Tumor Size Is Not Everything: Advancing Radiomics as a Precision Medicine Biomarker in Oncology Drug Development and Clinical Care. A Report of a Multidisciplinary Workshop Coordinated by the RECIST Working Group

Radiomics, the science of extracting quantifiable data from routine medical images, is a powerful tool that has many potential applications in oncology. The Response Evaluation Criteria in Solid Tumors Working Group (RWG) held a workshop in May 2022, which brought together various stakeholders to discuss the potential role of radiomics in oncology drug development and clinical trials, particularly with respect to response assessment. This article summarizes the results of that workshop, reviewing radiomics for the practicing oncologist and highlighting the work that needs to be done to move forward the incorporation of radiomics into clinical trials.

Pembrolizumab plus chemotherapy versus chemotherapy in untreated advanced pleural mesothelioma in Canada, Italy, and France: a phase 3, open-label, randomised controlled trial

BACKGROUND

Pleural mesothelioma usually presents at an advanced, incurable stage. Chemotherapy with platinum-pemetrexed is a standard treatment. We hypothesised that the addition of pembrolizumab to platinum-pemetrexed would improve overall survival in patients with pleural mesothelioma.

METHODS

We did this open-label, international, randomised phase 3 trial at 51 hospitals in Canada, Italy, and France. Eligible participants were aged 18 years or older, with previously untreated advanced pleural mesothelioma, with an Eastern Cooperative Oncology Group performance status score of 0 or 1. Patients were randomly assigned (1:1) to intravenous chemotherapy (cisplatin [75 mg/m2] or carboplatin [area under the concentration-time curve 5-6 mg/mL per min] with pemetrexed 500 mg/m2, every 3 weeks for up to 6 cycles), with or without intravenous pembrolizumab 200 mg every 3 weeks (up to 2 years). The primary endpoint was overall survival in all randomly assigned patients; safety was assessed in all randomly assigned patients who received at least one dose of study therapy. This trial is registered with ClinicalTrials.gov, NCT02784171, and is closed to accrual.

FINDINGS

Between Jan 31, 2017, and Sept 4, 2020, 440 patients were enrolled and randomly assigned to chemotherapy alone (n=218) or chemotherapy with pembrolizumab (n=222). 333 (76 %) of patients were male, 347 (79%) were White, and median age was 71 years (IQR 66-75). At final analysis (database lock Dec 15, 2022), with a median follow-up of 16·2 months (IQR 8·3-27·8), overall survival was significantly longer with pembrolizumab (median overall survival 17·3 months [95% CI 14·4-21·3] with pembrolizumab vs 16·1 months [13·1-18·2] with chemotherapy alone, hazard ratio for death 0·79; 95% CI 0·64-0·98, two-sided p=0·0324). 3-year overall survival rate was 25% (95% CI 20-33%) with pembrolizumab and 17% (13-24%) with chemotherapy alone. Adverse events related to study treatment of grade 3 or 4 occurred in 60 (27%) of 222 patients in the pembrolizumab group and 32 (15%) of 211 patients in the chemotherapy alone group. Hospital admissions for serious adverse events related to one or more study drugs were reported in 40 (18%) of 222 patients in the pembrolizumab group and 12 (6%) of 211 patients in the chemotherapy alone group. Grade 5 adverse events related to one or more drugs occurred in two patients on the pembrolizumab group and one patient in the chemotherapy alone group.

INTERPRETATION

In patients with advanced pleural mesothelioma, the addition of pembrolizumab to standard platinum-pemetrexed chemotherapy was tolerable and resulted in a significant improvement in overall survival. This regimen is a new treatment option for previously untreated advanced pleural mesothelioma.

FUNDING

The Canadian Cancer Society and Merck & Co.

