A phase 2 randomized study of oral docetaxel plus ritonavir (ModraDoc006/r) in patients with metastatic castration-resistant prostate cancer (mCRPC)

5016

Background: Intravenous (IV) docetaxel and oral prednisone is a standard of care regimen in patients (pts) with mCRPC. ModraDoc006 is an oral formulation of docetaxel. To enhance bioavailability of ModraDoc006, it is co-administered with ritonavir (/r). The ModraDoc006 and ritonavir combination is active in multiple docetaxel and cabazitaxel-resistant prostate cancer cell-lines The oral combination (ModraDoc006/r) was compared to IV docetaxel in a randomized phase 2b study in pts with mCRPC evaluating two doses of ModraDoc006/r (30-20/200-100 mg and 20-20/200-100 mg). Data on outcomes in the larger cohort, receiving the lower dose, are being presented. Methods: Eligible pts had mCRPC, performance status of 0-1 and no prior chemotherapy for mCRPC. Sixty-two pts were enrolled in open label 1:1 randomized study comparing ModraDoc006/r 20-20 mg combined with 200-100 mg ritonavir in a bi-daily weekly schedule (“20-20/200-100 mg”), with IV docetaxel 75 mg/m2 in 21-day cycles. All pts received 5 mg oral prednisone twice daily. Primary endpoint was radiographic progression free survival (rPFS) per PCWG-3 criteria. Secondary objectives included ORR, PSA-PFS, time to skeletal related events, disease control rate, duration of response, and safety assessments. Results: 31 pts were enrolled on IV docetaxel 75 mg/m2 and 31 on ModraDoc006/r 20-20/200-100 mg. Of these, 57 were included in the analysis for rPFS, and 32 pts with measurable disease were included in the ORR analysis. Median PSA was 46 (range 1 to 1460 ng/ml). Prior therapy with enzalutamide in 8 pts, abiraterone in 10 pts. ModraDoc006/r was better tolerated with 0% all grades neutropenia and anemia, as compared to 26% (19% ≥G3) and 16% respectively on IV docetaxel. Neuropathy was significantly reduced at 9.7% G1 only on ModraDoc006/r vs 9.7% G1 and 19.4% G2 on IV docetaxel, whereas alopecia was reduced to 16.1% G1 and 6.5% G2 on ModraDoc006/r vs. 22.6% G1 and 19.4% G2 on IV docetaxel. GI toxicities were broadly comparable with diarrhea 32% (3% ≥G3) vs 29%, nausea 29% vs 13% and stomatitis 3% (G3) vs 13% (3% ≥G3), respectively. Conclusions: ModraDoc006/r demonstrated a favorable safety profile and comparable efficacy to IV docetaxel in pts with mCRPC, thus providing a compelling rationale for conduct of an expanded pivotal program. A key clinical program focus is the comparison of ModraDoc006/r to best available therapy in refractory mCRPC. Studies of ModraDoc006/r in other malignancies are also in active development. Clinical trial information: NCT04028388. [Table: see text]

Phase 2 randomized trial of ModraDoc006/r, oral docetaxel plus ritonavir, versus intravenous docetaxel in metastatic castration resistant prostate cancer (mCRPC)

