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Multiple myeloma (MM) is characterized by recurrent relapses. Consequently, patients receive multiple therapy lines, including alkylating agents and immune modulators, which have been associated with secondary malignancies such as myelodysplastic syndrome (MDS). Anti-B-cell maturation antigen (BCMA) chimeric antigen receptor T cell (CART) therapy is efficacious in patients with relapsed/refractory (R/R) MM. However, the long-term complications, particularly MDS, are not well understood. Whether CART therapy causes or promotes MDS has not been thoroughly investigated. In this study, we explored the causal relationship between MDS and CART therapy. We retrospectively examined the prevalence of MDS-related morphological and mutational changes before and after administration of CART therapy in five patients. Among them, four developed MDS after CART therapy, while one had pre-existing MDS prior to CART. None of the four patients who developed post-CART MDS showed morphological MDS changes prior to CART therapy. However, all four patients exhibited molecular alterations associated with MDS in their pre-CART as well as post-CART therapy bone marrow. No new mutations were observed. Our findings provide initial evidence suggesting that anti-BCMA CART therapy in MM may promote expansion of pre-existing MDS clones rather than causing development of new clones.

The optimal high-dose methotrexate (HDMTX)-based combination therapy for primary central nervous system lymphoma is unknown. We report our experience with rituximab, HDMTX, procarbazine and lomustine (R-MPL) given as first-line treatment in our center. Fifty-two patients between 2006 and 2019 were included. Eighteen patients proceeded to autologous transplant or two cycles of intermediate-dose cytarabine. The median age was 62 y (range 28-94) and the Eastern Cooperative Oncology Group performance status (ECOG-PS) was ≥2 in 62% (32/52). The overall/complete response rates were 79% (41/52) and 52% (27/52), respectively. The median progression-free/overall survival was 19 m/84m, respectively. Grade 3-4 adverse events included infections (17%) and kidney injury (13%). Ten patients (19%) discontinued therapy for toxicity. There were no treatment-related deaths. In summary, in a cohort enriched in frail patients, R-MPL achieved good responses and OS and was safe for all ages. The PFS was sub-optimal, possibly explained by a low proportion of consolidation. This regimen should be evaluated prospectively.

Polatuzumab (Pola)-based regimens and chimeric antigen receptor T (CAR T) cells provide superior outcome compared to conventional chemoimmunotherapy in patients with relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL). Choosing between these strategies remains controversial. The efficacy of CAR T versus Pola-rituximab(R) /Pola-bendamustine(B)-R in R/R DLBCL patients after failing ≥2 lines of treatment was compared in a retrospective, 'real-world' study. Propensity score matching, for age, lymphoma category (de-novo/transformed), number of prior lines, Eastern Cooperative Oncology Group performance status and lactate dehydrogenase level, was applied to control for differences in patients' characteristics. Response rate, progression-free survival (PFS) and overall survival (OS) were analyzed. A total of 82 patients, treated with CAR T (n=41) or Pola-based regimens (n=41), were included. No treatment-related deaths occurred with CAR T vs. 3 (7.3%) with Pola. The overall and complete response rates were 83% and 58% with CAR T vs. 66% and 44% with Pola-based-regimens (p=0.077 and p=0.18, respectively). At a median follow-up of 9 months (range 1-19.2) and 16 months (range 0.7-25.3) for the CAR T and Pola arm respectively, the median PFS has not been reached for CAR T vs. 5.6 months for Pola (95% CI 3.6-7.6, p=0.014). Median OS has not been reached for CAR T vs. 10.8 months (95% CI 2.2-19.4) for Pola (p=0.026). To conclude, in a real-world setting, treatment with CAR T achieved superior PFS and OS compared to Pola-based regimens in patients with R/R DLBCL.

Introduction: Mutated RUNX1 is considered a poor prognostic factor and usually is mutually exclusive with NPM1 mutations. Monitoring of molecular markers for minimal residual disease provides a powerful tool to assess remission and guide clinical decisions. Methods: Newly diagnosed RUNX1-mutated AML patients, designated to intensive chemotherapy-based treatment or nonintensive regimens, were monitored for mutated RUNX1 transcript levels by qPCR with patient-specific primers. Samples were obtained along the treatment course and follow-up. Results: A clear correlation was observed between mutated RUNX1 levels and response to treatment as observed by flow cytometry and STR-based assessment. Conclusion: We demonstrate the feasibility of RUNX1-based MRD to correlate with the clinicopathological status of leukemia. We further suggest how RUNX1 qPCR monitoring can influence clinical decision-making and contribute to improved personalized patient care.

Neutropenia postchemotherapy is associated with favorable outcomes, which was attributed to optimal dosing. However, little is known about the neutrophil decline rate as a predictor of cancer outcomes, which may reflect a dynamic marker of chemosensitivity. We assessed the association between the neutrophil decline rate and disease outcomes in a known cohort of 212 lymphoma patients, treated with thiotepa, etoposide, cyclophosphamide, cytarabine, and melphalan (TECAM) conditioning followed by autologous transplant in our center between 2000 and 2013. Slower neutrophil decline rate was correlated with worse overall survival, mediated not by shorter time to progression (TTP), but rather by worse survival post-progression, possibly pointing to chemosensitivity at each line of therapy as the responsible mechanism. The effect was seen across histologies and was independent of stronger predictors of outcome like performance status (PS) and response before transplant. Prospective research is needed to confirm our results and expand their validity to other clinical scenarios.

Systemic capillary leak syndrome (SCLS) is a rare life-threatening disorder due to profound vascular leak. The trigger and the cause of the disease is currently unknown and there is no specific treatment. Here, we identified a rare heterozygous splice-site variant in theTLN1gene in a familial SCLS case, suggestive of autosomal dominant inheritance with incomplete penetrance. Talin1 has a key role in cell adhesions by activating and linking integrins to the actin cytoskeleton. This variant causes in-frame skipping of exon 54 and is predicted to affect talin’s c-terminal actin binding site (ABS3). Modelling the SCLS-TLN1variant by mimicking the actin-binding disruption inTLN1heterozygous endothelial cells resulted in disorganized endothelial adherens junctions. Mechanistically, we established that disruption of talin’s ABS3 sequestrates talin’s interacting partner, vinculin, at cell-extracellular matrix adhesions, leading to destabilization of the endothelial barrier. We propose that pathogenic variant inTLN1underlie SCLS, providing insight into the molecular mechanism of the disease which can be explored for future therapeutic interventions.SUMMARYSystemic capillary leak syndrome (SCLS) is a rare potentially lethal disease with unknown etiology and non-specific treatment. Here, we established a heterozygous splice variant of talin1, a key cell adhesion protein, as a genetic link to a familial SCLS case.

Remission assessment in acute myeloid leukemia has evolved over the recent years with the advent of molecular and flow-based minimal residual disease determination. Nonetheless, early time point such as day 5 and day 14 (D14), still have prognostic and therapeutic implications. D14 refractory disease is regarded as a poor prognostic factor, however the therapeutic intervention is still under debate, with evidence suggesting a successful re-induction might offer similar long-term outcome as D14 aplasia. Others advocate the use of more intensive salvage protocols as a mean to overcome the negative prognostic effect. In the current study, we compare outcome of D14 refractory AML patients treated with either re-induction or salvage protocol. More importantly, we identify response characteristics that might suggest which patients will benefit from re-induction approach. Accurate identification of chemotherapy refractory patients might allow the early incorporation of non-chemotherapy based protocols in the future.

