Hematocrit control and thrombotic risk in patients with polycythemia vera treated with ruxolitinib in clinical practice

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by unregulated red blood cell production resulting in elevated hemoglobin and/or hematocrit levels. Patients often have symptoms such as fatigue, pruritus, and painful splenomegaly, but are also at risk of thrombosis, both venous and arterial. Ruxolitinib, a selective Janus kinase inhibitor, is approved by the US Food and Drug Administration as second-line cytoreductive treatment after intolerance or inadequate response to hydroxyurea. Although ruxolitinib has been widely used in this setting, limited data exist in the literature on ruxolitinib treatment patterns and outcomes among patients with PV in routine clinical practice. We report a retrospective, observational, cohort study of patients treated for PV with ruxolitinib across three US centers (academic and regional practice) from December 2014-December 2019. The study included 69 patients, with a median follow-up duration of 3.7 years (95% CI, 2.9-4.4). Our data demonstrate very high rates of hematocrit control (88% of patients by three months and 89% by six months); few patients required dose adjustments or suspension. No arterial thromboses were observed; however, the follow-up duration does not allow for the generation of meaningful conclusions from this. Three patients had thrombotic events; one was in the setting of a second malignancy, one post-operative, and a third related to prolonged immobility. We also found that 28% of patients initiated ruxolitinib as a result of poorly controlled platelet counts, second only to hydroxyurea intolerance (46%) as a reason to start therapy. In clinical practice, ruxolitinib continues to be effective in controlling hematocrit levels after three and six months of treatment in patients and is associated with low thrombotic risk.

Upper respiratory tract SARS-CoV-2 viral shedding in cancer patients

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Background: SARS-CoV-2 virus has been shown to persist in respiratory tract in immunocompromised patients. However, such data are lacking for both asymptomatic and symptomatic SARS-CoV-2 infection in cancer patients. We share our single center experience on duration of SARS-CoV-2 viral presence in the upper respiratory tract of cancer patients with SARS-CoV-2 infection (asymptomatic and symptomatic) detected by viral PCR. Methods: This is retrospective review of cancer patients with documented SARS-CoV-2 infection and measurement of viral shedding at Levine Cancer Institute. Testing indications were COVID-19 symptomatic illness, pre-procedural and pre-chemo testing. Prolonged shedding was defined as presence of viral RNA beyond 30 days after first positive test. To document viral clearance, patients required 2 negative SARS-CoV-2 PCR test separated by at least 24 hours and maximum 3 weeks apart either by nasopharyngeal or nasal PCR swab. Differences in distributions were identified between patients shedding virus more than 30 days and less than 30 days using uni- and multivariable logistic regression models. Statistical significance was set at p < 0.10 to enter the multivariable model, and p < 0.05 to remain. Results: Demographic data: median age 62 (range 20-93); 58.5% females; 70% White, 21% Black, and 7.4% Hispanics. Comorbidities included hypertension 43.2%, diabetes 16.7% and chronic lung disease 3.7%. Underlying malignancies were breast cancer 25%, hematologic cancer 22%, lung cancer 16% and genitourinary 11%. Chemotherapy was received by 26.5% patients within 4 weeks prior to testing. 162 patients were identified median duration of 18 days (range 4-90 days). Of these, 76% patients were tested for non-symptomatic indication with median duration of shedding 17 days (range 6-80) and 23% were tested for clinical symptoms with median duration of shedding 29 days (range 4-90) (p = < 0.001); 50% of patients never developed symptoms, whereas 35% patients with non-symptomatic testing indication, subsequently developed symptoms. Viral clearance by day 30, day 45, day 60 and day 90 was 78%, 93%, 97% and 100% respectively. Univariate analysis did not show difference between patients with prolonged shedding vs those shedding less than 30 days for age, gender, race, ethnicity, underlying malignancy, co-morbidities including body mass index, diabetes, chronic lung conditions, hypertension, or receipt of cytotoxic chemo. Multivariable analysis showed that presence of symptoms at any point during SARS-CoV-2 infection (OR 5.9, 95% CI 2.4-14.5, p < 0.001) was associated with prolonged shedding. Conclusions: Symptomatic SARS-CoV-2 infection is associated with prolonged viral shedding in cancer patients. Cancer patients can have asymptomatic SARS-CoV-2 infection. More studies are warranted to understand viral kinetics and its clinical implications in cancer patients.

