The BCL2 inhibitor venetoclax has revolutionized the treatment of acute myeloid leukemia (AML) patients not benefitting from intensive chemotherapy. Nevertheless, treatment failure remains a challenge, and predictive markers are needed, particularly for relapsed or refractory (R/R) AML. Ex vivo drug sensitivity testing may correlate with outcomes, but its prospective predictive value remains unexplored. Here we report the results of the first stage of the prospective Phase 2 VenEx trial evaluating the utility and predictiveness of venetoclax sensitivity testing using different cell culture conditions and cell viability assays in patients receiving venetoclax-azacitidine (NCT04267081). Participants with de novo AML ineligible for intensive chemotherapy, R/R AML, or secondary AML were included. The primary endpoint was the treatment response in ex vivo sensitive participants and the key secondary endpoints were the correlation of sensitivity with responses and survival. Venetoclax sensitivity testing was successful in 38/39 participants. Experimental conditions significantly influenced predictive accuracy. Blast-specific venetoclax sensitivity measured in conditioned medium most accurately correlated with treatment outcomes; 88% of sensitive participants achieved treatment response. Median survival was significantly longer for ex vivo sensitive participants (14. 6 months for s ensitive, 3. 5 for insensitive, p < 0 . 001). T his analysis illustrates the feasibility of integrating drug-response profiling into clinical practice and demonstrates excellent predictivity.

Early identification of patients at risk of a severe course of hantaviral disease and lack of effective medication represent a global challenge in the treatment of this emerging infection. We describe a 67-year-old female patient with a history of chronic lymphoproliferative disease involving the spleen and an extremely severe acute Puumala hantavirus infection. She was treated with the bradykinin receptor antagonist icatibant and recovered. She is the second patient with a spleen abnormality and severe Puumala infection treated with icatibant in our hospital. We suggest that patients with spleen abnormalities may be more susceptible to severe hantavirus disease. The activation of the kinin-kallikrein system and the formation of bradykinin in hantavirus-infected endothelial cells indicate that the role of bradykinin receptor antagonist icatibant in the treatment of hantavirus disease is worth studying.

Thrombocytopenia and altered coagulation characterize all hantavirus infections. To further assess the newly discovered predictive biomarkers of disease severity during acute Puumala virus (PUUV) infection, we studied the associations between them and the variables reflecting coagulation, fibrinolysis and endothelial activation. Nineteen hospital-treated patients with serologically confirmed acute PUUV infection were included. Acutely, plasma levels of pentraxin-3 (PTX3), cell-free DNA (cf-DNA), complement components SC5b-9 and C3 and interleukin-6 (IL-6) were recorded as well as platelet ligands and markers of coagulation and fibrinolysis. High values of plasma PTX3 associated with thrombin formation (prothrombin fragments F1+2; r = 0.46, P = 0.05), consumption of platelet ligand fibrinogen (r = -0.70, P < 0.001) and natural anticoagulants antithrombin (AT) (r = -0.74, P < 0.001), protein C (r = -0.77, P < 0.001) and protein S free antigen (r = -0.81, P < 0.001) and a decreased endothelial marker ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 domain 13) (r = -0.48, P = 0.04). Plasma level of AT associated with C3 (r = 0.76, P < 0.001), IL-6 (r = -0.56, P = 0.01) and cf-DNA (r = -0.47, P = 0.04). High cf-DNA coincided with increased prothrombin fragments F1+2 (r = 0.47, P = 0.04). Low C3 levels reflecting the activation of complement system through the alternative route predicted loss of all natural anticoagulants (for protein C r = 0.53, P = 0.03 and for protein S free antigen r = 0.64, P = 0.004). Variables depicting altered coagulation follow the new predictive biomarkers of disease severity, especially PTX3, in acute PUUV infection. The findings are consistent with the previous observations of these biomarkers also being predictive for low platelet count and underline the cross-talk of inflammation and coagulation systems in acute PUUV infection.

Puumala hantavirus (PUUV) causes a hemorrhagic fever with renal syndrome (HFRS), also called nephropathia epidemica (NE), which is mainly endemic in Europe and Russia. The clinical features include a low platelet count, altered coagulation, endothelial activation, and acute kidney injury (AKI). Multiple connections between coagulation pathways and inflammatory mediators, as well as complement and kallikrein–kinin systems, have been reported. The bleeding symptoms are usually mild. PUUV-infected patients also have an increased risk for disseminated intravascular coagulation (DIC) and thrombosis.

The pathogenesis of thrombocytopenia in Puumala hantavirus (PUUV) infection is probably multifactorial. We aimed to evaluate the possible spleen enlargement during acute PUUV infection, and to determine its association with thrombocytopenia and disease severity. Magnetic resonance imaging (MRI) of the spleen was performed in 20 patients with acute PUUV infection. MRI was repeated 5-8 months later. The change in spleen length was compared with markers describing the severity of the disease. In all patients, the spleen length was increased in the acute phase compared with the control phase (median 129 mm vs 111 mm, p < 0.001). The change correlated with maximum C-reactive protein value (r = 0.513, p = 0.021) and inversely with maximum leukocyte count (r = -0.471, p = 0.036), but not with maximum serum creatinine level or minimum platelet count. Enlarged spleen, evaluated by MRI, was shown to be a common finding during acute PUUV infection. However, it does not associate with thrombocytopenia and acute kidney injury.