Long-term survival of patients with advanced melanoma treated with BRAF-MEK inhibitors

Recent results of patients with advanced melanoma treated with first-line BRAF-MEK inhibitors in clinical trials showed 5-year survival in one-third of patients with a median overall survival (OS) of more than 2 years. This study aimed to investigate these patients' real-world survival and identify the characteristics of long-term survivors. The study population consisted of patients with advanced cutaneous melanoma with a BRAF-V600 mutated tumor who were treated with first-line BRAF-MEK inhibitors between 2013 and 2017. Long-term survival was defined as a minimum OS of 2 years from start therapy. The median progression-free survival (mPFS) and median OS (mOS) of real-world patients ( n  = 435) were respectively 8.0 (95% CI, 6.8-9.4) and 11.7 (95% CI, 10.3-13.5) months. Two-year survival was reached by 28% of the patients, 22% reached 3-year survival and 19% reached 4-year survival. Real-world patients often had brain metastases (41%), stage IV M1c disease (87%), ECOG PS ≥2 (21%), ≥3 organ sites (62%) and elevated LDH of ≥250 U/I (49%). Trial-eligible real-world patients had an mOS of 17.9 months. Patients surviving more than 2 years ( n  = 116) more often had an ECOG PS ≤1 (83%), normal LDH (60%), no brain metastases (60%), no liver metastases (63%) and <3 organ sites (60%). Long-term survival of real-world patients treated with first-line BRAF-MEK inhibitors is significantly lower than that of trial patients, which is probably explained by poorer baseline characteristics of patients treated in daily practice. Long-term survivors generally had more favorable characteristics with regard to age, LDH level and metastatic sites, compared to patients not reaching long-term survival.

Abstract CT145: Repeated radium-223-chloride versus rhenium-188-HEDP in patients with metastatic castration-resistant prostate cancer: RaRe study

Background: For patients with castration-resistant prostate cancer (CRPC) metastatic to bone, treatment with bone seeking radiopharmaceuticals is an important treatment option, both for pain palliation and improvement of survival. Radium-223-chloride (an alpha-emitter) has a proven survival benefit. Some small clinical studies suggest that rhenium-188-HEDP, a beta-emitter that is well-known for its effect on pain palliation, may have a beneficial effect on survival as well. A major advantage of rhenium-188-HEDP, compared to radium-223-chloride is the production on-site at a healthcare institute, resulting in rapidly availability and lower costs. Other advantages of rhenium-188-HEDP includes more favorable physical characteristics (shorter half-life and longer penetration depth) and being more patient-friendly (3 instead of 6 administrations) compared to radium-223-chloride. Despite some promising data in small randomized studies, the potential effect on patient survival of rhenium-188-HEDP needs to be established in a randomized phase III study.

Methods: The RaRe trial is a multicenter, randomized, open-label, controlled phase III study comparing the efficacy of repeated treatment with radium-223-chloride and repeated treatment with rhenium-188-HEDP in patients with CRPC metastatic to bone. The aim of the trial is to include 402 participants who are randomized to one of the two treatment groups in a 1:1 ratio. The primary endpoint is overall survival (OS), and the secondary endpoints are pain response, quality of life (QoL), time to first occurrence of skeletal related event (SRE), prostate specific antigen (PSA) progression, total alkaline phosphatase (tALP) progression, and incremental cost-effectiveness. An interim analysis for futility will be performed after the inclusion of 90 patients in each treatment group.

Discussion: In this randomized phase III trial we hypothesize that treatment with rhenium-188-HEDP results in an improved survival in patients with CRPC metastatic to bone as compared to the current standard treatment with radium-223-chloride. We also expect to demonstrate that treatment with rhenium-188-HEDP improves pain response and quality of life of CRPC patients. Results coming from this study may help to find a better treatment for CRPC patients, while reducing costs. In current times of exponential growth of healthcare costs, we believe that this study is meaningful from the perspective of cost-effectiveness.

Clinicaltrials.gov identifier: NCT03458559. Registered 8 March 2018. Trial status: recruiting.

