Pasotuxizumab, a BiTE® immune therapy for castration-resistant prostate cancer: Phase I, dose-escalation study findings.

Aim: We report results of a first-in-human study of pasotuxizumab, a PSMA bispecific T-cell engager (BiTE®) immune therapy mediating T-cell killing of tumor cells in patients with advanced castration-resistant prostate cancer. Patients & methods: We assessed once-daily subcutaneous (SC) pasotuxizumab. All SC patients developed antidrug antibodies; therefore, continuous intravenous (cIV) infusion was assessed. Results: A total of 47 patients received pasotuxizumab (SC: n = 31, 0.5-172 µg/d; cIV: n = 16, 5-80 µg/d). The SC maximum tolerated dose was 172.0 µg/d. A sponsor change stopped the cIV cohort early; maximum tolerated dose was not determined. PSA responders occurred (>50% PSA decline: SC, n = 9; cIV, n = 3), including two long-term responders. Conclusion: Data support pasotuxizumab safety in advanced castration-resistant prostate cancer and represent evidence of BiTE monotherapy efficacy in solid tumors. Clinical trial registration: NCT01723475 (ClinicalTrials.gov).

Perioperative Changes and Progress in Photoselective Vaporization of the Prostate with GreenLight XPS 180 W System: A Single Center Experience.

PURPOSE: The study aimed to evaluate progression of GreenLight-XPS 180 W photoselective vaporization of the prostate (GL-XPS) with respect to effectiveness, efficacy, and safety over time at a tertiary referral high volume center. METHODS: The retrospective study included 375 men who underwent GL-XPS for symptomatic benign prostate obstruction (BPO) between June 2010 and February 2015. Primary outcome measurements were operation time (OT; min) and effective laser time (LT; min of OT) analyzed with regard to prostatic volume (PV; mL) (group 1 <40 mL up to 4 >80 mL in 20 mL steps) and the year of surgery (2010-2015). RESULTS: The median age was 72 years (range 64-79), the median PV was 58 mL (range 33-98) and the median PV increased from 42 mL in 2012 to 80 mL in 2015. The OT and LT clearly correlated with the PV, being doubled for glands of median 95 mL compared to median 30 mL while the applied laser energy per LT likewise steadily increased. Overall, both OT and LT could be significantly reduced each year by 37% (OT; p < 0.05) and 36% (LT; p < 0.05) within 5 years. The hospital stay (days) and catheterization time (days) remained constant, without any changes over time. The overall complication rate (Clavien-Dindo >2) ranged from 36 to 15% between 2010 and 2015. The pre (median 22 + 4) and postoperative International Prostate Symptom Score-Quality of Life (median 5 + 1) showed a sufficient reduction in symptomatic BPO. CONCLUSION: GL-XPS is a safe and effective surgical method for symptomatic BPO. Our single center experience showed a significant improvement of both OT and effective LT within 5 years whilst maintaining stable low complication rate and high patient satisfaction.

[Interdisciplinary Recommendations for the Treatment of Metastatic Renal Cell Carcinoma]. / Interdisziplinäre Empfehlungen zur Behandlung des metastasierten Nierenzellkarzinoms .

Thanks to the use of targeted therapies, the prognosis of patients with metastatic renal cell carcinoma (mRCC) has improved significantly. A median overall survival of more than 2 years is a realistic claim. These improvements are also reflected in recent discussions about 3 and more lines of therapy.Sunitinib, pazopanib, the combination of bevacizumab and interferon alpha, and temsirolimus are approved for first-line therapy of mRCC. Sunitinib and pazopanib are also approved for second-line therapy, which, for pazopanib, is confined to the use after cytokine failure. Everolimus (after tyrosine kinase inhibitor (TKI) treatment), sorafenib (after cytokines) and axitinib (after treatment with sunitinib or cytokines) are other compounds available for second-line therapy.3 new substances have recently been approved for second-line therapy: Nivolumab, cabozantinib, and lenvatinib combined with everolimus can be used after VEGF-targeted treatment has failed. It is for the first time that targeted immunotherapy and a combination of targeted substances are available for the treatment of mRCC.There is no new insight as to an optimal sequence therapy. Study results from a phase III trial suggest that the sequences sorafenib-sunitinib and sunitinib-sorafenib are equally effective.The purpose of an interdisciplinary expert meeting on RCC was to work out joint treatment recommendations based on current data and clinical experience and to integrate them into clinical routine practice. The results are presented in this publication.

