Addition of single dose gemtuzumab ozogamicin to intensive induction chemotherapy in core-binding factor acute myeloid leukemia

In a meta-analysis of 5 trials, the addition of gemtuzumab ozogamicin (GO) to intensive induction chemotherapy led to a survival benefit in patients with core-binding factor (CBF) acute myeloid leukemia (AML). Given the heterogeneous incorporation of GO in clinical trials, the ideal dose and schedule remains unclear. We conducted a single-center retrospective analysis to compare outcomes of patients with CBF-AML treated with intensive induction chemotherapy, with or without a single dose of GO 3 mg/m2, during induction only. We included 87 patients (GO=32, control=55). The composite complete remission (cCR) rate was higher in the control group (93%) compared to the GO group (82%) (p<0.001). The rate of measurable residual disease (MRD) negative cCR, by flow cytometry, was similar between both groups. There were no significant differences between the two groups in terms of toxicity. The 3-year relapse-free survival (RFS) for both groups was similar (71% vs 68%, p=0.5). The 3-year overall survival (OS) for the GO group was 68%, compared to 66% for the control group (p=0.9).In multivariable analysis, age and MRD positive status were risk factors for inferior outcomes. We find that survival of patients with CBF-AML is favorable in the real-world setting. The addition of single-dose GO, during induction, did not lead to a higher remission rate or survival benefit, when compared to intensive chemotherapy without GO. Further investigation into the incorporation of GO in the treatment algorithm for CBF-AML is needed.

Utility of end of induction bone marrow biopsy and survival outcomes in acute promyelocytic leukemia treated with fixed-dose induction regimen

Significant variations exist related to the end of induction practices in the management of Acute Promyelocytic Leukemia (APL). These variations include all-trans retinoic acid (ATRA)-arsenic trioxide (ATO) in fixed doses versus continuation until hematologic complete remission (CR) and performance versus omission of post-induction bone marrow biopsy to confirm morphological CR. A retrospective chart review was conducted of 61 patients (42 low/intermediate-risk and 19 high-risk) aged ≥ 18 years with newly diagnosed APL treated with fixed duration ATRA-ATO +/- cytoreduction at a tertiary medical center from December 2012 through March 2020. Of the 54 patients with post-induction bone marrow biopsy results, 52 (96%) demonstrated no morphologic evidence of APL while the remaining were equivocal. After 2.6 years median follow-up, no relapses occurred. The estimated 2-year overall survival rate of 95% suggests excellent outcomes with a fixed ATO induction regimen and safe omission of post-induction bone marrow biopsy irrespective of hematologic parameters.

Safe and Effective Use of Imatinib to Treat Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia During Pregnancy

Philadelphia chromosome positive (Ph+) B cell acute lymphoblastic leukemia (ALL) is extremely rare in pregnancy. Although the use of tyrosine kinase inhibitors (TKIs) has significantly improved outcomes of patients with Ph+ ALL, its use during pregnancy is not recommended due to the risk of fetal malformations. There are limited data on the use of TKIs during pregnancy and its long-term effects on the fetus. Within this context, we present a case of a 25-year-old woman diagnosed with Ph+ ALL during the third trimester and the safe and effective use of imatinib as treatment after failure of conventional chemotherapy.

Survival outcomes of patients with relapsed or refractory acute myeloid leukemia after venetoclax combined with hypomethylating agents

