Co-Producing Narratives and Indicators as Catalysts for Adaptive Governance of a Common-Pool Resource within a Protected Area

The theory and practice of adaptive management and adaptive governance have been widely studied in the complex social contexts that mediate how humans interact with ecosystems. Adaptive governance is thought to enable adaptive management in such contexts. In this study, we examine four often-used principles of adaptive governance (polycentric institutions, collaboration, social learning and complexity thinking) to develop a framework for reflecting on adaptive governance of a social-ecological system-the Knysna Estuary in South Africa. This estuary is a priority for biodiversity conservation, as well as a common-pool resource central to livelihoods. We used the framework to structure dialogue on the extent to which the four principles of adaptive governance were being applied in the management of the Knysna Estuary. The dialogue included diverse stakeholders, from those who have the power to influence adaptive management to those most dependent on the resource for their livelihoods. Based on a combination of theory and current reality we then identified eight indicators that could be used to guide a transition towards improved adaptive governance of the estuary. These indicators were assessed and supported by most stakeholders. The main contributions of our research are (a) a process for combining theory and stakeholder dialogue to reflect on adaptive governance of a social-ecological system; (b) a set of indicators or conditions that emerged from our participatory process that can be used for reflexive monitoring and adaptation of adaptive governance of Knysna Estuary; and (c) a real-world example of seeking complementary links between adaptive governance and adaptive management to promote effective management of complex social-ecological systems.

Antitumor activity of MDV3100 in pre- and post-docetaxel advanced prostate cancer: Long-term follow-up of a phase I/II study

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Background: MDV3100 is a novel androgen receptor (AR) antagonist selected for potent AR activity and devoid of partial agonist effects. A preliminary report of the phase I/II study described anti-tumor activity and adverse events (Scher HI et al. Lancet. 2010;375:1437). This abstract provides long-term follow-up on time to PSA and radiographic progression in this trial.

Methods: Patients (pts) with progressive castration resistant prostate cancer (CRPC) were enrolled in sequential cohorts of 3-6 pts at MDV3100 doses of 30, 60, 150, 240, 360, 480 and 600 mg/day. Once the tolerability of a dose was established, enrollment was expanded at doses ≥60 mg/day to include approximately 12 chemotherapy naïve (naïve) pts and 12 pts previously treated with docetaxel (post-chemo) per cohort.

Results: 140 pts were enrolled of which 18 (13%) pts continue on active treatment (16 naive and 2 post-chemo). The median time on treatment is 51 weeks for naïve and 17 weeks for post-chemo groups. Median time on treatment for the 18 patients still on study is 131 weeks. The median time to PSA progression, defined per-protocol as a ≥25% increase in PSA from baseline, was not met for naïve and was 33 weeks for post-chemo groups. Median time to PSA progression by Prostate Cancer Clinical Trials Working Group 2 criteria was 41 weeks for naïve and 20 weeks for post-chemo groups. Median time to radiographic progression was 56 weeks for naive and 24 weeks for post-chemo groups. Circulating tumor cell counts available for 128 of 140 pts showed 91% (70/77) with favorable pre-treatment counts (<5 cells/7.5 mL blood) remaining favorable post-treatment, while 49% (25/51) converted from unfavorable pre-treatment to favorable post-treatment.

Conclusions: MDV3100 demonstrates durable anti-tumor activity in pts with CRPC both before and after chemotherapy. Based on these promising results MDV3100 is currently being evaluated in two global phase III studies in pts with metastatic CRPC, the AFFIRM study in pts previously treated with docetaxel and the PREVAIL study in chemotherapy-naïve pts who have progressed on androgen deprivation therapy.

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Phase II multicenter study of abiraterone acetate (AA) plus prednisone therapy in docetaxel-treated castration-resistant prostate cancer (CRPC) patients (pts): Impact of prior ketoconazole (keto)

