US researchers have found that patients who can potentially benefit most from participation in clinical trials due to poor prognosis often are not included in eligibility criteria of existing medical illnesses.
A novel study revealed that some patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) -- bone marrow failure disorder--, who traditionally cannot be considered for clinical trials, responded well and were treated safely in this setting.
The researchers from University of Texas MD Anderson Cancer Center followed 109 patients with AML and MDS undergoing treatment with azacitidine (AZA) -- anti-cancer ("antineoplastic" or "cytotoxic") chemotherapy drug-- and vorinostat.
The research results were presented at the 58th Annual Meeting of the American Society for Hematology in San Diego.
"Most cancer clinical studies exclude patients with co-morbidities (is the presence of one or more additional diseases or disorders co-occurring with a primary disease or disorder), active or recent malignancies (a cancerous growth), organ dysfunction or poor performance status," said lead study author Guillermo Garcia-Manero.
"How these criteria protect patients is unclear. Although some are based on clinical reasoning, it seems these criteria are in place more to protect the drug or intervention being studied rather than the patient," he added.
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The study initially enrolled 30 patients aged 17 and older, who were not previously been treated for AML or MDS.
Patients eligible for the study either had poor performance, poor renal or hepatic function or any other active systemic disorder such as other cancer.
Sixty-day survival was 83 percent with low-grade gastrointestinal side effects reported.
Then, the study was expanded to include an additional 79 patients.
Sixty-day survival for the second group was 79 percent with a median overall survival of 7.6 months.
The average event-free survival was 4.5 months. Again, only low-grade gastrointestinal side effects were observed.
The study was designed with "stopping rules" that included monitoring of side effects and complete response rates.
Patients were immediately placed on another therapy if their assigned therapy did not indicate there would be a complete response within a 60-day period.
To define the minimum expected survival and response rates that would trigger the stopping rules, researchers relied on prior data of 181 patients previously treated at MD Anderson.
The study pointed to evaluate standard exclusion criteria, potentially increasing the pool of patient likely to benefit from therapy, with the aim of future larger clinical trials specifically treating patients with AML and MDS.