According to the findings of a clinical trial, treatment with the bortezomib-cyclophosphamide-dexamethasone (CyBorD) combination plus doxycycline does not improve progression-free survival (PFS) or cardiac PFS in patients with light chain amyloidosis.
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What Is Light Chain Amyloidosis?
Amyloid light chain amyloidosis is clinically defined
as a protein misfolding disorder. The organs and tissues such as the heart,
kidney, skin, stomach, small and large intestines, nerves, and liver swell and
lose function as a result of this condition. Medications kill plasma cells,
which are responsible for producing light chain proteins.
The trial randomized 140 Mayo 2004 stage II-III light
chain amyloidosis patients (median age 61 years) to receive either doxycycline
100 mg twice daily with nine cycles of CyBorD (doxycycline group, n=70) or nine
cycles of CyBorD alone (control group, n=70).
Primary outcome was 2-year PFS, which was defined as
the period between randomization and death, hematologic progression
(significant rise in free light chain), or organ progression (heart, kidney, or
liver). An increase in either N-terminal pro B-type natriuretic peptide or
cardiac troponin was used to describe cardiac progression.
In the doxycycline and control groups, respectively,
there were 34 (48.6%) and 33 (47.1%) individuals with stage II illness.
Progression occurred in 45.7 percent of doxycycline-treated patients and 42.9
percent of control patients, with no statistically significant difference
(hazard ratio [HR], 0.97, 95 percent confidence interval [CI], 0.59–1.60;
p=0.91).
Cardiac progression was seen in 41.4 percent of
doxycycline patients and 37.1 percent of control patients; however, the death
rate was the same in both groups at 35.7 percent at the end of the study. There
was no significant difference in cardiac PFS (HR, 0.91, 95 percent CI,
0.54–1.55; p=0.74) or overall survival (HR, 1.04, 95 percent CI, 0.60–1.81;
p=0.89) between the two groups.
Source: Circulation
2021;doi:10.1161/CIRCULATIONAHA.121.055953