Variant allele frequency in baseline circulating tumour DNA to measure tumour burden and to stratify outcomes in patients with RAS wild-type metastatic colorectal cancer: a translational objective of the Valentino study

INTRODUCTION

In patients with metastatic colorectal cancer (mCRC), baseline circulating tumour DNA (ctDNA) variant allele fraction (VAF) might serve as a surrogate of disease burden and should be evaluated in comparison with CEA and RECIST-defined sum of target lesions.

METHODS

In this pre-planned analysis of the VALENTINO trial, we included patients with RAS wild-type mCRC receiving upfront FOLFOX/panitumumab with available baseline liquid biopsy. CtDNA was analysed by means of a 14-gene NGS panel. For each patient, the gene with the highest VAF in ctDNA was selected.

RESULTS

The final cohort included 135 patients. The median VAF was 12.6% (IQR: 2.0-45.2%). Higher VAF was observed in patients with liver metastases and with synchronous metastases presentation. Patients with high VAF had poorer median OS compared to those with low VAF (21.8 vs 36.5 months; HR: 1.82, 95%CI: 1.20-2.76; p = 0.005). VAF outperformed baseline CEA and target lesion diameter in the prognostic stratification and remained significantly correlated with OS (p = 0.003) in a multivariate model. VAF was not significantly correlated with dimensional response and PFS.

CONCLUSION

CtDNA measured by VAF is prognostic in patients with RAS wild-type mCRC. Response and PFS after an anti-EGFR-based first-line strategy are independent from initial tumour burden.

Body mass index (BMI) and outcome of metastatic melanoma patients receiving targeted therapy and immunotherapy: a multicenter international retrospective study

BACKGROUND

Obesity is a risk factor for malignancy; however, its prognostic role in patients with metastatic melanoma is controversial. We aim to investigate the prognostic role of body mass index (BMI) in patients with metastatic melanoma receiving mitogen-activated pathway kinase inhibitors (MAPKi), immune checkpoint inhibitors (ICIs) alone or their sequence.

METHODS

Data on patients with metastatic melanoma receiving ≥1 line of systemic treatment were retrieved from prospectively collected databases. Progression-free survival (PFS) and overall survival (OS) were analyzed by means of multivariable stratified Cox regression models; disease control rate (DCR) was analyzed by multivariable stratified logistic regression models. Subgroup analyzes according to the type of treatments received, and in BRAF-mutated patients were pre-planned. All multivariable models included BMI, age, gender, American Joint Committee on Cancer stage, performance status, lactate dehydrogenase and treatment sequencing strategy as covariates.

RESULTS

Between November 2010 and November 2018, 688 patients from three Italian and two Polish centers were enrolled. 379 (57%) patients had M1c/d disease, 273 (41%) were female and the mean BMI was 27.1 (SD=4.9). Considering first-line treatment, 446 patients (66.8%) received ICIs and 222 MAPKi. No impact of BMI on OS was detected either considering the first line of ICIs, or ICIs sequencing (HR=1.02, 95% CI: 0.99 to 1.05, p=0.202, and HR=1.02, 95% CI: 0.99 to 1.04, p=0.237, respectively). A late effect of BMI on OS was found in patients treated with MAPKi: for five units increment, a 51% of risk reduction at 18 months and a 76% of risk reduction at 30 months were observed. No significant effect of BMI on PFS and DCR was found in any of the subgroup analyzes.

CONCLUSION

In patients with metastatic melanoma receiving ICIs, there is no impact of BMI on DCR, PFS and OS. The late prognostic effect of BMI in patients treated with MAPKi should be considered hypothesis generating and needs to be further investigated.

Liquid biopsy and radiological response predict outcomes following discontinuation of targeted therapy in patients with BRAF mutated melanoma

BACKGROUND

Outcomes of patients with metastatic melanoma discontinuing BRAF-targeted therapy for cumulative toxicity after sustained response are unknown.

PATIENTS AND METHODS

This retrospective case series analysis conducted at a single Cancer Center in Italy included patients with BRAF mutated metastatic melanoma treated with a BRAF inhibitor as a single agent or in combination with a MEK inhibitor between June 1, 2011 and January 1, 2020 and interrupting treatment after achieving complete response (CR) or long-lasting partial response (PR - i.e. > 12 months) due to cumulative toxicity.

RESULTS

We included 24 patients with a median treatment duration of 59.4 months (95%CI 55.4-63.4 - range 12-88). CR and PR were achieved in 71% and 29% of patients, respectively. At a median follow-up after treatment discontinuation of 37.8 months (95%CI 33.7-41.9), 12-months progression free survival after discontinuation (dPFS) rate was 70.8% (95%CI 54.8 - 91.6) and 24-months dPFS rate was 58.3% (95%CI 41.6 - 81.8). Baseline patients and tumor characteristics as well as treatment duration and best response did not significantly impact on dPFS. Patients with CR and negative circulating tumor DNA (ctDNA) at time of discontinuation had a significantly improved dPFS compared to patients with either radiological residual disease or ctDNA positivity (P = 0.007). No patient in CR with undetectable ctDNA experienced progression.

