Beta-adrenergic receptor blockade in angiosarcoma: Which beta-blocker to choose?

Propranolol monotherapy in angiosarcoma - A window-of-opportunity study (PropAngio)

BACKGROUND

Angiosarcoma is a rare and aggressive cancer of the endothelial cells. Propranolol, a non-selective β-blocker, was able to initiate apoptosis in angiosarcoma cell lines and its anti-tumor activity has been described in several case reports. The aim of this trial was to prospectively evaluate the anti-tumor activity of propranolol monotherapy in patients with angiosarcoma before proceeding to standard of care treatment.

METHODS

Propranolol was dosed 80 mg to 240 mg/day for 3 to 6 weeks according to a dose titration schedule. The primary endpoint was clinical response (response according to RECIST 1.1 or stable disease with improvement of cutaneous lesions) in at least three patients. Exploratory objectives included histologic response (>30% decrease in Ki-67), FDG PET response, and β-receptor expression levels.

RESULTS

Fourteen patients were enrolled. The median duration of treatment was 26 days (range 21-42 days). The median highest propranolol dose was 160 mg/day (range 80 - 240 mg). Two patients showed clinical response (14%, 95% CI 3-100%). One of these patients showed a partial metabolic response on PET-CT. None of the tumors showed histologic response. The most common adverse event was grade 1/2 bradycardia (86%). There were no grade ≥ 3 adverse events. ADRB2 was overexpressed in 16 out of 18 tumors, in both responders and non-responders. None of the tumors showed ADRB1 overexpression.

CONCLUSIONS

This window-of-opportunity trial did not show clinical efficacy of propranolol monotherapy. However, two out of 14 patients did show clinical benefit. ADRB1/2 expression did not correlate with clinical response.

Beta-blocker adjunct therapy as a prospective anti-metastatic with cardio-oncologic regulation

The prevailing treatment stratagem in cancer therapy still challenges the dilemma of a probable metastatic spread following an initial diagnosis. Including an anti-metastatic agent demands a significant focus to overrule the incidence of treatment failures. Adrenergic stimulation underlying the metastatic spread paved the way for beta blockers as a breakthrough in repurposing as an anti-metastatic agent. However, the current treatment approach fails to fully harness the versatile potential of the drug in inhibiting probable metastasis. The beta blockers were seen to show a myriad of grip over the pro-metastatic and prognostic parameters of the patient. Novel interventions in immune therapy, onco-hypertension, surgery-induced stress, induction of apoptosis and angiogenesis inhibition have been used as evidence to interpret our objective of discussing the potential adjuvant role of the drug in the existing anti-cancer regimens. Adding weight to the relative incidence of onco-hypertension as an unavoidable side effect from chemotherapy, the slot for an anti-hypertensive agent is necessitated, and we try to suggest beta-blockers to fill this position. However, pointing out the paucity in the clinical study, we aim to review the current status of beta blockers under this interest to state how the drug should be included as a drug of choice in every patient undergoing cancer treatment.