients with essential thrombocythemia (ET) and polycythemia vera (PV). To further define the role of rIFN-α, we investigated the outcomes of pegylated-rIFN-α2a (PEG) therapy in ET and PV patients previously treated with hydroxyurea (HU). The Myeloproliferative Disorders Research Consortium (MPD-RC)-111 study was an investigator-initiated, international, multicenter, phase 2 trial evaluating the ability of PEG therapy to induce complete (CR) and partial (PR) hematologic responses in patients with high-risk ET or PV who were either refractory or intolerant to HU. The study included 65 patients with ET and 50 patients with PV. The overall response rates (ORRs; CR/PR) at 12 months were 69.2% (43.1% and 26.2%) in ET patients and 60% (22% and 38%) in PV patients. CR rates were higher in CALR-mutated ET patients (56.5% vs 28.0%; P = .01), compared with those in subjects lacking a CALR mutation. The median absolute reduction in JAK2V617F variant allele fraction was -6% (range, -84% to 47%) in patients achieving a CR vs +4% (range, -18% to 56%) in patients with PR or nonresponse (NR). Therapy was associated with a significant rate of adverse events (AEs); most were manageable, and PEG discontinuation related to AEs occurred in only 13.9% of subjects. We conclude that PEG is an effective therapy for patients with ET or PV who were previously refractory and/or intolerant of HU. This trial was registered at www.clinicaltrials.gov as #NCT01259856.

Chromatin-Modifying Agent-Expanded Human Cord Blood Cells Display Reduced Allostimulatory Capacity.

The limited number of hematopoietic stem cells (HSC) within a single unit of human cord blood currently limits its use as an alternate graft source. However, we have developed a strategy using 5-aza-2'-deoxycytidine (5azaD) and trichostatin A (TSA), which expands transplantable HSC 7- to 10-fold. In our current studies, we have assessed the allostimulatory capacity of the 5azaD/TSA-expanded grafts. The coexpression of immunophenotypic dendritic cell (DC) markers, such as HLA-DR/CD86 and HLA-DR/CD11c as determined by flow cytometry, and the allostimulatory capacity of 5azaD/TSA-expanded cells as determined by MLC were both significantly lower than control. It has been previously demonstrated that STAT3 is indispensable for the differentiation of DC from HSC. Real-time quantitative PCR analysis revealed that 5azaD/TSA-expanded cells expressed more STAT3 transcript than control while also expressing increased transcripts for STAT3 inhibitors including SHP1, p21, and GATA1. Western blot analysis indicates that chromatin-modifying agent-expanded grafts displayed a reduced ratio of p-STAT3 to total STAT3 than control cultures, which is likely indicative of STAT3 inactivity in 5azD/TSA-expanded grafts. Culturing 5azaD/TSA-expanded cord blood cells in extended cultures reveals that they are still capable of generating DC. Notably, STAT3 inactivity was transient because the transcript levels of STAT3 and its inhibitors, including SHP1, were comparable between 5azaD/TSA and control cultures following extended culture. Taken together, our studies indicate that the reduced allostimulatory capacity of 5azaD/TSA-expanded cells is likely because of reversible inhibition of STAT3-dependent DC differentiation. These results suggest that a graft composed of 5azaD/TSA-expanded cells possesses relatively less allostimulatory response but is still capable of generating DC in permissive conditions.

Race/ethnicity and underlying disease influences hematopoietic stem/progenitor cell mobilization response: A single center experience.

BACKGROUND: Whether race/ethnicity plays a role in hematopoietic stem/progenitor cells (HSPC) mobilization in autologous donors has not been studied. We hypothesize that donor characteristic including race/ethnicity, age, sex, body mass index, and diagnostic groups influences HSPC mobilization. Diagnostic groups include healthy allogeneic donors, autologous multiple myeloma (MM) and non-MM donors. STUDY DESIGN AND METHODS: Here, we conducted a single-center retrospective study in 64 autologous patients and 48 allogeneic donors. Autologous donors were patients diagnosed with MM or non-MM. All donors were grouped as African American (AA), White (W), or "Other"(O). RESULTS: Multivariate analysis demonstrated diagnostic group differences for CD34+ cell yields between race/ethnicity. Specifically, non-MM patients had the lowest CD34+ cell yields in AA and O, but not in W. For pre-apheresis peripheral blood (PB) CD34+ cell numbers, race/ethnicity had a significant effect both in bivariate and multivariate analyses. Non-MM patients had the lowest, and AA patients had the highest PB CD34+ cells. The results support the view that past therapies used in MM are likely more conducive of recovery of HSPC. CONCLUSIONS: Our study shows that race/ethnicity and diagnostic group differences influenced CD34+ cell mobilization response across donor types. Interestingly, autologous MM donors with the aid of plerixafor displayed comparable CD34 yields to allogeneic donors. Even though both MM and non-MM donors received plerixafor, non-MM donors had significantly lower CD34 yields among AA and O donors but not in W donors. Larger studies would be required to validate the role of diagnostic groups and race/ethnicity interactions.

