Objective: To compare the efficacy of Letrozole and Gonadotropin, given alone or in combination, in controlled ovarian hyperstimulation in Clomiphene citrate poor responders. Study Design: Prospective, non-randomized observational study on Clomiphene citrate poor responders at the St. Luke's Medical Center setting from January to July 2006. Results: Letrozole and gonadotropins, whether given alone or in combination, have similar clinical outcomes in terms of endometrial thickness during ovulation and the number of dominant follicles developed. The use of gonadotropins results in 100% ovulation rate, similar to results when Letrozole is used as an adjunct. Letrozole significantly reduces the dose of gonadotropin required to develop a mature follicle. Conclusion: Since the use of Letrozole and gonadotropins for ovarian hyperstimulation had similar results, Letrozole has the advantage of reduced cost and greater patient acceptance. It may be used alone or in conjunction with gonadotropins for poor responders to Clomiphene citrate.
Human ; Female ; OVARIAN HYPERSTIMULATION SYNDROME ; GONADOTROPINS ; LETROZOLE

OBJECTIVE: To evaluate the therapeutic effect and safety of letrozole in the treatment of adolescent boys with idiopathic short stature (ISS). METHODS: A retrospective analysis was performed for the clinical data of 16 adolescent boys with ISS who had a bone age of ≥14 years. Among these boys, 8 were initially treated with recombinant human growth hormone (rhGH), followed by rhGH combined with letrozole during a bone age of 14-15.5 years. The other 8 boys were initially treated with rhGH combined with letrozole since their bone age was ≥14 years at diagnosis. Of the 16 boys, 16 were treated for not less than 6 months, 12 were treated for not less than 1 year, and 5 were treated for not less than 1.5 years. The increase in bone age, predicted adult height (PAH), final adult height, sex hormones, and adverse reactions after treatment were analyzed. RESULTS: After 6 months, 1 year, and 1.5 years of treatment, median bone age was increased by 0 year, 0.5 year, and 0.5 year respectively, which was significantly lower than the increase in age (P<0.05). There was a significant increase in PAH after treatment (P<0.05). Seven boys reached final height, which was significantly higher than PAH before treatment (P<0.05). All the 16 boys had significant increases in luteinizing hormone, follicle-stimulating hormone, and testosterone levels after treatment (P<0.05), with a significant reduction in the estradiol level and a significant increase in the insulin level at 1 year of treatment (P<0.05). There was a significant increase in the insulin-like growth factor-1 level at 6 months and 1 year of treatment (P<0.05). There were no significant changes in blood glucose, blood lipids, uric acid, and the three indices for thyroid function as monitored during treatment (P>0.05). CONCLUSIONS In adolescent boys with ISS and a high bone age, rhGH combined with letrozole can safely and effectively delay the increase in bone age and improve PAH and final adult height, with little adverse effect.
Adolescent ; Body Height ; Dwarfism ; Growth Disorders ; Human Growth Hormone ; Humans ; Letrozole ; therapeutic use ; Male ; Retrospective Studies

OBJECTIVE: To evaluate the efficacy and safety of the third-generation aromatase inhibitor letrozole in the treatment of McCune-Albright syndrome (MAS) girls with peripheral precocious puberty. METHODS: Twenty-one MAS girls with peripheral precocious puberty treated in Pediatrics Department of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine from March 2012 to June 2017 were enrolled in the study. Patients presented with repeated vaginal bleeding, premature breast enlargement, café-au-lait spots or dysplasia of bone fibers, and low levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH); and the congenital adrenal hyperplasia, estrogen-producing tumors, and exogenous estrogen intake were excluded. Letrozole were administrated at a dose of 0.5-2 mg·m ·d for 6 to 12 months. The patients were observed for changes in breast staging, vaginal bleeding, sex hormone levels, liver function and bone age changes, and changes in uterine and ovarian volume. RESULTS: After treatment, bone age/chronological age (BA/CA)was decreased from 1.23±0.30 to 1.11±0.18 ( < 0.01); the predicted adult height (PAH) increased from (156.2±5.9)cm to (158.4±2.1)cm after treatment ( < 0.05); the vaginal bleeding was reduced and the estradiol level decreased, while the teststosterone level and the uterus showed no significant increase, and no adverse reactions such as ovarian torsion and abnormal liver function were observed. CONCLUSIONS Precocious puberty is one of the most common endocrine manifestations in MAS. Our findings suggest that letrozole may be an effective and safe therapy to precocious puberty in girls with McCune-Albright Syndrome.
Aromatase Inhibitors ; Child ; China ; Female ; Fibrous Dysplasia, Polyostotic ; Humans ; Letrozole ; Puberty, Precocious

