Association between elevated white blood cell counts and thrombotic events in polycythemia vera: analysis from REVEAL

ABSTRACT

Polycythemia vera (PV) is a myeloproliferative neoplasm characterized by clonal proliferation of hematopoietic progenitor cells and is associated with an increased risk of thrombotic events (TEs). Established risk factors for TEs in patients with PV include advanced age, TE history, and elevated hematocrit. Although an association of TE with elevated white blood cell (WBC) counts has been suggested by retrospective studies, this relationship needs further validation. The prospective observational study of patients with polycythemia vera in US clinical practices (REVEAL) study collected prospective clinical data from 2510 patients with PV with a median follow-up of 44.7 months (range, 2-59 months) from enrollment. Using time-dependent covariate Cox proportional hazards models, blood counts were individually modeled with sex, age, disease duration, TE history at enrollment (baseline covariates), and treatment (time-dependent covariate). Analysis of 2271 participants identified 142 TEs in 106 patients. Significant associations with initial TE occurrence during the study period were observed for hematocrit level >45% (hazard ratio [HR], 1.84; 95% confidence interval [95% CI], 1.234-2.749; P = .0028) and WBCs >11 × 109/L (HR, 2.35; 95% CI, 1.598-3.465; P < .0001). Elevated WBC count was significantly associated with initial TE occurrence in both low-risk and high-risk PV. When hematocrit was controlled at ≤45%, WBC count >12 × 109/L was significantly associated with TE occurrence (HR, 1.95; 95% CI, 1.066-3.554; P = .0300). The results support incorporation of WBC count into PV risk stratification and studies of treatment strategies, and indicate the importance of controlling both hematocrit and WBC count in disease management. This trial was registered at www.clinicaltrials.gov as #NCT02252159.

Early intervention in myelofibrosis and impact on outcomes: A pooled analysis of the COMFORT-I and COMFORT-II studies

BACKGROUND

In a pooled analysis of the phase 3 Controlled Myelofibrosis Study With Oral JAK Inhibitor Treatment I (COMFORT-I) and COMFORT-II clinical trials, adult patients with intermediate-2 or high-risk myelofibrosis who received oral ruxolitinib at randomization or after crossover from placebo or best available therapy (BAT) had improved overall survival (OS).

METHODS

This post hoc analysis of pooled COMFORT data examined relevant disease outcomes based on the disease duration (≤12 or >12 months from diagnosis) before ruxolitinib initiation.

RESULTS

The analysis included 525 patients (ruxolitinib: ≤12 months, n = 84; >12 months, n = 216; placebo/BAT: ≤12 months, n = 66; >12 months, n = 159); the median age was 65.0-70.0 years. Fewer thrombocytopenia and anemia events were observed among patients who initiated ruxolitinib treatment earlier. At Weeks 24 and 48, the spleen volume response (SVR) was higher for patients who initiated ruxolitinib earlier (47.6% vs. 32.9% at Week 24, p = .0610; 44.0% vs. 26.9% at Week 48, p = .0149). In a multivariable analysis of factors associated with spleen volume reduction, a logistic regression model that controlled for confounding factors found that a significantly greater binary reduction was observed among patients with shorter versus longer disease duration (p = .022). At Week 240, OS was significantly improved among patients who initiated ruxolitinib earlier (63% [95% CI, 51%-73%] vs. 57% [95% CI, 49%-64%]; hazard ratio, 1.53; 95% CI, 1.01-2.31; p = .0430). Regardless of disease duration, a longer OS was observed for patients who received ruxolitinib versus those who received placebo/BAT.

CONCLUSIONS

These findings suggest that earlier ruxolitinib initiation for adult patients with intermediate-2 and high-risk myelofibrosis may improve clinical outcomes, including fewer cytopenia events, durable SVR, and prolonged OS.

PLAIN LANGUAGE SUMMARY

Patients with myelofibrosis, a bone marrow cancer, often do not live as long as the general population. These patients may also have an enlarged spleen and difficult symptoms such as fatigue. Two large clinical trials showed that patients treated with the drug ruxolitinib lived longer and had improved symptoms compared to those treated with placebo or other standard treatments. Here it was examined whether starting treatment with ruxolitinib earlier (i.e., within a year of diagnosis) provided benefits versus delaying treatment. Patients who received ruxolitinib within a year of diagnosis lived longer and experienced fewer disease symptoms than those whose treatment was delayed.

