Androgen-deprivation therapy plus chemotherapy in metastatic hormone-sensitive prostate cancer. A systematic review and meta-analysis of randomized clinical trials

Effect of chemotherapy in metastatic prostate cancer according to race/ethnicity groups

BACKGROUND

No North-American study tested the survival benefit of chemotherapy in de novo metastatic prostate cancer according to race/ethnicity. We addressed this void.

METHODS

We identified de novo metastatic prostate cancer patients within the Surveillance, Epidemiology, and End Results database (2014-2015). Separate and specific Kaplan-Meier plots and Cox regression models tested for overall survival differences between chemotherapy-exposed versus chemotherapy-naïve patients in four race/ethnicity groups: Caucasian versus African-American versus Hispanic/Latino vs Asian. Race/ethnicity specific propensity score matching was applied. Here, additional landmark analysis was performed.

RESULTS

Of 4232 de novo metastatic prostate cancer patients, 2690 (63.3%) were Caucasian versus 783 (18.5%) African-American versus 504 (11.8%) Hispanic/Latino versus 257 (6.1%) Asian. Chemotherapy rates were: 21.3% versus 20.8% versus 21.0% versus 20.2% for Caucasians versus African-Americans versus Hispanic/Latinos versus Asians, respectively. At 30 months of follow-up, overall survival rates between chemotherapy-exposed versus chemotherapy-naïve patients were 61.5 versus 53.2% (multivariable hazard ratio [mHR]: 0.76, 95 confidence interval [CI]: 0.63-0.92, p = 0.004) in Caucasians, 55.2 versus 51.6% (mHR: 0.76, 95 CI: 0.54-1.07, p = 0.11) in African-Americans, 62.8 versus 57.0% (mHR: 1.11, 95 CI: 0.73-1.71, p = 0.61) in Hispanic/Latinos and 77.7 versus 65.0% (mHR: 0.31, 95 CI: 0.11-0.89, p = 0.03) in Asians. Virtually the same findings were recorded after propensity score matching within each race/ethnicity group.

CONCLUSIONS

Caucasian and Asian de novo metastatic prostate cancer patients exhibit the greatest overall survival benefit from chemotherapy exposure. Conversely, no overall survival benefit from chemotherapy exposure could be identified in either African-Americans or Hispanic/Latinos. Further studies are clearly needed to address these race/ethnicity specific disparities.

Co-delivery of the autophagy inhibitor si-Beclin1 and the doxorubicin nano-delivery system for advanced prostate cancer treatment

Resistance to apoptosis is a key mechanism underlying how cancer cells evade tumor therapy. Autophagy can prevent anticancer drug-induced apoptosis and promote tumor resistance. The purpose of this study was to improve the sensitivity and efficacy of chemotherapeutic drugs through the inhibition of autophagy. Hydrophobic doxorubicin-hydrazone-caproyl-maleimide (DOX-EMCH) and autophagy-inhibiting si-Beclin1 were simultaneously delivered via the amphiphilic peptide micelle system (Co-PMs) using poly(L-arginine)-poly(L-histidine)-DOX-EMCH as the copolymer building unit. The constructed micelle system promoted the escape of si-Beclin1 from endosomes and the release of DOX into the nucleus. The Co-PMs exhibited 2.7-fold higher cytotoxicity and proapoptotic ability in PC3 cells than DOX treatment alone, demonstrating that si-Beclin1 could inhibit the autophagic activity of prostate cancer (PCa) cells by targeting the type III PI3K pathway and enhance the sensitivity of the cells to the chemotherapeutic drug DOX. In addition, the peptide micelles successfully passively targeted DOX and si-Beclin1 to the tumor tissue. Compared with DOX or si-Beclin1 treatment alone, the Co-PMs showed a 3.4-fold greater tumor inhibitory potential in vivo, indicative of a significant antiproliferative effect. Our results suggested that the Co-PMs developed in this study have the potential to combine autophagy inhibition and chemotherapy in cancer treatment, especially for PCa.

Impact of therapy on cancer metabolism in high-risk localized prostate cancer treated with neoadjuvant docetaxel and androgen deprivation therapy

BACKGROUND

The application of neoadjuvant docetaxel and androgen deprivation therapy before radical prostatectomy has been clinically recognized as beneficial for the overall and progression-free survival of patients with advanced prostate cancer. However, the mechanism underlying its clinical efficacy has not yet been reported.

METHODS

We conducted a randomized comparative study on about 100 patients with high-risk localized prostate cancer. Through nontarget metabolomics and tissue microarray immunohistochemistry, we investigated the difference in the endogenous metabolism of tumors in patients with prostate cancer who received or did not receive the neoadjuvant therapy.