Citation Format: Jessica C. Notohardjo, Esther W. Bouman-Wammes, Joyce M. van Dodewaard - de Jong, Haiko J. Bloemendal, Rogier Lange, Rob ter Heine, Henk M. Verheul, John M. de Klerk, Alfons J. van den Eertwegh. Repeated radium-223-chloride versus rhenium-188-HEDP in patients with metastatic castration-resistant prostate cancer: RaRe study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT145.

Abstract 1136: Tumor uptake and biodistribution of 89Zirconium-labeled ipilimumab in patients with metastatic melanoma during ipilimumab treatment

Introduction

Ipilimumab, a monoclonal antibody targeting CTLA-4, is approved for the treatment of metastatic melanoma and significantly improves overall survival. Because of the high costs and the potential serious toxicity of ipilimumab, it is of great importance to identify biomarkers that correlate with clinical activity and that can be used to select patients who will benefit from CTLA-4 blockade therapy.

We hypothesize that patients who do not respond to treatment with ipilimumab have lower drug levels in tumor tissues as compared to patients with a good response to therapy. In addition, we hypothesize that immune related adverse events (irAEs) are associated with high drug levels in the affected tissue. As irAEs usually occur approximately 6-8 weeks after the first injection of ipilimumab, we hypothesize that the drug levels in potentially affected tissues will increase at the second injection.

Experimental procedures

To visualize in vivo localization of ipilimumab in patients diagnosed with metastatic melanoma, 37 MBq, 10 mg 89Zr-labeled ipilimumab was injected within 2 hours after their first ipilimumab dose (3 mg/kg). Whole body PET/CT scans were obtained at 2h, 72h and 144h post injection and this procedure was repeated three weeks later at the second ipilimumab cycle. Biodistribution and tumor uptake were assessed visually by a nuclear physician. Focal uptake in tumor lesions exceeding local background was determined in volumes of interest (VOI) and SUVpeak values were obtained. Biodistribution was quantified by defining vital organs (i.e. lungs, kidneys, spleen, liver) and calculating mean %ID/kg. Blood was drawn for dosimetry and immunophenotyping at several time points during the trial. Presented here are initial results of the first three patients, up to 29 patients are planned to be included.

Results

Biodistribution of 89Zr-labeled ipilimumab showed a pattern distinctive for 89Zr-labeled antibodies with uptake in liver and spleen, as well as prolonged circulating antibody in the bloodstream corresponding to the pharmacokinetics of ipilimumab. Visual evaluation confirmed uptake of 89Zr-labeled ipilimumab in 5/12 evaluable tumor lesions, visible at both first and second injection of ipilimumab. Tumor uptake was comparable for 72h and 144h post injection with a mean of 6.9 %ID/kg (range 3.3-10.1) and a SUVpeak of 4.4 (range 2.3-8.9). There were no significant differences in tumor uptake between first and second dose of ipilimumab (mean 7.31 and 6.54 %ID/kg respectively).

Conclusions

Preliminary data of this ongoing study showed that the tracer is able to visualize and quantify uptake of ipilimumab in tumors. Correlations between tumor uptake and response to treatment will be presented. Furthermore, special interest will be given to uptake in lymphoid organs and locations for irAEs.

Citation Format: Iris H. Miedema, Gerben J. Zwezerijnen, Guus A. van Dongen, Daniëlle J. Vugts, Marc C. Huisman, Otto S. Hoekstra, Tanja D. de Gruijl, Hendrik M. Verheul, Catharina W. Menke, Alfons J. van den Eertwegh. Tumor uptake and biodistribution of 89Zirconium-labeled ipilimumab in patients with metastatic melanoma during ipilimumab treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1136.

Reproducibility and Repeatability of Semiquantitative 18F-Fluorodihydrotestosterone Uptake Metrics in Castration-Resistant Prostate Cancer Metastases: A Prospective Multicenter Study