Predictors of increased melphalan exposure correlate with overall survival, nonrelapse mortality, and toxicities in patients undergoing reduced-intensity allogeneic stem cell transplantation with fludarabine and melphalan.

The reduced-intensity conditioning regimen, fludarabine and melphalan 140 mg/m2 (FM140), is widely adopted in practice. Pharmacokinetic studies report 10-fold interpatient variability in melphalan exposure. We identified low hemoglobin (Hb) and/or creatinine clearance (CrCl), determinants of melphalan pharmacokinetic, as strong predictors of outcomes after high-dose melphalan and autologous transplant. We hypothesized that these variables could predict for outcomes after FM140. Overall survival was shorter in patients with a lower Hb (113 vs. 2536 days; p = 0.004), due to an increased rate of nonrelapse mortality (NRM) (p = 0.0005). Overall survival was also worse in patients with lower CrCl (75 vs. 317 days; p = 0.003), with a significantly worse nonrelapse mortality (p = 0.0023). In a multivariate analysis, a higher Hb and CrCl predicted for better overall survival (p = 0.017). In patients with a lower Hb, the median duration of hospitalization (p = 0.02) and the mean duration of diarrhea (p = 0.008) were longer. In patients with a lower CrCl, the median duration of hospitalization (p = 0.06) and the mean duration of diarrhea (p = 0.0009) longer, and the rate of infection was higher (p = 0.02). We show for the first time that Hb and CrCl represent important determinants of outcomes after FM140, suggesting that pharmacokinetic-directed dosing may be beneficial in achieving optimal outcomes.

PARP Inhibition Synergizes with Melphalan but Does not Reverse Resistance Completely.

High-dose melphalan (MEL) and autologous stem cell transplantation (ASCT) is the standard of care in the treatment of multiple myeloma (MM). Resistance to MEL has been linked to increased DNA repair. Here we sought to identify whether inhibition of poly(ADP-ribose) polymerase (PARP) synergizes with MEL and can overcome resistance. We tested the synergistic cytotoxicity of 3 inhibitors of PARP (PARPi)-veliparib (VEL), olaparib (OLA), and niraparib (NIRA)-combined with MEL in RPMI8226 and U266 MM cell lines, as well as in their MEL resistance counterparts, RPMI8226-LR5 (LR5) and U266-LR6 (LR6). The addition of VEL, OLA, and NIRA to MEL reduced the half maximal inhibitory concentration (IC50) in RPMI8226 cells from 27.8 µM to 23.1 µM, 22.5 µM, and 18.0 µM, respectively. Similarly, the IC50 of MEL in U266 cells was decreased from 6.2 µM to 3.2 µM, 3.3 µM, and 3.0 µM, respectively. In LR5 and LR6 cells, PARPi did not reverse MEL resistance. We confirmed this in a NOD/SCID/gamma null xenograft mouse model with either MEL-sensitive (RPMI8226) or MEL-resistant (LR5) MM. Treatment with a MEL-VEL combination prolonged survival compared with MEL alone in RPMI8226 mice (107 days versus 67.5 days; P = .0009), but not in LR5 mice (41 versus 39 days; P = .09). We next tested whether 2 double-stranded DNA repair mechanisms, homologous recombination (HR) and nonhomologous end-joining (NHEJ), cause MEL resistance in LR5 and LR6 cells. In an HR assay, LR6 cells had a 4.5-fold greater HR capability than parent U226 cells (P = .05); however, LR5 cells had an equivalent HR ability as parent RPMI8226 cells. We hypothesized that NHEJ may be a mediator of MEL resistance in LR5 cells. Given that DNA-PK is integral to NHEJ and may be a therapeutic target, we treated LR5 cells with the DNA-PK inhibitor NU7026 in combination with MEL. Although NU7026 alone at 2.5 µM had no cytotoxicity, in combination it completely reversed resistance to MEL (MEL IC50, 46.4 µM versus 14.4 µM). We examined the clinical implications of our findings in a dataset of 414 patients treated with tandem ASCT. High PARP1 expressers had lower survival compared with patients with low expression (median 42.7 months versus median not reached; P = .003). We hypothesized that combined expression of the HR gene BRCA1, the NHEJ gene PRKDC (DNA-PK), and PARP1 may predict survival and found that overexpression of 0 (n = 101), 1 or 2 (n = 287), or all 3 (n = 26) genes had a negative impact on median survival (undefined versus 57.8 months versus 14.8 months; P < .0001). Here we demonstrate that PARPi synergized with MEL, but that resistance (which may be due to HR and NHEJ pathways) is not completely reversed by PARPi. In addition, we observed that a 3-gene analysis may be tested to identify patients resistant or sensitive to high-dose MEL.