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Background: AA is a potent blocker of CYP17, required for synthesis of testosterone in the testes, adrenals, and prostate tissue. Study objectives included confirming AA antitumor activity and safety in multicenter setting, describing changes in ECOG PS, and comparing keto-naïve pts to keto-exposed pts. Methods: The 58 pts had progressive, metastatic CRPC and had failed hormonal therapy and up to two cytotoxic regimens, including docetaxel. AA (1,000 mg QD) and prednisone (5mg BID) were administered daily, the registration trial regimen. 56/58 pts had available data. Results: Baseline demographics: median age - 69.0 (44–86) yrs; median PSA - 151.00 (10.0–3846.0) ng/mL; ECOG 0 (n = 23), 1 (n = 30), 2 (n = 2), missing (n = 1); median prior hormonal therapies were 4 and chemo 1; 24 pts had prior keto, 32 pts were keto-naïve and 2 pts had no data on keto exposure. 45% pts had total maximal PSA decline ≥50%. Total maximal PSA decline (≥30%, ≥50% and ≥90%) in prior keto vs. keto-naïve pts was observed respectively, in: 10 (42%) vs. 20 (63%) pts; 8 (33%) vs. 17 (53%); 1 (4%) vs. 10 (31%). From 32 pts with ECOG 1 or 2, 16 pts (50%, 95% CI 32–68) improved (PS 1 to 0 in 14 pts, PS 2 to 1 in 1 pt; PS 2 to 0 in 1 pt); 39 pts (64% of total 58 pts) maintained PS. Median time to PSA progression was 169 days (95% CI 82–200): keto-naïve-198 days, prior keto-99 days. The majority of AA-related adverse events (AEs) were grade 1–2. No AA-related grade 4 AE was noted. Conclusions: Abiraterone acetate was well-tolerated and produced anti-tumor activity in heavily pretreated pts, as evidenced by PSA declines and improved PS. Incidence of mineralocorticoid-related AEs (HTN or hypokalemia) was reduced with the addition of low-dose prednisone. The keto-naïve post-docetaxel CRPC population was selected for the ongoing phase III pivotal study to confirm these results.

[Table: see text]

Phase II multicenter study of chemotherapy (chemo)-naive castration-resistant prostate cancer (CRPC) not exposed to ketoconazole (keto), treated with abiraterone acetate (AA) plus prednisone

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Background: AA is a potent inhibitor of the enzyme CYP17, a major contributor to androgen biosynthesis. Keto is also known to inhibit this enzyme but AA is many-fold stronger in its action. 33 pts with progressive metastatic disease, normal organ function, ECOG performance status (PS) 0–1, and no prior chemo were enrolled. Pts with prior keto treatment were excluded. AA (1000 mg qd) plus prednisone (5mg bid) were administered orally in 28 day cycles. Methods: Results: At baseline median age was 71.0 (range 52–85) yrs and median PSA was 24.7 (range 7.1–1110.0) ng/mL;19/26 pts (73%) had an ECOG PS of 0 and 7/26 (27%) had PS of 1; the median number of prior hormonal therapies was 2; all pts were on LHRHa and 73% of pts had received anti-androgen, all of whom had undergone prior anti-androgen withdrawal. Pts were evaluated at each cycle for PSA response according to PSAWG criteria. 27 pts have available data for PSA response. Total maximal PSA declines of ≥30%, ≥50%, ≥90% were observed in 89% (24/27), 85% (23/27) and 41% (11/27) pts, respectively. Week 12 PSA declines displayed a similar and sustained trend: ≥30%, ≥50% and ≥90% PSA decline in 82%, 78%, and 26% of pts. Post-treatment ECOG PS score was 0 in 24 (92%) pts: 19% experienced improvement in PS (PS 1 to 0 in 5 pts) and 19/19 pts maintained a PS of 0; Median time to PSA progression has not been reached. Majority of adverse events were grades 1–2. Incidence of hypokalemia - 12%; HTN - 6%; edema - 15%. One pt experienced a grade 3 drug-related HTN. Conclusions: Abiraterone acetate plus prednisone has significant anti-cancer activity in patients with metastatic CRPC not previously treated with ketoconazole or chemotherapy, as demonstrated by declines in PSA and improvement in performance status, and is well-tolerated.

[Table: see text]

Antitumor activity of MDV3100 in a phase I/II study of castration-resistant prostate cancer (CRPC)

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Background: MDV3100 is a novel AR antagonist selected for activity in prostate cancer model systems with overexpressed AR. In contrast to bicalutamide, MDV3100 blocks nuclear translocation of AR and DNA binding, and has no known agonist activity when AR is overexpressed. Antitumor activity of MDV3100 in a Phase I/II trial was assessed by prostate-specific antigen (PSA), soft tissue and osseous disease, circulating tumor cells (CTC), and time on treatment. Methods: Patients (pts) with progressive CRPC were enrolled in sequential cohorts of 3–6 pts at 30, 60, 150, 240, 360, 480 and 600 mg/day. Once the safety of a dose was established, enrollment was expanded at doses >60 mg/day to include 12 chemotherapy-naïve (naïve) and 12 post-chemotherapy pts per cohort. Results: 140 pts were enrolled. 114 pts at 30–360 mg/day have been followed for >12 weeks. PSA declines (>50% from baseline) were observed at week 12 in 57% (37/65) of naïve and 45% (22/49) of post-chemo pts. Data suggest a dose-response trend particularly in post-chemo pts where PSA responses were 32% at 60 and 150 mg/day and 58% at 240 and 360 mg/day. At 12 weeks, radiographic control (no progression) was observed in 35/47 pts (74%) with evaluable soft tissue lesions per PCWG2 guidelines and 50/81 pts (62%) with bone lesions. CTC counts on 101 of 114 pts showed 92% (56/61) with favorable (<5) counts pretreatment maintained favorable posttreatment counts, while 53% (21/40) converted from unfavorable to favorable posttreatment. For post-chemo pts, favorable retention was 100% (17/17) and unfavorable to favorable conversion at 240 and 360 mg/day was 60% (6/10). 87 pts at 30–240 mg/day have been followed for >24 weeks; 35 (40%) received treatment >24 weeks. At 600 mg/day, 2 of 3 pts had dose limiting toxicity (rash; seizure). Dose reductions due to fatigue were noted at 480 and 360 mg/day. Conclusions: MDV3100 is a promising candidate for the treatment of prostate cancer assessed by PSA, imaging, CTC, and time on treatment. The data suggest a dose-response trend and consistency across endpoints. Pt follow-up is continuing. The efficacy comparable to that at higher doses and the better adverse event profile, led to the selection of 240 mg/day as the recommended dose for a phase III trial in CRPC.