117

Background: Intravenous (IV) docetaxel and oral prednisone is a standard of care regimen in mCRPC. ModraDoc006 is a novel, oral tablet formulation of docetaxel. To enhance bioavailability, it is co-administered with ritonavir (/r), an inhibitor of cytochrome p450 3A4 and P-glycoprotein metabolic enzymes. The oral combination, denoted as ModraDoc006/r, may be superior to IV docetaxel in terms of safety profile, avoiding infusions, patient quality of life (QoL) and overall resource utilization. Safety of ModraDoc006/r in mCRPC was established in a previous phase Ib trial. Methods: We conducted an open label 1:1 randomized study of ModraDoc006/r bi-daily weekly dosing (BIDW) regimen versus IV docetaxel 75 mg/m2 in 21-day cycles. Initially, BIDW 30-20 mg ModraDoc006 combined with 200-100 mg ritonavir was administered on days 1, 8 and 15 of a 21-day cycle. After 39 patients the starting dose was reduced to 20-20 mg BIDW with ritonavir 200 mg in the morning and 100 mg with the evening dose to improve tolerability. All patients received 5 mg oral prednisone twice daily. Primary endpoint was radiographic progression free survival (rPFS) per PCWG-3 criteria. Secondary objectives were ORR, PSA-PFS, time to skeletal related events, disease control rate, duration of response, and safety assessments. Patient reported outcomes and health-related QoL was assessed with treatment satisfaction and FACT-P questionnaires at baseline and after cycles 3, 6 and 10. Results: Enrollment is complete with 101 patients accrued; 49 on IV docetaxel, 52 on ModraDoc006/r (21 on 30-20 mg and 31 on ModraDoc006/r 20-20 mg). 69 patients had measurable disease and median PSA was 67ng/ml (range 0,2 to 1697 ng/ml). IV docetaxel vs ModraDoc006/r 30-20 mg and 20-20 mg demonstrated ORR of 39% vs 50% and 33%, and PSA responses of 57% vs 53% and 48%. All grades neutropenia and neuropathy was noted in 0% and 6% with ModraDoc006/r 20-20 mg therapy and was better than the incidence of 14% (5% ≥G3) and 14% with ModraDoc006/r 30-20 mg, and 27% (20% ≥G3) and 31% respectively on IV docetaxel. Alopecia was also reduced at 23% on ModraDoc006/r 20-20 mg and 29% on ModraDoc006/r 30-20 mg vs 43% on IV docetaxel. GI toxicities were slightly more frequent, but predominantly mild, in the ModraDoc006/r arm: at 20-20 mg dose, all grades diarrhea 32% (3% ≥G3), nausea 29% and stomatitis 3% (G3); at 30-20 mg dose 62% diarrhea (19% ≥G3), 38% nausea and 14% stomatitis (5% ≥G3); and in IV docetaxel, 24% diarrhea, 16% nausea and 10% stomatitis (4% ≥G3). Conclusions: Hematological toxicities and adverse events neuropathy and alopecia were lower with ModraDoc006/r than with IV docetaxel. ModraDoc006/r represents a convenient, oral, tolerable option for patients with mCRPC. ModraDoc006/r has comparable efficacy and a favorable tolerability profile as compared to IV docetaxel and merits further development in patients with mCRPC. Clinical trial information: NCT04028388.

KEYNOTE-427 cohort B: First-line pembrolizumab (pembro) monotherapy for advanced non‒clear cell renal cell carcinoma (NCC-RCC)

4569

Background: Efficacy of PD-1 inhibitors (or any therapy) in NCC-RCC has not been established. KEYNOTE-427 (NCT02853344) is a single-arm, open-label, phase 2 study of pembro monotherapy in patients (pts) with advanced clear cell RCC (cohort A) and NCC-RCC (cohort B). Cohort B results are presented. Methods: 165 pts with histologically confirmed NCC-RCC, no prior systemic therapy, measurable disease (RECIST v1.1), and KPS ≥70% enrolled. Pts received pembro 200 mg IV Q3W for 35 cycles (~2 y) or until progressive disease (PD), unacceptable toxicity, or withdrawal. Primary end point: objective response rate (ORR) per RECIST v1.1 by blinded independent central review. Additional end points: duration of response (DOR), population description by sarcomatoid differentiation, histology and PD-L1 expression (combined positive score [CPS] ≥1 for PD-L1+). Results: Histology was confirmed by a central pathologist: papillary 72% (n = 118), chromophobe 13% (n = 21), unclassified 16% (n = 26); 62% were PD-L1+. At analysis, 49 pts had died and 3 had withdrawn. At median follow-up of 11.1 mo (range, 0.9-21.3), 56% of pts discontinued pembro due to PD or clinical progression. Overall ORR was 24.8% (95% CI, 18.5-32.2; 8 [4.8%] CR, 33 [20.0%] PR). Median DOR was not reached. For responding pts, 81.5% had a response ≥6 mo. 12-mo PFS and OS rates were 22.8% and 72.0%, respectively. ORR (95% CI) was 25.4% (17.9-34.3) with papillary, 9.5% (1.2-30.4) with chromophobe, and 34.6% (17.2-55.7) with unclassified NCC-RCC; for responding pts, 82.1%, 50.0%, and 87.5% had a response ≥6 mo, respectively. Median DOR was not reached in any group. ORR (95% CI) was 44.7% (28.6-61.7) for pts with sarcomatoid differentiation (n = 38). ORR (95% CI) was 33.3% (24.3-43.4) and 10.3% (3.9-21.2) with CPS≥1 and CPS < 1, respectively. Grade 3-5 treatment-related adverse events (TRAEs) occurred in 11% of pts. 6 pts died of AEs, 2 of TRAEs (pneumonia and cardiac arrest). Conclusions: Single-agent pembro showed encouraging antitumor activity in NCC-RCC, especially with papillary or unclassified histology. Safety profile of pembro was as expected. Updated data with additional follow-up will be presented. Clinical trial information: NCT02853344.