Patients with FLT3-mutated relapsed or refractory (R/R) acute myeloid leukemia (AML) have a dismal prognosis. Gilteritinib is a FLT3 tyrosine kinase inhibitor (TKI) recently approved for patients with R/R AML. We aimed to characterize real-world data regarding gilteritinib treatment in FLT3-mutated R/R AML and to compare outcomes with matched FLT3-mutated R/R AML patients treated with chemotherapy-based salvage regimens. Twenty-five patients from six academic centers were treated with gilteritinib for FLT3-mutated R/R AML. Eighty percent were treated with a prior intensive induction regimen and 40% of them received prior TKI therapy. Twelve patients (48%) achieved complete response (CR) with gilteritinib. The estimated median overall survival (OS) of the entire cohort was eight (CI 95% 0-16.2) months and was significantly higher in patients who achieved CR compared to those who did not (16.3 months, CI 95% 0-36.2 vs. 2.6 months, CI 95% 1.47-3.7; p value = 0.046). In a multivariate cox regression analysis, achievement of CR was the only predictor for longer OS (HR 0.33 95% CI 0.11-0.97, p = 0.044). Prior TKI exposure did not affect OS but was associated with better event-free survival (HR 0.15 95% CI 0.03-0.71, p = 0.016). An age and ELN-risk matched comparison between patients treated with gilteritinib and intensive salvage revealed similar response rates (50% in both groups); median OS was 9.6 months (CI 95% 2.3-16.8) vs. 7 months (CI 95% 5.1-8.9) in gilteritinib and matched controls, respectively (p = 0.869). In conclusion, in the real-world setting, gilteritinib is effective, including in heavily pre-treated, TKI exposed patients.

Venetoclax in combination with intensive therapies is explored in both the upfront and relapse/refractory (R/R) setting, and available data suggest that such regimens are effective albeit with added hematological and infectious toxicity. We conducted a multicenter retrospective cohort study of patients with acute myeloid leukemia (AML) treated with venetoclax in combination with FLAG-IDA protocol. Twenty-five patients were included in this analysis (median age 53.4 years). Most patients were treated for R/R AML (n = 24, 96%) with a median of one (range 0-3) previous lines of therapy and 44% of patients (n = 11) having prior allogeneic hematopoietic cell transplantation (HCT). Median follow-up was 10 (range, 4-26) months. Platelet and neutrophil recovery were observed at a median of 31 (95% CI 17.6-38.3) and 23 (95% CI 20-28) days, respectively. The most common adverse events were infectious (blood stream infections, 48% and invasive fungal infections, 32%). Thirty-day mortality was 12%. Composite complete remission (CRc) was 72% for the entire cohort and 91% in patients treated for post-HCT relapse. Incidences of relapse-free and overall survival at 12 months were 67% (95% CI 58-76%) and 50% (95% CI 31-69%), respectively. Real-world data show that the addition of venetoclax to FLAG-IDA protocol is effective in patients with high-risk AML, most notably in the post-HCT relapse setting. Prophylaxis and surveillance for infections are crucial.

Chimeric antigen receptor T cell (CAR-T) therapy is a novel approved treatment for hematological malignancies, still under development for solid tumors. Here, we use a rate equation-based mathematical model to discover regimens and schedules that maintain efficacy while potentially reducing toxicity by decreasing the amount of CAR-T infused. Tested on an in vivo murine model of spontaneous breast cancer, we show that our mathematical model accurately recapitulates in vivo tumor growth results achieved in the previous experiments. Moreover, we use the mathematical model to predict results of new therapy schedules and successfully prospectively validated these predictions in the in vivo. We conclude that using one tenth and even one percent of a full CAR-T dose used in preclinical trials can achieve efficacious results similar to full dose treatment.

Residual end of treatment (EOT) FDG-avid lesions are often due to infectious or inflammatory process and not due to refractory lymphoma. Nonetheless, such lesions prompt diagnostic and therapeutic interventions. We evaluate clinical and radiological characteristics of patients with EOT FDG-avid splenic lesions. Comparing metabolic volume (MV) ratio between EOT to interim, showed a marked difference between false positive and true positive lesions (0.5 vs 3.6, P = 0.02). EOT SUVmax was also significantly different between the groups (7 vs. 19, P = 0.02). We suggest EOT/interim-MV ratio as a tool to identify patients at low risk of refractory disease allowing non-invasive surveillance.

The coronavirus disease 2019 (COVID-19) pandemic has dominated nearly everyone’s life since its initial outbreak in the Hubei province of China in December 2019. The disease had spread quickly throughout the world causing extensive, widespread morbidity, over two million deaths, and economical and social devastation over the entire world. Researchers and pharmaceutical companies around the globe have been racing to develop potent and safe vaccines for the disease. Pfizer-BioNTech COVID-19 vaccine followed by Moderna COVID-19 mRNA-1273 vaccine were the first to receive FDA approval. These vaccines are based on messenger RNA novel technology and considered efficient in preventing contagion ensuring safety. Known side effects for this vaccine have been reported as very similar to those known for other vaccines. Specifically, lymphadenopathy has not been considered a common manifestation of COVID-19 vaccination. Israel has been cited as leading in the introduction of these vaccines, which are available for every citizen older than 16 years. Here, we present the cases of three patients who developed lymphadenopathy after the first dose of Pfizer-BioNTech COVID-19 vaccine. Time elapsed from the injection until the appearance of the enlarged nodes, clinical symptoms, and sonographic features differed between the patients, but in all cases gradual regression was noted in the enlarged nodes until complete resolution. Accordingly, to our knowledge, this is the first report describing post-COVID-19 vaccine lymphadenopathy detailing the clinical aspects, sonographic features, and outcomes.

The efficacy of polatuzumab vedotin in relapsed/refractory diffuse large B-cell lymphoma outside clinical study are undetermined. This retrospective study examined the efficacy and safety of polatuzumab vedotin administered in real life settings. Forty-seven patients, 31 with

Radiosensitivity differs in humans and likely among closely-related primates. Reasons for variation in radiosensitivity are not well known. We examined preirradiation gene expression in peripheral blood among male and female rhesus macaques which did or did not survive (up to 60 days) after whole-body irradiation with 700 cGy (LD66/60). RNA samples originated from a blinded randomized Good Laboratory Practice study in 142 irradiated rhesus macaques. Animals were untreated (placebo), or treated using recombinant human IL-12, G-CSF or combination of the two. We evaluated gene expression in a two-phase study design where phase I was a whole genome screen [next generation sequencing (NGS)] for mRNAs (RNA-seq) using five RNA samples from untreated male and female animals per group of survivor and non-survivor (total n = 20). Differential gene expression (DGE) was defined as a statistically significant and ≥2-fold up- or downregulation of mRNA species and was calculated between groups of survivors and non-survivors (reference) and by gender. Altogether 659 genes were identified, but the overlapping number of differentially expressed genes (DGE) observed in both genders was small (n = 36). Fifty-eight candidate mRNAs were chosen for independent validation in phase II using the remaining samples (n = 122) evaluated with qRT-PCR. Among the 58 candidates, 16 were of significance or borderline significance (t test) by DGE. Univariate and multivariate logistic regression analysis and receiver operating characteristic (ROC) curve analysis further refined and identified the most outstanding validated genes and gene combinations. For untreated male macaques, we identified EPX (P = 0.005, ROC=1.0), IGF2BP1 (P = 0.05, ROC=0.74) and the combination of EPX with SLC22A4 (P = 0.03, ROC=0.85) which appeared most predictive for the clinical outcome for treated and combined (untreated and treated) male macaque groups, respectively. For untreated, treated and both combined female macaque groups the same gene (MBOAT4, P = 0.0004, ROC = 0.81) was most predictive. Based on the probability function of the ROC curves, up to 74% of preirradiation RNA measurements predicted survival with a positive and negative predictive value ranging between 85-100% and associated odds ratios reflecting a 2-3-fold elevated risk for surviving per unit change (cycle threshold value) in gene expression. In conclusion, we identified gender-dependent genes and gene combinations in preirradiation blood samples for survival prediction after irradiation in rhesus macaques.

