A randomized phase II trial of CRLX101 in combination with bevacizumab versus standard of care in patients with advanced renal cell carcinoma

BACKGROUND

Nanoparticle-drug conjugates enhance drug delivery to tumors. Gradual payload release inside cancer cells augments antitumor activity while reducing toxicity. CRLX101 is a novel nanoparticle-drug conjugate containing camptothecin, a potent inhibitor of topoisomerase I and the hypoxia-inducible factors 1α and 2α. In a phase Ib/2 trial, CRLX101 + bevacizumab was well tolerated with encouraging activity in metastatic renal cell carcinoma (mRCC). We conducted a randomized phase II trial comparing CRLX101 + bevacizumab versus standard of care (SOC) in refractory mRCC.

PATIENTS AND METHODS

Patients with mRCC and 2-3 prior lines of therapy were randomized 1 : 1 to CRLX101 + bevacizumab versus SOC, defined as investigator's choice of any approved regimen not previously received. The primary end point was progression-free survival (PFS) by blinded independent radiological review in patients with clear cell mRCC. Secondary end points included overall survival, objective response rate and safety.

RESULTS

In total, 111 patients were randomized and received ≥1 dose of drug (CRLX101 + bevacizumab, 55; SOC, 56). Within the SOC arm, patients received single-agent bevacizumab (19), axitinib (18), everolimus (7), pazopanib (4), sorafenib (4), sunitinib (2), or temsirolimus (2). In the clear cell population, the median PFS on the CRLX101 + bevacizumab and SOC arms was 3.7 months (95% confidence interval, 2.0-4.3) and 3.9 months (95% confidence interval 2.2-5.4), respectively (stratified log-rank P = 0.831). The objective response rate by IRR was 5% with CRLX101 + bevacizumab versus 14% with SOC (Mantel-Haenszel test, P = 0.836). Consistent with previous studies, the CRLX101 + bevacizumab combination was generally well tolerated, and no new safety signal was identified.

CONCLUSIONS

Despite promising efficacy data on the earlier phase Ib/2 trial of mRCC, this randomized trial did not demonstrate improvement in PFS for the CRLX101 + bevacizumab combination when compared with approved agents in patients with heavily pretreated clear cell mRCC. Further development in this disease is not planned.

CLINICAL TRIAL IDENTIFICATION

NCT02187302 (NIH).

Sunitinib in combination with docetaxel and prednisone in patients (pts) with metastatic hormone-refractory prostate cancer (mHRPC)

5166

Background: Overexpression of VEGF and PDGF has been implicated in prostate cancer progression and bone metastases. Sunitinib is an oral, multitargeted inhibitor of VEGFRs, PDGFRs, and other tyrosine kinases which may improve the efficacy of chemotherapy in pts with mHRPC. We performed a multicenter phase I/II study of sunitinib in combination with docetaxel and prednisone as first-line therapy in pts with mHRPC. The combination dose was established in phase I (Zurita et al, ECCO. 2007). Final results from phase II will be reported. Methods: Pts received treatment in a 21-day cycle: sunitinib 37.5 mg/d on days 1–14, docetaxel 75 mg/m2 on day 1, and prednisone 5 mg BID on days 1–21. Dose reductions were permitted for treatment-related toxicity. The primary endpoint was PSA response rate (PSA Working Group Criteria). Secondary endpoints included tumor response rate (RECIST), safety and patient-reported outcomes. Results: Fifty-five pts were enrolled and 13 remained on study at the time of the data cutoff (1 Oct 08). Thirty-six discontinued from the study due to disease progression (16), adverse events (AEs; 13), consent withdrawal (6) and other (1). Six pts completed the study (16 cycles) and continued treatment on another protocol. Pts received a median of 23 weeks of therapy (range, 2–84). The most common treatment-related grade 3–4 AEs were neutropenia (75%), febrile neutropenia (15%), fatigue (15%), stomatitis (7%), and anorexia (7%). Sunitinib dose reduction to 25 mg/d was required in 14 pts (26%), and 3 pts (6%) had a further dose reduction to 12.5 mg/d. Docetaxel dose reduction to 60 mg/m2 was required in 18 pts (33%). PSA responses occurred in 31 pts (56%), with a preliminary median time to PSA progression of 42.1 weeks. Out of 33 pts with measurable disease, thirteen (39%) had a confirmed partial response (PR) and another 7 (21%) had an initial PR. The median progression-free and overall survivals have not been reached, but the probability of survival at 48 weeks is 92.4% (95% CI: 77.5, 97.6). Patient-reported assessments of pain and quality of life will be reported. Conclusions: Sunitinib in combination with docetaxel and prednisone is tolerated and has antitumor activity in pts with mHRPC, as indicated by both PSA and RECIST-defined tumor responses.

