Stephen M. Keefe

Management of Sorafenib-Related Adverse Events: A Clinician’s Perspective

Sorafenib, a tyrosine kinase inhibitor, is approved for the treatment of patients with unresectable hepatocellular carcinoma (HCC) and advanced renal cell carcinoma (RCC). It is being evaluated in phase II and III clinical trials, which include treatment as a single agent (locally advanced/metastatic radioactive iodine-refractory differentiated thyroid cancer [DTC]), as part of multimodality care (HCC), and in combination with chemotherapeutic agents (metastatic breast cancer). Sorafenib-related adverse events (AEs) that commonly occur across these tumor types include hand-foot skin reaction (HSFR), rash, upper and lower gastrointestinal (GI) distress (ie, diarrhea), fatigue, and hypertension. These commonly range from grade 1 to 3, per the Common Terminology Criteria for Adverse Events (CTCAE), and often occur early in treatment. The goal for the management of these AEs is to prevent, treat, and/or minimize their effects, thereby enabling patients to remain on treatment and improve their quality of life. Proactive management, along with ongoing patient education (before and during sorafenib treatment), can help to effectively manage symptoms, often without the need for sorafenib dose modification or drug holidays. Effective management techniques for common sorafenib-related AEs, as well other important disease sequelae not directly related to treatment, are presented. Recommendations and observations are based on physician/author experience and recommendations from published literature.

Bladder preservation in the treatment of muscle-invasive bladder cancer (MIBC): a review of the literature and a practical approach to therapy.

Bladder preservation therapies for muscle‐invasive bladder cancer (MIBC) have been developed to address the needs of two cohorts: patients with severe medical co‐morbidities for whom radical cystectomy is too high risk and patients with limited disease who wish to avoid aggressive surgery. There are multiple bladder preservation options, although the trimodal approach of maximal transurethral resection with chemoradiotherapy is the most strongly supported. While outcomes are worse for patients unfit for surgery than those otherwise fit for surgery, bladder preservation approaches still offer curative potential.

Bladder Cancer Patterns of Pelvic Failure: Implications for Adjuvant Radiation Therapy

PURPOSE Local-regional failures (LFs) after cystectomy with or without chemotherapy are common in locally advanced disease. Adjuvant radiation therapy (RT) could reduce LFs, but toxicity has discouraged its use. Modern RT techniques with improved normal tissue sparing have rekindled interest but require knowledge of pelvic failure patterns to design treatment volumes. METHODS AND MATERIALS Five-year LF rates after radical cystectomy plus pelvic node dissection with or without chemotherapy were determined for 8 pelvic sites among 442 urothelial bladder carcinoma patients. The impact of pathologic stage, margin status, nodal involvement, and extent of node dissection on failure patterns was assessed using competing risk analysis. We calculated the percentage of patients whose sites of LF would have been completely encompassed within various hypothetical clinical target volumes (CTVs) for postoperative radiation. RESULTS Compared with stage ≤pT2, stage ≥pT3 patients had higher 5-year LF rates in virtually all pelvic sites. Among stage ≥pT3 patients, margin status significantly altered the failure pattern whereas extent of node dissection and nodal positivity did not. In stage ≥pT3 patients with negative margins, failure occurred predominantly in the iliac/obturator nodes and uncommonly in the cystectomy bed and/or presacral nodes. Of these patients in whom failure subsequently occurred, 76% would have had all LF sites encompassed within CTVs covering only the iliac/obturator nodes. In stage ≥pT3 with positive margins, cystectomy bed and/or presacral nodal failures increased significantly. Only 57% of such patients had all LF sites within CTVs limited to the iliac/obturator nodes, but including the cystectomy bed and presacral nodes in the CTV when margins were positive increased the percentage of LFs encompassed to 91%. CONCLUSIONS Patterns of failure within the pelvis are summarized to facilitate design of adjuvant RT protocols. These data suggest that RT should target at least the iliac/obturator nodes in stage ≥pT3 with negative margins; coverage of the presacral nodes and cystectomy bed may be necessary for stage ≥pT3 with positive margins.

Incidence of Bladder Cancer in Patients With Type 2 Diabetes Treated With Metformin or Sulfonylureas

OBJECTIVE Previous studies evaluating the effect of metformin on cancer risk have been impacted by time-related biases. To avoid these biases, we examined the incidence of bladder cancer in new users of metformin and sulfonylureas (SUs). RESEARCH DESIGN AND METHODS This cohort study included 87,600 patients with type 2 diabetes in The Health Improvement Network database. Use of metformin or an SU was treated as a time-dependent variable. Cox regression–generated hazard ratios (HRs) compared metformin use with SU use, adjusted for age, sex, smoking, obesity, and HbA1c level. RESULTS We identified 196 incident bladder cancers in the metformin cohort and 66 cancers in the SU cohort. Use of metformin was not associated with decreased bladder cancer risk (HR 0.81 [95% CI 0.60–1.09]). This association did not differ by sex (P for interaction = 0.20). We observed no association with duration of metformin relative to SU use (3 to <4 years of use: 0.57 [0.25–1.34]; 4 to <5 years of use: 0.93 [0.30–2.85; ≥5 years of use: 1.18 [0.44–3.19]; P for trend = 0.26). CONCLUSIONS Use of metformin is not associated with a decreased incidence of bladder cancer. Similar methods should be used to study other cancers that have previously been identified as potentially preventable with metformin.