18F-fluorodihydrotestosterone (18F-FDHT) is a radiolabeled analog of the androgen receptor's primary ligand that is currently being credentialed as a biomarker for prognosis, response, and pharmacodynamic effects of new therapeutics. As part of the biomarker qualification process, we prospectively assessed its reproducibility and repeatability in men with metastatic castration-resistant prostate cancer. Methods: We conducted a prospective multiinstitutional study of metastatic castration-resistant prostate cancer patients undergoing 2 (test/retest) 18F-FDHT PET/CT scans on 2 consecutive days. Two independent readers evaluated all examinations and recorded SUVs, androgen receptor-positive tumor volumes, and total lesion uptake for the most avid lesion detected in each of 32 predefined anatomic regions. The relative absolute difference and reproducibility coefficient (RC) of each metric were calculated between the test and retest scans. Linear regression analyses, intraclass correlation coefficients (ICCs), and Bland-Altman plots were used to evaluate repeatability of 18F-FDHT metrics. The coefficient of variation and ICC were used to assess interobserver reproducibility. Results: Twenty-seven patients with 140 18F-FDHT-avid regions were included. The best repeatability among 18F-FDHT uptake metrics was found for SUV metrics (SUVmax, SUVmean, and SUVpeak), with no significant differences in repeatability among them. Correlations between the test and retest scans were strong for all SUV metrics (R2 ≥ 0.92; ICC ≥ 0.97). The RCs of the SUV metrics ranged from 21.3% (SUVpeak) to 24.6% (SUVmax). The test and retest androgen receptor-positive tumor volumes and TLU, respectively, were highly correlated (R2 and ICC ≥ 0.97), although variability was significantly higher than that for SUV (RCs > 46.4%). The prostate-specific antigen levels, Gleason score, weight, and age did not affect repeatability, nor did total injected activity, uptake measurement time, or differences in uptake time between the 2 scans. Including the most avid lesion per patient, the 5 most avid lesions per patient, only lesions 4.2 mL or more, only lesions with an SUV of 4 g/mL or more, or normalizing of SUV to area under the parent plasma activity concentration-time curve did not significantly affect repeatability. All metrics showed high interobserver reproducibility (ICC > 0.98; coefficient of variation < 0.2%-10.8%). Conclusion: Uptake metrics derived from 18F-FDHT PET/CT show high repeatability and interobserver reproducibility.

Abstract 4692: Local adjuvant treatment of clinical stage I-II melanoma with low dose CpG-B and/or GM-CSF: Long-term follow-up of three randomized controlled phase II trials

Introduction: Currently, there is no widely used adjuvant treatment available to improve survival after surgical excision of localized melanoma. Here, we present the clinical outcome of patients who participated in three randomized phase-II trials and received low-dose local immunotherapy, which was shown to be safe and to boost loco-regional and systemic anti-melanoma T cell immunity.

Patients and Methods: In three single-center, single-blinded, randomized and placebo (saline) controlled phase-II clinical trials, patients with early stage melanoma were treated with 1) Granulocyte/Macrophage-Colony Stimulating Factor (GM-CSF), 2) unmethylated CpG type-B oligodeoxynucleotide CpG7909 (CpG-B), and 3) CpG-B, alone or combined with GM-CSF, through 1-4 intradermal injections at the site of the primary melanoma excision scar, within 7 days preceding re-excision and sentinel lymph node (SLN) biopsy. For clinical follow-up analysis, all treated patients were grouped together (treated group n=36) as were the patients who received saline (saline group n=28).

Results: 10-year recurrence-free survival rate in the treated group was 94% (95% CI 78-98) versus 48% (95% CI 21-71) in the saline group (P=0.005), hazard ratio (HR) for recurrence was 0.15 (95% CI 0.06-0.60) for the treated group. This apparent antitumor efficacy was in line with the observation upon pathological examination of less tumor positive SLN in the treated group (P=0.05). The 10-year distant recurrence-free survival rate in treated patients was also higher (94%, 78-98 versus 59%, 28-81, HR 0.22, 0.07-0.93; P=0.04).

Conclusion: Local low-dose immunotherapy in patients with early-stage melanoma may offer durable protection against distant recurrences. These findings warrant further clinical exploration of this local non-toxic immune potentiating regimen.

Citation Format: Bas D. Koster, Mari F. van den Hout, Berbel J. Sluijter, Barbara G. Molenkamp, Ronald J. Vuylsteke, Arnold Baars, Paul A. van Leeuwen, Rik J. Scheper, Monique P. van den Tol, Alfons J. van den Eertwegh, Tanja D. de Gruijl. Local adjuvant treatment of clinical stage I-II melanoma with low dose CpG-B and/or GM-CSF: Long-term follow-up of three randomized controlled phase II trials [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4692. doi:10.1158/1538-7445.AM2017-4692

Extent and Location of Tumor-Infiltrating Lymphocytes in Microsatellite-Stable Colon Cancer Predict Outcome to Adjuvant Active Specific Immunotherapy

PURPOSE

To determine the prognostic and predictive value of tumor-infiltrating lymphocytes (TIL) in colon cancer in a cohort of patients who previously took part in a trial on adjuvant active specific immunotherapy (ASI).