To evaluate the efficacy and safety of aromatase inhibitor letrozole in treatment of male adolescents with idiopathic short stature (ISS). Seventy five boys with height less than 2 standard deviation (SD) below the mean who had entered puberty were enrolled in our study from 2004 to 2017, in the Pediatric Department of the First Affiliated Hospital, Sun Yat-Sen University. Among 75 patients, 28 in letrozole group received letrozole and spironolactone, 30 in gonadotrophin releasing hormone analogue (GnRHa) group received GnRHa injection and 17 had no intervention. Height velocity (HV), increment of bone age/chronological age (ΔBA/ΔCA), the final adult height (FAH) were compared among groups and the safety of letrozole treatment was evaluated. HV maintained faster during letrozole treatment when compared with other groups. HV during GnRHa treatment showed slightly decline in the first 6 months, but decreased remarkably after 6 months, and was significantly lower than that in letrozole group ( < 0.05). The maturation of BA slowed down in both letrozole and GnRHa groups. But the ΔBA/ΔCA in letrozole group during the first and the second year of treatment were significantly higher (0.67±0.09, 0.50±0.15, respectively) when compared with GnRHa group (0.59±0.16, 0.44±0.13, respectively) ( =2.78 and 2.20, all < 0.05). FAH in letrozole group and GnRHa group were (170±4) cm and (170±6)cm, there was no significant differences between the two groups ( >0.05), and both were higher than that in no intervention group (162±4 cm, < 0.01). After 6 months of letrozole treatment, testicular volumes and serum testerone levels increased; 39.2% (11/28) boys had clinical manifestations of hyperandrogenemia, and 82.1% (23/28) boys had decreased serum high-density lipoprotein (HDL) levels. Serum levels of HDL and testerone returned normal and the hyperandrogenemia disappeared after the cessation of letrozole treatment. No significant changes in serum triglyceride, serum low-density lipoprotein (LDL), fating serum levels of insulin and glucose, HOMA-IR were observed. No abnormal liver function, myalgia, scoliosis or aggravations of scoliosis was found. Long term letrozole therapy during puberty in boys with ISS can delay bone maturation without significant decrease of linear growth, and thus can improve the final adult height. No severe adverse reactions were found.
Adolescent ; Body Height ; Bone Development ; Child ; Gonadotropin-Releasing Hormone ; Growth Disorders ; Humans ; Letrozole ; therapeutic use ; Male

OBJECTIVE: To assess the efficacy of letrozole in treatment of children with congenital adrenal hyperplasia (CAH) due to steroid 21-hydroxylase deficiency (21-OHD). METHODS: Twenty eight children, including 19 boys and 9 girls aged 4-10y, with CAH due to 21-OHD were enrolled in the study. At the first six months of study, all children received conventional treatment with hydrocortisone or fludrocortisone, then letrozole was added to original regimen. The height velocity (HV), difference between bone age and chronological age (BA-CA), height standard diviation score based on bone age (HtSDS ), predicted adult height (PAH), Tanner phase, sex hormone, and possible adverse reaction were evaluated and compared between those before and after letrozole treatment. RESULTS: After 6 months of letrozole treatment, there was significant deceleration of HV, but it would recover soon. There was significant increase of HtSDS after 12 months of letrozole treatment ( < 0.05 or < 0.01), and significant changes in BA-CA after 18 months of letrozole treatment ( < 0.05). PAH of female children was significantly increased during letrozole treatment ( < 0.05), whereas PAH of male children was significantly increased 18 months after letrozole treatment ( < 0.05). Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were significantly increased, but did not meet the diagnostic criteria of central precocious puberty. Estradiol was significantly decreased ( < 0.01), but no changes in testosterone level was observed. During 24 months letrozole treatment, no hirsutism, severe acne, headache, bone pain, obesity, hypertension, rash and other adverse reactions were observed. CONCLUSIONS Letrozole can delay bone maturation and improve PAH, which can be used with conventional treatment for children with CAH due to 21-OHD, especially for those with high BA and low PAH.
Adrenal Hyperplasia, Congenital ; drug therapy ; Body Height ; Child ; Child, Preschool ; Female ; Humans ; Letrozole ; therapeutic use ; Male ; Puberty, Precocious