Targeting Vascular Endothelial Growth Factor Receptor in Thyroid Cancer: The Intracellular and Extracellular Implications

Our understanding of the molecular pathophysiology of differentiated thyroid cancer (DTC) has developed considerably over the last 10 years. Aberrant signaling through B-Raf and Akt has been implicated in the tumorigenesis of DTC. Moreover, these highly vascular tumors have proven to be sensitive to the inhibition of vascular endothelial growth factor receptor (VEGFR-2). It is likely that the multikinase inhibitors, sorafenib, sunitinib, axitinib, and motesanib, whose targets include VEGFR-2, exert their effects primarily through inhibition of endothelial cells. However, as VEGFR-2 is expressed on DTC cells, these compounds may have direct antitumor action. This review will discuss the key signaling pathways involved in thyroid cancer and their implications for targeted therapy. Clin Cancer Res; 16(3); 778–83

The Molecular Biology of Renal Cell Carcinoma

Renal cell carcinoma (RCC) includes a variety of disparate diseases, each of which displays interesting and novel molecular features, challenging some of the central tenets of cancer biology and lending unique insights into cancer-promoting mechanisms. The prevailing literature has focused on the most common type, the clear cell renal cell carcinoma (ccRCC) subgroup, in which familial and sporadic disease demonstrate similar molecular profiles. ccRCC is dominated by inactivating mutations in VHL, leading to constitutive activation of the hypoxia-inducible factors (HIFs) and resultant hypoxia response transcription signature, including changes that markedly affect cellular metabolic programs. Recent studies in ccRCC also have implicated mutations in regulators of chromatin remodeling and histone methylation. Although papillary and chromophobe histologies of RCC are highly distinct genetically, both have disruptions in metabolic signaling, suggesting that modulations of basic bioenergetics pathways may regulate kidney cell fates and phenotypes. Finally, emerging evidence of tumor heterogeneity and convergent evolution is reshaping our understanding of how these tumors evolve, underscoring which genetic events are driver mutations, and prompting further consideration of how to interpret molecular analyses of primary tumors in making assessments related to metastatic disease. The past few years have been a period of rapid discovery, which have expanded the opportunities for the renal cancer field to leverage new knowledge into developing diagnostic and therapeutic strategies.

Evaluating the safety and efficacy of axitinib in the treatment of advanced renal cell carcinoma

Axitinib is a tyrosine kinase inhibitor of vascular endothelial growth factor receptor, platelet-derived growth factor receptor-α, and c-kit. Phase I studies demonstrated 5 mg twice daily as the recommended starting dose with notable effects seen in renal cell carcinoma, an observation confirmed in Phase II trials. The trial of comparative effectivess of axitinib versus sorafenib in advanced renal cell carcinoma (AXIS) was an international randomized Phase III study designed for registration purposes, compared axitinib to sunitinib. This trial randomized 723 patients with metastatic kidney cancer to axitinib or sunitinib in the second-line setting and demonstrated a median progression-free survival of 6.7 months for axitinib versus 4.7 months for sorafenib (P<0.0001). Clinical benefit was detected regardless of prior therapy, but no overall survival benefit has been observed. Axitinib is well tolerated without a significant effect on quality of life. The most common grade 3 toxicities are hypertension (16%), diarrhea (11%), and fatigue (11%), with other notable side effects being anorexia, nausea, hand–foot syndrome, and rash. Patients who developed diastolic blood pressure >90 mmHg were noted to have significantly longer median overall survival and overall response rates when compared to normotensive patients. Therefore, the manufacturer recommends escalating the twice-daily dose to 7 mg and 10 mg, as tolerated, if there is no significant increase in blood pressure on treatment. Currently, axitinib is approved for use in the second-line setting for patients with metastatic renal cell carcinoma. Research is ongoing in other disease settings.

MRI Assessment of Early Tumor Response in Metastatic Renal Cell Carcinoma Patients Treated With Sorafenib

OBJECTIVE The purpose of this study was to examine early MRI changes in renal cell carcinoma (RCC) treated with the antiangiogenic agent sorafenib and to identify MRI biomarkers of RCC response to sorafenib. MATERIALS AND METHODS Sixteen patients with RCC were evaluated by MRI before and 3-12 weeks after commencing treatment with sorafenib. Two experienced MR radiologists, blinded to treatment status, independently graded tumor appearance on T1-weighted, T2-weighted, and gadolinium-enhanced images. The proportional odds mixed model was used to compare qualitative appearance of tumors before and after therapy. Time-to-progression was correlated with Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 and MR-modified Choi criteria, incorporating changes in both tumor enhancement and size. RESULTS After sorafenib therapy, there was a significant increase in T1 signal intensity of tumors (p < 0.0001) and a significant decrease in degree of tumor enhancement (p < 0.0001). The sum of unidimensional tumor diameters decreased significantly after therapy (p = 0.005). However, the average decrease in size at early follow-up was 13%, and all patients except one had stable disease by RECIST 1.0. Early responders defined by MR-modified Choi criteria had increased time-to-progression compared with nonresponders, whereas early RECIST evaluation did not predict clinical outcome. CONCLUSION Decreased enhancement and T1 shortening of tumors on MRI may be useful biomarkers of RCC response to angiogenesis inhibitors. Response criteria combining early changes in size and enhancement lead to better correlation with clinical outcome compared with size decrease alone.

