Effectiveness of empiric cardioprotective therapy in patients receiving cardiotoxic chemotherapies: systematic review & bayesian network meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Cardioprotective therapies represent an important avenue to reduce these limiting toxicities, including serious heart failure (HF) events. However, due to conflicting isolated reports, the true efficacy and optimal cardioprotective therapy at the time of anticancer treatment initiation is unclear. Therefore, we undertook a network meta-analysis to elucidate the most effective therapies at cardiotoxic HF prevention.

Purpose

To determine the efficacy, and optimal cardioprotective strategy in patients receiving cardiotoxic chemotherapies.

Methods

Leveraging the MEDLINE/Pubmed, CENTRAL, and clinicaltrials.gov databases, we identified all randomized controlled trials (RCTs) investigating cardioprotective therapies from inception to November 2021. Eligible cardioprotective classes included ACEIs, ARBs, Beta-blockers, dexrazoxane (DEX), statins, and mineralocorticoid receptor antagonists (MRA). The primary endpoint was the prevention of new-onset HF. The secondary outcomes were the mean difference in left ventricular ejection fraction (LVEF) change, the incidence of hypotension, and all-cause mortality. Network meta-analyses were used to assess the cardioprotective effects of each therapy to deduce the most effective therapies. Both analyses were undertaken using a Bayesian random-effects model to estimate risk ratios (RR) and 95% credible intervals (95% CrI).

Results

Overall, from 726 articles, 39 studies evaluating 5,931 participants (38.0±19.1 years, 72.0% females) were identified. Over a median follow-up of 6 months, use of any cardioprotective strategy was associated with a significant reduction in new-onset HF (RR:0.32; 95% CrI:0.19-0.55), improved LVEF (mean difference: 3.92%; 95% CrI:2.81-5.07), and increased hypotension (RR:3.27; 95% CrI:1.38-9.87); there was no difference in mortality (RR:1.03; 95% CrI:0.84-1.22). Based on the median risk of incident HF in the control groups being 3.28%, the number need to treat (NNT) for "any" cardioprotective therapy to prevent one incident HF event was 45 patients. For dexrazoxane and neurohormonal agents, the median NNT was 36 and 53 patients, respectively. In this network analysis, dexrazoxane was most effective at HF prevention [Surface Under the Cumulative Ranking curve (SUCRA): 81.47%] and MRA most effective at preserving LVEF (SUCRA: 99.22%). ARBs most greatly increased hypotension (RR:7.20; 95% CrI:2.46-26.94).

Conclusion

Cardiotoxicity remains a challenge for cancer patients requiring life-saving cancer therapies. The initiation of a cardioprotective strategy reduces incident HF. Additional head-to-head trials are needed to confirm the optimal preventative strategy.

Potential protective effects of melatonin on bone marrow of rats exposed to cytotoxic drugs

Myelosuppression is the most serious, dose limiting, toxicity of cytotoxic drugs. Efforts to protect the bone marrow have been only variably successful, and no agreement exists on how to approach this problem. Melatonin, the major hormonal product of the pineal gland, is supposed to have both chemoprotective and myelostimulatory effects. This experimental study was carried out to test these two effects on the bone marrow of rats, daily intraperitoneally injected with 100 microg melatonin. Injection of 10 mg aracytin for 10 days produced a significant (P < 0.01) decrease in red blood cells count (RBCs), total leucocytic count, as well as platelets count. When melatonin was injected along with aracytin, it would significantly increase (P < 0.05) RBC count and (P < 0.01) blood platelet count. Injection of melatonin after aracytin treatment would significantly increase (P < 0.01) RBC, total leucocytic and platelet counts in comparison with rats treated with aracytin only. The effects of melatonin were more clear in rats treated with it after aracytin injection than those treated with melatonin and aracytin at the same time. Furthermore, it was found that aracytin produced a significant (P < 0.01) decrease in serum total proteins, albumin, and significantly increased the (P < 0.01) albumin/globulin ratio. Melatonin injection would significantly increase (P < 0.01) total protein, globulin, and significantly decrease (P < 0.01) the albumin/glubulin ratio when injected either with aracytin or after aracytin treatment. These results indicate that melatonin protects bone marrow, lymphoid tissues from damaging effect of cytotoxic drugs, as well as stimulating the suppressed bone marrow.

Sequence and transcriptional analysis of the genes encoding the class-II topoisomerase of Mycoplasma gallisepticum

The gyrAB genes encoding the entire B and a portion of the A subunit of DNA gyrase (E.C. 5.99.1.3) from Mycoplasma gallisepticum (Mg), strain S6, were cloned and sequenced. These gyrAB genes are co-transcribed as a single, polycistronic mRNA transcript. The Mg gyrB appears unique among prokaryotic gyrB in its use of GUG as a start codon.