First-line pembrolizumab (pembro) monotherapy in advanced clear cell renal cell carcinoma (ccRCC): Updated results for KEYNOTE-427 cohort A

4570

Background: KEYNOTE-427 (NCT02853344) is an open-label, single-arm, phase 2 study to evaluate efficacy and safety of first-line single-agent pembro, a programmed death 1 (PD-1) inhibitor, in patients (pts) with ccRCC (cohort A) and non–clear cell RCC (cohort B). Updated follow up from cohort A are presented. Methods: Pts with histologically confirmed ccRCC, measurable per RECIST v1.1, and no prior systemic therapy were eligible. Pts received pembro 200 mg IV Q3W for 2 y or until confirmed progressive disease, unacceptable toxicity, or pt decision to withdraw. Primary end point was objective response rate (ORR; per RECIST v1.1 blinded independent central review). Additional end points included duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Results: 110 pts enrolled; median (range) follow-up was 18.0 (2.5-22.7) mo. Median age (range) was 64 (29-87); 38.2%, 47.3%, and 14.5% had favorable, intermediate, and poor IMDC risk, respectively; 47.3% were PD-L1 positive. Confirmed ORR was 36.4% with 3 (2.7%) CRs and 37 (33.6%) PRs. Median DOR was not reached. Median PFS was 7.1 mo (95% CI, 5.6-11.0) and median OS was not reached. Results by IMDC category are outlined in the table. By PD-L1 status, confirmed ORR was 44.2% and 29.3% for positive and negative, respectively. By sarcomatoid differentiation (n=11), confirmed ORR was 63.6%. Treatment-related AEs occurred in 80.9%, with pruritus (28.2%) and fatigue (28.2%) most commonly reported. One pt died of treatment-related pneumonitis. Conclusions: With a median 18-months’ follow up, first-line pembro monotherapy continued to show antitumor activity in pts with ccRCC. Meaningful responses were observed in pts with intermediate/poor IMDC risk, PD-L1 positive and sarcomatoid differentiated tumors. Safety profile was comparable to previously reported. Clinical trial information: NCT02853344. [Table: see text]

Health-related quality of life (HRQoL) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with olaparib in combination with abiraterone

234

Background: A Phase II trial showed that addition of olaparib (O) to abiraterone (A) led to significant radiographic progression-free survival benefit for patients (pts) with mCRPC vs placebo (P) + A (hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.44–0.97). We report predefined exploratory HRQoL analyses. Methods: This randomized, double-blind trial enrolled pts with mCRPC, post-docetaxel. Pts were randomized (71 per arm) to receive either O (300 mg bd, tablets) + A (1000 mg od) or P + A; all received prednisone (5 mg bd). Pts completed Functional Assessment of Cancer Therapy-Prostate (FACT-P total score [TS]; range 0–156, higher score = better HRQoL), Brief Pain Inventory–Short Form (BPI-SF) and worst bone pain (wbp) questionnaires (both range 0–10, higher score = more severe pain). Adjusted mean change from baseline was analysed using a mixed model for repeated measures, improvement by logistic regression and deterioration by log-rank test. Results: Overall compliance rates (O + A vs P + A) were 97% vs 96%, 92% vs 85%, and 96% vs 92% for FACT-P, BPI-SF and wbp, respectively. Best FACT-P TS response of ‘improved’ (increase ≥6 points from baseline at two consecutive visits) was reported by 22/67 (33%) evaluable pts in the O + A vs 18/64 (28%) pts in the P + A arm; the odds ratio (1.32; 95% CI 0.64–2.78) favored the O + A arm. Best FACT-P TS response of ‘worsened’ (decrease ≥6 points from baseline) was reported by 15 (22%) vs 22 (34%) pts. Adjusted mean change from baseline in FACT-P TS across all visits was -0.60 vs -2.09 in the O + A and P + A arms, respectively (difference 1.48; 95% CI -3.96–6.92). Time to deterioration (TTD) results are shown in the table. Clinical trial information: NCT01972217. Conclusions: Whilst not statistically significant, in this study a higher percentage of pts treated with O + A vs P + A had improved HRQoL, with fewer pts negatively affected. Ongoing phase III studies will help elucidate the impact of O on HRQoL in pts with mCRPC. (NCT01972217)[Table: see text]