CONCLUSION

The risk of progression is high even in patients with sustained sensitivity to BRAF/MEK inhibitors. Integration of liquid biopsy in clinical trials investigating optimal management of patients with sustained sensitivity to BRAF/MEK inhibitors is warranted.

IMPLICATIONS FOR PRACTICE

Outcomes of patients with metastatic melanoma discontinuing BRAF-targeted therapy for cumulative toxicity are unknown. We analyzed patients with sustained responses (median treatment duration 59.4 months). Twelve and 24-months progression free survival following discontinuation were 70.8% and 58.3% respectively. Complete response and negative ctDNA at time of discontinuation are promising prognostic biomarkers in this setting.

Assessing safety and activity of cabozantinib combined with lanreotide in gastroenteropancreatic (GEP) and thoracic neuroendocrine tumors (NETs): The phase II LOLA trial

TPS4167

Background: Well-differentiated (WD) NETs are a group of rare neoplasms with limited therapeutic options. New combinations of somatostatin analogs (SSAs) and investigational drugs are warranted to improve clinical outcomes. Cabozantinib (CAB) is an orally administered inhibitor of multiple tyrosine kinases, including c-MET and Vascular Endothelial Growth Factor Receptor 2 (VEGFR2), with a pivotal role in NET pathogenesis. The biological rationale of the synergistic effects of CAB plus SSAs lies in the concomitant modulation of the RAS/MAPK and PI3K/Akt/mTOR pathways both at the level of cancer cells and tumor stroma, leading to enhanced anti-proliferative and anti-angiogenic effects. CAB exhibited encouraging activity in a recent phase II trial of patients with progressive carcinoids and pancreatic (p)NETs (Chan JA et al. JCO 2017; 35:4_suppl, 228-228). The LOLA trial is the first prospective phase II study aiming to assess the safety and activity of CAB in combination with lanreotide (LAN) in WD NETs of GEP, thoracic and of unknown origin. Clinical trial information: NCT04427787. Methods: This is a multicenter, open-label, double-cohort, non comparative, non-randomized, three-stage phase II trial. Eligible patients have to meet the following inclusion criteria: diagnosis of advanced or metastatic, progressive, non-functioning WD thoracic NETs, GEP-NETs or NETs of unknown origin with Ki67 ≥10%; positive 68Ga-PET uptake or somatostatin receptor 2 immunohistochemical (IHC) stain; maximum 1 prior systemic regimen for metastatic disease. Two cohorts will be considered: pNETs and carcinoids. In the stage I, the primary objective is to find the optimal dose of CAB in combination with LAN and to evaluate the safety of the combination (defined as the percentage of patients experiencing grade 3-5 toxicities according to NCI-CTCAE v5.0). Starting dose of CAB is 60 mg/day continuously, plus LAN 120 mg every 28 days. In stage II and III, co-primary endpoints are safety and overall response rate (ORR) according to RECIST v1.1. The useful antitumor activity to be detected is fixed in ORR > 20%. Secondary endpoints are progression-free survival and overall survival. Exploratory objectives include the assessment of IHC expression of c-MET, AXL and VEGFR2, with the aim to identify predictive or prognostic tissue biomarkers. Enrolment started in July 2020, with an expected trial duration of 42 months comprehensive of accrual, treatment and follow-up. Considering a drop out rate of 5%, the maximum number of enrolled patients will be 69. Supported by a solid rationale, the trial has the potential to generate milestone data about the synergistic effects of CAB plus LAN in a group of NET patients with relatively aggressive disease and limited therapeutic options, for whom optimal treatment sequencing is not yet defined. Clinical trial information: NCT04427787.

Phase II study of preoperative (PREOP) chemoradiotherapy (CTRT) plus avelumab (AVE) in patients (PTS) with locally advanced rectal cancer (LARC): The AVANA study