Data from 11 Israeli centers, where venetoclax was used for relapsed/refractory AML after intensive chemotherapy, were retrospectively collected. During 2016-2019, forty patients were identified. Median age was 67 years (21-82), 60% males, median of 2(1-4) prior lines of treatment and 42% relapsed after allogeneic transplant. 62.5% of the patients received the venetoclax with hypomethylating agents and 22.5% with low dose cytarabine. Median follow-up was 5.5 months. Of the 29 patients who survived for more than two cycles of therapy, 22 (76%) achieved neutrophil recovery and 59% (

Previous studies and meta-analyses addressing COVID-19 in patients with hematological malignancies (HM) have reported dramatically high mortality rates of up to 34% [Vigenthira 2020, Garcia-Suarez 2020, Sharafeldin 2021]. These studies, however, were strongly biased towards hospitalized patients, and poorly represented patients who experienced a milder course of COVID-19, not requiring hospitalization. Jerusalem and its metropolitan area, comprising of over 1.3 million inhabitants, was the epicenter of Israel's COVID-19 crisis, with over 200,000 cases. Hadassah Medical Center, one of only two tertiary centers serving this multi-ethnic population, houses a Hematology Department that includes inpatient services, a hematopoietic stem cell transplant (HSCT) center, day care services and in-campus outpatient clinics. From February 20 th, 2020, we tracked patients with confirmed COVID-19 reporting to their treating hematologists while being hospitalized due to COVID-19, at routine visits to the hematology services, or remotely via phone or email communication. This assured the representation of COVID-19 cases of various clinical severities. Data were collected retrospectively and included demographics, comorbidities, hematological diagnoses and treatments, course of COVID-19 and, importantly, source of infection. Univariate and multivariate analyses were used to assess association between prognostic factors and outcomes including hospitalization, severe COVID-19 (per updated WHO criteria) and critical COVID-19, defined as a composite of ICU admission and mortality. Almost all the patients in this series were diagnosed prior to their vaccination. To the best of our knowledge, this is the largest single center series of HM patients with COVID-19 reported to date. Our series included 183 patients. Median age was 62.5 years, 57% were men, and 72% had at least one comorbidity. The most frequent hematological diagnoses were indolent lymphoma and CLL (40%), aggressive lymphoma (20%) and multiple myeloma (19%). At the time of COVID-19 diagnosis, 41% of the patients were receiving systemic anti-neoplastic treatment (excluding TKIs for CML and hydroxyurea for MPN), and 16% had undergone a previous allogeneic or autologous HSCT. Overall mortality, severe COVID-19, and hospitalization rates in the entire group were 9.8%, 14.2% and 32%, respectively, remarkably lower than in previous reports. Of the patients not receiving anti-neoplastic treatment, mortality and severe COVID-19 rates were comparable to those of the age-matched general population according to the Israeli Ministry of Health database [Table 1]. Consistent with previous studies, ischemic heart disease (IHD), dyslipidemia, chronic kidney disease, smoking and hypertension, as well as age and active anti-neoplastic treatment, each emerged as a risk factor significantly associated with hospitalization due to COVID-19 [Fig. 1, Table 2]. IHD, smoking, age and active treatment remained significant in multivariate analysis. Age and active treatment as well as ≥4 comorbidities were significantly associated with critical COVID-19. Interestingly, we observed a strong association between the number of prior anti-neoplastic treatment lines and critical COVID-19. Neither history of HSCT nor treatment with monoclonal antibodies were associated with COVID-19 outcomes. Notably, we did not detect any patient that contracted COVID-19 within the Hematology Department services, both inpatient and outpatient. Taken together, we present a different COVID-19 severity landscape in patients with HM as compared to previous observations. While active treatment was significantly associated with COVID-19 hospitalization and mortality, these rates were remarkably lower than previously reported. Despite harboring various degrees of immune suppression, patients with stable or indolent diseases not receiving active treatment appeared to be at a risk comparable to that of the age-matched general population, which depended largely on age and comorbidities. Routine preventive measures including symptom questioning, masks, and social distancing in both our inpatient and outpatient services provided a COVID-19-safe environment, obviating the need for changes in treatment schedules or assignment. These findings may have important consequences for future management of patients with HM in COVID-19 affected regions. Figure 1 Figure 1. Disclosures Lavie: AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Fees for lectures; BMS: Membership on an entity's Board of Directors or advisory committees; Takeda: Other: Fees for lectures; Roche: Other: Fees for lectures; Novartis: Other: Fees for lectures; Takeda: Consultancy. Goldschmidt: AbbVie: Consultancy, Research Funding.

Purpose Transcriptome changes can be expected in survivors after lethal irradiation. We aimed to characterize these in males and females and after different cytokine treatments 60 days after irradiation. Material and methods Male and female rhesus macaques (n = 142) received a whole-body exposure with 700 cGy, from which 60 animals survived. Peripheral whole blood was drawn pre-exposure and before sacrificing the surviving animals after 60 days. Results We evaluated gene expression in a three-phase study design. Phase I was a whole-genome screening (NGS) for mRNAs using five pre- and post-exposure RNA samples from both sexes (n = 20). Differential gene expression (DGE) was calculated between samples of survivors and pre-exposure samples (reference), separately for males and females. 1,243 up- and down-regulated genes were identified with 30–50% more deregulated genes in females. 37 candidate mRNAs were chosen for qRT-PCR validation in phase II using the remaining samples (n = 117). Altogether 17 genes showed (borderline) significant (t-test) DGE in groups of untreated or treated animals. Nine genes (CD248, EDAR, FAM19A5, GAL3ST4, GCNT4, HBG2/1, LRRN1, NOG, SYT14) remained with significant changes and were detected in at least 50% of samples per group. Panther analysis revealed an overlap between both sexes, related to the WNT signaling pathway, cell adhesion and immunological functions. For phase III, we validated the nine genes with candidate genes (n = 32) from an earlier conducted study on male baboons. Altogether 14 out of 41 genes showed a concordantly DGE across both species in a bilateral comparison. Conclusions Sixty days after radiation exposure, we identified (1) sex and cytokine treatment independent transcriptional changes, (2) females with almost twice as much deregulated genes appeared more radio-responsive than males, (3) Panther analysis revealed an association with immunological processes and WNT pathway for both sexes.