e18808

Background: Venetoclax in combination with hypomethylating agents (HMA+Ven) is the standard-of-care treatment for patients with newly diagnosed acute myeloid leukemia (AML) who are ineligible for intensive chemotherapy. HMA+Ven is also commonly used as salvage therapy for relapsed or refractory (R/R) AML. There is limited data regarding outcomes of AML patients after HMA+Ven failure. In clinical practice, survival following HMA+Ven failure, either as frontline or salvage therapy, is observed to be poor. Methods: We conducted a single center retrospective study to evaluate survival outcomes of AML patients who were R/R to HMA+Ven as frontline or salvage therapy. Patients ≥ 18 years of age with AML who initiated HMA+Ven between 06/2018 and 05/2021 were included. R/R AML was defined as clinically relevant disease with ≥ 5% blasts after prior complete remission/morphologic leukemia free state, refractoriness to at least two cycles of HMA+Ven, or progressive disease despite initiating HMA+Ven. Data cut-off was 02/07/2022. Overall survival (OS) was estimated using Kaplan-Meier method and outcome differences between sub-groups were assessed using the log rank test. Results: Forty-two patients met inclusion criteria. Baseline characteristics and treatment details are summarized in Table. The median OS of the overall cohort was 2.3 months (range 0.1-11.4). There was no significant difference in median OS between patients declared R/R to frontline vs salvage HMA+Ven (2.4 vs 1.8 months, hazard ratio [HR] = 0.84, 95% confidence interval [CI] 0.43-1.62). Patients who received treatment after HMA+Ven failure had longer median OS compared to patients who did not (n = 17, 4.7 vs 1.7 months, HR = 0.29, 95% CI 0.13-0.62). There was no significant difference in OS based on the sub-type of AML, ELN risk group, p53 mutation, or complex karyotype status. Conclusions: Data from our study support the clinical observation that AML patients with disease R/R to HMA+Ven, either as frontline or salvage therapy, have very poor survival outcomes. These results provide important prognostic information for clinicians and highlight the need for novel therapies for R/R AML.[Table: see text]

A phase 1 study of NTX-301, an oral DNMT1 inhibitor, in patients with MDS and AML (trial in progress)

TPS7077

Background: Patients with relapsed and/or refractory (r/r) myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML) who are not candidates for stem-cell transplantation have dismal outcomes. Novel therapies are needed. The nucleoside analogue NTX-301 (5-aza-4’-thio-2’-deoxycytidine or Aza-TdC) is incorporated into DNA, where it engages the active site of DNA methyltransferase I (DNMT1), a maintenance methyltransferase that contributes to the hypermethylation and silencing of tumor suppressor genes. DNMT1 can become trapped in a covalent complex with DNA, thus depleting free enzyme and inhibiting the normal maintenance methylation of CpG sites, resulting in re-activation of tumor suppressor genes. Preclinical data suggest a correlation between NTX-301 activity in leukemia xenograft models and decreased levels of DNMT1. NTX-301 offers an improvement over traditional DNA methyltransferase inhibitors (azacitidine, decitabine) by virtue of a higher incorporation rate into DNA at lower levels of cytotoxicity. Methods: This is a phase 1, open-label, multi-center, dose-escalation study to assess the safety, tolerability, and recommended myeloid monotherapy dose of NTX-301 in patients with r/r myeloid neoplasms. Patients ≥ 18 years with r/r higher-risk MDS (intermediate, high, very-high risk by IPSS-R), high-risk CMML (int-2/high by CPSS or CPSS-mol), or AML (marrow blasts ≤ 30% or WBC < 20,000 cells/µL without leukoreduction) are eligible. Other key eligibility criteria: Eastern Cooperative Oncology Group performance status 0–2; adequate cardiac, renal, and liver function; and resolved acute effects of any prior therapy. Successive cohorts of patients will receive escalating doses of NTX-301 starting from 2 mg QD. Each cycle is 21 days in duration (treatment for 5 days/week x 2 weeks and 1 week off). The trial incorporates accelerated titration design for dose level 1 and 2 followed by traditional 3+3 dose escalation design (3-6 patients per cohort) from dose level 3. Intrapatient dose escalation is allowed. NTX-301 treatment will continue until disease progression or unacceptable toxicity, whichever occurs first. Primary endpoints: incidence and severity of adverse events, dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), biologically effective dose (BED). Secondary endpoints: PK parameters of NTX-301, PD assessment through global hypomethylation assay and other markers in blood and marrow, and clinical efficacy [overall response rate (ORR), complete remission (CR), marrow CR (mCR), partial remission (PR), stable disease (SD), hematologic improvement (HI) per mIWG criteria]. After the MTD/BED is identified, the safety and efficacy of NTX-301 will be explored further in selected myeloid malignancies. The study began enrolling patients in January 2021 and is still recruiting. Clinical trial information: NCT04167917.

