A Phase 2 Trial of the Effect of Antiandrogen Therapy on COVID-19 Outcome: No Evidence of Benefit, Supported by Epidemiology and In Vitro Data

Background

Men are more severely affected by COVID-19. Testosterone may influence SARS-CoV-2 infection and the immune response.

Objective

To clinically, epidemiologically, and experimentally evaluate the effect of antiandrogens on SARS-CoV-2 infection.

Designs, settings, and participants

A randomized phase 2 clinical trial (COVIDENZA) enrolled 42 hospitalized COVID-19 patients before safety evaluation. We also conducted a population-based retrospective study of 7894 SARS-CoV-2–positive prostate cancer patients and an experimental study using an air-liquid interface three-dimensional culture model of primary lung cells.

Intervention

In COVIDENZA, patients were randomized 2:1 to 5 d of enzalutamide or standard of care.

Outcome measurements

The primary outcomes in COVIDENZA were the time to mechanical ventilation or discharge from hospital. The population-based study investigated risk of hospitalization, intensive care, and death from COVID-19 after androgen inhibition.

Results and limitations

Enzalutamide-treated patients required longer hospitalization (hazard ratio [HR] for discharge from hospital 0.43, 95% confidence interval [CI] 0.20–0.93) and the trial was terminated early. In the epidemiological study, no preventive effects were observed. The frail population of patients treated with androgen deprivation therapy (ADT) in combination with abiraterone acetate or enzalutamide had a higher risk of dying from COVID-19 (HR 2.51, 95% CI 1.52–4.16). In vitro data showed no effect of enzalutamide on virus replication. The epidemiological study has limitations that include residual confounders.

Conclusions

The results do not support a therapeutic effect of enzalutamide or preventive effects of bicalutamide or ADT in COVID-19. Thus, these antiandrogens should not be used for hospitalized COVID-19 patients or as prevention for COVID-19. Further research on these therapeutics in this setting are not warranted.

Patient summary

We studied whether inhibition of testosterone could diminish COVID-19 symptoms. We found no evidence of an effect in a clinical study or in epidemiological or experimental investigations. We conclude that androgen inhibition should not be used for prevention or treatment of COVID-19.

High-grade tumours promote growth of other less-malignant tumours in the same prostate

Prostate cancer is a multifocal disease, but if and how individual prostate tumours influence each other is largely unknown. We therefore explored signs of direct or indirect tumour–tumour interactions in experimental models and patient samples. Low‐metastatic AT1 and high‐metastatic MatLyLu (MLL) Dunning rat prostate cancer cells were injected into separate lobes of the ventral prostate of immunocompetent rats. AT1 tumours growing in the same prostate as MLL tumours had increased tumour size and proliferation compared to AT1 tumours growing alone. In addition, the vasculature and macrophage density surrounding the AT1 tumours were increased by MLL tumour closeness. In patient prostatectomy samples, selected to contain an index tumour [tumour with the highest grade, International Society of Urological Pathology (ISUP) grade 1, 2, 3 or 4] and a low‐grade satellite tumour (ISUP grade 1), cell proliferation in low‐grade satellite tumours gradually increased with increasing histological grade of the index tumour. The density of blood vessels and CD68⁺ macrophages also increased around the low‐grade satellite tumour if a high‐grade index tumour was present. This suggests that high‐grade tumours, by changing the prostate microenvironment, may increase the aggressiveness of low‐grade lesions in the organ. Future studies are needed to explore the mechanisms behind tumour–tumour interactions and their clinical importance. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Characterization of prostate cancer bone metastases according to expression levels of steroidogenic enzymes and androgen receptor splice variants

Background

Intra-tumoral steroidogenesis and constitutive androgen receptor (AR) activity have been associated with castration-resistant prostate cancer (CRPC). This study aimed to examine if CRPC bone metastases expressed higher levels of steroid-converting enzymes than untreated bone metastases. Steroidogenic enzyme levels were also analyzed in relation to expression of constitutively active AR variants (AR-Vs) and to clinical and pathological variables.

Methodology/Principal Findings

Untreated, hormone-naïve (HN, n = 9) and CRPC bone metastases samples (n = 45) were obtained from 54 patients at metastasis surgery. Non-malignant and malignant prostate samples were acquired from 13 prostatectomy specimens. Transcript and protein levels were analyzed by real-time RT-PCR, immunohistochemistry and immunoblotting. No differences in steroidogenic enzyme levels were detected between CRPC and HN bone metastases. Significantly higher levels of SRD5A1, AKR1C2, AKR1C3, and HSD17B10 mRNA were however found in bone metastases than in non-malignant and/or malignant prostate tissue, while the CYP11A1, CYP17A1, HSD3B2, SRD5A2, and HSD17B6 mRNA levels in metastases were significantly lower. A sub-group of metastases expressed very high levels of AKR1C3, which was not due to gene amplification as examined by copy number variation assay. No association was found between AKR1C3 expression and nuclear AR staining, tumor cell proliferation or patient outcome after metastases surgery. With only one exception, high AR-V protein levels were found in bone metastases with low AKR1C3 levels, while metastases with high AKR1C3 levels primarily contained low AR-V levels, indicating distinct mechanisms behind castration-resistance in individual bone metastases.