Systemic therapy in metastatic renal cell carcinoma.

PURPOSE: Current systemic treatment of targeted therapies, namely the vascular endothelial growth factor-antibody (VEGF-AB), VEGF receptor tyrosine kinase inhibitor (TKI) and mammalian target of rapamycin (mTOR) inhibitors, have improved progression-free survival and replaced non-specific immunotherapy with cytokines in metastatic renal cell carcinoma (mRCC). METHODS: A panel of experts convened to review currently available phase 3 data for mRCC treatment of approved agents, in addition to available EAU guideline data for a collaborative review as the plurality of substances offers different options of first-, second- and third-line treatment with potential sequencing. RESULTS: Sunitinib and pazopanib are approved treatments in first-line therapy for patients with favorable- or intermediate-risk clear cell RCC (ccRCC). Temsirolimus has proven benefit over interferon-alfa (IFN-α) in patients with non-clear cell RCC (non-ccRCC). In the second-line treatment TKIs or mTOR inhibitors are treatment choices. Therapy options after TKI failure consist of everolimus and axitinib. Available third-line options consist of everolimus and sorafenib. Recently, nivolumab, a programmed death-1 (PD1) checkpoint inhibitor, improved overall survival benefit compared to everolimus after failure of one or two VEGFR-targeted therapies, which is likely to become the first established checkpoint inhibitor in mRCC. Data for the sequencing of agents remain limited. CONCLUSIONS: Despite the high level of evidence for first and second-line treatment in mRCC, data for third-line therapy are limited. Possible sequences include TKI-mTOR-TKI or TKI-TKI-mTOR with the upcoming checkpoint inhibitors in perspective, which might settle a new standard of care after previous TKI therapy.

A Multicenter Randomized Noninferiority Trial Comparing GreenLight-XPS Laser Vaporization of the Prostate and Transurethral Resection of the Prostate for the Treatment of Benign Prostatic Obstruction: Two-yr Outcomes of the GOLIATH Study.

BACKGROUND: The GOLIATH study is a 2-yr trial comparing transurethral resection of prostate (TURP) to photoselective vaporization with the GreenLight XPS Laser System (GL-XPS) for the treatment of benign prostatic obstruction (BPO). Noninferiority of GL-XPS to TURP was demonstrated based on a 6-mo follow-up from the study. OBJECTIVE: To determine whether treatment effects observed at 6 mo between GL-XPS and TURP was maintained at the 2-yr follow-up. DESIGN, SETTING, AND PARTICIPANTS: Prospective randomized controlled trial at 29 centers in nine European countries involving 281 patients with BPO. INTERVENTION: Photoselective vaporization using the 180-W GreenLight GL-XPS or conventional (monopolar or bipolar) TURP. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary outcome was the International Prostate Symptom Score for which a margin of three was used to evaluate the noninferiority of GL-XPS. Secondary outcomes included Qmax, prostate volume, prostate specific antigen, Overactive Bladder Questionnaire Short Form, International Consultation on Incontinence Questionnaire Short Form, occurrence of surgical retreatment, and freedom from complications. RESULTS AND LIMITATIONS: One hundred and thirty-six patients were treated using GL-XPS and 133 using TURP. Noninferiority of GL-XPS on International Prostate Symptom Score, Qmax, and freedom from complications was demonstrated at 6-mo and was sustained at 2-yr. The proportion of patients complication-free through 24-mo was 83.6% GL-XPS versus 78.9% TURP. Reductions in prostate volume and prostate specific antigen were similar in both arms and sustained over the course of the trial. Compared with the 1(st) yr of the study, very few adverse events or retreatments were reported in either arm. Treatment differences in the Overactive Bladder Questionnaire Short Form observed at 12-mo were not statistically significant at 24-mo. A limitation was that patients and treating physicians were not blinded to the therapy. CONCLUSIONS: Twenty-four-mo follow-up data demonstrated that GL-XPS provides a durable surgical option for the treatment of BPO that exhibits efficacy and safety outcomes similar to TURP. PATIENT SUMMARY: The long-term effectiveness and safety of GLP-XLS was similar to conventional TURP for the treatment of prostate enlargement.

