Incidence and management of myelosuppression in patients with chronic- and accelerated-phase chronic myeloid leukemia treated with omacetaxine mepesuccinate

Haematological adverse events associated with tyrosine kinase inhibitors in chronic myeloid leukaemia: A network meta-analysis

AIMS

Despite their overall favourable safety profile, tyrosine kinase inhibitors (TKIs) are related to severe adverse events including haematological toxicities such as anaemia, leucopenia, neutropenia and thrombocytopenia. We designed a systematic review and network meta-analysis of randomised controlled trials to compare safety among TKIs (bosutinib, dasatinib, imatinib, nilotinib, ponatinib and radotinib) used by patients diagnosed with chronic myeloid leukaemia.

METHODS

We obtained data from the PubMed, Scopus, Web of Science, and SciELO databases. The Bayesian approach was used for direct and indirect comparisons, and the treatments were ranked by the surface under the cumulative ranking curve (SUCRA).

RESULTS

Seventeen studies were included in the network meta-analysis. Our data show that dasatinib was generally considered worse than the other TKIs, with SUCRA values ​​for 140 mg dasatinib of 90.3% for anaemia, 87.4% for leucopenia, 90.6% for neutropenia and 97.2% for thrombocytopenia. In addition, nilotinib was shown to be safer, with SUCRA values ​​for 600 and 800 mg doses of 21.9 and 35.8% for anaemia, 23.8 and 14.6% for leucopenia, 33.0 and 17.7% for neutropenia, and 28.7 and 32.6% for thrombocytopenia, respectively.

CONCLUSION

Dasatinib appeared as the least safe drug for chronic myeloid leukaemia, probably because it binds to multiple key kinase targets, being more prone to cause serious haematological adverse events. Nilotinib demonstrated a safer profile, mostly due to its selective binding capacity.

A phase II study of omacetaxine mepesuccinate for patients with higher-risk myelodysplastic syndrome and chronic myelomonocytic leukemia after failure of hypomethylating agents

The outcome of patients with myelodysplastic syndromes (MDSs) after failure of hypomethylating agents (HMAs) failure is poor with a median overall survival (OS) of only 4-6 months. Omacetaxine mepesuccinate (OM) is safe and effective in myeloid malignancies but has not been studied in MDS with HMA failure. We conducted a phase II study of OM in patients with MDS or chronic myelomonocytic leukemia (CMML) who had previously failed or been intolerant to HMAs. Patients received OM at a dose of 1.25 mg/m2 subcutaneously every 12 hours for 3 consecutive days on a 4- to 7-week schedule. The primary endpoints were the overall response rate (ORR) and OS. A total of 42 patients were enrolled with a median age of 76 years. The ORR was 33%. Patients with diploid cytogenetics were more likely to respond to OM than were those with cytogenetic abnormalities (58% vs 23%, respectively; P = .03). Overall, the median OS was 7.5 months and 1-year OS rate was 25%. Patients with diploid cytogenetics had superior OS to those with cytogenetic abnormalities (median OS 14.8 vs 6.8 months, respectively; P = .01). Two patients had ongoing response to OM of 2 years or longer (both MDS with diploid cytogenetics and RUNX1 mutation). The most common grade ≥ 3 adverse events were infections in 11 patients (26%), febrile neutropenia in 4 (10%), and hemorrhage in 3 (7%). Overall, OM was safe and active in patients with MDS or CMML who experienced HMA failure. These results support the further development of OM in this setting.

A Review of Omacetaxine: A Chronic Myeloid Leukemia Treatment Resurrected

The paradigm of targeted therapy was pioneered for chronic myeloid leukemia (CML). The advent of tyrosine kinase inhibitors (TKIs) has led to marked improvements in responses and overall survival; however, there is still a subset of patients that are either resistant through a multitude of mechanisms or intolerant to standard TKI therapy. Omacetaxine mepesuccinate (omacetaxine), a semisynthetic purified homoharringtonine compound, has been studied for over 40 years and was approved in 2012 by the Food and Drug Administration (FDA) for patients with CML refractory or intolerant to two or more TKIs. Omacetaxine has a novel mechanism of action-inhibition of protein synthesis, which does not overlap with kinase inhibition. Multiple studies have demonstrated that omacetaxine can achieve responses in heavily treated patients with either chronic-phase or accelerated-phase CML, regardless of the presence of mutations in the tyrosine kinase domain. This review will outline the tortuous story of omacetaxine, including preclinical and clinical studies of homoharringtonine, current indications, and management guidelines.

Plant Secondary Metabolites as Anticancer Agents: Successes in Clinical Trials and Therapeutic Application

Cancer is a multistage process resulting in an uncontrolled and abrupt division of cells and is one of the leading causes of mortality. The cases reported and the predictions for the near future are unthinkable. Food and Drug Administration data showed that 40% of the approved molecules are natural compounds or inspired by them, from which, 74% are used in anticancer therapy. In fact, natural products are viewed as more biologically friendly, that is less toxic to normal cells. In this review, the most recent and successful cases of secondary metabolites, including alkaloid, diterpene, triterpene and polyphenolic type compounds, with great anticancer potential are discussed. Focusing on the ones that are in clinical trial development or already used in anticancer therapy, therefore successful cases such as paclitaxel and homoharringtonine (in clinical use), curcumin and ingenol mebutate (in clinical trials) will be addressed. Each compound’s natural source, the most important steps in their discovery, their therapeutic targets, as well as the main structural modifications that can improve anticancer properties will be discussed in order to show the role of plants as a source of effective and safe anticancer drugs.