Chimeric antigen receptor T cell (CAR-T) therapy is a novel approved treatment for hematological malignancies, still under development for solid tumors. Here, we use a rate equation-based mathematical model to discover regimens and schedules that maintain efficacy while potentially reducing toxicity by decreasing the amount of CAR-T infused. Tested on an in vivo murine model of spontaneous breast cancer, we show that our mathematical model accurately recapitulates in vivo tumor growth results achieved in the previous experiments. Moreover, we use the mathematical model to predict results of new therapy schedules and successfully prospectively validated these predictions in the in vivo. We conclude that using one tenth and even one percent of a full CAR-T dose used in preclinical trials can achieve efficacious results similar to full dose treatment.

Objective: Bone density loss and increased risk for osteoporosis are of concern in Hodgkin lymphoma (HL) patients. Routinely performed positron emission tomography-computed tomography (PET-CT) scans could be informative in assessing bone mineral density (BMD). Methods: This retrospective study included 80 adults with newly diagnosed HL treated with standard first-line chemotherapy regimens. PET-CT scans performed at diagnosis (PET-CT1), at the end of chemotherapy (PET-CT2), and at follow-up after remission (PET-CT3) were used to assess BMD changes by measuring lumbar vertebrae CT attenuation. A CT attenuation threshold of 160 Hounsfield units was used to define abnormal BMD. Results: Following chemotherapy, comparison of PET-CT2 with PET-CT1 revealed a mean (standard deviation) 14.2% (10.4%) BMD reduction (P

Objective Daratumumab is a promising new antimyeloma agent. We report a single center "real-world" series of multiple myeloma (MM) and amyloidosis (AL) patients treated with daratumumab. Methods Forty-one patients were included: 7 second-line MM, 30 heavily pretreated (median number of therapies of 5) advanced MM, and 4 with AL. Results Second-line patients and advanced AL showed high rate of durable overall responses. However, advanced MM patients had a dismal prognosis with an overall response rate (ORR) of 36%, and a short median progression-free and overall survival of 2.3 and 6.6 months, respectively. Responses were particularly poor in patients with extramedullary plasmacytomas. Neither the addition of another agent to daratumumab nor changing to the next line of therapy produced significant durable responses in this patient population. Flow cytometry analysis demonstrated that CD38 expression level was not predictive of response. We show that CD38 expression dynamics by a commercially available anti-CD38 antibody after daratumumab administration was hindered by competitive binding of daratumumab. Conclusions Responses to daratumumab and combinations in patients with advanced MM, particularly with extramedullary disease, are low and short-lived, stressing the administration of this agent should be early in the course of the disease.

Hematopoietic syndrome of acute radiation syndrome (HSARS) is a life-threatening condition with no approved treatment. We compared recombinant human interleukin-12 (rHuIL-12; 175 ng/kg × 1) with vehicle, granulocyte-colony-stimulating factor (G-CSF; 10 µg/kg/day × 18), or rHuIL-12+G-CSF after lethal irradiation in rhesus monkeys in a Good Laboratory Practice, randomized, blinded, placebo-controlled study. Fluids, antibiotics, and blood products were not used. Survival at day 60 was significantly increased for rHuIL-12 versus G-CSF or vehicle. rHuIL-12/G-CSF combination provided no additional survival benefit over rHuIL-12. Both rHuIL-12 and rHuIL-12+G-CSF increased blood cell nadirs, induced earlier recovery of all hematopoietic lineages, and significantly decreased frequencies of severe cytopenias versus vehicle or G-CSF. In bone marrow, rHuIL-12 alone increased erythroid, myeloid, and megakaryocyte counts relative to vehicle or G-CSF. Thus, a single injection of rHuIL-12, without supportive medical intervention, significantly improved survival and promoted multilineage hematopoietic recovery in a nonhuman primate model of HSARS.

Intensive chemotherapy for newly diagnosed acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) is associated with significant treatment-related morbidity and mortality. Herein, we investigate how pretreatment characteristics relate to early adverse outcomes in such patients, studying 205 consecutive individuals receiving curative-intent induction chemotherapy with cytarabine and an anthracycline (“7 + 3”; n = 175) or a “7 + 3”-like regimen (n = 30). Among the entire cohort, baseline grade 4 neutropenia (i.e., absolute neutrophil count

PET-CT has been widely incorporated in the treatment of diffuse large B cell lymphoma (DLBCL) and Hodgkin's lymphoma (HD) both for staging at diagnosis and for evaluation of response to therapy. Residual FDG-avid lesions at the end of treatment (EOT) are often due to infectious or inflammatory process and not due to refractory lymphoma. Nonetheless, such lesions prompt diagnostic and therapeutic interventions. In the present study, we evaluate clinical and radiological characteristics of patients with EOT FDG-avid splenic lesions in hope to provide better tools to discern false from true lesions. The study cohort included patients with DLBCL or HD who had residual EOT FDG-avid splenic lesion with no evidence of active disease in other sites. Patients were concluded as false positive or true positive according to pathological results or long-term follow-up. Clinical and PET-CT characteristics were compared between the two groups. Our cohort included 9 patients with DLBCL and 2 with HD, of which 6 patients were determined to have false positive lesions and 5 true positive. Comparing metabolic volume (MV) ratio between EOT to interim (EOT/interim) tests showed a marked difference between false positive and true positive lesions (0.5 vs 3.6, p= 0.02). Notably, comparing EOT to diagnosis (EOT/Dx) MV showed a similar trend that did not reach statistical significance, highlighting MV EOT/interim ratio as a parameter with higher discriminative ability. EOT SUVmax was also significantly different between false positive and true positive (7 vs. 19, p=0.02). A MV EOT/interim ratio >3 has a 75% sensitivity and 100% specificity for the true positive group. Other clinical and PET-CT characteristics were not found to statistically differ between the groups. To date, this is the first report showing predictive ability of PET-CT characteristics to discern true from false positive residual FDG-avid splenic lesions. Our cohort is of small numbers, nonetheless, EOT/interim MV shows a clear opposite ratio with a decrease in the false positive compared to an increase in the true positive groups. We suggest EOT/interim MV ratio might be a tool to identify patients at low risk of refractory disease allowing non-invasive surveillance. Further larger studies will be needed to validate the role MV EOT/interim ratio as a tool to discriminate residual disease from false positive FDG-avid lesions. Disclosures No relevant conflicts of interest to declare.