3511

Background: Preop CTRT is considered the standard of care in the management of LARC. RT can induce antigen release from a low neoantigen-burden tumor (such as a mismatch repair proficient colorectal cancer) and activate dendritic cells leading to a CD8+ T lymphocyte-mediated anticancer immune response. In LARC patients, neoadjuvant CTRT increases PD-L1 expression in tumor cells, strongly suggesting a neoadjuvant combinatory strategy with RT and PD-1/PD-L1 pathway blockade. Based on such considerations, we have designed the AVANA study to investigate the role of Ave in combination with preop CTRT in LARC. Methods: This is an Italian multi-center, phase II study. Pts with resectable LARC, defined by the presence of at least one of the following features: cN+, cT4, high risk cT3, received standard preop CTRT (capecitabine 825 mg/sqm/bid 5 days/week+ 50.4 Gy in 28 fractions over 5.5 weeks) plus 6 cycles of Ave 10 mg/Kg every 2 weeks. Surgery with total mesorectal excision was performed at 8-10 weeks after the end of CTRT. The primary end-point was the pCR rate, defined as complete histological regression with no available tumor cells ypT0N0. Secondary end-points were R0 resection rate, tumor downstaging, local recurrence, sphincter preservation rate, progression-free survival, overall survival, safety profile, and the evaluation of exploratory predictive and/or prognostic biomarkers. Assuming as null hypothesis p0 a pCR rate of 15%, a significance level of 5% (one-side), and a power of 80%, a sample size of 101 pts was needed to detect an absolute increment of 10% in pCR rate (from 15% to 25%). The experimental regimen is considered for further studies if, in at least 22 pts, we observe a pCR. Results: From April 2019 to November 2020, a total of 101 resectable LARC pts were enrolled in 10 Italian Centers. The median age was 63 years (23-82), 62 (61.4%) pts were male, 93 (92%) had ECOG PS 0. At baseline, 94 (93%) and 16 (16%) pts had cN+ and cT4 LARC, respectively. All pts completed the induction phase. Out of 96 pts evaluable for pathological response, 22 (23%) pts achieved a pCR and 59 (61.5%) pts a major pathological response (a central review is ongoing). At this time, microsatellite status is available only in 39 pts, of which only one was instable. The rate of grade 3-4 non-immune and immune-related adverse events was 8% and 4%, respectively. Avelumab was early interrupted in 9 pts out 101, mainly due to toxicity. Conclusions: The combination of preop CTRT plus Ave showed a promising activity and a feasible safety profile. According to our statistical considerations, the experimental regimen will be considered for further studies. Updated results will be presented during the Congress. Sponsored by GONO and partially supported by Merck. EUDRACT 2017-003582-10. Clinical trial information: NCT03854799.

EGFR Amplification in Metastatic Colorectal Cancer

BACKGROUND

EGFR amplification occurs in about 1% of metastatic colorectal cancers (mCRCs) but is not routinely tested as a prognostic or predictive biomarker for patients treated with anti-EGFR monoclonal antibodies (mAbs). Herein, we aimed to characterize the clinical and molecular landscape of EGFR-amplified metastatic colorectal cancer (mCRC).

METHODS

In this multinational cohort study, we compared clinical data of 62 patients with EGFR-amplified vs. 1459 EGFR non-amplified mCRC, as well as comprehensive genomic data of 35 EGFR-amplified vs. 439 EGFR non-amplified RAS/BRAF wild-type and microsatellite stable (MSS) tumor samples.

RESULTS

EGFR amplification was statistically significantly associated with left primary tumor sidedness and RAS/BRAF wild-type status. All EGFR-amplified tumors were MSS and HER2 non-amplified. Overall, EGFR-amplified samples had higher median fraction of genome altered compared to EGFR non-amplified, RAS/BRAF wild-type MSS cohort. Patients with EGFR-amplified tumors reported longer overall survival (OS) (median OS = 71.3 months; 95% confidence interval [CI] = 50.7-NA) vs. EGFR non-amplified ones (24.0 months; 95% CI = 22.8-25.6; hazard ratio [HR] = 0.30, 95% CI = 0.20-0.44, P<.001; adjusted HR = 0.46, 95%CI = 0.30-0.69, P<.001). In the subgroup of patients with RAS/BRAF wild-type mCRC exposed to anti-EGFR-based therapy, EGFR amplification was again associated with better OS (median OS = 54.0 months [95% CI = 35.2-NA] vs. 29.1 months [95% CI = 27.0-31.9], respectively; HR = 0.46, 95%CI = 0.28-0.76, P=.002).

CONCLUSION

Patients with EGFR-amplified mCRC represent a biologically defined subgroup and merit dedicated clinical trials with novel and more potent EGFR targeting strategies beyond single-agent monoclonal antibodies.

Impact of Baseline and On-Treatment Glycemia on Everolimus-Exemestane Efficacy in Patients with Hormone Receptor-Positive Advanced Breast Cancer (EVERMET)

PURPOSE

The mTOR complex C1 (mTORC1) inhibitor everolimus in combination with the aromatase inhibitor exemestane is an effective treatment for patients with hormone receptor-positive (HR⁺), HER2-negative (HER2^-), advanced breast cancer (HR⁺/HER2^- aBC). However, everolimus can cause hyperglycemia and hyperinsulinemia, which could reactivate the PI3K/protein kinase B (AKT)/mTORC1 pathway and induce tumor resistance to everolimus.

EXPERIMENTAL DESIGN

We conducted a multicenter, retrospective, Italian study to investigate the impact of baseline and on-treatment (i.e., during first 3 months of therapy) blood glucose levels on progression-free survival (PFS) in patients with HR⁺/HER2^- aBC treated with everolimus-exemestane.