Risk factors for hospitalization for cancer patients with SARS-CoV-2 infection

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Background: Cancer patients are more susceptible to developing severe disease associated with SARS-CoV-2 infection. Herein, data from a high-volume cancer center is presented highlighting risk factors associated with hospitalization with COVID-19 disease. Methods: Cancer patients in the Levine Cancer Institute COVID19 database who were tested for SARS-CoV-2 due to clinical illness from March 1, 2020 to October 29, 2020 with 90 days follow-up are described here. Patients’ demographic and clinical information were retrospectively entered into a REDCap database from chart reviews. Differences in distributions were identified between hospitalized and non-hospitalized patients using the chi-squared test with uni- and multivariable logistic regression models. Statistical significance was set at p<0.05. Results: 228 patients with SARS-CoV-2 infection were identified, of whom 103 (45%) were hospitalized. Median age was 63 years (range 28-95). Race distribution for infection showed White 65%, followed by Black 26.8% and Hispanic ethnicity 16.7% , with a similar distribution for hospital admission. Median length of stay was 10 days (range 1-91) with no readmissions within 90 days. The most common underlying malignancies were breast (29.8%), hematologic (21.1%) and genitourinary (12.3%). The most common preexisting conditions included hypertension (55.7%), diabetes (27.2%) and cardiac disease (3.9%). The most common presenting symptoms were cough (50.2%), fever (38.4%), fatigue (37.8%) and shortness of breath (36.4%). Maximum oxygen requirements for hospitalized patients were ambient air (34%), nasal canula (34%), high/medium flow nasal canula (10%), non-invasive ventilation (13%) and mechanical ventilation (10%). Case fatality rate was 10% with diagnosis of COVID-19, including 21.4% of those admitted to the hospital and 51.7% of those admitted to the ICU. Univariable logistic regression analysis showed that age, sex, prior chemotherapy, upper gastrointestinal cancers, hematologic cancers, number of medical conditions, cardiac disease, chronic lung diseases, hypertension, and diabetes increased risk of hospitalization. Table shows results of multivariate analysis. Conclusions: The COVID-19 pandemic has caused high case fatality rates in our cancer patients. We identified age, cardiac disease, hematologic malignancy and receipt of chemotherapy within 4 weeks of diagnosis as risk factors for hospitalization. These data may help in prioritizing early intervention in vulnerable subgroups to improve survival outcomes. [Table: see text]

Dose escalation results of a phase 1b study of the MDM2 inhibitor AMG 232 with or without trametinib in patients (Pts) with relapsed/refractory (r/r) acute myeloid leukemia (AML)