MPN-103 A Real-World Evaluation of the Association Between Elevated Blood Counts and Thrombotic Events in Polycythemia Vera: Analysis of Data From the REVEAL Study

CONTEXT

Polycythemia Vera (PV) leads to elevated peripheral blood counts (PBCs) and increased thromboembolic events (TE) risk. The conventional model used to determine TE-risk and treatment strategy includes advanced age and TE-history. Association between TE-risk and elevated hematocrit (HCT) is established; association with white-blood-cell count (WBC) or platelet count (PLT) have not been assessed consistently.

OBJECTIVE

Evaluate association between elevated PBCs and TE-risk.

DESIGN

Real-world Prospective Observational Study of Patients with Polycythemia Vera in US Clinical Practices (REVEAL; NCT02252159).

SETTING

Clinical practice.

PATIENTS

Included: ≥3 post-enrollment PBCs; excluded: post-enrollment TE without PBCs <6 months before that TE.

INTERVENTIONS

Noninterventional.

MAIN OUTCOME MEASURES

Association was assessed by the time-dependent covariate Cox-proportional hazards model. Time-to-first post-enrollment TE was modeled; for patients with no TE, time was censored at last visit. Each lab parameter was individually modeled with sex, age, disease duration, and TE-history at enrollment (baseline covariates) and treatment (time-dependent covariates). Thresholds included: HCT>45%, WBC>11×10⁹/L, PLT>400×10⁹/L. Alternative thresholds included: WBC<7, ≥7-<8.5; ≥8.5-<11, ≥11×10⁹/L, WBC>12×10⁹/L with controlled HCT≤45%, and PLT>600×10⁹/L.

RESULTS

Of 2510 enrolled, 2271 patients were included: median age, 67 years (range, 22-95); male, 54.1%; median disease duration, 4.1 years (range, 0-56.3), TE-history, 20.1%; receiving hydroxyurea, 52.6%; TEs, 4.7% (arterial, 1.3%; venous, 3.3%). HCT>45% vs ≤45% (HR=1.84 [95% CI, 1.234-2.749], P=0.0028), WBC>11 vs ≤11×10⁹/L (HR=2.35 [1.598-3.465], P<0.0001), and PLT>400 vs ≤400×10⁹/L (HR=1.60 [1.088-2.359], P=0.0170) were each associated with significantly increased TE-risk. WBC≥ 11 vs <7×10⁹/L was associated with the highest TE-risk (HR=2.61 [1.594-4.262], P=0.0001). TE-risk was increased for PLT>600 vs ≤600×10⁹/L, but not significantly (HR=1.37 [0.763-2.468], P=0.2913). WBC>12 vs ≤ 12×10⁹/L was significantly associated with increased TE-risk at HCT≤45% (HR=1.95 [1.066-3.554], P=0.0300). In all models, advanced age, female sex, and TE-history were associated with increased TE-risk.

CONCLUSIONS

The results demonstrate significant associations individually between elevated HCT, PLT, WBC (>11 and >12×10⁹/L), and increased TE-risk. Elevated WBC (>12×10⁹/L) is significantly associated with increased TE-risk when HCT is controlled, indicating that TE-risk may be reduced by controlling WBC as well as HCT. These data support incorporation of PBCs into risk stratification and treatment strategies for PV patients.

Randomized phase 2 umbrella study of various neoadjuvant therapies for patients with muscle-invasive urothelial carcinoma of the bladder (MIBC) who are cisplatin-ineligible or refuse cisplatin therapy and undergoing radical cystectomy (Optimus)