Clinical significance of androgen secretion disorders in men with a malignancy

Cancer and its treatment can lead in men to testosterone deficiency, accompanied by somatic and mental symptoms. Germ cell tumours and their treatment may disturb the pituitary-gonadal axis, hence leading to significant clinical abnormalities. In some prostate cancer patients, castration, temporary or permanent, is a desired therapeutic condition. Yet, it is burdened with various side effects of complex intensity and significance. Last but not least, patients in the terminal stage of a malignancy present with low testosterone concentrations as a part of anorexia-cachexia syndrome. Oncological management of such patients disturbs their homeostasis, androgen metabolism included, which results in numerous complications and worsens their quality of life. In the present paper, we analysed the frequency and sequelae of testosterone deficiency in some clinical scenarios, on the basis of original papers, meta-analyses and reviews available in PubMed. Androgen secretion disorders in male cancer patients depend on a cancer type, stage and methods of treatment. Number of testicular cancer survivors is increasing, and as a consequence, more patients cope with late complications, testosterone deficiency included. Hormone therapy in prostate cancer patients significantly prolongs survival, and then numerous men experience long-term adverse effects of androgen deficiency. Those, in turn, particularly the metabolic syndrome, may contribute to increased mortality. Androgen deficiency is a part of cancer anorexia-cachexia syndrome. The role of androgen deficiency in cancer patients is still under debate, and further studies are urgently needed to establish appropriate clinical guidelines.

Association of Survival Benefit With Docetaxel in Prostate Cancer and Total Number of Cycles Administered: A Post Hoc Analysis of the Mainsail Study

Importance

The optimal total number of docetaxel cycles in patients with metastatic castration resistant prostate cancer (mCPRC) has not been investigated yet. It is unknown whether it is beneficial for patients to continue treatment upon 6 cycles.

Objective

To investigate whether the number of docetaxel cycles administered to patients deriving clinical benefit was an independent prognostic factor for overall survival (OS) in a post hoc analysis of the Mainsail trial.

Design, Setting, and Participants

The Mainsail trial was a multinational randomized phase 3 study of 1059 patients with mCRPC receiving docetaxel, prednisone, and lenalidomide (DPL) or docetaxel, prednisone, and a placebo (DP). Study patients were treated until progressive disease or unacceptable adverse effects occurred. Median OS was found to be inferior in the DPL arm compared with the DP arm. As a result of increased toxic effects with the DPL combination, patients on DPL received fewer docetaxel cycles (median, 6) vs 8 cycles in the control group. As the dose intensity was comparable in both treatment arms, we investigated whether the number of docetaxel cycles administered to patients deriving clinical benefit on Mainsail was an independent prognostic factor for OS. We conducted primary univariate and multivariate analyses for the intention-to-treat population. Additional sensitivity analyses were done, excluding patients who stopped treatment for reasons of disease progression and those who received 4 or fewer cycles of docetaxel for other reasons, minimizing the effect of confounding factors.

Main Outcomes and Measures

Total number of docetaxel cycles delivered as an independent factor for OS.

Results

Overall, all 1059 patients from the Mainsail trial were included (mean [SD] age, 68.7 [7.89] years). Treatment with 8 or more cycles of docetaxel was associated with superior OS (hazard ratio [HR], 1.909; 95% CI, 1.660-2.194; P < .001), irrespective of lenalidomide treatment (HR, 1.060; 95% CI, 0.924-1.215; P = .41). Likewise, in the sensitivity analysis, patients who received a greater number of docetaxel cycles had superior OS; patients who received more than 10 cycles had a median OS of 33.0 months compared with 26.9 months in patients treated with 8 to 10 cycles; and patients who received 5 to 7 cycles had a median OS of 22.8 months (P < .001).

Conclusions and Relevance

These findings suggest that continuation of docetaxel chemotherapy contributes to the survival benefit. Prospective validation is warranted.