RESULTS

We evaluated 809 patients with HR⁺/HER2^- aBC treated with everolimus-exemestane as any line of therapy for advanced disease. When evaluated as dichotomous variables, baseline and on-treatment glycemia were not significantly associated with PFS. However, when blood glucose concentration was evaluated as a continuous variable, a multivariable model accounting for clinically relevant patient- and tumor-related variables revealed that both baseline and on-treatment glycemia are associated with PFS, and this association is largely attributable to their interaction. In particular, patients who are normoglycemic at baseline and experience on-treatment diabetes have lower PFS compared with patients who are already hyperglycemic at baseline and experience diabetes during everolimus-exemestane therapy (median PFS, 6.34 vs. 10.32 months; HR, 1.76; 95% confidence interval, 1.15-2.69; P = 0.008).

CONCLUSIONS

The impact of on-treatment glycemia on the efficacy of everolimus-exemestane therapy in patients with HR⁺/HER2^- aBC depends on baseline glycemia. This study lays the foundations for investigating novel therapeutic approaches to target the glucose/insulin axis in combination with PI3K/AKT/mTORC1 inhibitors in patients with HR⁺/HER2^- aBC.

Uncommon targets in non-small cell lung cancer: Everyone wants a slice of cake

Target therapies completely changed the clinical approach in EGFR mutated and ALK rearranged non-small cell lung cancer, ensuring these patients exceptional outcomes with a better toxicity profile compared to conventional chemotherapy. In recent years, beyond EGFR and ALK alterations, new data are emerging about less common alterations, new drugs have been already approved and others agents have been recently investigated or are currently under investigation. In this review we will discuss some uncommon alterations in non-small cell lung cancer such as ROS1, BRAF, RET, HER2, NTRK, MET and other targets that are in an early evaluation phase. We will summarize the characteristics of patients harboring these alterations, the already approved or under investigation therapies and the related resistance mechanisms.

The Added Value of Baseline Circulating Tumor DNA Profiling in Patients with Molecularly Hyperselected, Left-sided Metastatic Colorectal Cancer

PURPOSE

The routine use of liquid biopsy is not recommended for the choice of initial treatment for patients with metastatic colorectal cancer (mCRC).

EXPERIMENTAL DESIGN

We included patients with left-sided, RAS/BRAF wild-type, HER2-negative, and microsatellite stable mCRC, treated with upfront panitumumab/FOLFOX-4 in the Valentino study. We performed amplicon-based genomic profiling of 14 genes in baseline plasma samples and compared these data with tumor tissue ultra-deep sequencing results. Specific gene mutations in circulating tumor DNA (ctDNA) and their clonality were associated with progression-free survival (PFS), overall survival (OS), and radiological dynamics.

RESULTS

Ten and 15 of 120 patients had a mutation of RAS and PIK3CA in ctDNA, with a positive concordance with tissue deep sequencing of only 31.3% and 47.1%, respectively. Presence of RAS or PIK3CA mutations in baseline ctDNA was associated with worse median PFS [8 vs. 12.8 months; HR, 2.49; 95% confidence interval (CI), 1.28-4.81; P = 0.007 and 8.5 vs. 12.9 months; HR, 2.86; 95% CI, 1.63-5.04; P < 0.001] and median OS (17.1 vs. 36.5 months; HR, 2.26; 95% CI, 1.03-4.96; P = 0.042 and 21.1 vs. 38.9 months; HR, 2.18; 95% CI, 1.16-4.07; P = 0.015). RAS mutations in ctDNA were associated with worse RECIST response, early tumor shrinkage, and depth of response, while PIK3CA mutations were not. Patients with higher levels of RAS/PIK3CA variant allele fraction (VAF) in ctDNA had the worst outcomes (VAF ≥ 5% vs. all wild-type: median PFS, 7.7 vs. 13.1 months; HR, 4.02; 95% CI, 2.03-7.95; P < 0.001 and median OS, 18.8 vs. 38.9 months; HR, 4.07; 95% CI, 2.04-8.12; P < 0.001).

CONCLUSIONS

Baseline ctDNA profiling may add value to tumor tissue testing to refine the molecular hyperselection of patients with mCRC for upfront anti-EGFR-based strategies.

Predictive role of microsatellite instability for PD-1 blockade in patients with advanced gastric cancer: a meta-analysis of randomized clinical trials

BACKGROUND

Several post hoc analyses of randomized controlled trials (RCTs) suggested the importance of microsatellite instability (MSI) as a positive predictive factor to immunotherapy in patients with advanced gastric cancer (GC); however, individually these have low statistical power.

METHODS

RCTs investigating treatment with or without an anti-programmed cell death protein 1 (PD-1) agent for advanced GC and providing outcome according to MSI status were selected. The hazard ratio (HR) and the odds ratio were used to compare the treatment effect on survival outcomes and tumor response, respectively, for anti-PD-1-based therapy compared with standard therapy. Evidence for treatment effect by MSI status was evaluated by a test of interaction.