Introduction: On November 2018 the FDA approved the treatment of venetoclax together with hypomethylating agent (HMA) or low dose cytarabine (LDAC) for newly diagnosed AML patients who cannot tolerate intensive chemotherapy. There is limited data regarding the efficacy and safety of venetoclax in the setting of relapsed/refractory patients who received intensive chemotherapy for their disease. Methods: In this study, data were collected retrospectively from Israeli medical centers where venetoclax was used as an advanced line of treatment after intensive chemotherapy. Venetoclax was given as a combination with HMA or LDAC or as monotherapy. Results: 40 patients with AML were included in the study, 60% were Males. The median age at time of diagnosis was 67 years (range, 21-82). 27 (67.5%) patients had de-novo AML and 13 (32.5%) had secondary disease; 7 (17.5%) patients had a history of MDS and 6 (15%) of MPN. 37% of the patients had normal karyotype (20% of them had FLT3-ITD mutation), 23% had complex karyotype. Based on the 2017 ELN risk classification, 12.5% had favorable risk, 42.5% - intermediate and 45% had high risk. At presentation, 87.5% of the patients received the '7+3' protocol as induction therapy but only 45% achieved a CR. Ultimately, 57.5% of the patients achieved a CR post consolidation/ salvage therapy. 42.5% underwent allogeneic hematopoietic cell transplant (HCT); 71% received myeloablative conditioning and the others reduced intensity. The median time from diagnosis to starting venetoclax was 6 (1-64) months. Patients received venetoclax after a median of 2 (range, 1-4) prior lines of treatment (not including HCT). The median age at starting venetoclax was 68.5 years (range, 22-83). The ECOG performance status at starting venetoclax was 0-1 in 67.5% of the patients, 2 in 22.5% and 3 in 10% of the patients. The median daily dose of venetoclax was 400 mg (range: 100-800 mg). Venetoclax was given together with HMA (mostly azacitidine) in 62.5% of the patients and with LDAC in 22.5%. In 12.5% of the patients it was given as monotherapy and in 1 patient it was given with the FLAG-IDA regimen. The median number of cycles of venetoclax that were given so far is 2.75 (range: 0.5-14). None of the patients experienced tumor lysis syndrome (TLS). 27.5% of the patients did not survive more than 2 months. Of the 29 patients who survived longer than 2 months, 76% achieved neutrophil recovery and 77% of them recovered also their platelet count. In 52% of those who survived more than 2 months, CR/CRi was confirmed by bone marrow (BM) examination. Taken together, 76% of the patients who survived more than 2 months achieved blood cell count recovery and in 68% of them it was confirmed as CR/CRi by BM examination. At a median follow-up of 5.5 months, 35% of the patients are still alive and 57% of them are still on venetoclax. The leading cause of death (81%) was disease progression. The median OS from starting venetoclax of all the patients and of those who survived more than 2 months was 5.5 and 6.5 months, respectively (Figure 1). Conclusions: Venetoclax was given to high risk AML patients with relapsed/refractory disease after intensive chemotherapy and in around 40% of the patients also after HCT. The treatment was tolerable and no patient developed TLS. Among those who survived more than 2 months, the CR/CRi rate, or at least blood cell count recovery rate, was high (76%) and the median OS was 6.5 months. These retrospective data, albeit in a heterogeneous group of previously treated patients with AML, demonstrate that the combination of venetoclax with HMA or LDAC is safe and active also in AML patients with advanced disease. Its precise role for patients who relapse after intensive chemotherapy needs to be evaluated in a prospective clinical trial. Figure 1 Disclosures Wolach: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaker; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Speaker. Rowe:BioSight: Consultancy. OffLabel Disclosure: Venetoclax for relapsed/ refractory AML

Introduction The therapeutic options for diffuse large cell B cell lymphoma (DLBCL) patients (pts) that fail to respond/relapse after≥2 treatment regimens are limited. The SCHOLAR-1 study reported an overall response/ complete remission (ORR/CR) rates of 26%/ 7% with a median overall survival (OS) of 6.3 months in chemorefractory and early relapsing DLBCL pts. Polatuzumab vedotin (Pola) is a conjugated antibody that delivers the microtubule inhibitor MMAE to CD79b-expressing cells. Polatuzumab administered in combination with Bendamustine-Rituximab (P-BR) has been recently approved by the FDA for pts with relapsed/refractory (R/R) DLBCL that failed to respond≥2 prior therapies. The current study investigated the tolerability and efficacy of Pola mainly with BR, in DLBCL pts, treated through a compassionate program after failing ≥2 prior regimens. Methods Data of all pts with consecutive R/R DLBCL, treated with Pola-BR or Pola-R (2-8 cycles) in 11 Israeli centers between 6/2018 and -5/2019 were analyzed. Inclusion criteria for this study were: R/R DLBCL (denovo and transformed follicular lymphoma [t-FL]), age ≥ 18 years, ≥ 2 prior treatments. We evaluated pt characteristics, treatment details and toxicities, overall response and CR rates, progression free survival (PFS) and OS. Cox regression model was used to define factors affecting outcomes. Results 34 patients- (denovo DLBCL, n=24 and t-FL, n=10 ⌈50% -non CGB and 50% - GCB type⌉) were included. Median age at Pola administration was 65.5 (range 60-72) years. Stage ≥3 disease was recorded in 88% and IPI ≥3 in 73.5%. Median prior lines was 3 (range 3-5); including anthracyclines and rituximab in 100% and cisplatin-based regimens in 91%. 32% relapsed after ASCT and 9% after CART infusion. 53% had primary refractory disease, 29% had refractory relapse and 18% had prior sensitive relapse. 22 pts received Pola-B, mostly with Rituximab (n=19), and 12 received Pola-R. In 5 pts, Pola-based regimen was used as a bridge for Allo SCT (all responded CR, n=4 and PR, n=1) and in 6 as a bridge to CARTs (all responded CR n=1, PR n=2, SD n=3). Median number of Pola B cycles was 3 (3-5) and median Pola-R cycles was 4 (3-6). Median B dose per cycle was 90 mg/m2 (45-90). GCSF was used in 47%. Early treatment discontinuation due to progressive disease (PD) occurred in 8 (23%) of the entire cohort: 23% of Pola-B pts and 25% of Pola-R pts. Safety: Hematological AEs grade 3-4, reported with Pola- B vs Pola-R were: neutropenia (45.5.% vs 33%), thrombocytopenia (25% vs 8%) and anemia (23% vs 17%). Infections were recorded in 41% and 36% of Pola-B pts and Pola-R respectively. Neutropenic fever was reported in 36% in Pola-B pts and none in Pola-R. Pulmonary infections were recorded in 33.3% and 27.3% of Pola-B and Pola-R pts respectively, resulting in death in one pt. Peripheral neuropathy occurred in 18% of Pola- B pts (grade ≤2) vs 8% with Pola -R. Hospitalization due to AEs was recorded in 41% of Pola-B vs 25% of Pola-R. Pola dose reduction due to AE was reported in 1 pt (8%) in the Pola-R. Efficacy: ORR for the entire cohort was 65%, including 38% CRs and 27% PRs. 12% pts attained SD and 23% experienced PD. ORR was higher in non-GCB than in GCB pts 80% vs 43% (p=0.036). Median follow up of the entire cohort from Pola administration was 4.4 months (range 0.6-11.4). 6 months projected OS and PFS were 83% and 63%, respectively. Post Pola treatment in pts that failed to respond/Relapsed post pola: 8 patients had PD; 3 died from progression, 1-CART, 1-Allo SCT, 2-paliative care and 1-unknown. Additional 5 pts progressed during follow up; 4-CART and 1-palliative care. 1 patient continues Pola treatment after achieving SD. Univariate analysis for factors predicting PFS and OS GCB type (HR-1.816, P=0.055), Primary refractory vs relapsed disease (HR-1.507, p=0.049) and a higher number of prior lines since diagnosis (HR-1.35, p=0.079) tended to be associated with shorter time to progression. T-FL vs denovo DLBCL was associated with decreased OS (p=0.008). Data of 60 patients, including pts treated recently, therefore, not evaluable at the time of abstract submission, would be presented at ASH. Conclusions The toxicity of Pola-based regimen was relatively low. Pola based treatment provided an encouraging PFS and OS in pts with R/R DLBCL that failed to respond ≥2 prior therapies, treated in a real-life setting. Primary refractory disease, higher number prior lines and t-FL vs denovo DLBCL were associated with inferior outcome. Figure Disclosures Herishanu: Roche: Honoraria; AbbVie: Honoraria; Janssen: Honoraria.