A European multicenter randomized noninferiority trial comparing 180 W GreenLight XPS laser vaporization and transurethral resection of the prostate for the treatment of benign prostatic obstruction: 12-month results of the GOLIATH study.

PURPOSE: We present the 1-year results of the GOLIATH prospective randomized controlled trial comparing transurethral resection of the prostate to GreenLight XPS for the treatment of men with nonneurogenic lower urinary tract symptoms due to prostate enlargement. The updated results at 1 year show that transurethral resection of the prostate and GreenLight XPS remain equivalent, and confirm the therapeutic durability of both procedures. We also report 1-year followup data from several functional questionnaires (OABq-SF, ICIQ-SF and IIEF-5) and objective assessments. MATERIALS AND METHODS: A total of 291 patients were enrolled at 29 sites in 9 European countries. Patients were randomized 1:1 to undergo GreenLight XPS or transurethral resection of the prostate. The trial was designed to evaluate the hypothesis that GreenLight XPS is noninferior to transurethral resection of the prostate on the International Prostate Symptom Score at 6 months. Several objective parameters were assessed, including maximum urinary flow rate, post-void residual urine volume, prostate volume and prostate specific antigen, in addition to functional questionnaires and adverse events at each followup. RESULTS: Of the 291 enrolled patients 281 were randomized and 269 received treatment. Noninferiority of GreenLight XPS was maintained at 12 months. Maximum urinary flow rate, post-void residual urine volume, prostate volume and prostate specific antigen were not statistically different between the treatment arms at 12 months. The complication-free rate at 1 year was 84.6% after GreenLight XPS vs 80.5% after transurethral resection of the prostate. At 12 months 4 patients treated with GreenLight XPS and 4 who underwent transurethral resection of the prostate had unresolved urinary incontinence. CONCLUSIONS: Followup at 1 year demonstrated that photoselective vaporization of the prostate produced efficacy outcomes similar to those of transurethral resection of the prostate. The complication-free rates and overall reintervention rates were comparable between the treatment groups.

Toxicities following treatment with bisphosphonates and receptor activator of nuclear factor-κB ligand inhibitors in patients with advanced prostate cancer.

CONTEXT: Advanced prostate cancer (PCa) is associated with skeletal complications, both as a result of bone metastases and because of fractures associated with fragility due to androgen-deprivation therapy (ADT). Osteoclast inhibitors are commonly used to reduce skeletal complications but are associated with a number of potential adverse events. OBJECTIVE: To review clinical trials of osteoclast inhibitors in advanced PCa, to discuss the adverse event profile of these agents, and to discuss strategies to address specific adverse events. EVIDENCE ACQUISITION: PubMed was searched for reports of clinical trials of osteoclast inhibitors in advanced PCa. As zoledronic acid and denosumab are used most commonly in this disease, these trials were the focus. The literature was reviewed to identify key publications addressing the prevention and management of adverse events associated with these drugs. EVIDENCE SYNTHESIS: The major findings of the trials and the adverse events are discussed. Prevention and management of common adverse events are addressed. CONCLUSIONS: Zoledronic acid prevents loss of bone mineral density associated with ADT and delays skeletal-related events in metastatic castration-resistant PCa (mCRPC). Denosumab reduces the incidence of fragility fractures associated with ADT, delays the onset of bone metastases in nonmetastatic castration-resistant disease, and is superior to zoledronic acid in the prevention of skeletal complications in mCRPC. Adverse events associated with both agents include osteonecrosis of the jaw and hypocalcemia. Hypocalcemia is more common with denosumab. Zoledronic acid requires dose modifications for renal insufficiency, is contraindicated in severe renal insufficiency, and has been associated with deterioration of renal function. Appropriate patient selection with close attention to dental health, supplementation with calcium and vitamin D, and monitoring of laboratory values are effective strategies to minimize the impact of adverse events associated with osteoclast inhibitors in advanced PCa.