RESULTS

The phase III KEYNOTE-062, CheckMate-649, JAVELIN Gastric 100 and KEYNOTE-061 trials were included. A total of 2545 patients with evaluable MSI status were included and 123 (4.8%) had MSI-high cancers. The HR for overall survival benefit with anti-PD-1-based regimens was 0.34 (95% CI: 0.21-0.54) for MSI-high cancers versus 0.85 [95% confidence interval (CI): 0.71-1.00] for microsatellite stable. The treatment effect was significantly different in the two subgroups (P for interaction 0.003). In the MSI-high subgroup, the HR for progression-free survival was 0.57 (95% CI: 0.33-0.97; P = 0.04) and the odds ratio for response was 1.76 (95% CI: 1.10-2.83; P = 0.02).

CONCLUSIONS

Patients with MSI-high GC should be regarded as a specific and highly immunosensitive population worthy of dedicated clinical trials.

Systemic doxycycline for pre-emptive treatment of anti-EGFR-related skin toxicity in patients with metastatic colorectal cancer receiving first-line panitumumab-based therapy: a post hoc analysis of the Valentino study

INTRODUCTION

The combination of anti-EGFRs and doublet chemotherapy is considered the optimal upfront option for patients with RAS/BRAF wild-type left-sided metastatic colorectal cancer (mCRC). The prophylactic or reactive treatment with tetracyclines for EGFR inhibitor-induced skin toxicity is currently clinical practice, though non-conclusive results are available.

METHODS

We performed a post hoc analysis of the Valentino study that randomized RAS wild-type mCRC patients to two panitumumab-based maintenance regimens after the first-line induction, aimed at assessing the safety and efficacy of the administration of a pre-emptive doxycycline prophylaxis for anti-EGFR-related skin toxicity. We assessed the rate of treatment-related and panitumumab-related adverse events (AEs), treatment intensity, progression-free survival (PFS), and overall survival (OS).

RESULTS

A total of 226 patients, out of the 229 enrolled in the Valentino study, were eligible for the analysis. Overall, 143 (63%) and 83 (37%) patients received or not the antibiotic prophylaxis for skin toxicity. Any grade and G3/4 panitumumab-related AEs were reported in 89% versus 92% (p = 0.650) and 27% versus 27% (p = 1.000) patients who received or not the pre-emptive prophylaxis, respectively. Any grade and G3/4 skin rash occurred in 81% versus 90% (p = 0.085) and 27% versus 25% (p = 0.876) patients receiving or not the prophylaxis, respectively. No significant differences in terms of treatment duration, treatment delays or dose reductions, PFS, and OS were observed in the two sub-populations.

CONCLUSION

The adequate management of anti-EGFR-related skin toxicity is fundamental to optimize the outcome of mCRC patients, balancing the survival benefit with patients' quality of life, especially in the first-line setting.

Validation of the Colon Life nomogram in patients with refractory metastatic colorectal cancer enrolled in the RECOURSE trial

BACKGROUND

The RECOURSE trial (Study of TAS-102 in Patients With Metastatic Colorectal Cancer Refractory to Standard Chemotherapies) demonstrated an overall survival (OS) benefit of trifluridine/tipiracil (FTD/TPI) vs placebo in refractory metastatic colorectal cancer (mCRC). Given the limited benefit of later line treatments, we developed the Colon Life nomogram to assess the 12-week death probability in the refractory setting.

METHODS

This post hoc analysis of RECOURSE included patients with available data to calculate the nomogram score: Eastern Cooperative Oncology Group Performance Status, primary tumor resection, lactate dehydrogenase, and peritoneal metastases. The nomogram calibration was assessed by calibration plots and C-index. The nomogram prognostic and predictive ability was assessed by Cox model analyses and the nomogram score predictive value was explored according to the cutoff identified at maximum value of the Youden index in time-dependent receiver operating characteristic curve analysis.

RESULTS

Overall, 251 trial patients were evaluable: 90 in the placebo arm and 161 in the FTD/TPI arm. The calibration was optimal in the placebo arm (C-index 0.807) and suboptimal in the FTD/TPI arm (0.657). The cutoff of the nomogram score of 23 showed the best discriminative ability for 12-week OS (hazard ratio 3.46, 95% confidence interval 2.17-5.51 for scores 40 vs 15) and had maximum value of the Youden index (0.381). Median OS and 3-month PFS were 9.0 vs 7.5 months and 39.3% vs 5.2%, respectively, for FTD/TPI vs placebo in the low-risk group (score <23) and 4.8 vs 3.4 months and 22.3% vs 9.8% in the high-risk group (score ⩾23) (interaction NS).

