Uzzo, Robert G.

Objectives: To report the outcomes of minimally invasive (MIS) nephrectomy following immune checkpoint inhibitor (ICI) therapy. Materials and Methods: This multicenter retrospective cohort study included consecutive patients who underwent nephrectomy following ICI therapy at five high-volume US academic centers between 2015 and 2023. Baseline clinical features and perioperative findings were recorded. After propensity-score matching (PSM), outcomes were compared between MIS and open nephrectomies. The primary outcome was 90-day complications, and secondary outcomes included length of hospital stay (LOS) and 90-day readmission. Results: A total of 158 patients were included, of whom 76 and 82 underwent MIS and open nephrectomies, respectively. The MIS procedures included robotic ( n = 56) and laparoscopic ( n = 20). A total of six (8%) patients converted to open. On multivariable analysis, patients with nonmetastatic vs metastatic renal-cell carcinoma (RCC) (hazard ratio [HR] 3.1, p = 0.01), those with smaller tumor size (HR 1.2 for each cm, p = 0.001), and no clinical evidence of inferior vena cava thrombus (HR 29, p = 0.002) were more likely to undergo the MIS approach compared with open approach. After PSM, including 56 MIS and 36 open nephrectomies, the MIS group compared with the open group had lower estimated blood loss (100 vs 460 mL, p < 0.001) and shorter LOS (2 vs 4 days, p < 0.001). Nevertheless, 90-day complications and readmissions were similar between the two groups. There were no 90-day mortality rates in either group. Conclusion: The MIS approach appears safe and offers more favorable perioperative outcomes compared with open surgery in properly selected patients with advanced RCC who are candidates for nephrectomy following ICI therapy.

4526 Background: Standard methotrexate, vinblastine, doxorubicin and cisplatin (MVAC) demonstrates a survival benefit in the neoadjuvant setting for patients (pts) with muscle invasive bladder cancer (MIBC). Compared with standard MVAC, AMVAC yielded higher response rates with less toxicity in the metastatic setting. Methods: Pts with MIBC, cT2-T4a, and N0-N1 with CrCl >=50 and adequate hepatic and marrow function were eligible. Pts received 3 cycles of AMVAC (methotrexate 30 mg/m2, vinblastine 3 mg/m2, doxorubicin 30 mg/m2, cisplatin 70mg/m2) on day 1, with pegfilgrastim 6 mg day 2 or 3, every 2 weeks. Pts with CrCl < 60 could receive cisplatin split over 2 days. Radical cystectomy (RC) with lymph node dissection was performed 4-8 weeks after the last dose of chemotherapy. Primary endpoint was pathologic complete response (pCR) rate. Results: Accrual is complete with 44 MIBC pts enrolled at 2 institutions (FCCC, TJU) over a 25 month period. Median age 64 (range 45-83). Three withdrew from study early and are not evaluable for response (2 physician discretion, 1 withdrawal of consent). An additional 8 are currently receiving treatment on study with toxicity and response data pending. Of the 33 evaluable pts for whom final data is available, 30 received all 3 cycles of AMVAC at full dose. Three pts received < 3 cycles due to grade 3 fatigue (1), low platelets (1), and disease progression precluding RC (1). 32/33 pts underwent RC, all within 8 weeks of last chemotherapy. Median time from start of chemotherapy to RC was 9.7 wks (range 4.6-13 wks). 13/33 pts (39.4%, 95% CI, 22.7-56.1%) had a pCR. An additional 3 (9.1%) were downstaged to non muscle invasive disease. For the intent to treat cohort (n=36) 8 pts had grade 3-4 AMVAC related adverse events, the most common being anemia (3), fatigue (3) and neutropenia (2) and overall pCR rate was 36.1%. (95% CI, 20.4-51.8%). All pts will have completed study treatment by April 2012. Final results will be presented. Conclusions: Neoadjuvant AMVAC is well tolerated and preliminary results show a pCR rate similar to that reported for standard 12-week MVAC, suggesting that AMVAC for three cycles (6 weeks) is a safe and efficient alternative.

560 Background: Level I evidence exists demonstrating the efficacy of the mTOR inhibitor everolimus (EVE) in decreasing tumor volume of syndromic angiomyolipomas (AMLs) among patients with Tuberous Sclerosis. No prospective data are available regarding the effect of mTOR inhibition on growth kinetics in patients with sporadic AMLs. Methods: We conducted a multi-institutional, prospective, phase 2 trial with an optimal two-stage Simon design in patients presenting with > 3cm sporadic AMLs who were candidates for surgical or percutaneous intervention. Response was defined as ≥25% volumetric reduction of the AML. Planned enrollment was 43 patients to test the null hypothesis at a 5% level of significance with 80% power. Baseline, 4- and 6-month volumetric analysis was performed by dynamic contrast-enhanced MRI (DCE-MRI). Patients received EVE 10mg for four 28-day cycles, at which point EVE was discontinued in those with < 25% volumetric reduction. Those with ≥ 25% volumetric reduction received two additional cycles of EVE. Dose reductions and interruptions were allowed to 5 mg QOD. Conservative stopping rules were established for toxicity, given the benign nature of AMLs. Results: The early stopping rules for both efficacy and toxicity were invoked. We enrolled 20 patients (median age = 68) from 5 centers with 21 sporadic AMLs. 11/20 (55%) patients completed 4 cycles of EVE, while 7/20 (35%) completed 6 cycles. Median days on treatment was 88 (2 cycles). 4/20 (20%) patients were withdrawn due to toxicity, while 8/20 (40%) withdrew due to personal preference. Dose reductions were required in 6/20 (30%) patients, and 5/20 (25%) patients had grade 3 toxicities which resolved upon discontinuation or dose reduction of EVE. At 4-month MRI, 10/16 (62.5%) patients had a ≥25% reduction in volume (mean = 54.1% decrease). At 6-month MRI, 8/12 (66.6%) patients had a ≥25% reduction in volume (mean = 51.5% decrease). Conclusions: EVE was effective in reducing tumor volume in patients with sporadic AMLs but was associated with a high rate of treatment termination due to patient preference or prespecified AEs. Neoadjuvant EVE may be useful in potentiating surgical resection of large or anatomically complex AMLs. Clinical trial information: NCT02539459.

Whereas VHL inactivation is a primary event in clear cell renal cell carcinoma (ccRCC), the precise mechanism(s) of how this interacts with the secondary mutations in tumor suppressor genes, including PBRM1 , KDM5C / JARID1C , SETD2 , and/or BAP1 , remains unclear. Gene expression analyses reveal that VHL, PBRM1, or KDM5C share a common regulation of interferon response expression signature. Loss of HIF2α, PBRM1, or KDM5C in VHL-/- cells reduces the expression of interferon stimulated gene factor 3 (ISGF3), a transcription factor that regulates the interferon signature. Moreover, loss of SETD2 or BAP1 also reduces the ISGF3 level. Finally, ISGF3 is strongly tumor-suppressive in a xenograft model as its loss significantly enhances tumor growth. Conversely, reactivation of ISGF3 retards tumor growth by PBRM1-deficient ccRCC cells. Thus after VHL inactivation, HIF induces ISGF3, which is reversed by the loss of secondary tumor suppressors, suggesting that this is a key negative feedback loop in ccRCC.