TPS599

Background: A growing body of data support that the key to generating anti-tumor immune responses triggered by administration of immuno-oncology (IO) agents, is the activation and invasion of T lymphocytes. Checkpoint inhibitors (CPIs) are being actively explored in the neoadjuvant setting of MIBC. CPIs documented 30-40% pathologic complete response-rates (ypT0N0) in previous trials. Increasingly, novel IO agents are being developed in combinations with anti PD(L)-1 therapies. Understanding the changes in the tumor microenvironment that occur with the addition of novel immunomodulating agents to PD(L)-1 inhibitors can help inform whether a compound is viable for further development. The OPTIMUS trial is a window of opportunity, neoadjuvant platform design study in MIBC patients that are cisplatin-ineligible. The study investigates the addition of the indoleamine 2, 3-dioxygenase 1 (IDO1) inhibitor epacadostat to the PD-1 inhibitor retifanlimab. The platform design allows for investigation of other novel immune-modulating combinations. Methods: This is an open-label, randomized, Phase 2, multi-treatment group, window-of-opportunity, platform study for participants with MIBC undergoing radical cystectomy who refuse or are not eligible for cisplatin-based neoadjuvant chemotherapy (NCT04586244). Participants are randomized based on tumor tissue PD-L1 CPS ≥ 10 or PD-L1 CPS < 10 to one of the following treatment groups: Treatment Group A (epacadostat + retifanlimab); Treatment Group B (retifanlimab monotherapy); Treatment Group C (epacadostat monotherapy). 18 patients will be enrolled in each of Treatment Groups A and B. 9 patients will be enrolled into Treatment Group C. Total treatment duration is a maximum of 10 weeks. The platform study design allows for addition of future treatment groups. Pre-treatment biopsy is obtained through transurethral resection of bladder tumor (TURBT), followed by neoadjuvant treatment, followed by radical cystectomy. In all treatment groups, tissue from the surgical specimen(s) is collected and compared with the initial pre-treatment samples. The primary endpoint is the change from baseline in CD8+ lymphocytes within resected tumor. Secondary endpoints include safety and tolerability, rates of ypT0N0 response, and major pathologic response. Exploratory analyses include tumoral changes in gene cell expression profile, immune-cell protein and metabolic marker levels, and spatial relationships between cell types. Plasma is also collected and will be investigated for changes in cytokines and other inflammatory or metabolic markers. Clinical trial information: NCT04586244.

Dapagliflozin twice daily or once daily: effect on pharmacokinetics and urinary glucose excretion in healthy subjects

The primary objective of this single-centre, open-label crossover study (NCT01072578) was to assess the effect of dapagliflozin on the amount of glucose in the blood and urine in healthy volunteers when dapagliflozin was administered once a day (10 mg) versus twice a day (5 mg every 12 h) after 5 days of dosing. At steady state, the AUC(ss)₀₋₂₄ (area under the dapagliflozin curve (0-24 hours) at steady state), C(ss,av) (average concentration at steady state) between dapagliflozin 5 mg twice daily and 10 mg once daily were similar AUC(ss)₀₋₂₄ [5 mg bid, (458.0 (28.7)) and 10 mg qd, (470.0 (28.5))] and C(ss,av) [5 mg bid 18.8 (28.9)) and 10 mg qd, (19.6(28.5))], but minimum and maximum plasma levels of dapagliflozin differed significantly. Percent inhibition of renal glucose reabsorption (%IRGRA) and total urinary glucose excretion over 24 h were similar for both doses. The relationship between the mean dapagliflozin concentration and %IRGRA and the total urinary glucose excreted was well described by a maximum effect model. The results indicate that dapagliflozin may be used for either once daily or twice daily administration.

Twice-daily dapagliflozin co-administered with metformin in type 2 diabetes: a 16-week randomized, placebo-controlled clinical trial

AIMS

To evaluate the efficacy and safety of twice-daily dosing of dapagliflozin and metformin, exploring the feasibility of a fixed-dose combination.

METHODS

In this 16-week, phase III, randomized, double-blind placebo-controlled study, adults who were receiving metformin administered twice daily (≥1500 mg/day) and had inadequate glycaemic control were randomized 1:1:1:1 to receive dapagliflozin twice daily (2.5 or 5 mg), placebo or dapagliflozin 10 mg once daily (which was included as a benchmark). The primary endpoint was change from baseline glycated haemoglobin (HbA1c) level. Secondary endpoints included changes in fasting plasma glucose (FPG) level and body weight.

RESULTS

Four hundred adults were randomized to dapagliflozin (2.5 mg twice daily, 5 mg twice daily, 10 mg once daily) or placebo co-administered with metformin twice daily. At 16 weeks, the adjusted mean change in HbA1c from baseline was significantly reduced in the dapagliflozin 2.5 mg twice daily and 5 mg twice daily groups versus placebo (-0.52 vs. -0.30%, p = 0.0106 and -0.65% vs. -0.30%, p < 0.0001). There were also significantly greater improvements for dapagliflozin twice daily groups versus placebo in FPG body weight and achievement of HbA1c level of <7%. Efficacy outcomes for dapagliflozin twice daily were numerically similar to those for dapagliflozin once daily. Dapagliflozin twice daily was well tolerated.

CONCLUSIONS

Dapagliflozin 2.5 or 5 mg twice daily added to metformin was effective in reducing glycaemic levels in patients with type 2 diabetes inadequately controlled with metformin alone. This study supports the development of a fixed-dose combination regimen.