EXPERIMENTAL DESIGN

We determined the number and location of CD3 and CD8 positive T cells in archival tumor samples of 106 colon cancers. We correlated stromal and epithelial TIL numbers with tumor stage and treatment and determined the effects on disease-specific survival (DSS) and recurrence-free interval (RFI).

RESULTS

On the basis of the data presented, we concluded that (i) high numbers of stromal CD3 T cells have positive prognostic value measured as DSS for patients with stage II microsatellite-stable tumors and (ii) high numbers of epithelial CD8-positive T cells have positive prognostic value measured as RFI for the group of patients with stage II microsatellite-stable tumors as well as for the whole group (so stage II plus stage III together). Furthermore, we concluded that high numbers of pre-existing stromal CD3-positive T cells are of positive predictive value in adjuvant ASI treatment measured as DSS as well as RFI.

CONCLUSIONS

ASI therapy may contribute to an improved DSS and RFI in patients with microsatellite-stable colon tumors harboring high numbers of pre-existing stromal CD3(+) TIL. Validation in future clinical trials is awaited.

Abstract 1649: Extent and location of tumor infiltrating lymphocytes in colon cancer predicts outcome to adjuvant active specific immunotherapy

Purpose: We investigated the prognostic and predictive value of tumor infiltrating lymphocytes (TIL) in colorectal cancer in a cohort of patients who previously took part in a trial on adjuvant Active Specific Immunotherapy (ASI).

Experimental Design: We determined the numbers of CD3+ and CD8+ cells in archival tumor samples of 110 colorectal cancer patients as total infiltrating TIL, intraepithelial TIL and stromal TIL. Survival curves were used to determine the prognostic and predictive value of TIL.

Results: Patients with microsatellite instable (MSI) tumors had higher numbers of intraepithelial CD3+ and CD8+ TIL compared to patients with microsatellite stable (MSS) tumors. Patients with MSI tumors had a good prognosis. Patients with MSS cancers with high intraepithelial or stromal TIL numbers had a better prognosis compared to those with low TIL numbers. Significant survival benefits were found for the disease specific survival (DSS) and recurrence free interval (RFI) for patients with high infiltrates of stromal CD3+ or intraepithelial CD8+ cells. Additionally high numbers of total CD8+ and high stromal CD8+ cells gave a significant difference in RFI compared to low TIL numbers. The numbers of TIL found in MSS tumors also have predictive value with respect to response to adjuvant ASI treatment. Compared to controls significance was reached in ASI treated patients with high total CD3, high stromal CD3 or high stromal CD8 numbers in DSS as well as RFI.

Conclusion: ASI therapy is effective in patients with MSS colorectal tumors harboring high numbers of preexisting stromal CD3 or CD8 positive TIL.

Citation Format: Erik Hooijberg, Annelies W. Turksma, Marc Shamier, Kevin Lam, Veerle MH Coupe, Vincent A. de Weger, Jeroen AM Belien, Alfons J. van den Eertwegh, Gerrit A. Meijer, Chris JLM Meijer. Extent and location of tumor infiltrating lymphocytes in colon cancer predicts outcome to adjuvant active specific immunotherapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1649. doi:10.1158/1538-7445.AM2014-1649

Clinical effects of adjuvant active specific immunotherapy differ between patients with microsatellite-stable and microsatellite-instable colon cancer

PURPOSE

Active specific immunotherapy (ASI) consisting of an autologous tumor cell vaccine given as adjuvant treatment has been shown to improve recurrence-free survival of patients with colon cancer. The aim of the current retrospective study was to investigate whether the beneficial effects of ASI given as adjuvant treatment correlated with microsatellite instability (MSI), which is considered an important biologic determinant of colon cancer.

EXPERIMENTAL DESIGN

Microsatellite status was assessed on archival tumor material from patients with stage II and III colon cancer. Microsatellite status was next associated with clinical outcome in control and ASI treatment groups using Kaplan-Meier analysis.