Circulating Tumor Cells in a Phase 3 Study of Docetaxel and Prednisone with or without Lenalidomide in Metastatic Castration-resistant Prostate Cancer

Elevated circulating tumor cell (CTC) blood levels (≥5 cells/7.5ml) convey a negative prognosis in metastatic castration-resistant prostate cancer but their prognostic significance in patients receiving chemotherapy is uncertain. The association between CTC counts (at baseline or after treatment), overall survival (OS), and response to docetaxel with lenalidomide was evaluated in a 208-patient subset from the MAINSAIL trial, which compared docetaxel-prednisone-lenalidomide and docetaxel-prednisone-placebo in metastatic castration-resistant prostate cancer patients. Baseline CTCs were <5 cells/7.5ml blood in 87 (42%) patients and ≥5 cells/7.5ml in 121 (58%) patients. Neither tumor response nor prostate-specific antigen response correlated with baseline CTCs. However, CTC count ≥5 cells/7.5ml was significantly associated with lower OS (hazard ratio: 3.23, p = 0.0028). Increases in CTCs from <5 cells/7.5ml to ≥5 cells/7.5ml after three cycles were associated with significantly shorter OS (hazard ratio: 5.24, p=0.025), whereas CTC reductions from ≥5 cells/7.5ml to <5 cells/7.5ml were associated with the best prognosis (p=0.003).

PATIENT SUMMARY

Our study in metastatic castration-resistant prostate cancer patients treated with docetaxel chemotherapy, with or without lenalidomide, showed that patient survival was best predicted by circulating tumor cell count at the start of treatment. A rising circulating tumor cell count after three cycles of therapy predicted poor survival, while a decline predicted good survival.

Vinflunine-gemcitabine versus vinflunine-carboplatin as first-line chemotherapy in cisplatin-unfit patients with advanced urothelial carcinoma: results of an international randomized phase II trial (JASINT1)

This randomized phase II study examined the use of vinflunine in combination with gemcitabine or carboplatin as first-line chemotherapy in cisplatin-ineligible patients with advanced urothelial carcinoma. Both doublets were feasible and offered a similar 77% disease control rate. Response rate (44%), overall survival (14 months) and less haematological toxicity favoured vinflunine–gemcitabine.

Background

There is no standard first-line chemotherapy for advanced urothelial carcinoma (aUC) in cisplatin-ineligible (cisplatin-unfit) patients. The study assessed the efficacy and tolerability profile of two vinflunine-based cytotoxic regimens in this setting.

Patients and methods

Patients with aUC a creatinine clearance (CrCl) of <60 but ≥30 ml/min, performance status 0 or 1 and no prior chemotherapy for advanced disease were randomized (1 : 1). They received vinflunine 250 or 280 mg/m² (based on baseline CrCl) on day 1, plus either gemcitabine [750 mg/m² escalated to 1000 mg/m² in cycle 2 if no toxicity grade (G) ≥2 on days 1 and 8 (VG) or plus carboplatin area under the curve 4.5 day 1 (VC) every 21 days]. To detect a 22% improvement in each arm compared with H0 (41%) in the primary end point, disease control rate (DCR = complete response + partial response + stable disease), 31 assessable patients per arm were required (α = 5%, β = 20%).

Results

Sixty-nine patients were enrolled (34 VG, 35 VC). Less G3/4 haematological adverse events (AEs) were reported with VG: neutropaenia was seen in 38% (versus 68% with VC) and febrile neutropaenia in 3% (versus 14% with VC) of patients. No major differences were observed for non-haematological AEs. DCR was 77% in both groups; overall response rate (ORR) was 44.1% versus 28.6%, with a median progression-free survival of 5.9 versus 6.1 months and median OS of 14.0 versus 12.8 months with VG and VC, respectively.

Conclusion

Both vinflunine-based doublets offer a similar DCR, ORR and OS. The better haematological tolerance favours the VG combination, which warrants further study.

ClinicalTrials.gov protocol identifier

NCT 01599013.

