Patient survey points to need for innovative dosing strategies in MBC
medwireNews: The high side-effect burden of metastatic breast cancer (MBC) treatments warrants the development of innovative dosing strategies to maintain quality of life, suggest the results of an advocate-led survey of patients.
Speaking at the 2021 ASCO Annual Meeting, Anne Loeser, from the Patient-Centered Dosing Initiative based in Salt Lake City, Utah, USA, explained that patients with MBC usually begin treatments at the recommended starting dose, which is based on the maximum tolerated dose identified in early-phase clinical trials.
However, this comes with certain challenges, she said, such as the fact that “the maximum tolerated dose may not be applicable for targeted therapies because dose-limiting toxicities may not occur even in doses above normal biological dose.”
Moreover, patient responses and tolerability in the real world “may vary from that which is seen in clinical trials because patients in clinical trials are subject to rigid inclusion and exclusion criteria,” added Loeser.
The team therefore sought to understand “tolerability from the patient’s perspective” and ascertain their views regarding an alternate paradigm that would involve the personalization of a drug’s “starting dose in clinical practice based upon the patient’s unique attributes.”
Of the 1221 MBC patients who completed the 27-question online survey created by patient advocates, 99% were women, 88% were White, and just under half (46%) had been diagnosed within 2 years. Eighty-two percent of the participants had received targeted therapy, 77% had received endocrine therapy, and 55% had received chemotherapy.
A total of 86% of the respondents reported ever having a “bad” side effect from treatment, of whom 20% visited the emergency department or hospital due to a treatment-related side effect, and 43% missed at least one dose as a result of side effects.
Fatigue was the most common side effect, experienced by 90% of participants, followed by nausea and low blood counts in 62% each, diarrhea in 57%, neuropathy in 55%, pain and mouth sores/gum issues in 52% each, and constipation in 51%.
Almost all (98%) of the respondents who had a side effect said that they told their doctors and 82% received assistance.
The most common strategy for mitigating side effects was dose reduction, used in 66% of participants, and of these, 71% said they felt better on the lower dose, while 12% said they felt better initially but then felt the same. The majority (64%) only needed one dose reduction to alleviate the side effects.
Ninety-two percent of the respondents expressed a willingness to discuss drug dosing with their physicians based on their personal characteristics, 7% did not know, and just 1% said they would not be willing to engage in such a discussion.
In conclusion, Loeser highlighted the ongoing research by the Patient-Centered Dosing Initiative, including a medical oncologist survey to accompany this patient survey, and also outlined plans to engage with the pharmaceutical industry in order to answer questions on dosage level efficacy, such as the outcomes of patients on the maximum tolerated versus lower doses.
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