CONCLUSION

The Colon Life nomogram is an accurate tool for estimating life expectancy in refractory mCRC. The benefit of FTD/TPI was independent of the predicted risk of early death.

An Italian Retrospective Survey on Bone Metastasis in Melanoma: Impact of Immunotherapy and Radiotherapy on Survival

Background

We performed a multicenter retrospective observational study to investigate the impact of clinical–pathological features and therapeutic strategies on both the complications and survival of patients with bone metastases (BMs) from malignant melanoma.

Patients and Methods

A total of 305 patients with melanoma and radiological evidence of BMs were retrospectively enrolled from 19 Italian centers. All patients received conventional treatments in accordance with each own treating physician’s practice. Both univariate and multivariate models were used to explore the impact of melanoma features, including skeletal-related events (SREs), and different treatments on both overall survival (OS) and time-to-SREs. The chi-squared test evaluated the suitability of several parameters to predict the occurrence of SREs.

Results

Eighty-three percent of patients had metachronous BMs. The prevalent (90%) bone metastatic site was the spine, while 45% had involvement of the appendicular skeleton. Forty-seven percent experienced at least one SRE, including palliative radiotherapy (RT) in 37% of cases. No melanoma-associated factor was predictive of the development of SREs, although patients receiving early treatment with bone-targeted agents showed 62% lower risk and delayed time of SRE occurrence. Median OS from the diagnosis of bone metastasis was 10.7 months. The multivariate analysis revealed as independent prognostic factors the number of BMs, number of metastatic organs, baseline lactate dehydrogenase levels, and treatment with targeted therapy or immunotherapy. Subgroup analyses showed the best OS (median = 16.5 months) in the subset of patients receiving both immunotherapy and palliative RT.

Conclusion

Based on our results, patients undergoing immunotherapy and palliative RT showed an OS benefit suggestive of a possible additive effect. The apparent protective role of bone targeting agent use on SREs observed in our analysis should deserve prospective evaluation.

Systemic Treatment of Patients With Gastrointestinal Cancers During the COVID-19 Outbreak: COVID-19-adapted Recommendations of the National Cancer Institute of Milan

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak poses a major challenge in the treatment decision-making of patients with cancer, who may be at higher risk of developing a severe and deadly SARS-CoV-2 infection compared with the general population. The health care emergency is forcing the reshaping of the daily assessment between risks and benefits expected from the administration of immune-suppressive and potentially toxic treatments. To guide our clinical decisions at the National Cancer Institute of Milan (Lombardy region, the epicenter of the outbreak in Italy), we formulated Coronavirus-adapted institutional recommendations for the systemic treatment of patients with gastrointestinal cancers. Here, we describe how our daily clinical practice has changed due to the pandemic outbreak, with the aim of providing useful suggestions for physicians that are facing the same challenges worldwide.

Risk of disease progression (PD) following discontinuation of BRAF±MEK targeted therapies for reasons other than PD in patients (pts) with metastatic or unresectable melanoma

10053

Background: In pts with metastatic melanoma bearing BRAF V600E/K mutations BRAF V600±MEK inhibitors are administered until PD/unacceptable toxicity. In patients achieving durable responses, outcomes following discontinuation for reasons other than PD are largely unknown. Methods: We identified all patients who interrupted BRAF±MEK inhibitors for reasons other than PD after complete (CR) or partial response (PR) from a clinical dataset of patients with BRAF mutated metastatic/unresectable melanoma treated with targeted therapy at a single Institution. Results: We included 24 pts. Fifteen (62.5%) and 9 (37.5%) pts were treated respectively with BRAF inhibitor monotherapy and BRAF+MEK inhibitor combination. All pts had normal baseline LDH and ECOG PS0, 2 (8%) pts had brain metastases and 15 (62.5%) had multi-organ metastatic involvement. Dose reduction was required for 12 (50%) pts. Median treatment duration was 59 (12-88) months. Causes of discontinuation were unacceptable toxicity (19 pts-79%) and consent withdrawal (5 pts-21%). At the time of discontinuation, 17 (71%) and 7 (29%) pts had achieved respectively CR and PR. At a median follow up of 31 (8-59) months after treatment discontinuation, 9 (37.5%) pts had experienced PD. Median time to PD after treatment discontinuation was 9 (3-16) months. At time of PD, 2 (22%) pts displayed involvement of new organ sites. Risk of PD following discontinuation was respectively 31% and 45% at 12 and 24 months. Neither baseline characteristics nor treatment duration and time to best response influenced risk of PD; we found a non-significant trend towards higher risk of relapse for patients interrupting treatment with residual disease compared to those who interrupted treatment after achieving CR [HR 3.3; 95%CI (0.8–14.1); log-rank p = 0.081]. After PD, 6 pts received BRAF+MEK inhibitors with a response rate of 100% and 3/6 pts achieving CR. Conclusions: In a subset of patients with favorable prognostic characteristics and retained sensitivity to BRAF±MEK inhibitors, treatment discontinuation was associated with relevant risk of relapse with about one third of pts experiencing PD within one year. Biomarker studies are needed to identify pts who might safely discontinue therapy due to sustained toxicity, especially after achieving CR.