RESULTS

Many endogenous metabolic pathways, especially nucleotide synthesis, glutathione metabolism, citric acid cycle, and lipid synthesis, in prostate cancer tissue were altered after the neoadjuvant treatment, and the levels of nearly 90% of the differentially regulated metabolites were significantly decreased. Moreover, the levels of key enzymes in the cellular energy pathways were downregulated in tumor tissues and upregulated in adjacent tissues after the treatment. The positive and negative effects of the neoadjuvant therapy on normal and tumor cells in the prostate, respectively, resulted in the activation of the former and inhibition of the latter, which helped in reducing the number of tumors and weakened their aggressiveness.

CONCLUSIONS

From the perspective of endogenous metabolism in tumors, we have confirmed that neoadjuvant therapy can significantly downregulate important pathways for biosynthesis and energy metabolism in prostate cancer tissue, and thereby, inhibit tumor growth and metastasis.

New Opportunities for Targeting the Androgen Receptor in Prostate Cancer

Recent genomic analyses of metastatic prostate cancer have provided important insight into adaptive changes in androgen receptor (AR) signaling that underpin resistance to androgen deprivation therapies. Novel strategies are required to circumvent these AR-mediated resistance mechanisms and thereby improve prostate cancer survival. In this review, we present a summary of AR structure and function and discuss mechanisms of AR-mediated therapy resistance that represent important areas of focus for the development of new therapies.

Treatment with docetaxel in combination with Aneustat leads to potent inhibition of metastasis in a patient-derived xenograft model of advanced prostate cancer

Background:

Docetaxel used for first-line treatment of advanced prostate cancer (PCa) is only marginally effective. We previously showed, using the LTL-313H subrenal capsule patient-derived metastatic PCa xenograft model, that docetaxel combined with Aneustat (OMN54), a multivalent plant-derived therapeutic, led to marked synergistic tumour growth inhibition. Here, we investigated the effect of docetaxel+Aneustat on metastasis.

Methods:

C4-2 cells were incubated with docetaxel, Aneustat and docetaxel+Aneustat to assess effects on cell migration. The LTL-313H model, similarly treated, was analysed for effects on lung micro-metastasis and kidney invasion. The LTL-313H gene expression profile was compared with profiles of PCa patients (obtained from Oncomine) and subjected to IPA to determine involvement of cancer driver genes.

Results:

Docetaxel+Aneustat markedly inhibited C4-2 cell migration and LTL-313H lung micro-metastasis/kidney invasion. Oncomine analysis indicated that treatment with docetaxel+Aneustat was associated with improved patient outcome. The drug combination markedly downregulated expression of cancer driver genes such as FOXM1 (and FOXM1-target genes). FOXM1 overexpression reduced the anti-metastatic activity of docetaxel+Aneustat.

Conclusions:

Docetaxel+Aneustat can inhibit PCa tissue invasion and metastasis. This activity appears to be based on reduced expression of cancer driver genes such as FOXM1. Use of docetaxel+Aneustat may provide a new, more effective regimen for therapy of metastatic PCa.

[Patients with metastatic prostate cancer : Recommendations for primary hormonal or chemohormonal therapy]

The standard treatment for patients with metastatic, hormone-sensitive prostate cancer (mCSPC) has so far consisted of medical or surgical castration. However, two published clinical trials using docetaxel in combination with castration (CHAARTED and STAMPEDE) recently provided evidence for a substantial improvement in overall survival. The survival benefit was 14 and 22 months, respectively, in the two trials. In addition, the CHAARTED trial showed that patients with high-volume disease may benefit most from chemohormonal treatment. According to the current available evidence, the new standard of treatment for patients therefore consists of castration in combination with docetaxel-based chemotherapy, which should be offered to all patients who are fit to receive chemotherapy. With the results of the LATITUDE and a further study-arm of the STAMPEDE trial, the combination of androgen-deprivation therapy (ADT) plus abiraterone/prednisone has recently become an alternative treatment to chemohormonal treatment. This combination leads to an identical survival benefit compared to chemohormonal treatment and is recommended by expert panels. Based on the current evidence, it is not possible to decide which patient may benefit from chemohormonal treatment and who will benefit from the combination of ADT plus abiraterone/prednisone.

[Drug therapy of hormone-sensitive metastatic prostate cancer : Consensus paper of the AKO/AUO]

BACKGROUND

The standard treatment of patients with metastatic, hormone-sensitive prostate cancer (mCSPC) currently consists of medical or surgical castration. The addition of a cytotoxic chemotherapy was unable to provide a survival benefit over castration alone in several clinical trials using different chemotherapy regimens.

RESULTS

Even a preliminary clinical trial using a docetaxel-based chemohormonal combination did not show a survival benefit. In contrast, two more recently published clinical trials (CHAARTED and STAMPEDE) using docetaxel in combination with castration provided evidence for a substantial improvement in overall survival. The survival benefit was 14 and 22 months in the two trials. In addition, the CHAARTED trial showed that patients with high volume disease may benefit most from chemohormonal treatment.

CONCLUSION

According to the current available evidence, the new standard of treatment for patients therefore consists of castration in combination with docetaxel-based chemotherapy and should be offered to all patients who are fit to receive chemotherapy.