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Background: The ubiquitin ligase MDM2 inhibits the tumor suppressor p53. In preclinical AML models, MDM2 inhibitors have antitumor activity as monotherapy that is synergistic when combined with MEK inhibitors. This open-label phase 1b study assessed the maximum tolerated dose (MTD), pharmacokinetics (PK), and preliminary antitumor activity of the investigational oral, selective MDM2 inhibitor AMG 232 as monotherapy or combined with the MEK kinase inhibitor trametinib in pts with r/r AML. Methods: Pts with r/r AML received AMG 232 for 7 days every 2 weeks (7 days on/7 days off) at 60, 120, 240, 480, and 960 mg PO QD as monotherapy (Arm 1) or combined with trametinib 2 mg PO QD (Arm 2). Primary endpoints were the incidence of adverse events (AEs), dose-limiting toxicities (DLTs), and PK. Additional endpoints included best response (revised IWG) and serum MIC-1 level (increased MIC-1 suggests p53 activation). p53 target gene ( P21, BAX, and PUMA) expression in bone marrow was assessed by microarray. Results: In total, 35 pts (Arm 1, n = 26; Arm 2, n = 9; median age, 68 y; range, 26–86) were treated. Arm 1 enrolled AMG 232 at 60 mg (n = 4), 90 mg (n = 4), 180 mg (n = 5), 240 mg (n = 3), and 360 (n = 10). Twenty-two (85%) pts in Arm 1 had treatment-related AEs; the most common were nausea (n = 14), diarrhea (n = 14), and vomiting (n = 6). No DLTs occurred; one pt is still on treatment. The MTD was determined as 360 mg based on tolerance of gastrointestinal toxicity. Arm 2 enrollment is ongoing at a fixed AMG 232 dose of 60 mg plus trametinib (n = 9). AMG 232 plasma exposure increased with dose escalation; PK was unaffected by trametinib. Trametinib PK was as expected. Increases from baseline (BL) to day 10 in serum MIC-1 were dose dependent. Evidence of increased P21, BAX, and PUMA expression (BL to day 7 or 8) was seen (n = 3). One pt (Arm 2) had complete remission (CR); three pts (Arm 1) achieved CRi/MLFS. Median response duration was 66 days [range, 21–377+]). Conclusions: AMG 232 monotherapy was tolerable in pts with r/r AML at doses up to 360 mg on a 7 days on/7 days off schedule with expected PK, on-target biological effects, and early evidence of antileukemia activity. Clinical trial information: NCT02016729.

Response and survival rates with frontline hypomethylating agent (HMAs) in favorable risk AML

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Background: HMAs are an accepted frontline therapy for AML patients (pts) who are unfit for intensive induction therapy (IIT), particularly pts with unfavorable cytogenetics and/or p53 mutations. However, little is known about the response of favorable risk AML to HMAs. We previously reported that NPM1 mutated and/or CD34- AML status were predictors of response to HMAs. Here, we evaluated responses to frontline HMAs in AML. Methods: A total of 117 patients with de novo AML diagnosed between 7/2013 and 9/2016 were evaluated based on pt and disease related variables, overall response rate (ORR = CR + CR with incomplete count recovery + hematologic remission (ANC > 1000/µL, Hgb > 10g/dL, Plts > 100,000/µL, & no circulating blasts)), and overall survival (OS). Categorical variables were compared using Fisher’s exact test. Kaplan Meier methods estimated survival outcomes, and log rank tests compared survival between groups. Multivariable analyses were performed using Cox proportional hazards models. Results: 51 pts, considered unfit for IIT, received frontline HMAs. ORR and OS were highest in the ELN favorable risk AML pts (n = 13; ORR = 92%, p = .009; median OS = 17.5 months, p = .022). Among 41 NPM1 mutated pts, 15 received HMAs; and 26 received intensive induction. ORRs were 73% and 84%, respectively (p = .434). No difference was found in OS distributions between the HMA and IIT groups in univariate and multivariate (adjusted for age and FLT3 status) models (p = .329 and .241, respectively). Interestingly, ORR was 100% among 9 HMA-treated pts with NPM1 mutated, CD34-, FLT3/ITD-, cytogenetically normal AML. Conclusions: HMA therapy is highly effective frontline treatment in favorable risk AML pts considered unfit for IIT. Survival results with HMAs in NPM1 mutated AML are comparable to those of fitter pts treated with IIT. In selected favorable risk pts considered unfit for standard induction, HMAs can be a successful bridge to potentially curative therapy, including more intensive therapy or transplant. Cytogenetically normal AML with an isolated NPM1 mutation and CD34- status appears to be exceptionally responsive to frontline treatment with HMAs. Prospective validation of these findings is necessary.