Development of a method for clinical pharmacokinetic testing to allow for targeted Melphalan dosing in multiple myeloma patients undergoing autologous transplant.

AIMS: High dose melphalan (HDM) and autologous stem cell transplant (ASCT) is standard of care for multiple myeloma (MM), but there is significant variability in melphalan exposure (area under the plasma drug concentration-time curve, AUC) when using body surface area-based dosing. Our aim was to establish a method of pharmacokinetic (PK) testing for real-time melphalan dose adjustments. METHODS: We performed a prospective PK study of melphalan 140 or 200 mg/m2 in MM patients undergoing ASCT. Twenty MM patients were administered HDM on days -2 and - 1, with PK sampling at 8-10 time points. PK testing was performed on day -2 in all patients, and on day -1 in 5 patients. RESULTS: Less than 20% interpatient variation in the day -2 and - 1 AUC was observed. The day -2 range in AUC (4.95-11.28 mg h/L) confirmed significant interpatient variability. The hypothetical total dose ranged from 133-302 mg/m2 to achieve the total median AUC. A 4-time point AUC (0, 30, 150 and 240 min) highly correlated with the AUC from the 8-time point schedule. A higher AUC correlated with increased risk of febrile neutropenia (P = .05). CONCLUSION: Here we outline the methods to establish novel melphalan dosing using PK testing in MM patients undergoing ASCT to target a desired melphalan AUC.

Polypharmacy and potentially inappropriate medication use is highly prevalent in multiple myeloma patients and is improved by a collaborative physician-pharmacist clinic.

OBJECTIVE: To compare polypharmacy and potentially inappropriate medication use in multiple myeloma patients receiving care under a traditional, physician-managed, or collaborative physician-pharmacist clinic. DESIGN: Retrospective chart review. SETTING: Urban academic cancer center. DATA SOURCE: Computerized electronic record. PATIENTS: Forty-four patients in the traditional physician-managed clinic and 57 patients in the collaborative physician-pharmacist clinic. MEASUREMENTS AND MAIN RESULTS: Patients in the collaborative clinic took fewer medications on average (9 vs. 7, p = 0.045). Although the median number of myeloma-related medications was higher (2 vs. 4, p < 0.0001), the number of non-myeloma-related medications was lower (7 vs. 3, p < 0.0001) in the collaborative clinic. Polypharmacy rates were high in both clinics (93% vs. 84%, p = 0.22). However, the collaborative clinic had a lower rate of polypharmacy of non-myeloma medications (71 vs. 33%, p = 0.0003), including both minor (five to nine medications, 48 vs. 28%, p = 0.06) and major (≥10 medications, 23 vs. 5%, p = 0.02) polypharmacy. Minor polypharmacy of myeloma-related medications was higher in the collaborative clinic (32 vs. 2%; p = 0.0002). Multivariate analysis showed a reduced risk of having a higher number of medications (Relative risk (RR) 0.79, 95% confidence interval 0.67-0.93; p = 0.004), a lower risk of having any polypharmacy of non-myeloma-related medications (RR 0.41, 95% confidence interval 0.25-0.67; p < 0.001) and a lower risk of receiving potentially inappropriate medication (RR 0.62, 95% confidence interval 0.41-0.95; p = 0.029) in the collaborative clinic. CONCLUSIONS: Multiple myeloma patients have a high rate of polypharmacy but comanagement with a pharmacist reduced the number of all medications, but in particular the number of non-myeloma-related medications.

Synergistic Cytotoxic Effect of Busulfan and the PARP Inhibitor Veliparib in Myeloproliferative Neoplasms.

