Table 3.

Predicted median MPA concentrations (ng/mL) and 95% CIs for a population of women with median weight of 66 kg who inject Depo-SC every three or every four months in the abdomen or thigh for 1 year of treatment. Observed values are from the trial of the 4-month regimen conducted between 2017 and 2020 [5].

	4-Mo regimen		3-Mo regimen	Prediction ratio (4- vs 3-mo)
Timepoint	Observed	Predicted	Predicted
First dose trough	0.28	0.28 (0.26, 0.30)	0.35 (0.32, 0.39)	0.80 (0.77, 0.84)
Second dose trough	0.42	0.40 (0.38, 0.43)	0.54 (0.50, 0.58)	0.75 (0.71, 0.79)
12-mo trougha	0.46	0.46 (0.42, 0.49)	0.69 (0.65, 0.73)	0.66 (0.64, 0.68)
Steady state trougha	NA	0.49 (0.44, 0.55)	0.75 (0.69, 0.81)	0.66 (0.64, 0.68)
12-mo after last doseb	0.08c	0.08 (0.05, 0.12)	0.10 (0.06, 0.14)	0.82 (0.80, 0.83)

^a12-month troughs are MPA level at the end of the 1-year treatment period. Asymptotic, steady state troughs were estimated based on the accumulation ratio, 1/[1-exp(-λ∙τ)], where λ is the terminal absorption rate and τ is the dosing interval.

^b12-months after last dose corresponds to 8 and 9 months after the end of a 1-year treatment period for the four- and 3-month regimens, respectively. Since an extra month has passed for the 3-month regimen, the ratio of MPA levels 12-months after last dose (0.82) is not as extreme as the ratio at treatment month 12 (0.66).

^c46 weeks after last dose. This value conservatively assumes that 5 of 20 subjects who ovulated or discontinued prior to week 46 would have had the lowest MPA levels, had they been observed.