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Clinical Pharmacology

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Results of vaginal maturation indexes at cycles 6 and 13 showed that the differences from placebo were statistically significant (p < 0.001) for all treatment groups (conjugated estrogens alone and conjugated estrogens/medroxyprogesterone acetate treatment groups).

Effects on the endometrium

In a 1-year clinical trial of 1,376 women (average age 54.0 ± 4.6 years) randomized to PREMPRO 0.625 mg/2.5 mg (n=340), PREMPRO 0.625 mg/5 mg (n=338), PREMPHASE 0.625 mg/5 mg (n=351), or Premarin 0.625 mg alone (n=347), results of evaluable biopsies at 12 months (n=279, 274, 277, and 283, respectively) showed a reduced risk of endometrial hyperplasia in the two PREMPRO treatment groups (less than 1 percent) and in the PREMPHASE treatment group (less than 1 percent; 1 percent when focal hyperplasia was included) compared to the Premarin group (8 percent; 20 percent when focal hyperplasia was included). See Table 4.

TABLE 4. INCIDENCE OF ENDOMETRIAL HYPERPLASIA AFTER ONE YEAR OF TREATMENT

  Groups
  PREMPRO PREMPRO PREMPHASE Premarin
  0.625 mg/2.5 mg 0.625 mg/5 mg 0.625 mg/5 mg 0.625 mg
Total number of patients 340 338 351 347
Number of patients with evaluable biopsies 279 274 277 283
No. (%) of patients with biopsies
  • all focal and non-focal hyperplasia 2 ( < 1)* 0 (0)* 3 (1)* 57 (20)
  • excluding focal cystic hyperplasia 2 ( < 1)* 0 (0)* 1 ( < 1)* 25 (8)
* Significant (p < 0.001) in comparison with Premarin (0.625 mg) alone.

In the first year of the Health and Osteoporosis, Progestin and Estrogen (HOPE) Study, 2,001 women (average age 53.3 ± 4.9 years) of whom 88 percent were Caucasian were treated with either Premarin 0.625 mg alone (n = 348), Premarin 0.45 mg alone (n = 338), Premarin 0.3 mg alone (n = 326) or PREMPRO 0.625 mg/2.5 mg (n = 331), PREMPRO 0.45 mg/1.5 mg (n = 331) or PREMPRO 0.3 mg/1.5 mg (n = 327). Results of evaluable endometrial biopsies at 12 months showed a reduced risk of endometrial hyperplasia or cancer in the PREMPRO treatment groups compared with the corresponding Premarin alone treatment groups, except for the PREMPRO 0.3 mg/1.5 mg and Premarin 0.3 mg alone groups, in each of which there was only 1 case. See Table 5.

No endometrial hyperplasia or cancer was noted in those patients treated with the continuous combined regimens who continued for a second year in the osteoporosis and metabolic substudy of the HOPE study. See Table 6.

TABLE 5. INCIDENCE OF ENDOMETRIAL HYPERPLASIA/CANCERa AFTER ONE YEAR OF TREATMENTb

  Groups
Patient Prempro
0.625 mg/
2.5 mg		 Premarin
0.625
mg		 Prempro
0.45 mg/
1.5 mg		 Premarin
0.45 mg		 Prempro
0.3 mg/
1.5 mg		 Premarin
0.3 mg
Total number of patients 331 348 331 338 327 326
Number of patients with evaluable biopsies 278 249 272 279 271 269
No. (%) of patients with biopsies
•hyperplasia/cancera
(consensusc)		 0 (0)d 20 (8) 1 ( < 1)a,d 9 (3) 1 ( < 1)e 1 ( < 1)a
a All cases of hyperplasia/cancer were endometrial hyperplasia except for 1 patient in thePremarin 0.3 mg group diagnosed with endometrial cancer based on endometrial biopsy, and 1patient in the Premarin/MPA 0.45 mg/1.5 mg group diagnosed with endometrial cancer based onendometrial biopsy.
b Two (2) primary pathologists evaluated each endometrial biopsy. Where there was lack ofagreement on the presence or absence of hyperplasia/cancer between the two, a third pathologistadjudicated (consensus).
c For an endometrial biopsy to be counted as consensus endometrial hyperplasia or cancer, atleast 2 pathologists had to agree on the diagnosis.
d Significant (p < 0.05) in comparison with corresponding dose of Premarin alone.e: Non-significant in comparison with corresponding dose of Premarin alone.

TABLE 6. OSTEOPOROSIS AND METABOLIC SUBSTUDY, INCIDENCE OF ENDOMETRIAL HYPERPLASIA/CANCERa AFTER TWO YEARS OF TREATMENTb

Patient Groups
Prempro
0.625 mg/
2.5 mg		 Premarin
0.625mg		 Prempro
0.45 mg/
1.5 mg 		Premarin
0.45 mg		 Prempro
0.3 mg/
1.5 mg		 Premarin
0.3 mg
Total number of patients 75 65 75 74 79 73
Number of patients with evaluable biopsies 62 55 69 67 75 63
No. (%) of patients with biopsies
•hyperplasia/cancera
(consensusc)		 0 (0)d 15 (27) 0 (0)d 10 (15) 0 (0)d 2 (3)
a All cases of hyperplasia/cancer were endometrial hyperplasia in patients who continued for asecond year in the osteoporosis and metabolic substudy of the HOPE study.
b Two (2) primary pathologists evaluated each endometrial biopsy. Where there was lack ofagreement on the presence or absence of hyperplasia/cancer between the two, a third pathologistadjudicated (consensus).
c For an endometrial biopsy to be counted as consensus endometrial hyperplasia or cancer, atleast 2 pathologists had to agree on the diagnosis.
d Significant (p < 0.05) in comparison with corresponding dose of Premarin alone.

Effects on uterine bleeding or spotting
Brand Name: Prempro
Generic Name: Conjugated Estrogens, Medroxyprogesterone Acetate
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