Sequential mTOR inhibitor treatment with temsirolimus in metastatic renal cell carcinoma following failure of VEGF receptor tyrosine kinase inhibitors.

PURPOSE: Agents targeting the mammalian target of rapamycin (mTOR) pathway, e. g. everolimus, can provide clinical benefit in pretreated patients with metastatic renal cell carcinoma (mRCC), but data from randomized trials on the sequential use of temsirolimus are lacking. We retrospectively studied the efficacy and safety of temsirolimus therapy following failure of rTKI therapy. METHODS: Twenty-nine patients treated with temsirolimus (25 mg/week) following progression on rTKI therapy were studied at four institutions. All patients had failed at least one prior rTKI therapy (sunitinib, n = 6; sorafenib, n = 1; both, n = 22). Over 80% had two or more prior therapies. Data on efficacy (response assessment, progression-free survival [PFS], overall survival [OS]) and safety (NCI-CTC) were analyzed. RESULTS: Adverse events occurred in 90% of patients with the majority being grade 1 (n = 4, 14%) or grade 2 (n = 12, 41%). Most grade 3/4 toxicities (n = 10, 34%) were manageable and included anemia (n = 4, 14%), leukopenia/neutropenia (n = 2, 7%), hyperglycemia (n = 1, 3%), acidosis/alkalosis (n = 2, 7%), and infection (n = 1, 3%). One patient discontinued temsirolimus for grade 3 pneumonitis. Median (range) PFS and OS were 5.1 months (1-10.4) and 18.0 months (12.6-23.3), respectively. Best response included partial response (n = 1) and stable disease (n = 15) for a disease control rate of 55%, and disease progression of 45% (n = 13). CONCLUSIONS: Temsirolimus after rTKI failure appears to provide promising safety and efficacy comparable to other treatment options in pretreated patients with mRCC.

Novel low-cost prostate resection trainer-description and preliminary evaluation.

BACKGROUND: Transurethral resection of the prostate (TURP) is a challenging operation for residents with limited endoscopic experience. A number of virtual TURP simulators have been validated in the past. This study is the first description and preliminary evaluation of a non-virtual, low-cost TURP trainer as a teaching tool for residents in urology. METHODS: Dr K. Forke's prostatic resection trainer (PRT; LS 10-2/S, Samed GmbH, Dresden, Germany) was tested during the surgical training of a resident. Under the supervision of an experienced senior surgeon, three aspects were examined: the resection trainer's approximation to reality, the ease of instruction, and the potential capability to improve surgeons' psychomotor abilities with regard to the three-dimensional (3D) guidance of the instrument. The improvement in resection speed (RS) of residents with no PRT training (control group) was also compared to the results of the PRT-trained resident. RESULTS: During the PRT training, the resident displayed clear improvement in resection quality (RQ) and a 27% increase in RS (p = 0.03). In the post-training stage, the PRT-trained resident showed a more constant progress rate, to a maximum RS of 0.37 g/min (35% increase; p = 0.01), whereas the control group displayed varied RS learning curves. Composed of a synthetic material, which can be resected by standard instruments, the trainer offers a haptical experience that is particularly realistic and may provide an increased learning rate. CONCLUSION: From the findings, we conclude that this novel PRT is suitable for daily use and offers an effective and more affordable alternative to virtual simulators. Further validation studies will follow and new fields of application will be tested.