IDH1 inhibitor-induced neutrophilic dermatosis in a patient with acute myeloid leukemia

Ivosidenib is an oral inhibitor of mutant Isocitrate dehydrogenase 1 (IDH1). It is approved for treatment of patients with relapsed or refractory IDH1-mutated acute myeloid leukemia (AML) and patients with newly diagnosed IDH1-mutated AML who are 75 years or older or those who are ineligible to receive intensive chemotherapy. While generally well tolerated, differentiation syndrome has been reported in 15-20% of patients. Here, we report a case of acute febrile neutrophilic dermatosis or Sweet's syndrome in conjunction with the use of ivosidenib for the treatment of relapsed AML. We discuss the clinical presentation of this rare entity, review relevant literature, and comment on its association with differentiation syndrome.

Acute Lymphoblastic Leukemia, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Acute Lymphoblastic Leukemia (ALL) focus on the classification of ALL subtypes based on immunophenotype and cytogenetic/molecular markers; risk assessment and stratification for risk-adapted therapy; treatment strategies for Philadelphia chromosome (Ph)-positive and Ph-negative ALL for both adolescent and young adult and adult patients; and supportive care considerations. Given the complexity of ALL treatment regimens and the required supportive care measures, the NCCN ALL Panel recommends that patients be treated at a specialized cancer center with expertise in the management of ALL This portion of the Guidelines focuses on the management of Ph-positive and Ph-negative ALL in adolescents and young adults, and management in relapsed settings.

Predicting outcomes after acute reperfusion therapy for basilar artery occlusion

BACKGROUND AND PURPOSE

Basilar artery occlusion (BAO) leads to high rates of morbidity and mortality, despite successful recanalization. The discordance between flow restoration and long-term functional status clouds clinical decision-making regarding further aggressive care. We sought to develop and validate a practical, prognostic tool for the prediction of 3-month favorable outcome after acute reperfusion therapy for BAO.

METHODS

This retrospective, multicenter, observational study was conducted at four high-volume stroke centers in the USA and Europe. Multivariate regression analysis was performed to identify predictors of favorable outcome (90-day modified Rankin scale scores 0-2) and derive a clinically applicable prognostic model (the Pittsburgh Outcomes after Stroke Thrombectomy-Vertebrobasilar (POST-VB) score). The POST-VB score was evaluated and internally validated with regard to calibration and discriminatory ability. External validity was assessed in patient cohorts at three separate centers.

RESULTS

In the derivation cohort of 59 patients, independent predictors of favorable outcome included smaller brainstem infarct volume on post-procedure magnetic resonance imaging (P < 0.01) and younger age (P = 0.01). POST-VB score was calculated as: age + (10 × brainstem infarct volume). POST-VB score demonstrated excellent discriminatory ability [area under the receiver-operating characteristic curve (AUC) = 0.91] and adequate calibration (P = 0.88) in the derivation cohort (Center A). It performed equally well across the three external validation cohorts (Center B, AUC = 0.89; Center C, AUC = 0.78; Center D, AUC = 0.80). Overall, a POST-VB score < 49 was associated with an 88% likelihood of favorable outcome, as compared to 4% with a score ≥ 125.

CONCLUSIONS

The POST-VB score effectively predicts 3-month functional outcome following acute reperfusion therapy for BAO and may aid in guiding post-procedural care.