A Phase 1 Trial of the Safety, Tolerability, and Biological Effects of Intravenous Enadenotucirev (EnAd), a Novel Oncolytic Virus, in Combination with Chemoradiotherapy in Locally Advanced Rectal Cancer (CEDAR)

PURPOSE/OBJECTIVE(S)

Novel treatment combinations are required to increase response rates in rectal cancer. EnAd is an intravenous, tumor selective, oncolytic adenovirus with high affinity for malignant colorectal epithelial cells. Pre-clinical evidence of synergy with radiation warranted further clinical evaluation and assessment of safety in combination with chemoradiation (CRT), 25 × 2Gy and concurrent capecitabine.

MATERIALS/METHODS

EnAd was escalated using 2 dose levels of viral particles (1 × 1012, 3 × 1012), given Monday, Wednesday, Friday over 3 schedules (pre-CRT, pre & post CRT). Toxicity and efficacy were used as dual end points in escalation decisions. A 2-parameter and 3-parameter logistic Time to Event Continual Reassessment Method (TiTE-CRM) were used estimate the dose-toxicity and dose-efficacy relationship, respectively. Results are shown as probability and 95% credible interval (Cr.I). The dose limiting toxicity (DLT) window was 13 weeks. Patients who had not completed their DLT window at the time of a dose decision were included in the safety analysis but down-weighted according to their follow-up time and amount of IMP received. Efficacy was assessed at 13 weeks using MRI Tumor Regression Grade (mrTRG), where mrTRG 1-2 equals response. The trial (NCT03916510) was conducted in 4 UK centers.

RESULTS

A total of 13 patients were enrolled, 12 of whom were evaluable. Median age was 57 (range 31-84), and 10/13 were male. One patient had two G3 adverse events (AE); diarrhea, acute kidney injury. All other adverse events (AEs) were G1 or 2, with no G4/5 events. The most common AE by organ system was gastrointestinal (20.8%, G1). There were two observed DLTs on Dose schedule 3; leg swelling and acute kidney injury. Responses and toxicities increased with escalating schedules of EnAd (Table 1).

CONCLUSION

CEDAR is the first trial to successfully combine an intravenous oncolytic adenovirus with radiation, demonstrating the feasibility and acceptability of this approach, and a new paradigm in radiosensitization in rectal cancer. Within this small Phase I study, EnAd demonstrated an acceptable safety profile with evidence of a higher-than-expected rate of response by mrTRG. Translation analysis of tissue, blood and microbiome for biological correlates of radiation synergy is underway.

FUNDING

PsiOxus, CRUK (A24474).

SPONSOR

University of Oxford.

Association of Molecular Profiles and Mutational Status With Distinct Histological Lung Adenocarcinoma Subtypes. An Analysis of the LACE-Bio Data

BACKGROUND

Adjuvant chemotherapy (AC) is indicated for stage II and stage III lung adenocarcinomas (ADC). Using the LACE Bio II database, we analyzed the distribution of various mutations across the subtypes of ADCs and studied the prognostic and predictive roles of PD-L1, TMB, and Tumor Infiltrating Lymphocytes (TILs).

MATERIALS AND METHODS

Clinical and genomic data from the LACE Bio II data were extracted. Patients were divided into ADC subtypes, in which the grouping was done based on their known clinical behavior (Lepidic [LEP], Acinar/Papillary [ACI or PAP], Micropapillary/Solid [MIP or SOL], Mucinous [MUC] and Others). Kaplan-Meier (KM) and log-rank test were used to compare survival based on PD-L1, TMB, TILs and combinations of TMB with PD-L1 and TILs. Adjusted Hazard Ratios (HR) were analyzed with Overall Survival (OS), Disease-Free Survival (DFS) and Lung Cancer-Specific Survival (LCSS) as endpoints.

RESULTS

A total of 375 ADC patients were identified. MIP/SOL was the subtype most commonly positive for various biomarkers. PD-L1 Negative/high TMB was associated with better outcomes in terms of OS (HR = 0.46 [0.23-0.89], P = .021) and DFS (HR = 0.52 [0.30-0.90], P = .02), relative to PD-L1 Negative/low TMB. High TMB predicted worse outcome with AC use in terms of OS (ratio of hazard ratio rHR = 2.75 [1.07-7.04], P = .035). Marked TILs had better outcome with AC for DFS (rHR = 0.22 [0.06-0.87], P = .031 and LCSS (rHR = 0.08 [0.01-0.66], P = .019) respectively. There was also a beneficial effect of AC among patients with Marked TILs/low TMB in terms of DFS (rHR = 0.06 [0.01-0.53], P = .011).