Rapid rate of peripheral blood blast clearance accurately predicts complete remission in acute myeloid leukemia

The cancer stem cell (CSC) hypothesis states that only a small fraction of a malignant cell population is responsible for tumor growth and relapse. Understanding the relationships between CSC dynamics and cancer progression may contribute to improvements in cancer treatment. Analysis of a simple discrete mathematical model has suggested that homeostasis in developing tissues is governed by a "quorum sensing" control mechanism, in which stem cells differentiate or proliferate according to feedback they receive from neighboring cell populations. Further analysis of the same model has indicated that excessive stem cell proliferation leading to malignant transformation mainly results from altered sensitivity to such micro-environmental signals. Our aim in this work is to expand the analysis to the dynamics of established populations of cancer cells and to examine possible therapeutic avenues for eliminating CSCs. The proposed model considers two populations of cells: CSCs, which can divide indefinitely, and differentiated cancer cells, which do not divide and have a limited lifespan. We assume that total cell density has negative feedback on CSC proliferation and that high CSC density activates CSC differentiation. We show that neither stimulation of CSC differentiation nor inhibition of CSC proliferation alone is sufficient for complete CSC elimination and cancer cure, since each of these two therapies affects a different subpopulation of CSCs. However, a combination of these two strategies can substantially reduce the population sizes and densities of all types of cancer cells. Therefore, we propose that in clinical trials, CSC differentiation therapy should only be examined in combination with chemotherapy. Our conclusions are corroborated by clinical experience with differentiating agents in acute promyelocytic leukemia and neuroblastoma.

Glioblastoma (GBM), a highly aggressive (WHO grade IV) primary brain tumor, is refractory to traditional treatments, such as surgery, radiation or chemotherapy. This study aims at aiding in the design of more efficacious GBM therapies. We constructed a mathematical model for glioma and the immune system interactions, that may ensue upon direct intra-tumoral administration of ex vivo activated alloreactive cytotoxic-T-lymphocytes (aCTL). Our model encompasses considerations of the interactive dynamics of aCTL, tumor cells, major histocompatibility complex (MHC) class I and MHC class II molecules, as well as cytokines, such as TGF-beta and IFN-gamma, which dampen or increase the pro-inflammatory environment, respectively. Computer simulations were used for model verification and for retrieving putative treatment scenarios. The mathematical model successfully retrieved clinical trial results of efficacious aCTL immunotherapy for recurrent anaplastic oligodendroglioma and anaplastic astrocytoma (WHO grade III). It predicted that cellular adoptive immunotherapy failed in GBM because the administered dose was 20-fold lower than required for therapeutic efficacy. Model analysis suggests that GBM may be eradicated by new dose-intensive strategies, e.g., 3 x 10(8) aCTL every 4 days for small tumor burden, or 2 x 10(9) aCTL, infused every 5 days for larger tumor burden. Further analysis pinpoints crucial bio-markers relating to tumor growth rate, tumor size, and tumor sensitivity to the immune system, whose estimation enables regimen personalization. We propose that adoptive cellular immunotherapy was prematurely abandoned. It may prove efficacious for GBM, if dose intensity is augmented, as prescribed by the mathematical model. Re-initiation of clinical trials, using calculated individualized regimens for grade III-IV malignant glioma, is suggested.

Despite recent advances, treatment of patients with aggressive Non-Hodgkin's lymphoma (NHL 2 ) has yet to be optimally designed. Notwithstanding the contribution of molecular treatments, intensiflcation of chemotherapeutic regimens may still be beneflcial. Hoping to aid in the design of intensifled chemotherapy, we put forward a mathematical and computational model that analyses the efiect of Doxorubicin on NHL over a wide range of patho-physiological conditions. The model represents tumour growth both in difiusion-limited settings, that is, in small avascular tumours and tumour cords, and in perfusion-limited settings, e.g. in well-vascularized tumours. Model simulations indicated the presence of a critical regimen intensity below which treatment will fall short of tumour elimination. Taking this critical intensity into account, we compared two regimen intensiflcation strategies: Dose escalation and regimen densiflcation, i.e. reducing the inter-dosing interval. In the difiusion-limited setting, dose escalation was somewhat more e-cient than regimen densiflcation. In the perfusion-limited setting, both intensiflcation strategies yielded similar results. The present study coupled with a realistic myelotoxicity model may add insight on the optimisation of NHL intensifled chemotherapy design.

Meeting abstracts IL-12 is a heterodimeric, pro-inflammatory cytokine that enhances the cytotoxic activity of natural killer (NK) cells and cytotoxic CD8+ T-lymphocytes, and induces an IFN-α-dominated Th1 CD4+ T-lymphocyte response. IL-12 as an immunotherapeutic agent administered subcutaneously

Interleukin-12 (IL-12) is a pro-inflammatory cytokine known for its role in immunity, and previous studies have shown that IL-12 provides mitigation of radiation injury. In this study, we utilize a multimodal microscopy system equipped with second harmonic generation (SHG) and fluorescence lifetime imaging microscopy (FLIM) to examine the effect of IL-12 on collagen structure and cellular metabolic activity in vivo during skin wound healing. This preliminary study illustrates the highly dynamic and heterogeneous in vivo microenvironment of the wounded skin. In addition, results suggest that IL-12 triggers a significantly more rapid and greater cellular metabolic response in the wounded animals. These results can elucidate insights into the response mechanism of IL-12 in both wound healing and acute radiation syndrome.

A mathematical model that describes the effects of acute radiation exposure on thrombopoiesis in primates and humans is presented. Thrombopoiesis is a complex multistage dynamic process with potential differences between species. Due to known differences in cellular radiosensitivities, nadir times, and cytopenia durations, direct extrapolation from rhesus to human platelet dynamics is unrealistic. Developing mathematical models of thrombopoiesis for both humans and primates allows for the comparison of the system's response across species. Thus, data obtained in primate experiments can be extrapolated to predictions in humans. Parameter values for rhesus macaques and humans were obtained either from direct experimental measurements or through optimization procedures using dynamic data on platelet counts following radiation exposure. Model simulations accurately predict trends observed in platelet dynamics: at low radiation doses platelet counts decline after a time lag, and nadir depth is dose dependent. The models were validated using data that was not used during the parameterization process. In particular, additional experimental data was used for rhesus, and accident and platelet donor data was used for humans. The model aims to simulate the average response in rhesus and humans following irradiation. Variation in platelet dynamics due to individual variability can be modeled using Monte Carlo simulations in which parameter values are sampled from distributions. This model provides insight into the time course of the physiological effects of radiation exposure, information which could be valuable for disaster planning and survivability analysis and help in drug development of radiation medical countermeasures.

Neutropenia is a significant dose-limiting toxicity of cancer chemotherapy, especially in dose-intensified regimens. It is widely treated by injections of Granulocyte Colony-Stimulating Factor (G-CSF). However, optimal schedules of G-CSF administration are still not determined. In order to aid in identifying more efficacious and less neutropenic treatment protocols, we studied a detailed physiologically-based computer model of granulopoiesis, as affected by different treatment schedules of doxorubicin and/or Granulocyte Colony-Stimulating Factor (G-CSF). We validated the model as evident from accurate prediction of clinical data on human granulopoiesis in healthy individuals and in doxorubicin-treated cancer patients, with or without G-CSF support. Based on our model, we suggest new G-CSF administration regimens. These regimens include reduced G-CSF doses, optimally timed post-chemotherapy. Application of these regimens can lead to minimization of G-CSF side effects, as well as more cost-effective and less myelotoxic protocols. Currently clinical trials are being designed in order to test these new treatment regimens.