Student loan debt and visa status influence on career choices for hematology and medical oncology fellows in the United States

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Background: There are multiple factors influencing future career plans for US hematology/oncology fellows. The objective of this study is to evaluate the effects of student loan debt and visa status as potential factors affecting their career choices. Methods: A total of 159 US hematology/oncology fellowship programs were contacted, program directors forwarded the survey to current hematology/oncology fellows and recent graduates (classes of 2019, 2018 and 2017). The survey consisted of 13 questions regarding their student loan debt and visa status, research experience, initial career plan, current career for graduates, the influence of student loan debt and visa status on their career decisions (academic, private practice, industry), and whether or not their training programs had resources or mentorship to help them deal with those factors. We used a scale of 1-5 to determine how much each factor affected career choice (1 = extremely unaffected, 5 = extremely affected). Results: A total of 220 physicians have participated, 177 (80.5%) fellows and 43 (19.5%) graduates. For graduates, 35% had student loans during fellowship, 40% of them thought that their loans affected their career choice with a score of 4-5. 93% of graduates with student loans answered that they weren't aware of resources/mentorship to address their loans effect on their career. 44% of graduates were on J1/H1 visa during training, 74% of them thought that their visa status affected their career choice with score of 4-5. 63% of graduates who were on visa answered that they weren't aware of resources/mentorship to address visa status as a factor influencing their career options. For current fellows, 51% have student loans, one third of them thought that their loans affected their career choice with score 4-5. 77% of fellows with student loans answered that they weren't aware of resources/mentorship to address their loans effect on their career. 16% of current fellows are on J1/H1 visa, 66% of them thought that their visa status is affecting their career choice with score 4-5. 62% of fellows who are on visa answered that they weren't aware of resources/mentorship to address visa status as a factor influencing their career options. Conclusions: Hematology/oncology fellows report that student loan debt and visa status are important factors affecting their career decisions. The majority of hematology/oncology fellows in this survey weren’t aware of resources or mentorship to help deal with these factors. Mentors need to be aware of these factors to help fellows achieve their career goals.

Infarct Volume Predicts Hospitalization Costs in Anterior Circulation Large-Vessel Occlusion Stroke

BACKGROUND AND PURPOSE

Anterior circulation large-vessel occlusion stroke, one of the most devastating stroke subtypes, is associated with substantial economic burden. We aimed to identify predictors of increased acute care hospitalization costs associated with anterior circulation large-vessel occlusion stroke.

MATERIALS AND METHODS

Comprehensive cost-tracking software was used to calculate acute care hospitalization costs for patients with anterior circulation large-vessel occlusion stroke admitted July 2012 to October 2014. Patient demographics and stroke characteristics were analyzed, including final infarct volume on follow-up neuroimaging. Predictors of hospitalization costs were determined using multivariable linear regression including subgroup cost analyses by treatment technique (endovascular, IV tPA-only, and no reperfusion therapy) and sensitivity analyses incorporating patients initially excluded due to early withdrawal of care.

RESULTS

Three hundred forty-one patients (median age, 69 years; interquartile range, 57-80 years; median NIHSS score, 16; interquartile range, 13-21) were included in our primary analysis. Final infarct volume, parenchymal hematoma, baseline NIHSS score, ipsilateral carotid stenosis, age, and obstructive sleep apnea were significant predictors of acute care hospitalization costs. Final infarct volume alone accounted for 20.87% of the total cost variance. Additionally, final infarct volume was consistently the strongest predictor of increased cost in primary, subgroup, and sensitivity analyses.

CONCLUSIONS

Final infarct volume was the strongest predictor of increased hospitalization costs in anterior circulation large-vessel occlusion stroke. Acute stroke therapies that reduce final infarct volume may not only improve clinical outcomes but may also prove cost-effective.

Indoles derived from intestinal microbiota act via type I interferon signaling to limit graft-versus-host disease