Efficacy and Safety of Immune Checkpoint Inhibitors in Patients with Microsatellite Instability-High End-Stage Cancers and Poor Performance Status Related to High Disease Burden

BACKGROUND

Few real-world series on the efficacy and safety of anti-programmed cell death protein-1(PD-1)/programmed death ligand-1(PD-L1)-based therapy are available in molecularly unselected patients with poor performance status (PS) and specific types of advanced cancers, because such populations are typically excluded from clinical trials due to poor life expectancy and risk of toxicity.

MATERIALS AND METHODS

This multicenter retrospective case series included patients with microsatellite instability (MSI)-high metastatic cancers with Eastern Cooperative Oncology Group (ECOG) PS of 2 or 3 not related to comorbidities receiving anti-PD-1 with or without anti-CTLA-4 therapy after failure of at least one prior treatment line.

RESULTS

We included 27 patients with six diverse tumor types: colorectal (n = 18), gastric (n = 5), biliary tract, pancreatic, small bowel, and endometrial cancers (n = 1 each). Baseline ECOG PS was 2 (74%) or 3 (26%). Overall response rate was 33%, with six partial and three complete responses. Median time to response was 3.1, months and median duration of response was 16.9 months. Median progression-free survival was 3.4 months (95% CI: 2.3 to not evaluable), and 18-month overall survival was 50.8% (95% confidence interval, 32.7-78.8). Baseline variables were not associated with survival outcomes. ECOG PS 1 was reached by 52% of patients in a median time of 6 weeks, and ECOG PS 0 was reached by 30% of patients in a median time of 10 weeks.

CONCLUSION

In a high proportion of patients with MSI-high cancers and poor performance status related to end-stage disease, salvage immunotherapy can induce potentially long-lasting "Lazarus responses". Immunotherapy decisions near the end-of-life should be carefully integrated with predictive biomarkers and with palliative care measures in the real-world setting.

IMPLICATIONS FOR PRACTICE

In this retrospective cohort study of 27 pretreated patients with microsatellite instability (MSI)-high cancers and Eastern Cooperative Oncology Group performance status of 2 or 3 not related to comorbidities, PD-1/PD-L1-based therapy induced a RECIST response in 33% of patients, with a median duration of 16.9 months, and an improvement of performance status in 52% of patients. MSI-high status can be used in clinical practice as a tumor-agnostic predictive biomarker to select critically ill patients with end-stage cancers for salvage immunotherapy.

Safety and activity of radium-223 in metastatic castration-resistant prostate cancer: the experience of Istituto Nazionale dei Tumori

INTRODUCTION

Therapeutic decision-making in metastatic castration-resistant prostate cancer (mCRPC) represents an open challenge. Radium-223 is approved for patients with symptomatic bone metastases, no visceral involvement, progressing after at least 2 lines of systemic therapy, or ineligible for any other systemic treatment.

METHODS

We performed a retrospective, observational study on patients with mCRPC treated with radium-223 at our institution outside of clinical trials, to assess the safety and activity in a real-world population. Data regarding baseline patient/disease characteristics and treatment outcomes (number of cycles, treatment-related adverse events [AEs], cause of discontinuation, and best response) were collected.

RESULTS

Overall, 41 patients were treated from September 2015 to September 2018. Median age was 73 years; baseline Eastern Cooperative Oncology Group Performance Status (ECOG PS) was 0, 1, or 2 in 15%, 80%, and 5% of cases, respectively; and 3%, 41%, 44%, and 12% of patients had <6, 6-20, >20, and superscan bone lesions, respectively. A median number of 5 cycles (interquartile range 3-6) with median dose 19.52 MBq (interquartile range 12.87-24.83) was received. Treatment schedule was completed in 49% of cases; discontinuations due to AEs, disease-related death, or disease progression occurred in 24%, 33%, and 43% of patients, respectively. Any-grade AEs occurred in 73% and grade 3/4 treatment-related AEs occurred in 29% of patients, mainly anemia, decreased platelet count, and fatigue. No skeletal-related events or treatment-related deaths were recorded. After treatment, 66%, 2%, and 32% of patients had a stable, improved, or deteriorated ECOG PS versus baseline, respectively, and 24%, 61%, and 15% reported a stable, improved, or worsened pain symptom control. Post-treatment versus baseline alkaline phosphatase was reduced or stable in 46% and increased in 54% of patients, whereas prostate-specific antigen was decreased or stable in 83% and increased in 17% of patients.

CONCLUSIONS

Our study provides clinically useful real-world data on radium-223, highlighting the importance of multidisciplinary patient management to guarantee the best continuum of care for patients with mCRPC.