Sequence therapy in patients with metastatic renal cell carcinoma: comparison of common targeted treatment options following failure of receptor tyrosine kinase inhibitors.

BACKGROUND: The best sequence of targeted therapy in patients with metastatic renal cell carcinoma (mRCC) has not been sufficiently defined. OBJECTIVE: To describe the efficacy and toxicity of sequential everolimus (EV) versus receptor tyrosine kinase inhibitor (rTKI) following failure of first rTKI treatment. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of 108 patients receiving rTKI or EV after progression on rTKI therapy at two German academic centres. INTERVENTION: Sequence of systemic targeted treatment with sunitinib (n=85) or sorafenib (n=23) followed by EV (n=62) or another rTKI (n=46; sorafenib, n=35; sunitinib, n=11). MEASUREMENTS: We measured response rate (Response Evaluation Criteria in Solid Tumours 1.0) and toxicity. Survival analysis (Kaplan-Meier method and Cox regression) was conducted for progression-free survival (PFS) and overall survival (OS). RESULTS AND LIMITATIONS: Main patient characteristics did not significantly differ by sequence of treatment groups (rTKI-rTKI vs rTKI-EV). Response rate following first rTKI failure was not significantly different between sequential therapies with a disease control rate of 51.6% (EV) and 43.5% (rTKI). The corresponding median PFS was 3.6 mo (95% confidence interval [CI], 1.8-5.4) for EV and 4.0 mo (3.2-4.9) for rTKI treatment. The estimated OS was longer for the rTKI-EV group (43 mo; 95% CI, 33.9-52.1) than for the rTKI-rTKI group (29 mo; 95% CI, 18.6-39.5; p=0.03), but this difference lost statistical significance in multivariable-adjusted analyses. Intrinsic rTKI resistance was independently associated with inferior subsequent PFS (hazard ratio [HR]: 1.79; 95% CI, 1.15-3.62; p=0.015) and OS (HR: 6.54; 95% CI, 3.01-14.20; p<0.001). Limitations are the retrospective design, limited numbers of cases, and residual confounding factors. CONCLUSIONS: The sequence therapies rTKI-EV and rTKI-rTKI may be equally efficacious in terms of PFS and response rate, whereas a tendency towards superior survival was observed for the rTKI-EV sequence. These data, particularly the potential benefit of an early change of mode of action, need confirmation in randomised comparative trials.

Intrinsic resistance to tyrosine kinase inhibitors is associated with poor clinical outcome in metastatic renal cell carcinoma.

BACKGROUND: Data on sequential therapy in patients with metastatic renal cell carcinoma (mRCC) and intrinsic resistance to receptor tyrosine kinase inhibitor (rTKI) treatment remains vague. METHODS: We retrospectively studied treatment characteristics and outcome of mRCC patients refractory to first rTKI therapy. RESULTS: Thirty-five mRCC patients (male, 18; female, 11) with primary resistance to first rTKI therapy (sunitinib, n = 28; sorafenib, n = 7) and a median treatment interval of 2.4 months (1 - 4.6) were identified. In 22 patients, progressive disease (PD) was determined by a new metastatic lesion. Of these, 16 patients received subsequent therapy with 12 patients remaining refractory and 4 patients achieving disease stabilization. In 13 patients continuous growth of existing metastatic lesions determined PD. Of these, 9 received sequential therapy with 6 achieving disease stabilization. Altogether, 25 patients were treated sequentially (rTKI: n = 15; mTOR-inhibitor: n = 10) and achieved a median PFS of 3.2 months (range, 1-16.6). Fifteen patients failed to respond to either line of therapy. Disease control was not associated with type of subsequent therapy. Median OS was 14.9 months (CI: 5.5-24.4). CONCLUSION: Intrinsic resistance to rTKI is associated with a low chance of response to sequential therapy and a poor prognosis in mRCC patients.