Multiple treatment modalities are available for MF, but most result in inevitable relapse. Therefore, new treatment strategies that improve response rate and prolong response duration are greatly needed. TSEBT is a highly effective therapy in MF. LD-TSEBT (12 Gy) is much more tolerable than the conventional 36+ Gy dose, thereby allowing for re-treatment; however, LD-TSEBT has a less favorable complete response rate and response duration. Combining LD-TSEBT with immunostimulatory modalities in MF has a strong biological rationale, since radiation-induced exposure of cancer-specific antigens should be synergistic with concomitant stimulation of anti-cancer immune responses. Interleukin-12 is a robust candidate for radioimmunotherapy, as IL-12 has significant anti-MF activity as monotherapy, is very well tolerated without overlapping toxicity with TSEBT, and is a potent stimulator of innate and adaptive immunity. We report on a single-arm open-label phase 2a trial of combination of LD-TSEBT and NM-IL-12. Ten patients are planned for enrollment. Eligibility includes MF-type CTCL stages IB-IIIB and patients must be eligible for LD-TSEBT. TSEBT is started on study day 1 (fractionated 4 Gy/week, up to 12 Gy). NM-IL-12 is administered subcutaneously at 150 ng/kg on days 2 and 15, followed by 6 maintenance doses q4w at 100 ng/kg. The primary endpoint is safety with secondary endpoints being response rate and PFS. Currently, 6 patients are enrolled, 5 evaluable for response; 4 male; median age 55; three have stage IB, one IIB and one IIIB. Median number of previous therapies is 2 (0-6). The treatment was well-tolerated with only grade 1 or 2 AEs; most common AEs include grade 1 headache and chills. One patient achieved CR, 2 PR, and 2 SD. Median follow-up is so far 15 weeks and 5 patients remain on study. One patient has been withdrawn from the study due to development of a suspected PLC (pityriasis lichenoides chronica)-like skin reaction requiring topical steroid therapy. PK and PD analysis was completed in the first 4 patients. It demonstrated measurable drug levels in all patients studied, Cmax being 10.8-56.1 pg/ml achieved at 5-24 hours post injection. Interferon-γ and IP-10 (hallmark PD markers of IL-12 activity) were measurable after the first and the second injections in all patients. Levels of the inhibitory cytokine IL-10 were generally measurable after NM-IL-12 injections, but were very low ( Total RNA was extracted from patient blood samples and subjected to qRT-PCR. Gene specific primers were used to analyse intracellular expression of the IL-12 receptor and immune cell markers. Ongoing work investigates an activated cellular phenotype at week 15 of LD-TSEBT and NM-IL-12 treatment compared with the respective baseline samples. Overall these early results demonstrate that NM-IL-12 can be safely administered together with LD-TSEBT in CTCL patients. Encouraging clinical activity is observed including a CR. Enrollment is currently ongoing and planned PD and correlative biomarker studies are in progress. A phase 2B randomized trial of NM-IL-12 and low dose TSEBT compared against low-dose TSEBT alone in patients with MF is being developed based on the apparent benign AE profile as compared to approved systemic therapies. Disclosures Kim: Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tetralogic: Research Funding; Neumedicine: Research Funding; Merck: Research Funding; Kyowa Kirin Pharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Portola: Consultancy; miRagen: Research Funding; Innate: Research Funding; Horizon Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty Seven Inc: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Soligenix: Research Funding. Ma:Neumedicines: Employment. Kha:Neumedicines: Employment. Lawrence:Neumedicines: Employment, Patents & Royalties. Vainstein:Neumedicines: Employment. Basile:Neumedicines: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Background Recombinant human interleukin 12 (rHuIL-12) regulates hematopoiesis and cell-mediated immunity. Based on these hematopoietic and immunomodulatory activities, a recombinant human IL-12 (rHuIL-12) is now under development to address the unmet need for a medical countermeasure against the hematopoietic syndrome of the acute radiation syndrome (HSARS) that occurs in individuals exposed to lethal radiation, and also to serve as adjuvant therapy that could provide dual hematopoietic and immunotherapeutic benefits in patients with cancer receiving chemotherapy. We sought to demonstrate in healthy subjects the safety of rHuIL-12 at single, low doses that are appropriate for use as a medical countermeasure for humans exposed to lethal radiation and as an immunomodulatory anti-cancer agent. Methods Two placebo-controlled, double-blinded studies assessed the safety, tolerability, pharmacokinetics and pharmacodynamics of rHuIL-12. The first-in-human (FIH) dose-escalation study randomized subjects to single subcutaneous injections of placebo or rHuIL-12 at 2, 5, 10, and 20 μg doses. Due to toxicity, dose was reduced to 15 μg and then to 12 μg. The phase 1b expansion study randomized subjects to the highest safe and well tolerated dose of 12 μg. Results Thirty-two subjects were enrolled in the FIH study: 4 active and 2 placebo at rHuIL-12 doses of 2, 5, 10, 12, and 15 μg; 1 active and 1 placebo at 20 μg. Sixty subjects were enrolled in the expansion study: 48 active and 12 placebo at 12 μg dose of rHuIL-12. In both studies, the most common adverse events (AEs) related to rHuIL-12 were headache, dizziness, and chills. No immunogenicity was observed. Elimination of rHuIL-12 was biphasic, suggesting significant distribution into extravascular spaces. rHuIL-12 triggered transient changes in neutrophils, platelets, reticulocytes, lymphocytes, natural killer cells, and CD34+ hematopoietic progenitor cells, and induced increases in interferon-γ and C-X-C motif chemokine 10. Conclusion A single low dose of rHuIl-12 administered subcutaneously can elicit hematological and immune-mediated effects without undue toxicity. The safety and the potent multilineage hematopoietic/immunologic effects triggered by low-dose rHuIL-12 support the development of rHuIL-12 both as a radiation medical countermeasure and as adjuvant immunotherapy for cancer. Trial registration ClinicalTrials.gov: NCT01742221

Intensive chemotherapy for newly diagnosed acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) is associated with significant treatment-related morbidity and mortality. Herein, we investigate how pretreatment characteristics relate to early adverse outcomes in such patients, studying 205 consecutive individuals receiving curative-intent induction chemotherapy with cytarabine and an anthracycline ("7 + 3"; n = 175) or a "7 + 3"-like regimen (n = 30). Among the entire cohort, baseline grade 4 neutropenia (i.e., absolute neutrophil count500 cells/µL) was associated with development of fever (P = 0.04), documented infection (P0.0001), and bacteremia (P = 0.002) but not requirement for intensive care unit-level care; after exclusion of the 30 patients who received "7 + 3"-like induction, baseline grade 4 neutropenia remained associated with documented infection (P0.0001) and bacteremia (P = 0.0005). Among patients achieving a complete remission with the initial treatment cycle, grade 4 neutropenia was associated with delayed neutrophil count recovery (P0.0001). Low monocyte and lymphocyte counts at baseline were similarly associated with increased risk of documented infection or bacteremia. After adjustment for age, gender, disease type, cytogenetic/molecular risk, and performance status, the risk of fever, documented infection, or bacteremia was 1.87 (95% confidence interval: 1.04-3.34; P=0.04)-fold, 4.95 (2.20-11.16; P0.001)-fold, and 3.14 (0.99-9.98; P=0.05)-fold higher in patients with initial grade 4 neutropenia. Together, our studies identify severe baseline neutropenia as a risk factor for infection-associated adverse events after induction chemotherapy and may provide the rationale for the risk-adapted testing of myeloid growth factor support in this high-risk AML/MDS patient subset.