[Table: see text]

Response to docetaxel (D)/carboplatin (C)-based chemotherapy as first- and second-line therapy in patients with metastatic hormone-refractory prostate cancer (HRPC)

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Background: Effective treatment options for HRPC patients are limited. We evaluated efficacy of D/C-based chemotherapy as first- and second-line chemotherapy. Methods: We retrospectively identified all patients with HRPC treated with D/C-based chemotherapy at DFCI. Regimens either included estramustine (EDC) or not (DC). Patients treated with EDC received D 20–70 mg/m2 q1–4 weeks, E 140mg TID and C AUC 4–6 q 3–4 weeks. Patients treated with DC received D 50–70 mg/m2 and C AUC 4–5 q 3–4 weeks. PSA declines and measurable response were assessed per PSA Working Group and RECIST criteria, respectively. Time to event from chemotherapy initiation based on Kaplan-Meier method. Results: 58 patients were included: 27 patients received EDC, 35 received DC, and 4 received both regimens. Median age and PSA at initiation of chemotherapy was 58 years (range: 42–78) and 132.6 ng/ml (range: 0.3–5352.5), respectively. Table shows median duration of PSA response and TTP, by regimen. Most patients received EDC as first-line chemotherapy (89%). PSA declines ≥ 50% were observed in 24 patients (88.9%, 95% C.I. 71–98) and PSA declined in all 27 patients by a median of 81.3 % (range 33–100). Of 8 patients with measurable disease (MD), 2 had confirmed PR and 4 had SD. Median survival was 17.5 months (95% C.I. 12.0–24.5). 34 out of 35 patients received DC as ≥ 2nd line chemotherapy. PSA declines ≥ 50% were seen in 7 DC patients (20%, 95%C.I. 8–37) and PSA declined in 24 patients with a median of 37.7 % (range 2.0–100). Of 15 patients with MD at baseline, one had confirmed CR, one had PR, and 6 patients had SD. Median survival was 14.8 months (95% C.I. 9–19). The most common reversible grade 4 toxicity with either regimen was neutropenia (6.9%). Conclusions: D/C-based chemotherapy is well tolerated and active in HRPC. As first line chemotherapy, EDC demonstrated PSA declines ≥50% in 88.9% of patients. DC was active as ≥ 2nd-line chemotherapy with PSA declines ≥50% seen in 20%.

[Table: see text]

No significant financial relationships to disclose.

Chemo-hormonal therapy for biochemical progression of prostate cancer

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Background: Androgen deprivation therapy (ADT) is effective for relapsed prostate cancer, but is rarely curative. The purpose of this trial was to determine the feasibility, toxicity and PSA response of chemotherapy and ADT for men with PSA relapse. Methods: Eligible men had a rising PSA and no metastases after prostatectomy and/or radiation for localized disease. Treatment consisted of four cycles of docetaxel (70 mg/M2) every 21 days and estramustine 280 mg three times daily on days 1–5. After chemotherapy, goserelin acetate and bicalutamide 50 mg daily were prescribed for 15 months. Results: Sixty-two patients were enrolled at four institutions: median age 65 (range 49–78), median PSA 3.01 ng/mL (range 0.08–47.04), 24% Gleason 8–10. A complete PSA response (CR) was defined as PSA at or below assay-specific lower limit (0.01–0.2 ng/mL). The proportion of patients with CR after chemotherapy, after ADT and at one year off ADT was 53%, 63% and 36%. Testosterone was > 100 ng/dL (median 250 ng/dL) one year off ADT in 97%. Patients with a PSA < 3.0 ng/mL had a significantly longer time to progression (p-value 0.0002). At the time of last follow-up 24/56 (43%) who are at least one year off ADT have not progressed. Median TTP is 34 months from treatment initiation (maximum 74 months free from progression). Toxicity was manageable with no toxic deaths: there were 4 thromboses on chemotherapy and 38% of cycles were associated with grade III/IV neutropenia with 5 cases of documented infections. Conclusion: Chemotherapy prior to hormone therapy was feasible for early prostate cancer relapse. Forty-three percent of men who are at least one year off ADT with recovered testosterone have not progressed. This approach is being tested in a randomized trial with investigation of predictors of response.