Areas suspicious for prostate cancer: MR-guided biopsy in patients with at least one transrectal US-guided biopsy with a negative finding--multiparametric MR imaging for detection and biopsy planning.

PURPOSE: To prospectively investigate the incremental value of multiparametric magnetic resonance (MR) imaging compared with standard T2-weighted imaging for biopsy planning. MATERIALS AND METHODS: The study was approved by the institutional review board; informed consent was obtained. Consecutive patients underwent T2-weighted imaging supplemented with multiparametric 1.5-T MR imaging, consisting of hydrogen 1 ((1)H) MR spectroscopy, diffusion-weighted (DW) imaging, and contrast material-enhanced MR imaging. Quantitative parameters were calculated: (choline plus creatine)-to-citrate ratio, apparent diffusion coefficient, and volume transfer constant and exchange rate constant. The prostate was divided into 20 standardized areas. Each area was classified as benign, inconclusive, or suspicious at T2-weighted imaging, followed by quantitative evaluation of all inconclusive and suspicious areas with multiparametric MR imaging. MR-guided biopsy was performed in lesions classified as suspicious for cancer with at least one of the techniques after transfer to three-dimensional T2-weighted images. Diagnostic parameters were calculated on a per-lesion and per-patient basis for all combinations of T2-weighted imaging with multiparametric MR imaging. RESULTS: Fifty-four patients had a median of two prior transrectal ultrasonographic biopsies with negative findings. Each patient had a median of three suspicious lesions. Prostate cancer was demonstrated in 21 of 54 patients. Biopsy was performed in 178 lesions; 53 were positive for prostate cancer. Detection rates and test negative results, respectively, were as follows: T2-weighted imaging, 70% and 50%; T2-weighted imaging and (1)H MR spectroscopy, 81% and 32%; T2-weighted imaging and contrast-enhanced MR imaging, 83% and 29%; T2-weighted imaging and DW imaging, 85% and 30%; T2-weighted imaging, (1)H MR spectroscopy, and contrast-enhanced MR imaging, 91% and 13%; T2-weighted imaging, (1)H MR spectroscopy, and DW imaging, 94% and 15%; T2-weighted imaging, DW imaging, and contrast-enhanced MR imaging, 94% and 13%; T2-weighted imaging, (1)H MR spectroscopy, DW imaging, and contrast-enhanced MR imaging, 100% and 0%. CONCLUSION: Only the combination of T2-weighted imaging with all three multiparametric techniques depicts all identifiable prostate cancers; a double combination with DW imaging and (1)H MR spectroscopy or contrast-enhanced MR imaging misses 6%, while reasonably reducing the number of areas needing biopsy.

Systemic immune tuning in renal cell carcinoma: favorable prognostic impact of TGF-ß1 mRNA expression in peripheral blood mononuclear cells.

Renal cell carcinoma (RCC) can inhibit protective immunity by induction of immunosuppressive cells that produce inhibitory cytokines such as interleukin (IL)-10 and transforming growth factor (TGF)-ß. If this immunosuppression influences response to kinase inhibitors such as sorafenib is not known. Therefore, we asked for the prognostic influence of cells with immunosuppressive properties in peripheral blood (pB) in a cohort of metastatic clear cell renal cell carcinoma (mRCC) patients uniformly receiving sorafenib treatment. IL-10 and TGF-ß mRNA levels, regulatory T-cell (Treg) counts, and frequencies of IL-10/TGF-ß producing mononuclear cell subsets were determined in pB from 46 patients with mRCC before receiving sorafenib treatment. Relationship between established clinical and laboratory prognostic factors and outcome were examined by univariate and multivariate Cox regression analysis. IL-10 and TGF-ß1 mRNA levels, and frequencies of CD4(+)CD25high/CD3(+) and CD4(+)CD25highFoxP3(+)/CD3(+)Treg cells were significantly higher in mRCC patients compared with healthy individuals. Monocytes were suggested as main producers of IL-10 and TGF-ß. In a multivariate analysis low ECOG score and-surprisingly-high TGF-ß1 mRNA levels were independently associated with favorable progression-free survival (P=0.005 and P=0.003, respectively) and overall survival (P=0.001 and P=0.039, respectively). In conclusion, mRCC is associated with an immunosuppressive phenotype in peripheral blood. The positive prognostic influence of high TGF-ß1 mRNA expression levels may reflect immune promoting functions of TGF-ß in combined activity with inflammatory cytokines.