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Patient-reported outcomes in a randomized trial of everolimus with metastatic renal cell carcinoma patients

e17516

Background: Patient-reported outcomes (PRO), including health-related quality of life (HRQL), were assessed in a Phase III trial of everolimus in metastatic renal cell carcinoma (mRCC) patients. Methods: Patients with mRCC were randomized (n=416) to receive everolimus or placebo plus best supportive care. Patients completed the FACT-Kidney Symptom Index- Disease Related Symptoms (FKSI-DRS) and EORTC-QLQ C30 at baseline and monthly during treatment. Karnofsky Performance Status (KPS) was also assessed at baseline and monthly during treatment. Primary analyses included time to deterioration defined as a decrease from baseline of at least 3 points for FKSI-DRS, at least 10% for EORTC Physical Function (PF) and Global Quality of Life (QL) scales, and at least 10 points for KPS. Secondary analyses considered tumor progressions that occurred prior to deterioration or censoring date as FKSI deterioration events and compared time to PRO deterioration by tumor progression. Comparisons were made using stratified log-rank tests and Cox proportional hazard models. Results: Time to deterioration in KPS was longer in the everolimus arm, and time to deterioration in FKSI-DRS was slightly longer ( Table ). There was no difference in time to deterioration in PF or QL. Secondary analyses showed median time to deterioration in FKSI-DRS was approximately doubled for the everolimus arm compared to placebo, and patients who progressed experienced a more rapid deterioration in FKSI-DRS and QL scores. Conclusions: Compared to placebo everolimus delayed progression of disease-related symptoms and KPS. No effect on time to deterioration of PF or QL could be determined. Secondary analyses suggest a delay in deterioration in kidney cancer related symptoms via tumor control.

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A phase II trial of gemcitabine and docetaxel in hormone-refractory metastatic prostate cancer

14501

Background: Docetaxel is a microtubule stabilizing agent with demonstrated ability to improve survival in patients (pts) with hormone refractory metastatic prostate cancer (HRMPC). Gemcitabine is a nucleoside analogue that exhibits broad antitumor activity, although as a single agent has modest activity in advanced prostate cancer. The combination of docetaxel and gemcitabine has demonstrated significant activity in a variety of chemotherapy resistant neoplasms. We performed a phase II study of this combination to assess its safety and antitumor activity in chemotherapy naïve patients with HRMPC. Methods: Eligible pts had HRMPC with radiologic and/or biochemical evidence of progression following antiandrogen withdrawal with castrate testosterone levels, ECOG PS 0–2 and adequate organ function; no prior chemotherapy was permitted. Gemcitabine (800 mg/m2) was administered on days 1 and 8 and docetaxel (75mg/m2) on day 8 every 21 days for a maximum of 6 cycles. Results: Twenty-nine pts have been enrolled to date with 22 currently evaluable for response, all are evaluable for toxicity. The median age was 68. The average number of cycles completed was 4.9. Nine pts have experienced grade 4 neutropenia (1 neutropenic fever admission). Twelve of 29 pts have required dose delays secondary to wbc or platelets, two pts have required dose modification. Non-hematologic grade 3/4 toxicities include 1 pt with a PE, 1 grade 4 dyspnea, 1 grade 4 GI bleed. Four pts (18%) achieved measurable disease + PSA, partial response (PR), 7 (32%) additional pts had >50% decline in PSA, for a composite overall response rate of 50%. Conclusions: The combination of gemcitabine and docetaxel is moderately toxic primarily impacting bone marrow reserve. Although there is evidence of significant antitumor activity, the ulitmiate utility of this doublet remains undefined. Accrual to this study is ongoing.

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