OBJECTIVE: To investigate the efficacy and safety of aromatase inhibitor letrozole in treatment of male children with disorders of sex development (DSD). METHODS: Clinical data of 12 male DSD children with a mean age of 14.6±2.5 years admitted to Peking Union Medical College Hospital from January 2014 to January 2016 were retrospectively analyzed. The patients were treated with letrozole (1.25-2.5 mg, once a day) for 3 months or longer, and followed up for 0.5-2.5 years. Clinical manifestation and laboratory test findings were documented, and the efficacy and safety were evaluated. RESULTS: After half-year treatment, the blood luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone levels of patients increased (all < 0.05), and estrogen levels decreased from baseline ( < 0.05). After 1 year of treatment, the blood testosterone level was significantly higher ( < 0.05); the LH and FSH levels tended to increase and the estrogen level tended to decrease, but there was no significant statistical difference ( >0.05). Semen was routinely detected in 8 patients, and sperms were detected in semen of 3 patients with hypospadias. There were no significant changes in biochemical results after treatment, and no significant adverse event was observed during the treatment. CONCLUSIONS Letrozole can effectively increase testosterone levels in patients with disorders of sex development and promote spermatogenesis, it has no significant adverse effects in short-term administration.
Adolescent ; Child ; Disorders of Sex Development ; drug therapy ; Follicle Stimulating Hormone ; Humans ; Letrozole ; therapeutic use ; Luteinizing Hormone ; Male ; Retrospective Studies ; Testosterone

Objective: To compare the effect of different endocrine therapy drugs on liver function in patients with early breast cancer. Methods: A retrospective cohort study was conducted to include 4 318 patients with early breast cancer who received adjuvant endocrine therapy in Department of Breast Surgery, Peking Union Medical College Hospital from January 1, 2013 to December 31, 2021. All the patients were female, aged (51.2±11.3) years (range: 20 to 87 years), including 1 182 patients in the anastrozole group, 592 patients in the letrozole group, 332 patients in the exemestane group, and 2 212 patients in the toremifene group. The mixed effect model was used to analyze and compare the liver function levels of patients at baseline, 6, 12, 18, 24, 36, 48, 60 months of medication, and 1 year after drug withdrawal among the three aromatase inhibitors (anastrozole, letrozole, exemestane) and toremifene. Results: ALT and AST of the 4 groups were significantly higher than the baseline level at 6 months (all P<0.01), and there were no significant differences in total bilirubin, direct bilirubin and AST levels among all groups one year after drug withdrawal (P: 0.538, 0.718, 0.061, respectively). There was no significant difference in the effect of all groups on AST levels (F=2.474, P=0.061), and in the effect of three aromatase inhibitors (anastrozole, letrozole, and exemestane) on ALT levels (anastrozole vs. letrozole, P=0.182; anastrozole vs. exemestane, P=0.535; letrozole vs. exemestane, P=0.862). Anastrozole and letrozole had significantly higher effects on ALT levels than toremifene (P<0.01, P=0.009). The proportion of abnormal liver function in each group increased significantly at 6 months compared with baseline, and then the proportion showed a decreasing trend over time. Conclusions: Three aromatase inhibitors (anastrozole, letrozole, and exemestane) and toremifene can significantly increase the level of ALT and AST in patients with breast cancer, and the levels can gradually recover to the baseline after 1 year of drug withdrawal. The effect of non-steroidal aromatase inhibitors (anastrozole, letrozole) on ALT levels is greater than toremifene.
Female ; Humans ; Anastrozole ; Aromatase Inhibitors/therapeutic use* ; Bilirubin ; Breast Neoplasms/drug therapy* ; Letrozole ; Liver ; Retrospective Studies ; Toremifene ; Young Adult ; Adult ; Middle Aged ; Aged ; Aged, 80 and over

OBJECTIVE: To evaluate the clinical effect of letrozole (LE) alone on the ovulation induction in endometrial preparation for frozen-thawed embryo transfer (FET). METHODS: Totally 253 FET cycles were analyzed by case control study from October 2010 to June 2011. We divided ovulation disorders or menstrual disorders divided into 2 groups: a LE group on ovulation induction cycle (n=85), and a hormone replacement therapy (HRT) cycle group (n=84). Meanwhile those who ovulated normally were included in a natural cycle group (n=84). Demographics and clinical parameters of reproductive correlation of all patients were observed among these groups. RESULTS: The average clinical pregnancy rate of the LE group was higher than that of HRT cycle group (54.1% vs 44.04%; P<0.05). The difference in the parameters such as patients' demographics and other clinical indexs had no statistical significance (P>0.05). The estradiol level on human chorionic gonadotrophin (HCG) administration day in the natural cycle group [(341.19±113.14) pg/mL] was higher than that of the LE group [(279.70±127.80) pg/mL] (P<0.05). There was no significant difference in the number of maturation follicles and endometrial thickness on the HCG administration day between the LE group and the natural cycle group (P>0.05). CONCLUSION Ovulation induction with LE alone for endometrial preparation is superior to HRT cycle in FET and has similar clinical process and outcome to those of the natural cycle. It can be applied in endometrial preparation for FET effectively for those with anovulation or menstrual disorder.
Case-Control Studies ; Cryopreservation ; Embryo Transfer ; Endometrium ; drug effects ; physiology ; Female ; Fertility Agents, Female ; therapeutic use ; Fertilization in Vitro ; Humans ; Letrozole ; Nitriles ; therapeutic use ; Ovulation Induction ; methods ; Triazoles ; therapeutic use