CONCLUSION

High TMB has a prognostic role in resectable lung ADC. The high TMB group had a poor outcome with AC, suggesting that this group may be better served with immune checkpoint therapy.

Abstract P3-07-10: CCTG IND.236: A Phase 1b trial of combined CFI-402257 and weekly paclitaxel in patients with HER2-negative (HER2-) advanced breast cancer (aBC)

CCTG IND.236: A Phase 1b trial of combined CFI-402257 and weekly paclitaxel in patients with HER2-negative (HER2-) advanced breast cancer (aBC) Philippe L. Bedard, Mihaela Mates, John Hilton, Nathalie Levasseur, Arif Awan, Amirrtha Srikanthan, David Cescon, Karen Gelmon, Andrew Robinson, Nancy Drummond-Ivars, Irene Li, Laleh Rastgou, Jackie Edwards, Linda Hagerman, Siwei Zhang, Mark Bray, Lesley Seymour, Moira Rushton-Marovac, Pierre-Olivier Gaudreau Background: CFI-402257 is a selective oral inhibitor of TTK protein kinase, a critical regulator of the mitotic spindle assembly checkpoint overexpressed in breast cancer (BC). CFI-402257 monotherapy has anti-proliferative and cytotoxic activity and enhances antitumor activity of paclitaxel in BC xenograft models. Material and methods: Primary objectives were to establish safety and Recommended Phase 2 dose (RP2D) of CFI-402257 combined with weekly paclitaxel (Phase 1b) and Overall Response Rate (ORR) as per RECIST 1.1 (Phase 2). Patients with HER2- aBC with adequate organ function, PS 0-1, previously treated with >1 non-taxane chemotherapy, were eligible. A 3+3 design was used for Phase 1b, with dose limiting toxicities (DLTs) assessed during cycle 1 (28 days). Starting dose CFI-402257 was 84mg (DL1 = 84mg, DL2 = 112mg, DL3 = 168mg, DL4 = 210mg and DL5 = 252mg) on a 2-day on, 5-day off schedule with paclitaxel 80mg/m2 day 1, 8, 15. Safety assessments were performed weekly (CTCAE v5.0) and response every 2 cycles. A Simon 2-stage design was used for Phase 2 (stage 2 required ≥4 responses in 17 evaluable patients from stage 1). Results: 37 patients received a total of 260 cycles including all 5 dose levels. Median age was 59; 92% ER+/HER2-; 49% PS1; 22% 3 prior chemotherapy lines; 41% 4 sites of metastatic disease, and 81% had received prior CDK4/6 inhibitors. Grade 3 hematological adverse events (AEs, all dose levels) were neutropenia (70%), lymphopenia (41%) and anemia (14%). Six DLTs occurred: 5 dose-related grade 4 neutropenia and 1 febrile neutropenia. Three DLTs occurred at DL3, two at DL4, and one at DL5. Three serious AEs (two at DL3, and one at DL4) at least possibly related to treatment were seen: 2 febrile neutropenia and 1 skin infection (all grade 3). Frequent AEs (˃5%; all dose levels) considered at least possibly related to treatment were: diarrhea (38%), nausea (30%), fatigue (27%), vomiting (16%), anorexia (14%), maculo-papular rash (14%), oral mucositis (11%), alopecia (11%) and pruritus (8%). DL3 (168mg) was selected as RP2D. ORR was 3/36=8% and 1/17=5.9% in all vs Phase 2 evaluable patients, respectively. Clinical Benefit Rate (CBR; defined as complete response, partial response or stable disease ˃16 weeks in duration) was 18/33=54.6% and 10/17=58.8% in all vs Phase 2 evaluable patients, respectively. During Phase 2, the 17 evaluable patients from stage 1 did not meet pre-specified threshold for anti-tumor activity to proceed to stage 2. Conclusions: CFI-402257 and paclitaxel was well tolerated, with neutropenia as the main toxicity. DL3 (168mg) was selected as RP2D. Phase 2 ORR and CBR was 5.9% and 58.8%, respectively; during Phase 2, the 17 evaluable patients from stage 1 did not meet the pre-specified threshold for anti-tumor activity to proceed to stage 2 and the trial was closed to accrual on April 7, 2022. Final analysis and correlative analyses are ongoing. Acknowledgements: Coordinated by the CCTG. Funding supported by SU2C Canada - Canadian Cancer Society Breast Cancer Dream Team Research Funding (SU2C-AACR-DT-18-15) and OICR. CFI-402257 provided by Treadwell Therapeutics.