Prognostic and Predictive Value of Microsatellite Instability, Inflammatory Reaction and PD-L1 in Gastric Cancer Patients Treated with Either Adjuvant 5-FU/LV or Sequential FOLFIRI Followed by Cisplatin and Docetaxel: A Translational Analysis from the ITACA-S Trial

BACKGROUND

Patients with high microsatellite instability (MSI) gastric cancer (GC) show improved survival and no benefit or harm from adjuvant and/or perioperative chemotherapy. The role of immune microenvironment in GC is largely unknown.

MATERIALS AND METHODS

In the present study, 256 tumor tissue blocks were centrally collected from patients enrolled in ITACA-S, a randomized adjuvant trial of 5-FU/LV versus sequential FOLFIRI and cisplatin-docetaxel. MSI status was assessed by multiplex PCR, inflammatory reaction by H&E morphological assessment, and programmed death-ligand 1 (PD-L1) expression by immunohistochemistry.

RESULTS

Overall, 9% patients had MSI-high tumors, 23% had high inflammatory reaction, 11% had tumor PD-L1 ≥ 1%, and 11% had stromal PD-L1 ≥ 1%. A significant association with disease-free survival (DFS) and overall survival (OS) was found for MSI-high (hazard ratio [HR], 0.43; p = .02; HR, 0.40; p = .02) and high inflammatory reaction (HR, 0.55; p = .010; HR, 0.53; p = .008) but not for PD-L1. At multivariable analysis, only MSI showed an independent association with both DFS (p = .02) and OS (p = .01), whereas inflammatory reaction showed an independent association only with OS (p = .04). Patients with tumor PD-L1 ≥ 1% had a significantly longer DFS in sequential chemotherapy than in than 5-FU/LV arm (interaction p = .04) and a trend for OS (interaction p = .12).

CONCLUSION

Our data suggest that MSI status could be a useful prognostic biomarker in patients with radically resected stage II-III GC and should be used as stratification factor in future trials. Tumor PD-L1 ≥ 1% should be further investigated as a potential predictor of benefit from intensive chemotherapy.

IMPLICATIONS FOR PRACTICE

In this post hoc analysis of patients with radically resected gastric cancer randomized to an intensive sequential chemotherapy regimen versus 5-FU/LV monotherapy as adjuvant treatment in the ITACA-S trial, MSI-high status was independently associated with better disease-free survival and overall survival (OS) and inflammatory reaction was independently associated with better OS. Moreover, tumor PD-L1 expression ≥1% was associated with greater benefit from intensive sequential chemotherapy compared with 5-fluorouracil plus leucovorin (5-FU/LV), whereas PD-L1 expression <1% was not, conditioning a statistically significant interaction between such biomarker and treatment arms. The meta-analysis of individual patients' data from available studies could yield data on the role of MSI status that could inform clinical decisions.

Temozolomide and irinotecan (TEMIRI regimen) as salvage treatment of irinotecan-sensitive advanced colorectal cancer patients bearing MGMT methylation

Background

Non-randomized studies showed that temozolomide (TMZ) achieves an average 10% response rate in heavily pretreated metastatic colorectal cancer (mCRC) patients with promoter methylation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT). In this phase II trial, irinotecan and temozolomide (TEMIRI) combination regimen was assessed in irinotecan-sensitive, MGMT methylated/microsatellite stable (MSS) pretreated mCRC patients.

Patients and methods

Key inclusion criteria were centrally confirmed MGMT methylation by methylation-specific PCR, MSS mCRC, progression after at least two prior chemotherapy regimens for advanced disease and irinotecan-free interval >3 months. TEMIRI (TMZ 150 mg/m2 on days 1-5 plus irinotecan 100 mg/m2 on days 1, 15 q28 days) was administered for six cycles, followed by maintenance with TMZ. The primary end point was overall response rate (ORR). Exploratory translational analyses included MGMT immunohistochemistry (IHC) and methyl-BEAMing (MB).

Results

Between December 2014 and June 2017, 25 patients were enrolled. The primary end point was met, since six patients achieved a partial response [ORR 24%, 95% confidence interval (CI) 11% to 43%]. At a median follow-up of 15.6 months, median progression-free survival (mPFS) and overall survival (mOS) were 4.4 and 13.8 months, respectively. Only four (16%) patients had ≥ grade 3 (CTCAE 4.0) adverse events. All patients whose cancer was MGMT-positive IHC were non-responders. Consistently, patients with MGMT-negative/low tumors had a significantly longer mPFS than others (6.9 versus 2.0 months; hazard ratio = 0.29, 95% CI 0.02-0.41; P = 0.003) and a non-significant trend for longer mOS. MB testing showed similar accuracy.

Conclusions

TEMIRI regimen is a safe and active option in pre-treated, irinotecan-sensitive mCRC patients with MGMT methylation.