Biomodulatory Treatment of Patients with Castration-Resistant Prostate Cancer: A Phase II Study of Imatinib with Pioglitazone, Etoricoxib, Dexamethasone and Low-Dose Treosulfan

Therapeutic options for patients with castration-resistant prostate cancer (CRPC) remain limited. In a multicenter, Phase II study, 65 patients with histologically confirmed CRPC received a biomodulatory regimen during the six-month core study. Treatment comprised daily doses of imatinib mesylate, pioglitazone, etoricoxib, treosulfan and dexamethasone. The primary endpoint was prostate-specific antigen (PSA) response. Responders could enter an extension phase until disease progression or intolerable toxicity occurred. Mean PSA was 45.3 ng/mL at baseline, and 77 % of patients had a PSA doubling time <3 months. Of the 61 evaluable patients, 37 patients (60.6 %) responded or had stable disease and 23 of them (37.7 % of 61 patients) were PSA responders. Among the 23 responders mean PSA decreased from 278.9 ± 784.1 ng/mL at baseline to 8.8 ± 11.6 ng/mL at the final visit (week 24). The progression-free survival (PFS) was 467 days in the ITT population. Of the 947 adverse events, 57.6 % were suspected to be drug-related, 13.8 % led to dose adjustment or permanent discontinuation and 40.2 % required concomitant medication. This novel combination approach led to an impressive PSA response rate of 37.7 % in CRPC patients. The good PSA response and PFS rate combined with the manageable toxicity profile suggest an alternative treatment option.

Effects of zoledronic acid on bone mineral density in premenopausal women receiving neoadjuvant or adjuvant therapies for HR+ breast cancer: the ProBONE II study

The effects of bisphosphonates on altered bone turnover marker (BTM) levels associated with adjuvant endocrine or chemotherapy in early breast cancer have not been systematically investigated. In ProBONE II, zoledronic acid decreased these elevated BTM levels and increased bone mineral density (BMD) during adjuvant therapy, consistent with its antiresorptive effects.

INTRODUCTION

Adjuvant chemotherapy or endocrine therapy for early hormone receptor-positive breast cancer (HR(+) BC) is associated with rapid BMD loss and altered BTM levels. Adjuvant bisphosphonate studies demonstrated BMD increases, but did not investigate BTM effects. The randomized, double-blind, ProBONE II study investigated the effect of adjuvant zoledronic acid (ZOL) on BMD and BTM in premenopausal women with early HR(+) BC.

METHODS

Seventy premenopausal women with early HR(+) BC received adjuvant chemotherapy and/or endocrine therapy plus ZOL (4 mg IV every 3 months) or placebo for 24 months. Primary endpoint was change in lumbar spine BMD at 24 months versus baseline. Secondary endpoints included femoral neck and total femoral BMD changes, changes in BTM, and safety.

RESULTS

Lumbar spine BMD increased 3.14% from baseline to 24 months in ZOL-treated participants versus a 6.43% decrease in placebo-treated participants (P < 0.0001). Mean changes in T- and Z-scores, and femoral neck and total femoral BMD, showed similar results. Bone resorption marker levels decreased ∼ 55% in ZOL-treated participants versus increases up to 65% in placebo-treated participants (P < 0.0001 for between-group differences). Bone formation marker (procollagen I N-terminal propeptide) levels decreased ∼ 57% in ZOL-treated participants versus increases up to 45% in placebo-treated participants (P < 0.0001 for between-group differences). Adverse events were consistent with the established ZOL safety profile and included one case of osteonecrosis of the jaw after a tooth extraction.

CONCLUSIONS

Adding ZOL to adjuvant therapy improved BMD, reduced BTM levels, and was well tolerated in premenopausal women with early HR(+) BC receiving adjuvant chemotherapy and/or endocrine therapy.

P2-19-03: Influence of Zoledronic Acid on BMD in Premenopausal Women with Breast Cancer and Neoadjuvant or Adjuvant Chemotherapy and/or Endocrine Treatment – The ProBone Studies

Background: Based on baseline bone mineral density (BMD), adjuvant chemotherapy or endocrine therapy for early breast cancer patients can lead to substantially increased fracture risk. A significant decrease of BMD &gt;10% after 2 years of chemotherapy (CT) and/or endocrine therapy (ET) has been reported. In recent studies, zoledronic acid (ZOL) produced an increase in BMD in premenopausal and postmenopausal patients with breast cancer (ABCSG-12, Z-FAST, ZO-FAST, etc). In addition, a significant increase in disease-free survival (DFS) with ZOL vs no ZOL was observed in most of these studies.

Methods: The aim of 2 single-center, placebo-controlled, randomized studies—Probone I and Probone II—was to investigate the effect of adjuvant treatment with ZOL on BMD in premenopausal women with early breast cancer treated with CT and/or ET. Patients with hormone-receptor-negative (HR−) breast cancer (Probone I) were treated with (neo)adjuvant CT; patients with hormone-receptor-positive (HR+) breast cancer (Probone II) were treated with ET alone or in combination with (neo)adjuvant CT. Randomized patients received ZOL 4 mg or placebo IV every 3 months for 24 months. The primary objective was the change in BMD at the lumbar spine between baseline and month 24 (measured by dual-energy X-ray absorptiometry [DXA]). Secondary objectives included DFS; BMD at total hip, femur, and os calcis; quantitative ultrasonometry (QUS) at os calcis and phalanges; markers of bone turnover (C-telopeptide of type I collagen [CTX] and N-terminal propeptide of type I procollagen [P1NP]); endocrine hormones (follicle-stimulating hormone [FSH], estradiol, testosterone, sex hormone-binding globulin [SHBG], parathyroid hormone [PTH], vitamin D, anti-Müllerian hormone [AMH], inhibin A/B, etc); pathologic fractures; and safety and tolerability.

Results: 70 HR+ and 11 HR− breast cancer patients have been enrolled into the studies. The last patient will have been treated for 24 months by the end of June 2011.

Conclusions: The effects of ZOL on lumbar spine BMD at 24 months and secondary endpoints will be presented at the meeting.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-19-03.