The effect of low-dose GTx-758 on free testerone levels in men with metastatic castration resistant prostate cancer (mCRPC).

2014 ◽  
Vol 32 (4_suppl) ◽  
pp. 60-60 ◽  
Author(s):  
Evan Y. Yu ◽  
Robert H. Getzenberg ◽  
Jordan Smith ◽  
Michael L. Hancock ◽  
Ronald Tutrone ◽  
...  

60 Background: Luteinizing hormone-releasing hormone (LHRH) agents used for androgen deprivation therapy (ADT) were designed to lower total testosterone (T) levels to those achieved by orchiectomy for palliative care of advanced prostate cancer. This castration equivalent level was based upon the lower limits of quantitation (50ng/dL) of outdated assays. Contemporary assays reveal that actual total T levels in men after orchiectomy are significantly lower (<20ng/dL), with 30 to 40% of men on LHRH agonists not achieving that level. There is growing literature showing that lower T levels correlate with improved outcomes. Additionally, the biologically active form of T is unbound, free T. GTx-758 (Capesaris) is an oral estrogen receptor α agonist that increases sex hormone binding globulin (SHBG), lowers free T levels, and ameliorates estrogen deficiency side effects associated with ADT. Methods: In a phase II open label study (G200712), 38 men with metastatic castration resistant prostate cancer (mCRPC) were continued on their current form of ADT along with a low dose of GTx-758, 125 mg, for at least 90 days. Exclusion criteria included men at increased risk for venous thrombolic events (VTE). Results: The initial 14 patients in this trial completed 90 days on study and are evaluable for select trial endpoints. All treated men had a greater than or equal to a 150% increase in SHBG levels. Eleven of the 14 men began the study with suboptimal castration (free T >0.7 pg/ml) and 91% (10 out of 11) of these men became optimally castrated by day 90. Four out of 14 patients had a more than 45% decrease in prostate-specific antigen. Stable or improved hot flashes and bone turnover markers were observed in 71% and 73% of treated men, respectively. While some patients experienced adverse events, none were vascular related and there were no serious adverse events or VTEs. Conclusions: The majority of patients on an LHRH agonist enrolled in this phase II study had suboptimal levels of free T that were further lowered by GTx-758 administration. GTx-758 treatment resulted in stabilization and/or improvement in reported hot flashes and bone turnover, two major side effects of ADT. While the phase II clinical trial is ongoing, and full results are forthcoming, these preliminary findings show that 125 mg of GTx-758 has clinical effectiveness and is well tolerated. Exploration of 250 mg a day is planned. Clinical trial information: NCT01615120.

2020 ◽  
pp. JCO.20.01576
Author(s):  
Simon J. Crabb ◽  
Gareth Griffiths ◽  
Ellice Marwood ◽  
Denise Dunkley ◽  
Nichola Downs ◽  
...  

PURPOSE Capivasertib is a pan-AKT inhibitor. Preclinical data indicate activity in metastatic castration-resistant prostate cancer (mCRPC) and synergism with docetaxel. PATIENTS AND METHODS ProCAID was a placebo controlled randomized phase II trial in mCRPC. Patients received up to ten 21-day cycles of docetaxel (75 mg/m2 intravenous, day 1) and prednisolone (5 mg twice daily, oral, day 1-21) and were randomly assigned (1:1) to oral capivasertib (320 mg twice daily, 4 days on/3 days off, from day 2 each cycle), or placebo, until disease progression. Treatment allocation used minimization factors: bone metastases; visceral metastases; investigational site; and prior abiraterone or enzalutamide. The primary objective, by intention to treat, determined if the addition of capivasertib prolonged a composite progression-free survival (cPFS) end point that included prostate-specific antigen progression events. cPFS and overall survival (OS) were also assessed by composite biomarker subgroup for PI3K/AKT/PTEN pathway activation status. RESULTS One hundred and fifty patients were enrolled. Median cPFS was 7.03 (95% CI, 6.28 to 8.25) and 6.70 months (95% CI, 5.52 to 7.36) with capivasertib and placebo respectively (hazard ratio [HR], 0.92; 80% CI, 0.73 to 1.16; one-sided P = .32). Median OS was 31.15 (95% CI, 20.07 to not reached) and 20.27 months (95% CI, 17.51 to 24.18), respectively (HR, 0.54; 95% CI, 0.34 to 0.88; two-sided P = .01). cPFS and OS results were consistent irrespective of PI3K/AKT/PTEN pathway activation status. Grade III-IV adverse events were equivalent between arms (62.2%). The most common adverse events of any grade deemed related to capivasertib were diarrhea, fatigue, nausea, and rash. CONCLUSION The addition of capivasertib to chemotherapy did not extend cPFS in mCRPC irrespective of PI3K/AKT/PTEN pathway activation status. The observed OS result (a secondary end point) will require prospective validation in future studies to address potential for bias.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e17571-e17571
Author(s):  
Kanta Makphanchareonkit ◽  
Thitiya Sirisinha Dejthevaporn ◽  
Dittapol Muntham ◽  
Phichai Chansriwong