The intestinal microbiota in allogeneic bone marrow transplant (allo-BMT) recipients modulates graft-versus-host disease (GVHD), a systemic inflammatory state initiated by donor T cells that leads to colitis, a key determinant of GVHD severity. Indole or indole derivatives produced by tryptophan metabolism in the intestinal microbiota limit intestinal inflammation caused by diverse stressors, so we tested their capacity to protect against GVHD in murine major histocompatibility complex-mismatched models of allo-BMT. Indole effects were assessed by colonization of allo-BMT recipient mice with tryptophanase positive or negative strains of Escherichia coli, or, alternatively, by exogenous administration of indole-3-carboxaldehyde (ICA), an indole derivative. Treatment with ICA limited gut epithelial damage, reduced transepithelial bacterial translocation, and decreased inflammatory cytokine production, reducing GVHD pathology and GVHD mortality, but did not compromise donor T-cell-mediated graft-versus-leukemia responses. ICA treatment also led to recipient-strain-specific tolerance of engrafted T cells. Transcriptional profiling and gene ontology analysis indicated that ICA administration upregulated genes associated with the type I interferon (IFN1) response, which has been shown to protect against radiation-induced intestinal damage and reduce subsequent GVHD pathology. Accordingly, protective effects of ICA following radiation exposure were abrogated in mice lacking IFN1 signaling. Taken together, these data indicate that indole metabolites produced by the intestinal microbiota act via type I IFNs to limit intestinal inflammation and damage associated with myeloablative chemotherapy or radiation exposure and acute GVHD, but preserve antitumor responses, and may provide a therapeutic option for BMT patients at risk for GVHD.

Performance of CT ASPECTS and Collateral Score in Risk Stratification: Can Target Perfusion Profiles Be Predicted without Perfusion Imaging?

BACKGROUND AND PURPOSE

Endovascular trials suggest that revascularization benefits a subset of acute ischemic stroke patients with large-artery occlusion and small-core infarct volumes. The objective of our study was to identify thresholds of noncontrast CT-ASPECTS and collateral scores on CT angiography that best predict ischemic core volume thresholds quantified by CT perfusion among patients with acute ischemic stroke.

MATERIALS AND METHODS

Fifty-four patients with acute ischemic stroke (<12 hours) and MCA/intracranial ICA occlusion underwent NCCT/CTP during their initial evaluation. CTP analysis was performed on a user-independent platform (RApid processing of PerfusIon and Diffusion), computing core infarct (defined as CBF of <30% normal). A target mismatch profile consisting of infarction core of ≤50 mL was selected to define candidates with acute ischemic stroke likely to benefit from revascularization.

RESULTS

NCCT-ASPECTS of ≥9 with a CTA collateral score of 3 had 100% specificity for identifying patients with a CBF core volume of ≤50 mL. NCCT-ASPECTS of ≤6 had 100% specificity for identifying patients with a CBF core volume of >50 mL. In our cohort, 44 (81%) patients had an NCCT-ASPECTS of ≥9, a CTA collateral score of 3, or an NCCT-ASPECTS of ≤6.

CONCLUSIONS

Using an NCCT-ASPECTS of ≥9 or a CTA collateral score of 3 best predicts CBF core volume infarct of ≤50 mL, while an NCCT-ASPECTS of ≤6 best predicts a CBF core volume infarct of >50 mL. Together these thresholds suggest that a specific population of patients with acute ischemic stroke not meeting such profiles may benefit most from CTP imaging to determine candidacy for revascularization.

Activation of microglial P2Y12 receptor is required for outward potassium currents in response to neuronal injury

Microglia, the resident immune cells in the central nervous system (CNS), constantly survey the surrounding neural parenchyma and promptly respond to brain injury. Activation of purinergic receptors such as P2Y12 receptors (P2Y12R) in microglia has been implicated in chemotaxis toward ATP that is released by injured neurons and astrocytes. Activation of microglial P2Y12R elicits outward potassium current that is associated with microglial chemotaxis in response to injury. This study aimed at investigating the identity of the potassium channel implicated in microglial P2Y12R-mediated chemotaxis following neuronal injury and understanding the purinergic signaling pathway coupled to the channel. Using a combination of two-photon imaging, electrophysiology and genetic tools, we found the ATP-induced outward current to be largely dependent on P2Y12R activation and mediated by G-proteins. Similarly, P2Y12R-coupled outward current was also evoked in response to laser-induced single neuron injury. This current was abolished in microglia obtained from mice lacking P2Y12R. Dissecting the properties of the P2Y12R-mediated current using a pharmacological approach revealed that both the ATP and neuronal injury-induced outward current in microglia was sensitive to quinine (1mM) and bupivacaine (400μM), but not tetraethylammonium (TEA) (10mM) and 4-aminopyridine (4-AP) (5mM). These results suggest that the quinine/bupivacaine-sensitive potassium channels are the functional effectors of the P2Y12R-mediated signaling in microglia activation following neuronal injury.