BCR-ABL mutations result in clinical resistance to ABL tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). Although in vitro 50% inhibitory concentration (IC(50)) values for specific mutations have been suggested to guide TKI choice in the clinic, the quantitative relationship between IC(50) and clinical response has never been demonstrated. We used Hill's equation for in vitro response of Ba/F3 cells transduced with various BCR-ABL mutants to determine IC(50) and the slope of the dose-response curve. We found that slope variability between mutants tracked with in vitro TKI resistance, provides particular additional interpretive value in cases where in vitro IC(50) and clinical response are disparate. Moreover, unlike IC(50) alone, higher inhibitory potential at peak concentration (IPP), which integrates IC(50), slope, and peak concentration (Cmax), correlated with improved complete cytogenetic response (CCyR) rates in CML patients treated with dasatinib. Our findings suggest a metric integrating in vitro and clinical data may provide an improved tool for BCR-ABL mutation-guided TKI selection.

One-third of patients with myelodysplastic syndrome (MDS) progress to secondary acute myeloid leukemia (sAML), with its concomitant poor prognosis. Recently, multiple mutations have been identified in association with MDS-to-sAMLtransition, but it is still unclear whether all these mutations are necessary for transformation. If multiple independent mutations are required for the transformation, sAML risk should increase with time from MDS diagnosis. In contrast, if a single critical biological event determines sAML transformation; its risk should be constant in time elapsing from MDS diagnosis. To elucidate this question, we studied a database of 1079 patients with MDS. We classified patients according to the International Prognostic Scoring System (IPSS), using either the French-American-British (FAB) or the World Health Organization (WHO) criteria, and statistically analyzed the resulting transformation risk curves of each group. The risk of transformation after MDS diagnosis remained constant in time within three out of four risk groups, and in all four risk groups, when patients were classified according to FAB or to the WHO-determined criteria, respectively. Further subdivision by blast percentage or cytogenetics had no influence on this result. Our analysis suggests that a single random biological event leads to transformation to sAML, thus calling for the exclusion of time since MDS diagnosis from the clinical decision-making process.

Gemtuzumab ozogamicin (GO) is a chemotherapy-conjugated anti-CD33 monoclonal antibody effective in some patients with acute myeloid leukemia (AML). The optimal treatment schedule and optimal timing of GO administration relative to other agents remains unknown. Conventional pharmacokinetic analysis has been of limited insight for the schedule optimization. We developed a mechanism-based mathematical model and employed it to analyze the time-course of free and GO-bound CD33 molecules on the lekemic blasts in individual AML patients treated with GO. We calculated expected intravascular drug exposure (I-AUC) as a surrogate marker for the response to the drug. A high CD33 production rate and low drug efflux were the most important determinants of high I-AUC, characterizing patients with favorable pharmacokinetic profile and, hence, improved response. I-AUC was insensitive to other studied parameters within biologically relevant ranges, including internalization rate and dissociation constant. Our computations suggested that even moderate blast burden reduction prior to drug administration enables lowering of GO doses without significantly compromising intracellular drug exposure. These findings indicate that GO may optimally be used after cyto-reductive chemotherapy, rather than before, or concomitantly with it, and that GO efficacy can be maintained by dose reduction to 6 mg/m(2) and a dosing interval of 7 days. Model predictions are validated by comparison with the results of EORTC-GIMEMA AML19 clinical trial, where two different GO schedules were administered. We suggest that incorporation of our results in clinical practice can serve identification of the subpopulation of elderly patients who can benefit most of the GO treatment and enable return of the currently suspended drug to clinic.

Introduction Peripheral neurotoxicity and neuropathic pain are well-known complications of several anti-cancer chemotherapeutic agents. Such pain might cause an impairment of the patient's quality of life and is a common limiting factor of anti-cancer chemotherapy. Neurotoxicity in orofacial structures has been previously described as diffuse jaw pain or numbness. Currently, localized pulpal pain is not listed as a possible complication of cytotoxic therapy. The aim of this report was to suggest cytotoxic-induced neurotoxicity as a differential diagnosis for toothache during anti-cancer therapy. Methods We described the diagnostic process in a patient suffering from severe pulpal pain in apparently intact teeth during cytotoxic therapy. A non-Hodgkin's lymphoma patient complained of 2 episodes of excruciating dental pain evoked by mouth breathing, which caused nocturnal awakenings. Results Both episodes developed immediately after administrations of cyclophosphamide as part of an anti-cancer chemotherapy protocol. Clinical parameters and radiographic characteristics eliminated other possible dental and facial etiologies. Pulp extirpation (pulpectomy) resulted in immediate pain relief. In both episodes, cytologic evaluation of the extirpated pulp tissue failed to show inflammation or an infiltration of lymphoma cells. Conclusions This case presented a circumstantial relation between the clinical presentation of dental pain, with associated significant impairment of the patient's quality of life, and the timing of administrations of high-dose cyclophosphamide. It suggests that chemotherapy-induced toxicity might manifest as pulpitis-like toothache, which might present a diagnostic challenge for the dental practitioner.

Biomathematics has enabled the development of a range of new theories dealing with significant problems of disease progression and control, hitherto beyond the reach of “snapshot”, experimental biology. Mathematical modeling of the underlying pathological and physiological processes in a patient is tied with the detailed relevant pharmacokinetics (PK) and pharmacodynamics (PD) that provides improved understanding of how the aspects of treatment scheduling may affect the patient. This article discusses the application of mathematical modeling tools to elucidate the hematological disorder thrombocytopenia in different animal species, and to accurately describe the efficacy and safety of the thrombocytopenia-alleviating drugs, thrombopoietin, and interleukin-11. Keywords: biomathematics; mathematical modeling; pharmacodynamics (PD); pharmacokinetics (PK); thrombopoietin; interleukin-11

Neutropenia, frequently a side effect of chemo- and radiotherapy, increases susceptibility to microbial infections and is a life-threatening condition. For realistically predicting drug treatment effects on granulopoiesis, we have constructed a new mathematical model of granulopoiesis in the bone marrow and in the peripheral blood, featuring cell cycle phase transition and detailed granulocyte-colony stimulating factor (G-CSF) pharmacokinetics (PK) and pharmacodynamics (PD), including intracellular second messenger. Using this model, in conjunction with clinical results, we evaluated the system parameters, implemented those in the model and successfully retrieved the results of several independent clinical experiments under a wide range of G-CSF regimens. Our results show that the introduction of G-CSF-controlled intracellular second messenger is indispensable for precise retrieval of the clinical results, and suggest that the half-life of this messenger varies between a single and multiple G-CSF administration schedules. In addition, our model provided reliable steady-state, as well as dynamic, estimations of human granulopoiesis parameters. These included an estimation of apoptosis index in the post-mitotic compartment, which corroborates previous results. At present the model is used for suggesting improved drug regimens.