No significant financial relationships to disclose.

Mifepristone (RU-486) in androgen independent prostate cancer

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Background: The androgen receptor (AR) plays a critical role in the development and progression of prostate cancer, and available antiandrogens do not turn off AR transcription completely. Mifepristone (RU-486) is a potent inhibitor of AR and acts by both competing with dihydrotestosterone (DHT) and binding with the AR co-repressor nuclear receptor co-repressor (NCoR), converting AR from a transcriptional activator to a transcriptional repressor. Methods: 22 patients with AIPC, PSA ≥5 ng/mL, and documented bone metastases were treated with mifepristone 200 mg PO QD until disease progression. Correlative studies include measurement of testosterone, cortisol, androstenedione, DHT, DHEA (dehydroepiandrosterone), and DHEA sulfate levels at baseline and during therapy. Results: Patients were treated a median of 84 days (range 10–182 d). Median PSA at time of enrollment was 41.9 ng/mL (range 5.2–1930.9 ng/mL). No patients demonstrated a PSA response. 13 patients have discontinued treatment, 12 for progressive disease (11 PSA progression and 1 bony progression) and 1 for grade 3 toxicity (GI bleed after 10 d on treatment). 6 patients are still on therapy with stable disease after a median 98 d. In 11 patients, baseline testosterone levels were mean 28.4 ng/dL (range <20–49 ng/dL). After one month of therapy, testosterone increased to mean 66.6 ng/dL (range 16–104 ng/dL) (p = 0.001). Compared to baseline, one month androstenedione and DHEAS levels were elevated in the majority of patients. Conclusions: Mifepristone demonstrated limited activity in AIPC patients. Potential efficacy was most likely limited by a rapid elevation in testosterone levels. We hypothesize that inhibition of glucocorticoid receptor led to an increase in ACTH with subsequent elevation of adrenal androgens and conversion to DHT. These preliminary data suggest that even moderate increases in systemic testosterone levels may stimulate tumor growth. These data also emphasize the continued importance of adrenal androgens and AR transcription in prostate cancer biology.

No significant financial relationships to disclose.

Phase II study of low dose (LD) and high dose (HD) premarin in androgen independent prostate cancer (AIPC)

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Background: Estrogens, including DES, transdermal estradiol, estramustine and PC-SPES, have shown antitumor activity in AIPC. We tested two doses of Premarin to determine efficacy and safety of this commonly available estrogen. Methods: Patients with progressive AIPC were eligible. Prior estrogen use, significant cardiac or thromboembolic disease, and concurrent steroids were not allowed. Patients were randomized to Premarin 1.25 mg once (LD) or 3 times (HD) daily. Prophylactic breast irradiation was encouraged and warfarin 1 mg daily was required, unless contraindicated. After the first stage of accrual, the LD arm was closed because of limited activity, while the HD arm continued to the 2nd stage. Results: 46 patients were enrolled; 17 patients were randomized to LD Premarin, 29 patients assigned to HD Premarin by randomization or direct assignment. One patient withdrew consent prior to therapy. Median follow up is 5.3 months. Median age was 69 years (range 52–86) and median PSA 84.6 ng/ml (range 2.5–794.1). 19 patients (41%) had measurable disease. PSA declines ≥ 50% were seen in 0% (95% C.I., 0–19.5) and 32.1% (95% C.I., 15.9–52.4) of patients treated with LD and HD premarin. 1 patient treated with HD Premarin had a partial measurable response (8.3%; 95% C.I., 0.2–38.5). Median time to progression was 3.3 and 3.2 months in the LD and HD arms, respectively. Premarin was well tolerated in 45 evaluable patients. One grade 4 toxicity was noted, a stroke in the LD arm. Grade 3 toxicity was rare with 1 allergic reaction, 2 DVTs and 3 episodes of GI toxicity in one patient. Two patients experienced grade 3 elevations in PT requiring modification of warfarin dose. No significant gynecomastia was reported. Analysis of serially drawn hormone levels and molecular correlates of treatment response is pending. Conclusions: HD Premarin is associated with a 32.1% PSA response rate, while no responses were seen with LD Premarin. A measurable response was noted in 1 of 12 patients treated with HD Premarin. Toxicity was modest, though thromboembolism was seen even with prophylactic warfarin. Ongoing studies are evaluating molecular and clinical predictors of response.

No significant financial relationships to disclose.