Sunitinib treatment for patients with advanced clear-cell renal-cell carcinoma after progression on sorafenib.

BACKGROUND: Sorafenib and sunitinib are tyrosine kinase inhibitors with largely overlapping specificities, approved for the treatment of metastatic renal-cell carcinoma (RCC). It was unclear whether the similarities of the two drugs would lead to complete cross-resistance, or whether sequential application would be efficacious. METHODS: Patients with metastatic RCC and progression on sorafenib treatment were treated with repeated cycles of sunitinib, 50 mg for 4 weeks, followed by a 2-week break. Response (Response Evaluation Criteria in Solid Tumors, RECIST) was assessed every second cycle. RESULTS: A total of 22 patients with progression on sorafenib were accrued. Initially, sorafenib treatment was efficacious in all patients, with 7 showing partial response (PR) and 15 stable disease (SD), and subsequent disease progression. With 4 PRs (18%) and 12 SD (55%) a disease control rate of 73% was achieved. The median progression-free survival (PFS) on sunitinib was 21.5 weeks; median overall survival (OS) was not reached. Estimated 1-year PFS and OS were 31 and 60%, respectively. There was no apparent relationship between response to sorafenib and outcome on sunitinib. CONCLUSION: In our cohort of patients with RCC and progression after initial efficacy of sorafenib, the efficacy data of second-line sunitinib were close to published results of first-line treatment, suggesting limited clinically relevant cross-resistance.

Can tyrosine kinase inhibitors be discontinued in patients with metastatic renal cell carcinoma and a complete response to treatment? A multicentre, retrospective analysis.

BACKGROUND: Discontinuation of treatment with tyrosine kinase inhibitors (TKIs) and readministration in case of recurrence could improve quality of life (QoL) and reduce treatment costs for patients with metastatic renal cell carcinoma (mRCC) in which a complete remission (CR) is achieved by medical treatment alone or with additional resection of residual metastases. OBJECTIVE: To evaluate whether TKIs can be discontinued in these selected patients with mRCC. DESIGN, SETTING, AND PARTICIPANTS: A retrospective analysis of medical records and imaging studies was performed on all patients with mRCC treated with TKIs (n=266) in five institutions. Patients with a CR under TKI treatment alone or with additional metastasectomy of residual disease following a partial response (PR), in which TKIs were discontinued, were included in the analysis. Outcome criteria analysed were time to recurrence of previous metastases, occurrence of new metastases, symptomatic progression, improvement of adverse events, and response to reexposure to TKIs. INTERVENTIONS: Sunitinib 50mg/day for 4 wk on and 2 wk off, sorafenib 800mg/day. MEASUREMENTS: Response according to Response Evaluation Criteria in Solid Tumours (RECIST). RESULTS AND LIMITATIONS: We identified 12 cases: 5 CRs with sunitinib, 1 CR with sorafenib, and 6 surgical CRs with sunitinib followed by residual metastasectomy. Side-effects subsided in all patients off treatment. At a median follow-up of 8.5 mo (range: 4-25) from TKI discontinuation, 7 of 12 patients remained without recurrence and 5 had recurrent disease, with new metastases in 3 cases. Median time to progression was 6 mo (range: 3-8). Readministration of TKI was effective in all cases. The study is limited by small numbers and retrospective design. CONCLUSIONS: Discontinuation of TKI in patients with mRCC and CR carries the risk of progression with new metastases and potential complications. Further investigation in a larger cohort of patients is warranted before such an approach can be regarded as safe.