Randomized phase II study with window-design to evaluate anti-tumor activity of the survivin antisense oligonucleotide (ASO) ly2181308 in combination with docetaxel for first-line treatment of castrate-resistant prostate cancer (CRPC)

5019

Background: In prostate cancer, expression of survivin, a protein that inhibits apoptosis, is associated with resistance to taxanes and poor outcome. LY2181308 reduces survivin expression and consequently is expected to improve activity of taxanes, such as docetaxel. A randomized phase II study was conducted to assess the activity of the combination. Methods: Adult patients (pts) with CRPC, ECOG performance status <2, and no bone or CNSmetastases were randomized 1:2 to standard docetaxel/prednisone every 21 days (Arm A) or standard therapy combined with LY2181308 given as a 3-hr IV infusion (Arm B). Analysis was planned and performed after 130 pts progressed or died. This assessment provided a 70% chance of detecting a difference in progression-free survival (PFS) at the 10% significance level. Initially, LY2181308 was given as a loading dose (3 consecutive days) and then as a weekly 3-hr IV maintenance dose. Arm B also included a window treatment with LY2181308 monotherapy equivalent to a 21-day cycle of docetaxel before starting combined treatment. The primary endpoint was PFS. Results: This study enrolled 154 pts. The median PFS for Arm B was 8.64 (90% CI, 7.39–10.45) months vs. 9.00 (90% CI, 7.00–10.09) months in Arm A, showing no statistical difference (log rank p=0.755). The median overall survival (OS) for Arm B was 27.04 (90% CI, 19.94–33.41) months vs. 29.04 (90% CI, 20.11–39.26) months for Arm A (log-rank p= 0.838). The PSA responses (>50% reduction in PSA) were similar: 56.9% for Arm A and 56.1% in Arm B (p=0.856). Most pts had no pain or mild pain at baseline and during the active period. Pts treated in Arm B had a higher frequency of serious and nonserious adverse events (AEs) than those in Arm A. The observed AE and pharmacokinetic (PK) profiles were consistent with the known safety and PK profiles of LY2181308 and docetaxel. Conclusions: The addition of LY2181308 to a standard docetaxel/prednisone regimen showed no improvement in PFS, PSA response, and OS in first line CRPC pts. The safety profile of docetaxel and LY2181308 is predictable and consistent with the known safety profiles. Clinical trial information: NCT00642018.

Updated analysis of the phase III, double-blind, randomized, multinational study of radium-223 chloride in castration-resistant prostate cancer (CRPC) patients with bone metastases (ALSYMPCA)

LBA4512

Background: Radium-223 chloride (Ra-223), a targeted alpha-emitter, targets bone metastases (mets) with high-energy alpha-particles of short range (<100 µm). ALSYMPCA, a phase III double-blind, randomized, multinational study, compared Ra-223 plus best standard of care (BSC) vs placebo plus BSC in CRPC patients (pts) with bone mets. In a planned interim analysis (n = 809), based on 314 events, Ra-223 significantly improved overall survival (OS) vs placebo (median 14.0 mo vs 11.2 mo, respectively; HR = .695; 95% CI, .552-.875; 2-sided p = .00185). Secondary endpoints were met and Ra-223 safety was favorable. An updated analysis was conducted prior to the crossover to further assess the effect of Ra-223 on the primary endpoint (OS), secondary endpoints including skeletal-related events (SREs), and safety. Methods: Eligible pts had confirmed symptomatic CRPC with ≥ 2 bone mets; no known visceral mets; and were post-docetaxel, unfit for docetaxel, or had declined docetaxel. Pts were randomized 2:1 to receive 6 injections of Ra-223 (50 kBq/kg IV) q4wks or matching placebo. An updated descriptive analysis of OS, based on 528 events, was performed including data from all randomized pts prior to implementing crossover to Ra-223 for placebo pts. Results: 921 pts (Ra-223, n = 614; placebo, n = 307) were randomized from 6/2008-2/2011. Ra‑223 significantly improved OS vs placebo (median 14.9 mo vs 11.3 mo, respectively; HR = .695; 95% CI, .581-.832; p = 0.00007), and time to first SRE was significantly prolonged (median 15.6 mo vs 9.8 mo, respectively; HR = 0.658; 95% CI, 0.522-0.830; p = 0.00037). Safety and tolerability of Ra-223 remained favorable, with low myelosuppression (e.g., gr 3/4 neutropenia in 2.2% and 0.7% and gr 3/4 thrombocytopenia in 6.3% and 2% of the Ra-223 and placebo groups, respectively). Conclusions: On updated analysis, the median OS benefit for Ra-223 increased from 2.8 to 3.6 months, with a hazard ratio of 0.695 (i.e., 30.5% reduction in risk of death). Ra-223 is an effective therapy that improves OS and time to first SRE with a highly favorable safety profile, and may provide a new standard of care for CRPC pts with bone mets.