RESULTS

We identified 162 (83%) microsatellite-stable tumors (MSS) and 34 (17%) MSI tumors. Patients with MSI tumors did well in recurrence-free interval (RFI) as well as disease-specific survival (DSS) irrespective of treatment arm and tumor stage. Patients with MSI tumors had significantly fewer recurrences and prolonged DSS than those with MSS tumors. Patients with MSS Dukes B tumors who received ASI treatment showed a significantly improved recurrence-free survival compared with controls. ASI treatment did not improve recurrence-free interval or DSS for patients with MSS Dukes C tumors.

CONCLUSION

This retrospective study indicated that patients with MSI tumors did well, irrespective of treatment arm and tumor stage. The data also indicate that the clinical benefit, measured as recurrence-free survival, from adjuvant ASI treatment of patients with colon cancer was restricted to patients with MSS Dukes B tumors.

Phase I-II study of everolimus and low-dose oral cyclophosphamide in patients with metastatic renal cell cancer

BACKGROUND

For patients with metastatic renal cell cancer (mRCC) who progressed on vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitor therapy, the orally administered mammalian target of rapamycin (mTOR) inhibitor everolimus has been shown to prolong progression free survival. Intriguingly, inhibition of mTOR also promotes expansion of immunosuppressive regulatory T cells (Tregs) that can inhibit anti-tumor immune responses in a clinically relevant way in various tumor types including RCC. This study intends to investigate whether the antitumor efficacy of everolimus can be increased by preventing the detrimental everolimus induced expansion of Tregs using a metronomic schedule of cyclophosphamide.

METHODS/DESIGN

This phase I-II trial is a national multi-center study of different doses and schedules of low-dose oral cyclophosphamide in combination with a fixed dose of everolimus in patients with mRCC not amenable to or progressive after a VEGF-receptor tyrosine kinase inhibitor containing treatment regimen. In the phase I part of the study the optimal Treg-depleting dose and schedule of metronomic oral cyclophosphamide when given in combination with everolimus will be determined. In the phase II part of the study we will evaluate whether the percentage of patients progression free at 4 months of everolimus treatment can be increased from 50% to 70% by adding metronomic cyclophosphamide (in the dose and schedule determined in the phase I part). In addition to efficacy, we will perform extensive immune monitoring with a focus on the number, phenotype and function of Tregs, evaluate the safety and feasibility of the combination of everolimus and cyclophosphamide, perform monitoring of selected angiogenesis parameters and analyze everolimus and cyclophosphamide drug levels.

DISCUSSION

This phase I-II study is designed to determine whether metronomic cyclophosphamide can be used to counter the mTOR inhibitor everolimus induced Treg expansion in patients with metastatic renal cell carcinoma and increase the antitumor efficacy of everolimus.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT01462214, EudraCT number 2010-024515-13, Netherlands Trial Register number NTR3085.

Potent antitumor immunity generated by a CD40-targeted adenoviral vaccine

In situ delivery of tumor-associated antigen (TAA) genes into dendritic cells (DC) has great potential as a generally applicable tumor vaccination approach. Although adenoviruses (Ad) are an attractive vaccine vehicle in this regard, Ad-mediated transduction of DCs is hampered by the lack of expression of the Ad receptor CAR on the DC surface. DC activation also requires interaction of CD40 with its ligand CD40L to generate protective T-cell-mediated tumor immunity. Therefore, to create a strategy to target Ads to DCs in vivo, we constructed a bispecific adaptor molecule with the CAR ectodomain linked to the CD40L extracellular domain via a trimerization motif (CFm40L). By targeting Ad to CD40 with the use of CFm40L, we enhanced both transduction and maturation of cultured bone marrow-derived DCs. Moreover, we improved transduction efficiency of DCs in lymph node and splenic cell suspensions in vitro and in skin and vaccination site-draining lymph nodes in vivo. Furthermore, CD40 targeting improved the induction of specific CD8(+) T cells along with therapeutic efficacy in a mouse model of melanoma. Taken together, our findings support the use of CD40-targeted Ad vectors encoding full-length TAA for in vivo targeting of DCs and high-efficacy induction of antitumor immunity.