53 U.S. Patient Perspectives on Capivasertib Plus Fulvestrant: Dosing, Tolerability, and Blood Glucose Monitoring From Qualitative Interviews

Background

Capivasertib, an AKT inhibitor, is administered on a 4-days-on/3-days-off schedule (4-on/3-off) and requires fasting glucose monitoring due to the risk of hyperglycemia, a known on-target effect of PI3K/AKT pathway inhibition. Real-world patient perspectives on treatment experience can inform patient education and supportive care.

Methods

We conducted qualitative interviews using a structured discussion guide to explore US patients’ perspectives on capivasertib dosing, tolerability, adverse event (AE) management, and blood glucose (BG) monitoring. The interim sample included 43 adults with metastatic breast cancer who received 1 or more weeks of capivasertib with fulvestrant in routine care. Patients providing documentation of capivasertib prescription were interviewed in English from July 2025 to November 2025. Those who discontinued capivasertib more than 6 months prior to the interview were excluded. Data were analyzed by content analysis.

Results

Most participants reported that the 4-on/3-off dosing was easy to follow, and many appreciated periodic “off” days. In general, participants expressed a neutral view of their BG monitoring schedule and its impact on daily activities. For BG monitoring at a clinic, patient experiences varied by logistical factors: stronger caregiver support and closer clinic proximity were associated with fewer challenges. Among those monitoring BG at home, most felt confident in self-monitoring techniques; however, financial barriers were noted for some when test strips were not covered by insurance. Participants generally characterized AE education from their care teams as thorough and could recall what actions to take if AEs occurred. Nonetheless, a small subset exhibited knowledge gaps: some were unsure about which symptoms indicated severe hyperglycemia requiring urgent medical attention. In addition, patients who tested at home often lacked clear guidance on what constituted a high BG result. Most participants characterized diarrhea, rash, oral mucositis, and hyperglycemia as manageable—particularly those with prior chemotherapy experience—although a subset reported diarrhea as significantly affecting daily functioning. While many felt confident following home management instructions, some were reluctant to use supportive medications (eg, antidiarrheal) due to medication burden or uncertainty about dosing, and others delayed contacting their health care providers until symptoms became more severe.

Conclusions

BG monitoring requirements were broadly acceptable and minimally disruptive, but experiences were shaped by support networks, access, and out-of-pocket costs. Although AE education was perceived as thorough, gaps were observed in recognizing severe hyperglycemia, identifying actionable home blood glucose thresholds, and understanding or willingness to use supportive medications. These findings support reinforcing standardized hyperglycemia education, clarifying home-monitoring action thresholds, and providing proactive, practical guidance on supportive care to improve patient outcomes and effective AE management.