Citation Format: Philippe Bedard, Mihaela Mates, John Hilton, Nathalie Levasseur, Arif Awan, Amirrtha Srikanthan, David W. Cescon, Karen Gelmon, Andrew Robinson, Nancy Drummond-Ivars, Irene Li, Laleh Rastgou, Jackie Edwards, Linda Hagerman, Siwei Zhang, Mark Bray, Lesley Seymour, Moira Rushton, Pierre-Olivier Gaudreau. CCTG IND.236: A Phase 1b trial of combined CFI-402257 and weekly paclitaxel in patients with HER2-negative (HER2-) advanced breast cancer (aBC) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-07-10.

Abstract P3-07-14: A phase II study of CFI-400945 in patients with advanced/metastatic cancer: Canadian Cancer Trials Group (CCTG) IND.237

Background:

CFI-400945 is a selective oral inhibitor of Polo-like Kinase 4 (PLK4), a controller of centriole duplication and mitotic progression identified by functional screening of genomically unstable breast cancer (BC). IND.237 (NCT01954316) is an open label, multicentre, phase 2 study in HER2 negative metastatic breast cancer (MBC) with 3 cohorts, 1 enriched for PTEN loss of function. Enrollment started in 2018 at 64mg based on a previously established recommended phase 2 dose (RP2D). The initial patients had higher than expected grade 3/4 neutropenia which led to a voluntary hold and dose de-escalation; the new RP2D was declared at 32mg as previously reported Here we report the results of the phase 2 study of CFI-400945 in advanced BC patients.

Materials and Methods:

49 patients were enrolled across 3 cohorts: 1: triple negative; 2: ER+/HER2- PTEN low (by IHC); 3: ER+/HER2-, PTEN intact. The primary outcome is objective response rate (ORR); secondary outcomes included disease control rate (DCR) >16w, and safety. A Simon 2-stage design was used (9 – 25 pts planned for each cohort). CFI-400945 would be considered active if ≥3 responses were observed in any given cohort. Eligibility included ECOG 0-1, adequate organ function and receipt of at ≥1 prior line of cytotoxic chemotherapy in any setting including anthracycline taxane (unless contraindicated). Treatment was 32mg 7d on 7d off in cycle 1 (cycle length=28d), then continuously starting cycle 2. Safety assessments were performed each cycle and response (RECIST 1.1) every 2 cycles.

Results:

60 patients have been screened, 49 enrolled: 10 were in initial dose ranging and were excluded from phase 2 response assessment. 10 patients were enrolled in cohort 1, 4 in cohort 2, and 25 in cohort 3. Table 1 presents patient characteristics and response results. 1 patient in cohort 3 has not had disease re-assessed at time of abstract submission. The most common adverse events have been cytopenias, nausea, fatigue, headache, constipation and vomiting. Less than 5% of patients experienced a non-hematologic AE > grade 3; 33% experienced ≥ grade 3 neutropenia.

Conclusions:

CFI-400945 32mg is well tolerated in this MBC population with moderate incidence of uncomplicated neutropenia. The TNBC cohort so this arm has been closed to further accrual for lack of responses. The PTEN loss group has been slow to accrue and remains open. Responses in the ER+/HER2- arm are encouraging – results from patients remaining on study are awaited and correlative studies to identify features associated with responses are underway.

