Rat telemetry

Arterial blood pressure was measured using radiotelemetry, as previous in‐house data indicated this species and model to be sensitive to induced blood pressure elevation following treatment with VEGFR‐2 inhibitors. Briefly, male Han Wistar rats were implanted with HD‐S11 transmitters (Data Sciences International, St. Paul, MN USA) under isoflurane anaesthesia at Charles River Laboratories (Margate, UK) and allowed to recover for at least 2 weeks. Animals were transferred to the AstraZeneca facility at around 2–3 months old. The animals were pair‐housed in standard rat individually ventilated cages with a non‐instrumented companion throughout the study. Cages were prepared with bedding material and enrichment.

After the acclimatization period of a minimum of 7 days, compound was administered by oral gavage (10% DMSO, 60% PEG400) on day 0 (at 10:00 h) and subsequently with the test item on day 1. Depending on the test item and dose, additional doses of test item were administered on days 2 and 3. Due to the ascending dose design, animals were not randomized to a dose group. Each group consisted of six rats, as a power analysis and previous in‐house data indicate that this number is sufficient to detect a 5 to 10 mmHg increase in blood pressure. Rats weighed 376–650 g at time of treatment. Blood samples (obtained via tail vein using micro‐sampling – 32 μL collected blood volume) were taken for confirmation of exposure at 2 h post‐dose. Clinical signs were monitored. The study design is outlined in the Supporting Information.

Systolic blood pressure was obtained as a series of 1 min averages which was subsequently averaged over 2 h consecutive periods (average of 120 data points) or a super‐interval of 10–22 h post‐dose (average of 720 data points). For the PKPD analysis of the rat telemetry studies, data were binned into 2 h intervals, including a pre‐dose, each day of dosing and washout period.