Global deterioration of cardiovascular mechanics by carfilzomib treatment is associated with proteasome activity in patients with relapsed multiple myeloma

Background

Carfilzomib (CFZ) is a second generation irreversible proteasome inhibitor that has been shown to improve overall survival in patients with relapsed or refractory multiple myeloma (MM) but is associated with cardiac toxicity in MM. Because ubiquitin-proteasome system (UPS) is involved in cardiovascular homeostasis exploring the effects of proteasome inhibition on cardiac mechanics, in a clinical setting, would provide novel insight of the clinical role of UPS in cardiovascular disease.

Aim

To gain a thorough understanding of proteasome inhibition on myocardial mechanics in a clinical setting.

Methods

We prospectively evaluated 48 patients with relapsed or refractory MM and an indication to receive CFZ treatment [median age: 67.5, interquartile range (64–73), 66.7% men]. All patients underwent cardiac ultrasonography at an initial visit, at the first day of the 3rd month (C3D1, n=25) and at the last day of cycle 6 (C6D16, n=48). Pulse wave velocity (PWV) was used to assess arterial stiffness and calculate arterial-ventricular coupling (VAC) by the ratio (PWV/global longitudinal strain (GLS)). Carfilzomib was administered at 27mg/m2 on days 1 (C1D1) and 2 (C1D2) of cycle 1 and at 56mg/m2 thereafter. Blood was drawn at baseline, C3D1 and C6D16 to measure proteasome activity (PrA). Patients were followed up for carfilzomib–related cardiovascular adverse events.

Results

Regarding systolic function, between baseline and C6D16, we noticed deterioration in left ventricular ejection fraction (LVEF) (57.7±5.4% vs 56.1±7.19%, p=0.022), GLS (−20.51±2.78 vs −18.88±3.45%, p=0.003), S wave of LV longitudinal strain rate and radial strain (p<0.05 for both). Markers of LV diastolic function also deteriorated at 6 months including early diastolic (Ea) mitral annular velocity (7.27±1.83cm/sec vs 6.7±1.64cm/sec, p=0.008) and E wave of LV longitudinal strain rate (1.1±0.37sec-1 vs 0.95±0.36sec-1, p=0.010). Left atrial volume (LAV) and index (LAVi) increased both at 3 and 6 months (p<0.05). Peak LA strain at reservoir phase (peak atrial longitudinal strain, PALS) was also decreased at 6th and 3rd month measurements (p<0.05), whereas LA strain rate at reservoir function (s wave) was decreased, compared to baseline, only at 6th month (p=0.001). RV longitudinal strain also decreased between 3rd and 6th month (p=0.039). Furthermore, PWV/GLS also deteriorated at 6 months (−0.56±0.13 vs −0.64±0.21, p=0.001). By linear mixed models analysis, we found that changes in proteasome activity were associated with changes in PWV/GLS (p=0.017), LAV (p=0.015) and LAVi (p=0.009), and PALS (p=0.014).

Conclusion

CFZ treatment was associated with global deterioration of markers of myocardial systolic and diastolic function and VAC. The observed association of changes in proteasome activity with VAC and left atrial function and structure supports a direct effect of proteasome inhibition on the cross-talk between LV and arterial function and LV diastolic function.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Amgen

Aortic hemodynamic parameters as predictors of incident or deteriorating hypertension during carfilzomib therapy in patients with relapsed multiple myeloma

Background

Carfilzomib (CFZ) improves survival in relapsed/refractory multiple myeloma but is associated with cardiovascular adverse events, among which hypertension is commonly reported.

Purpose

To evaluate aortic hemodynamics as possible predictors for CFZ-associated hypertension.

Methods

In a prospective study of 48 patients treated with Kd (CFZ 20/56 mg/m2 and dexamethasone) followed until disease progression or cycle 6 for a median of 10 months, patients underwent peripheral hemodynamic assessment, including applanation tonometry, which allows estimation of aortic blood pressure and arterial wave reflections and assessment of pulse wave velocity, which allows estimation of aortic stiffness. Hemodynamic parameters were examined at baseline and at pre-specified time points before and 24 hours after drug infusion.

Results

Thirteen patients (27.1%) developed hypertension or merited more intensive anti-hypertensive treatment (grade I or II: 6.25%, grade III: 20.8%). Patients with new onset or worsening hypertension had increased aortic [130±12.9 mmHg versus 115±16.7 mmHg, p=0.004] and peripheral systolic blood pressure (SBP) [145±15.7 mmHg versus 130±19.5 mmHg, p=0.001] at baseline. Patients distributed at highest tertile of baseline aortic SBP (log-rank test p=0.0001, Figure) or baseline peripheral SBP (log-rank test p=0.002) had significantly higher risk for CFZ associated hypertension as compared to those distributed at lower tertiles. After adjustment for age, gender and baseline hypertension, increased aortic [HR=8.0, 95% CIs 2.4–26.6, p=0.001] and peripheral SBP [HR=4.85, 95% CIs 1.53–15.4, p=0.007] remained significantly associated with hypertension. After adjustment for both baseline peripheral and aortic SBP in the same multivariable core model, aortic SBP was the only independent predictor of the study outcome (p=0.041). Accordingly, baseline aortic SBP was associated with higher discriminative value as compared to peripheral SBP [AUC: 0.819, 95% CIs 0.722–0.916 versus 0.724, 95% CIs 0.570–0.878, respectively]. Further adjustment for all cardiotoxicity risk factors using forced inclusion in non-parsimonious multivariable Cox regression models, revealed that increased aortic and peripheral SBP remained independent predictors of hypertensive events (p<0.05 for both).

Conclusion

Baseline aortic hemodynamics are associated with hypertension during CFZ treatment. Aortic SBP at baseline was the strongest predictor of CFZ-associated hypertensive adverse events, suggesting that an initial assessment of aortic blood pressure may facilitate discrimination of patients in need of close monitoring during treatment.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Funding from the Hellenic Foundation for Research and Innovation (HFRI) and the General Secretariat for Research and Technology (GSRT), under grant agreement No [1285].

Addition of cyclophosphamide and higher doses of dexamethasone do not improve outcomes of patients with AL amyloidosis treated with bortezomib

Bortezomib, in combination with dexamethasone (VD) or with the addition of cyclophosphamide (VCD), is highly effective in patients with amyloid light-chain (AL) amyloidosis. Currently, VCD is considered as a primary regimen for patients with AL, but it is not clear whether the addition of cyclophosphamide to VD further and significantly improves efficacy, given the substantial activity of bortezomib itself. We retrospectively compared the outcomes of 101 patients with AL amyloidosis who received VD (n=59) or VCD (n=42) in two consecutive periods. Early mortality after adjustment for Mayo stage was similar. On intent to treat, a hematologic response rate was 68% for patients treated with VD and 78% for VCD (P=0.26), while complete response+very good partial response (CR+VGPR) rate was 47.5% and 35%, respectively. Higher doses of dexamethasone or twice-weekly bortezomib were not associated with significantly higher CR+VGPR rates. Organ responses occurred in similar rates between the two groups. Median survival was similar (33 vs 36 months, P=0.45) even after adjustment for Mayo stage and dose and schedule of bortezomib and dexamethasone. In conclusion, bortezomib even with low doses of dexamethasone is effective for the treatment of AL amyloidosis; higher doses of dexamethasone and addition of cyclophosphamide do not seem to have a profound effect on efficacy and survival.