Variations in FLT3 ligand levels during the course of AML treatment

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Background: FLT3 ligand (FL) is a hematopoietic growth factor expressed in many tissues. AML patients who are administered myeloablative therapy exhibit a marked and transient rise in plasma FL concentrations. Furthermore, the presence of high concentrations (1000 pg/mL) of FL impedes the efficacy of FLT3 tyrosine kinase inhibitors in vitro. However, the behavior of FL concentrations throughout the course of AML treatment remains unknown. This pilot study was undertaken to track the relationship between AML therapy and FL levels over time. Methods: Ten AML patients were enrolled in an IRB-approved procurement protocol. Blood samples were collected at weekly intervals for one year, and plasma was isolated by centrifugation. Plasma FL and stem cell factor (SCF) concentrations were measured by ELISA. Results: We observed four distinct patterns in FL fluctuations. First, in all cases where induction or consolidation chemotherapy resulted in an aplastic bone marrow (nine patients), FL concentrations rose markedly and consistently to levels >1000 pg/mL following the administration of chemotherapy. Second, in three of four patients whose leukemia was refractory to induction chemotherapy, FL concentrations remained below 500 pg/mL during induction. Third, in two patients receiving the FLT3 TKI sorafenib, FL concentrations did not rise above 500 pg/mL while on this medication. Fourth, in one patient receiving the hypomethylating agent 5-azacitidine, FL concentrations remained below 100 pg/mL throughout the course of therapy. SCF concentrations did not vary throughout the course of chemotherapy. Conclusions: An “FL surge” was seen when cytotoxic chemotherapy resulted in aplasia. This FL surge was not seen with sorafenib or 5-azacitidine. In addition, the FL surge was attenuated in three patients whose leukemia was refractory to chemotherapy. These observations give rise to two new hypotheses regarding FL: 1) It is possible to maintain lower FL levels with targeted agents than with chemotherapy; and 2) Residual leukemia appears to inhibit the FL surge, providing indirect evidence of cross-talk between leukemia and the stromal microenvironment. This inhibition may be the explanation for why AML patients develop pancytopenia early in relapse.

Response rates in patients with relapsed/refractory acute myeloid leukemia with FLT3-ITD mutation using 5-azacitadine plus sorafenib

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Background: Outcome of patients with relapsed acute myeloid leukemia (AML) with FLT3-ITD mutation is poor. Elevated FLT3 ligand levels (FL) secondary to cytotoxic chemotherapy is a putative mechanism of resistance to the FLT3 kinase inhibitors. We hypothesized that FL levels will be lower when combining sorafenib with less intensive therapy such as 5-Azacytidine (5-Aza). This study was conducted to evaluate the efficacy and tolerability of the combination of sorafenib and 5-Aza in patients with refractory or relapsed AML with FLT3-ITD mutation. Methods: Patients were eligible if they had relapsed or refractory AML and were 18 years of age or older. They received 5-Aza 75 mg/m2 IV daily x 7 days and sorafenib 400 mg PO BID continuously; cycles were repeated in approximately one month intervals. Results: 38 patients with AML with a median age of 60 years (range, 24-87) were enrolled. 4 were inevaluable as they never received therapy or discontinued it before response assessment. FLT-3-ITD was detected in 30 (88%) patients. They had received a median of 2 prior treatments (range, 0-6); 13 (38%) had received ≥ 3 prior regimens and 8 had failed prior FLT3 kinase inhibitor. Response rate was 41%, including 6 (17%) with CRi, 4 (12) with CRp, 3 (9%) with CR, and 1(3%) PR. The median time to achieving CR/CRi was 2 cycles (Range, 1-6) and the median duration of CR/CRi was 3 months (Range, 1–12). Conclusions: Combination of 5-Aza and sorafenib is effective for patients with relapsed AML with FLT-3-ITD mutation.