Conclusions/Significance

Induced capacity of converting adrenal-gland derived steroids into more potent androgens was indicated in a sub-group of PC bone metastases. This was not associated with CRPC but merely with the advanced stage of metastasis. Sub-groups of bone metastases could be identified according to their expression levels of AKR1C3 and AR-Vs, which might be of relevance for patient response to 2^nd line androgen-deprivation therapy.

Abstract B68: The microenvironment decides how prostate tumors respond to castration treatment

Although androgen deprivation is the standard therapy for metastatic prostate cancer the mechanisms for the initial response and subsequent relapse are largely unknown. The stroma and vasculature are necessary for castration-induced involution of the normal prostate, and androgen-independent tumors respond to castration when surrounded by normal prostate tissue. This suggests that the microenvironment is highly important for the therapeutic effect of castration.

To further explore this, androgen-sensitive rat prostate tumor cells (Dunning G) were injected into the rat prostate and/or bone marrow (to simulate bone metastasis) and analyzed for response to castration. Tumors in the prostate responded well to castration with decreased tumor size, both in already established tumors and when tumor cells were injected in castrated animals. The size of bone metastases was, however, unaffected by castration. Both groups developed lung metastasis but castration tended to increase rather than decrease pulmonary tumor burden.

To further explore the mechanisms behind this we have established in vitro cell lines from bone metastasis of both castrated and control rats. In our ongoing experiments we are examining if these cells are responsive to castration if instead placed within the prostate environment or if the resistance to therapy has become stable. The response to castration is also further explored in lung metastasis. Our results suggest that the metastatic environment is highly important for the establishment of castration resistant prostate cancer and that the mechanisms behind this need to be further explored.

Citation Format: Sofia Halin Bergström, Stina Rudolfsson, Tove Dahl Scherdin, Anders Bergh. The microenvironment decides how prostate tumors respond to castration treatment [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B68.

Abstract B8: Hypoxia enhances androgen receptor activation in prostate cancer cells in response to low levels of androgens

Hypoxia is an important microenvironmental factor influencing tumor progression and treatment response. The understanding how hypoxia is regulating the behavior of cancer cells has to be further explored. The androgen receptor (AR) acts as a transcriptional factor controlling development or progression of prostate cancer (PC). Androgen ablation by castration is the common therapy for advanced PC but eventually most of the tumors relapse to a castration-resistant state and grow even in a low androgen environment. The remaining androgens that are still present after therapy may continue to promote AR activation. The most potent AR ligands, testosterone (T) and dihydrotestosterone (DHT), can be synthesized locally in the prostate from adrenal androgens and castration-resistant PC and bone metastases are shown to express increased levels of enzymes responsible for androgen metabolism (Akr1c3 one of several enzymes).

As castration results in a transient tissue hypoxia and solid tumors are generally hypoxic prior to treatment we investigated how hypoxia affects AR activation in androgen-sensitive prostate cancer CWR22Pc cells additional to steroidal treatment. Hypoxia upregulated the mRNA expression of the androgen-responsive NKX3.1 and prostate specific antigen (PSA), and facilitated translocation of AR to the nucleus in the presence of 0,01 nM DHT or 100 nM androstenediol. The androstenediol activation of AR simultaneously increased mRNA expression of the androgen converting enzyme Akr1c3 possibly resulting in metabolism of androstenediol to T or DHT.

This study shows that the AR can be hypersensitized to low levels of androgens in PC cells grown in a hypoxic milieu as in solid tumors and after castration. A consequence of exposure of PC cells to hypoxia is a possible increase in local biosynthesis of T and DHT from adrenal androgens or a direct ligand binding effect by adrenal androgen to activate the AR.

Citation Format: Stina Rudolfsson, Erik Toolanen, Anders Bergh. Hypoxia enhances androgen receptor activation in prostate cancer cells in response to low levels of androgens [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr B8.

Mast cells are novel independent prognostic markers in prostate cancer and represent a target for therapy

Mast cells affect growth in various human tumors, but their role in prostate cancer (PC) is unclear. Here, we identify mast cells as independent prognostic markers in PC using a large cohort of untreated PC patients with a long follow-up. By analyzing mast cells in different tissue compartments, our data indicate that intratumoral and peritumoral mast cells have anti- opposed to protumor properties. Intratumoral mast cells negatively regulate angiogenesis and tumor growth, whereas peritumoral mast cells stimulate the expansion of human prostate tumors. We also observed mast cell recruitment particularly to the peritumoral compartment in men during the formation of castrate-resistant prostate tumors. In our ortothopic rat model, mast cells accumulated in the peritumoral tissue where they enhanced angiogenesis and tumor growth. In line with this, prostate mast cells expressed high levels of the angiogenic factor FGF-2. Similar to the situation in men, mast cells infiltrated rat prostate tumors that relapsed after initially effective castration treatment, concurrent with a second wave of angiogenesis and an up-regulation of FGF-2. We conclude that mast cells are novel independent prognostic markers in PC and affect tumor progression in animals and patients. In addition, peritumoral mast cells provide FGF-2 to the tumor micro environment, which may contribute to their stimulating effect on angiogenesis.