Occult Pelvic Lymph Node Involvement in Bladder Cancer: Implications for Definitive Radiation

PURPOSE To inform radiation treatment planning for clinically staged, node-negative bladder cancer patients by identifying clinical factors associated with the presence and location of occult pathologic pelvic lymph nodes. METHODS AND MATERIALS The records of patients with clinically staged T1-T4N0 urothelial carcinoma of the bladder undergoing radical cystectomy and pelvic lymphadenectomy at a single institution were reviewed. Logistic regression was used to evaluate associations between preoperative clinical variables and occult pathologic pelvic or common iliac lymph nodes. Percentages of patient with involved lymph node regions entirely encompassed within whole bladder (perivesicular nodal region), small pelvic (perivesicular, obturator, internal iliac, and external iliac nodal regions), and extended pelvic clinical target volume (CTV) (small pelvic CTV plus common iliac regions) were calculated. RESULTS Among 315 eligible patients, 81 (26%) were found to have involved pelvic lymph nodes at the time of surgery, with 38 (12%) having involved common iliac lymph nodes. Risk of occult pathologically involved lymph nodes did not vary with clinical T stage. On multivariate analysis, the presence of lymphovascular invasion (LVI) on preoperative biopsy was significantly associated with occult pelvic nodal involvement (odds ratio 3.740, 95% confidence interval 1.865-7.499, P<.001) and marginally associated with occult common iliac nodal involvement (odds ratio 2.307, 95% confidence interval 0.978-5.441, P=.056). The percentages of patients with involved lymph node regions entirely encompassed by whole bladder, small pelvic, and extended pelvic CTVs varied with clinical risk factors, ranging from 85.4%, 95.1%, and 100% in non-muscle-invasive patients to 44.7%, 71.1%, and 94.8% in patients with muscle-invasive disease and biopsy LVI. CONCLUSIONS Occult pelvic lymph node rates are substantial for all clinical subgroups, especially patients with LVI on biopsy. Extended coverage of pelvic lymph nodes up to the level of the common iliac nodes may be warranted in subsets of patients.

Efficacy of the nanoparticle–drug conjugate CRLX101 in combination with bevacizumab in metastatic renal cell carcinoma: results of an investigator-initiated phase I–IIa clinical trial

BACKGROUND Anti-angiogenic therapies are effective in metastatic renal cell carcinoma (mRCC), but resistance is inevitable. A dual-inhibition strategy focused on hypoxia-inducible factor (HIF) is hypothesized to be active in this refractory setting. CRLX101 is an investigational camptothecin-containing nanoparticle-drug conjugate (NDC), which durably inhibits HIF1α and HIF2α in preclinical models and in gastric cancer patients. Synergy was observed in the preclinical setting when combining this NDC and anti-angiogenic agents, including bevacizumab. PATIENTS AND METHODS Patients with refractory mRCC were treated every 2 weeks with bevacizumab (10 mg/kg) and escalating doses of CRLX101 (12, 15 mg/m(2)) in a 3 + 3 phase I design. An expansion cohort of 10 patients was treated at the recommended phase II dose (RP2D). Patients were treated until progressive disease or prohibitive toxicity. Adverse events (AEs) were assessed using CTCAE v4.0 and clinical outcome using RECIST v1.1. RESULTS Twenty-two patients were response-evaluable in an investigator-initiated trial at two academic medical centers. RCC histologies included clear cell (n = 12), papillary (n = 5), chromophobe (n = 2), and unclassified (n = 3). Patients received a median of two prior therapies, with at least one prior vascular endothelial tyrosine kinase inhibitor therapy (VEGF-TKI). No dose-limiting toxicities were observed. Grade ≥3 AEs related to CRLX101 included non-infectious cystitis (5 events), fatigue (3 events), anemia (2 events), diarrhea (2 events), dizziness (2 events), and 7 other individual events. Five of 22 patients (23%) achieved partial responses, including 3 of 12 patients with clear cell histology and 2 of 10 patients (20%) with non-clear cell histology. Twelve of 22 patients (55%) achieved progression-free survival (PFS) of >4 months. CONCLUSIONS CRLX101 combined with bevacizumab is safe in mRCC. This combination fulfilled the protocols predefined threshold for further examination with responses and prolonged PFS in a heavily pretreated population. A randomized phase II clinical trial in mRCC of this combination is ongoing.