Patients with high-risk myeloproliferative neoplasms (MPNs), and in particular myelofibrosis (MF), can be cured only with allogeneic hematopoietic stem cell transplantation (HSCT). Because MPNs and JAK2V617F-mutated cells show genomic instability, stalled replication forks, and baseline DNA double-strand breaks, DNA repair inhibition with poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors represents a potential novel therapy. Because the alkylating agent busulfan is integral in conditioning regimens for HSCT and leads to stalled replication forks through DNA strand cross-linking, we hypothesized that PARP inhibition with veliparib in combination with busulfan may lead to synergistic cytotoxicity in MPN cells. We first treated 2 MPN cell lines harboring the JAK2V617F mutation (SET2 and HEL) with veliparib at increasing concentrations and measured cell proliferation. SET2 and HEL cells were relatively sensitive to veliparib (IC50 of 11.3 µM and 74.2 µM, respectively). We next treated cells with increasing doses of busulfan in combination with 4 µM veliparib and found that the busulfan IC50 decreased from 27 µM to 4 µM in SET2 cells and from 45.1 µM to 28.1 µM in HEL cells. The mean combination index was .55 for SET2 cells and .40 for HEL cells. Combination treatment of SET2 cells caused G2M arrest in 53% of cells, compared with 30% with veliparib alone and 35% with busulfan alone. G2M arrest was associated with activation of the ATR-Chk1 pathway, as shown by an immunofluorescence assay for phosphorylated Chk1 (p-Chk1). We then tested in vivo the effect of combined low doses of busulfan and veliparib in a JAK2V617F MPN-AML xenotransplant model. Vehicle- and veliparib-treated mice had similar median survival of 39 and 40 days, respectively. Combination treatment increased median survival from 47 days (busulfan alone) to 50 days (P = .02). Finally, we tested the combined effect of busulfan and veliparib on CD34+ cells obtained from the bone marrow or peripheral blood of 5 patients with JAK2V617F-mutated and 2 patients with CALR-mutated MF. MF cells treated with the combination of veliparib and busulfan showed reduced colony formation compared with busulfan alone (87% versus 68%; P = .001). In contrast, treatment of normal CD34+ cells with veliparib did not affect colony growth. Here we show that in vivo confirmation that treatment with the PARP-1 inhibitor veliparib and busulfan results in synergistic cytotoxicity in MPN cells. Our data provide the rationale for testing novel pretransplantation conditioning regimens with combinations of PARP-1 inhibition and reduced doses of alkylators, such as busulfan and melphalan, for high-risk MPNs or MPN-derived acute myelogenous leukemia.

Impact of High-Molecular-Risk Mutations on Transplantation Outcomes in Patients with Myelofibrosis.

Mutational profiling has demonstrated utility in predicting the likelihood of disease progression in patients with myelofibrosis (MF). However, there is limited data regarding the prognostic utility of genetic profiling in MF patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HCT). We performed high-throughput sequencing of 585 genes on pre-transplant samples from 101 patients with MF who underwent allo-HCT and evaluated the association of mutations and clinical variables with transplantation outcomes. Overall survival (OS) at 5 years post-transplantation was 52%, and relapse-free survival (RFS) was 51.1 % for this cohort. Nonrelapse mortality (NRM) accounted for most deaths. Patient's age, donor's age, donor type, and Dynamic International Prognostic Scoring System score at diagnosis did not predict for outcomes. Mutations known to be associated with increased risk of disease progression, such as ASXL1, SRSF2, IDH1/2, EZH2, and TP53, did not impact OS or RFS. The presence of U2AF1 (P = .007) or DNMT3A (P = .034) mutations was associated with worse OS. A Mutation-Enhanced International Prognostic Scoring System 70 score was available for 80 patients (79%), and there were no differences in outcomes between patients with high risk scores and those with intermediate and low risk scores. Collectively, these data identify mutational predictors of outcome in MF patients undergoing allo-HCT. These genetic biomarkers in conjunction with clinical variables may have important utility in guiding transplantation decision making.

A novel drug interaction between busulfan and blinatumomab.

Busulfan is an alkylating agent used in pre-transplant conditioning for patients undergoing hematopoietic stem cell transplantation. Several factors contribute to variations in busulfan drug disposition including bioavailability, age, liver function, genetic polymorphisms, and concurrent administration of other drugs. Busulfan is metabolized by hepatic oxidation via the cytochrome P450 3A4 system as well as through conjugation with glutathione. Interactions with drugs such as phenytoin, itraconazole, and metronidazole have been reported to alter busulfan clearance and result in sub- or supra-therapeutic concentrations. We report a case of a clinically significant drug interaction between intravenous busulfan and the bifunctional T-cell engager, blinatumomab, observed through busulfan therapeutic drug monitoring. We found that busulfan clearance was reduced resulting in a higher area under the concentration-time curve when it was administered 48 h after blinatumomab. Repeat busulfan pharmacokinetic testing two weeks later demonstrated increased clearance of the drug and a 31% higher dose recommendation. Similar to other protein therapeutics, cytokine elevations during blinatumomab treatment can lead to cytochrome 3A4 suppression. We hypothesize that the increased busulfan levels observed could be related to a cytokine-mediated CYP3A4 suppression. This represents a unique pharmacologic consideration in hematopoietic stem cell transplantation which would impact several drugs that undergo CYP3A4 metabolism, including calcineurin inhibitors, cyclophosphamide, sirolimus, and triazole antifungals. Additionally, this mechanism of CYP3A4 suppression may be relevant in treatments and disease states where cytokine levels are elevated such as haploidentical stem cell transplantation, graft-versus-host disease, and use of chimeric antigen receptor T-cell therapy.