Performance and Predictive Value of a User-Independent Platform for CT Perfusion Analysis: Threshold-Derived Automated Systems Outperform Examiner-Driven Approaches in Outcome Prediction of Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Treatment strategies in acute ischemic stroke aim to curtail ischemic progression. Emerging paradigms propose patient subselection using imaging biomarkers derived from CT, CTA, and CT perfusion. We evaluated the performance of a fully-automated computational tool, hypothesizing enhancements compared with qualitative approaches. The correlation between imaging variables and clinical outcomes in a cohort of patients with acute ischemic stroke is reported.

MATERIALS AND METHODS

Sixty-two patients with acute ischemic stroke and MCA or ICA occlusion undergoing multidetector CT, CTA, and CTP were retrospectively evaluated. CTP was processed on a fully operator-independent platform (RApid processing of PerfusIon and Diffusion [RAPID]) computing automated core estimates based on relative cerebral blood flow and relative cerebral blood volume and hypoperfused tissue volumes at varying thresholds of time-to-maximum. Qualitative analysis was assigned by 2 independent reviewers for each variable, including CT-ASPECTS, CBV-ASPECTS, CBF-ASPECTS, CTA collateral score, and CTA clot burden score. Performance as predictors of favorable clinical outcome and final infarct volume was established for each variable.

RESULTS

Both RAPID core estimates, CT-ASPECTS, CBV-ASPECTS, and clot burden score correlated with favorable clinical outcome (P < .05); CBF-ASPECTS and collateral score were not significantly associated with favorable outcome, while hypoperfusion estimates were variably associated, depending on the selected time-to-maximum thresholds. Receiver operating characteristic analysis demonstrated disparities among tested variables, with RAPID core and hypoperfusion estimates outperforming all qualitative approaches (area under the curve, relative CBV = 0.86, relative CBF = 0.81; P < .001).

CONCLUSIONS

Qualitative approaches to acute ischemic stroke imaging are subject to limitations due to their subjective nature and lack of physiologic information. These findings support the benefits of high-speed automated analysis, outperforming conventional methodologies while limiting delays in clinical management.

Similar survival for patients undergoing reduced-intensity total body irradiation (TBI) versus myeloablative TBI as conditioning for allogeneic transplant in acute leukemia

PURPOSE

Hematopoietic stem cell transplantation (HSCT) is the mainstay of treatment for adults with acute leukemia. Total body irradiation (TBI) remains an important part of the conditioning regimen for HCST. For those patients unable to tolerate myeloablative TBI (mTBI), reduced intensity TBI (riTBI) is commonly used. In this study we compared outcomes of patients undergoing mTBI with those of patients undergoing riTBI in our institution.

METHODS AND MATERIALS

We performed a retrospective review of all patients with acute leukemia who underwent TBI-based conditioning, using a prospectively acquired database of HSCT patients treated at our institution. Patient data including details of the transplantation procedure, disease status, Karnofsky performance status (KPS), response rates, toxicity, survival time, and time to progression were extracted. Patient outcomes for various radiation therapy regimens were examined. Descriptive statistical analysis was performed.

RESULTS

Between June 1985 and July 2012, 226 patients with acute leukemia underwent TBI as conditioning for HSCT. Of those patients, 180 had full radiation therapy data available; 83 had acute lymphoblastic leukemia and 94 had acute myelogenous leukemia; 45 patients received riTBI, and 135 received mTBI. Median overall survival (OS) was 13.7 months. Median relapse-free survival (RFS) for all patients was 10.2 months. Controlling for age, sex, KPS, disease status, and diagnosis, there were no significant differences in OS or RFS between patients who underwent riTBI and those who underwent mTBI (P=.402, P=.499, respectively). Median length of hospital stay was shorter for patients who received riTBI than for those who received mTBI (16 days vs 23 days, respectively; P<.001), and intensive care unit admissions were less frequent following riTBI than mTBI (2.22% vs 12.69%, respectively, P=.043). Nonrelapse survival rates were also similar (P=.186).