Radium-223 chloride (Ra-223) impact on skeletal-related events (SREs) and ECOG performance status (PS) in patients with castration-resistant prostate cancer (CRPC) with bone metastases: Interim results of a phase III trial (ALSYMPCA)

4551

Background: Ra-223, a 1st-in-class alpha-pharmaceutical, targets bone metastases (mets) with high-energy alpha-particles of short range (<100 μm). ALSYMPCA, a phase III, double-blind, randomized, multinational study, compared Ra-223 plus best standard of care (BSC) v placebo (pbo) plus BSC in patients (pts) with bone mets in CRPC. The primary endpoint was OS; secondary endpoints included SREs and ECOG PS. Methods: Eligible pts had progressive, symptomatic CRPC with ≥ 2 bone mets on scintigraphy and no known visceral mets; were receiving BSC; and either previously received docetaxel, were docetaxel ineligible, or refused docetaxel. Pts were randomized 2:1 to 6 injections of Ra‑223 (50 kBq/kg IV) q4 wks or matching pbo and stratified by prior docetaxel use, baseline ALP level, and current bisphosphonate use. Results: 921 pts were randomized from 6/2008-2/2011. In a planned interim analysis (n = 809), Ra-223 significantly improved OS v pbo (median OS 14.0 v 11.2 mo, respectively; two-sided P = .00185; HR = .695; 95% CI, .552-.875).SREs were lower in the Ra-223 v pbo group, and time to 1st SRE was significantly delayed (median time to SRE 13.6 mo v 8.4 mo, respectively; P = .00046; HR = .610; 95% CI, .461-.807). The proportion of pts with ECOG PS deterioration (≥ 2 points) was less in Ra-223 v pbo group at Wk 12 and Wk 24 (4%, 15/389 v 9%, 16/180 and 7%, 16/236 v 12%, 10/83, respectively). Time to ECOG PS deterioration (≥ 2 points) was significantly delayed by Ra-223 v pbo (P = .003; HR = .62; 95% CI, .46-.85). Conclusions: Ra-233 significantly delayed time to 1st SRE and SRE components, notably SCC. Fewer pts in the Ra-223 group had ECOG PS deterioration. Ra-223 improves OS with excellent safety and may provide a new standard of care for CRPC pts with bone mets. [Table: see text]

Updated analysis of the phase III, double-blind, randomized, multinational study of radium-223 chloride in castration-resistant prostate cancer (CRPC) patients with bone metastases (ALSYMPCA)

LBA4512

The full, final text of this abstract will be available at abstract.asco.org at 12:01 AM (EDT) on Monday, June 4, 2012, and in the Annual Meeting Proceedings online supplement to the June 20, 2012, issue of Journal of Clinical Oncology. Onsite at the Meeting, this abstract will be printed in the Monday edition of ASCO Daily News.

Recovery of dendritic cell counts and function in peripheral blood of cancer patients after chemotherapy

Dendritic cell (DC) counts and function were assayed in peripheral blood of lymphoma and solid tumor patients before and after chemotherapy. The DC counts declined significantly within the first week from the start of chemotherapy, recovered in the second week, and exceeded the baseline values in the third week. DC recovery was usually similar after the first and after the last cycle of chemotherapy. DC1 and DC2 subsets followed the pattern of reconstitution found for the DC population as a whole. Monocytes and granulocytes recovered 1-2 weeks later than DC. The primary proliferative response to keyhole lympet hemocyanin (KLH), totally DC-dependent, declined within the first week from the start of chemotherapy, and in the majority of patients (including those initially unresponsive) recovered along with DC counts. The recovered responsiveness to KLH, but not to anti-CD3 antibody, disappeared at the end of chemotherapy in lymphoma and some solid tumor patients. Prolonged depletion of CD4+ T cells could contribute to the loss of responsiveness in lymphoma patients receiving multiple cycles of chemotherapy. However, in some solid tumor patients, the reactivity to KLH was absent, despite the reconstitution of both DC and CD4+ T-cell counts. Our data show that numerical reconstitution of DC is not necessarily accompanied by functional recovery. The early recovery of DC should be considered while designing protocols for DC collection for immunotherapy.