AIM: To evaluate the effect of Cocus nucifera L. flowers in reducing the major multiple symptoms of letrozole-induced polycystic ovarian disease (PCOD) in female rats. METHOD: Female, virgin Wistar rats were treated with letrozole (1 mg/kg body wt) to induce PCOD, and after 21 days of induction rats were administered orally with 100 and 200 mg·kg(-1) of Cocus nucifera flower aqueous extract, respectively. Estrus cycle and blood sugar were monitored once a week throughout the study. After scarification, various biochemical parameters, such as antioxidant status (superoxide dismutase (SOD) and glutathione reductase (GSH)) of the uterus homogenate, lipid profile (total cholesterol (TC), high density lipoprotein (HDL), low density lipoprotein (LDL), and triglycerides (TG)) of the serum were determined. Weights of the uterus and ovaries were separately monitored. The characteristics of changes in the ovary were evaluated by histopathological studies. RESULTS: GC-MS analysis of the aqueous extract showed the presence of volatile and pharmacologically active phytoconstituents. C. nucifera flower extract-treated groups showed estrus cyclicity and increased uterus weight which indicates the estrogenic effect. The improved blood sugar level, ideal lipid profile, good antioxidant status, and histopathology results revealed the recovery from poly cystic ovaries. CONCLUSION The results indicate that C. nucifera flower is a potential medicine for the treatment of PCOD and this study supports the traditional uses of C. nucifera flower.
Animals ; Antioxidants ; metabolism ; Blood Glucose ; metabolism ; Cocos ; chemistry ; Estrus ; drug effects ; Female ; Flowers ; chemistry ; Gas Chromatography-Mass Spectrometry ; Hypoglycemic Agents ; pharmacology ; therapeutic use ; Letrozole ; Lipids ; blood ; Nitriles ; Oils, Volatile ; analysis ; pharmacology ; therapeutic use ; Ovary ; drug effects ; pathology ; Phytoestrogens ; pharmacology ; therapeutic use ; Phytotherapy ; Plant Extracts ; chemistry ; pharmacology ; therapeutic use ; Polycystic Ovary Syndrome ; blood ; chemically induced ; drug therapy ; pathology ; Rats, Wistar ; Triazoles ; Uterus ; drug effects

OBJECTIVE: To investigate the therapeutic mechanism of letrozole, the third-generation aromatase inhibitor, on endometriotic lesions in a rat model and its effect on the apoptosis of ectopic endometrial cells. METHODS: Endometriosis was induced by autotransplanting pieces of uterus onto the peritoneum in rats. The rats with successful ectopic implants were divided into 2 groups: A letrozole group (n=15) and a control group (n=15). The volume, appearance, and histopathology of ectopic implant were determined before and after the treatment. Expression of P450arom, COX-2, bcl-2, and bax in the ectopic implant was detected by immunohistochemistry and RT-PCR in the 2 groups. RESULTS: The volume of ectopic implant in the letrozole group was significantly reduced compared with the control group (P<0.05). The protein and mRNA levels of P450arom and COX-2 in the ectopic implant were significantly decreased in the letrozole group compared with the control group (P<0.05). There was a positive correlation between the expression of P450arom and the expression of COX-2 (r=0.943, P<0.001; r=0.913, P<0.001). The protein and mRNA expression of bcl-2 was significantly decreased (P<0.05), and the bax protein and mRNA expression was significantly increased (P<0.05) in the ectopic implant with an increased bax/bcl-2 ratio in the letrozole group compared with the control group (P<0.05). CONCLUSION Letrozole can obviously reduce the size of ectopic implant through decreasing P450arom and COX-2 expression, suppressing the secretion of estrogen, inhibiting the proliferation, and inducing the apoptosis of ectopic implants.
Animals ; Apoptosis ; drug effects ; Aromatase ; metabolism ; Aromatase Inhibitors ; therapeutic use ; Cyclooxygenase 2 ; metabolism ; Endometriosis ; drug therapy ; pathology ; Endometrium ; metabolism ; pathology ; Female ; Letrozole ; Nitriles ; therapeutic use ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; Triazoles ; therapeutic use ; bcl-2-Associated X Protein ; metabolism