CONCLUSIONS

No differences in OS or RFS were seen between all patients undergoing riTBI and those undergoing mTBI, despite older age and potential increased comorbidity of riTBI patients. riTBI regimens were associated with shorter length of hospital stay, fewer intensive care unit admissions, and similar rates of nonrelapse survival, which may reflect reduced toxicity. Prospective trials comparing riTBI and mTBI are warranted.

Pharmacoeconomic analysis of palifermin to prevent mucositis among patients undergoing autologous hematopoietic stem cell transplantation

Trials have shown benefits of palifermin in reducing the incidence and severity of oral mucositis in patients with hematological malignancies undergoing autologous hematopoietic stem cell transplantation (HSCT) with total body irradiation (TBI)-based conditioning regimens. Similar outcome data are lacking for patients receiving non-TBI-based regimens. We performed a retrospective evaluation on the pharmacoeconomic benefit of palifermin in the setting of non-TBI-based conditioning and autologous HSCT. Between January 2002 and December 2010, 524 patients undergoing autologous HSCT for myeloma (melphalan 200 mg/m²) and lymphoma (high-dose busulfan, cyclophosphamide, and etoposide) as preparative regimen were analyzed. Use of patient-controlled analgesia (PCA) was significantly lower in the palifermin-treated groups (myeloma: 13% versus 53%, P < .001; lymphoma: 46% versus 68%, P < .001). Median total transplant charges were significantly higher in the palifermin-treated group, after controlling for inflation (myeloma: $167,820 versus $143,200, P < .001; lymphoma: $168,570 versus $148,590, P < .001). Palifermin treatment was not associated with a difference in days to neutrophil engraftment, length of stay, and overall survival and was associated with an additional cost of $5.5K (myeloma) and $14K (lymphoma) per day of PCA avoided. Future studies are suggested to evaluate the cost-effectiveness of palifermin compared with other symptomatic treatments to reduce transplant toxicity using validated measures for pain and quality of life.

Engineering a stable and selective peptide blocker of the Kv1.3 channel in T lymphocytes

Kv1.3 potassium channels maintain the membrane potential of effector memory (T(EM)) T cells that are important mediators of multiple sclerosis, type 1 diabetes mellitus, and rheumatoid arthritis. The polypeptide ShK-170 (ShK-L5), containing an N-terminal phosphotyrosine extension of the Stichodactyla helianthus ShK toxin, is a potent and selective blocker of these channels. However, a stability study of ShK-170 showed minor pH-related hydrolysis and oxidation byproducts that were exacerbated by increasing temperatures. We therefore engineered a series of analogs to minimize the formation of these byproducts. The analog with the greatest stability, ShK-192, contains a nonhydrolyzable phosphotyrosine surrogate, a methionine isostere, and a C-terminal amide. ShK-192 shows the same overall fold as ShK, and there is no evidence of any interaction between the N-terminal adduct and the rest of the peptide. The docking configuration of ShK-192 in Kv1.3 shows the N-terminal para-phosphonophenylalanine group lying at the junction of two channel monomers to form a salt bridge with Lys(411) of the channel. ShK-192 blocks Kv1.3 with an IC(50) of 140 pM and exhibits greater than 100-fold selectivity over closely related channels. After a single subcutaneous injection of 100 microg/kg, approximately 100 to 200 pM concentrations of active peptide is detectable in the blood of Lewis rats 24, 48, and 72 h after the injection. ShK-192 effectively inhibits the proliferation of T(EM) cells and suppresses delayed type hypersensitivity when administered at 10 or 100 microg/kg by subcutaneous injection once daily. ShK-192 has potential as a therapeutic for autoimmune diseases mediated by T(EM) cells.