e17571 Background: Abiraterone acetate and prednisolone (AAP) + ADT has been approved for treatment metastatic castration-resistant prostate cancer (CRPC) in the standard dose 1,000 mg with fasting state. Data in Ramathibodi hospital showed patients who had treated with standard dose of Abiraterone acetate (AA); had PSA response 47.83%. Previous studies showed using low dose AA of 250 mg with food had the non-inferiority results in efficacy. AA was not be reimbursed in Thailand, so the ability to use a highly effective drug at a quarter of the dose, could help in patient accessibility to cancer treatments. We sought to test the hypothesis that low-dose AA with food would have the comparable activity in Thai CRPC patients in both of the pre-Docetaxel and post Docetaxel treatment groups, and exploring the quality of life (QOL) of these patients. Methods: An observational cohort enrolled newly diagnosed metastasis CRPC at Ramathibodi hospital from 1st Jan 2019 to 31st Dec 2019. Patients were assigned to AA (250mg) with actual daily life meal. We collected the data of serum PSA and the adverse events every 4 weeks for 4 months. The QOL data was collected with the EuroQoL (EQ-5D) questionnaire which were done at baseline and every 4 weeks. The primary end point was PSA response that defined as PSA decreased ≥ 50% from PSA level at baseline. The secondary endpoint were the depth of PSA change, QOL and adverse events by using Fisher's exact test and T-test. Results: 21 patients were enrolled. At 12 weeks, there were 11 patients (52.38%) achieved 50% PSA response and 6 patients (28.57%) achieved 90% PSA response. The adverse events occurred 23.8%, and mostly were mild grade. The adverse events were comparable with the historical data in standard dose of AA. Low dose AA has significantly shown the improvement in quality of life from baseline (p < 0.001), and especially the significant improvement in pre-Docetaxel subgroup. Conclusions: Low-dose AA with food has good efficacy in PSA response, adverse events and QOL. Moreover, low dose AA shows more efficacy especially in pre-Docetaxel mCRPC patients. Low dose AA may be helping in reducing cost of cancer care, enabling in delivering affordable cancer care and increasing value of treatment.


2016 ◽  
Vol 34 (2_suppl) ◽  
pp. 185-185
Author(s):  
Evan Y. Yu ◽  
Michael L. Hancock ◽  
Tamas Babicz ◽  
Ronald F. Tutrone ◽  
Christopher Ng ◽  
...  

185 Background: Recently approved agents that target the androgen receptor pathway emphasize the importance of the persistent activity of the androgen receptor pathway in castration-resistant prostate cancer (CRPC). This raises the possibility that agents with distinct mechanisms of action may add value. GTx-758 is a selective ERα agonist that can increase SHBG and therefore reduce biologically active testosterone (T) levels. Reported here are the results, including the final primary endpoint analysis, from the 250 mg daily GTx-758 cohort of a phase II clinical trial in men on LHRH agonists that developed CRPC. Methods: This phase II open label trial (G200712, NCT01615120) treated men with high risk nmCRPC or mCRPC with T levels < 50 ng/dL who continued to receive their current form of ADT along with either 125 mg or 250 mg of GTx-758 daily, for at least 90 days. The primary endpoint was the proportion of men with a PSA decline ≥ 50% by day 90, while secondary endpoints included serum total and free T, sex hormone binding globulin (SHBG), bone turnover markers and hot flashes. Results: The 250 mg cohort (n = 39) has completed the time period for assessment of the primary endpoint. Ten of the 39 (26%) subjects exhibited a ≥ 50% decrease in PSA by Day 90, with 11/39 (28%) by Day 120, while 18/39 (46%) had PSA declines of ≥ 30%. Median SHBG levels increased 301% of baseline, confirming the principal mechanism of drug action. While on study, median free T decreases of 44% were observed across all subjects and 20/26 (77%) of the subjects with baseline serum free T levels > 0.7 pg/ml fell below this level. Therefore, 250 mg GTx-758 decreased free testosterone levels in an additive fashion to their existing LHRH therapy. The bone turnover biomarker, C-telopeptide, decreased in 79% of the subjects. 250 mg of GTx-758 has been generally well tolerated with two reported possibly drug related SAEs (VTE and MI). Conclusions: In this phase II trial, 250 mg daily GTx-758 has activity, likely mediated by lowering free T levels in patients with CRPC on LHRH therapy, and may provide amelioration of estrogen deficiency side effects associated with ADT. Clinical trial information: NCT01615120.


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