Acknowledgements: Sponsored by the Canadian Cancer Trials Group. Supported by Stand Up To Cancer Canada (scientific partner AACR) Canadian Cancer Society (CCS) Breast Cancer Dream Team Research Funding, Ontario Institute for Cancer Research (funding provided by the Government of Ontario) and grants from CCS to CCTG.

Table 1. Table 1. Patient characteristics and response rates in each cohort treated with CFI-400945.

Citation Format: David W. Cescon, John Hilton, Philippe Bedard, Phillip Blanchette, Rossanna C. Pezo, Ayesha Bashir, Vikaash Kumar, Terry L. Ng, Arif Awan, Anthony Lott, Jacques Antoun Raphael, Linda Hagerman, Mark Bray, Lindsay Muyot, Jesus Fuentes Antras, Lesley Seymour, Dongsheng Tu, Pierre-Olivier Gaudreau, Moira Rushton. A phase II study of CFI-400945 in patients with advanced/metastatic cancer: Canadian Cancer Trials Group (CCTG) IND.237 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-07-14.

Abstract P3-07-18: CCTG IND.239: A phase 2 study of combined CFI-400945 and durvalumab in patients with advanced triple negative breast cancer (aTNBC)

CCTG IND.239: A phase 2 study of combined CFI-400945 and durvalumab in patients with advanced triple negative breast cancer (aTNBC) John Hilton, David W. Cescon, Andrew Robinson, Sukhbinder Dhesy-Thind, Sara Kristina Taylor, Arif Awan, Terry Ng, Moira Rushton, Marie-France Savard, Lindsay Muyot, Marie Claude Reeves, Linda Hagerman, Hongbo Lui, Mark Bray, Dongsheng Tu, Lesley Seymour, Pierre-Olivier Gaudreau Background: CFI-400945 is a selective oral inhibitor of Polo-like Kinase 4 (PLK4), which controls centriole duplication and mitotic progression, and was identified as a drug target based on functional screening of genomically unstable breast cancers. CFI-400945 monotherapy has anti-proliferative activity and enhances antitumor activity when combined with anti-PD-1 immune checkpoint blockade in transplantable murine cancer models. Material and methods: In this multi-centre phase II trial of CFI-400945 and durvalumab combination therapy, the primary objective was overall response rate (ORR) per RECIST 1.1. Patients with aTNBC with adequate organ function, PS 0-1, previously treated with >1 line of chemotherapy including anthracycline and/or taxane, were eligible. CFI-400945 32mg monotherapy was administered on a 7-day on, 7-day off schedule for cycle 1 (which reduced the likelihood of significant hematologic toxicity). From cycle 2 onwards, CFI-400945 32mg daily was administered in combination with durvalumab 1500mg IV every 28 days; responses were assessed every 8 weeks. Following trial activation, 3 patients received a CFI-400945 dose of 40mg (same schedule) for a total of 9 cycles before 32mg was declared as the new recommended phase 2 dose (based on other ongoing trials using CFI-400945). A Simon 2-stage design was used; ≥3/15 responses in stage 1 were required to expand to stage 2. Exploratory PD-L1 expression was measured on immune and tumor cells using the SP263 assay. Results: 15 patients received a total of 45 cycles (1-12 cycles per patient). Median age was 56 (31-76); 53% PS1; 20% 3 prior chemotherapy lines and; 27% 4 sites of metastatic disease. Immune vs tumor cell PD-L1 expression was 1% in 50% and 23% of patients, respectively (immune and tumor cell expression was mutually exclusive). Immune vs tumor cell PD-L1 expression was 10% in 17% and 15% of patients, respectively. Grade 3 hematological adverse events (AEs) were lymphopenia (40%), neutropenia (20%), anemia and thrombocytopenia (7% for both). One serious AE at least possibly related to treatment was seen: grade 3 febrile neutropenia. Frequent AEs (˃5%) considered at least possibly related to CFI-400945 were: nausea and anorexia (both 20%), fatigue and dysgeusia (both 13%), headache, dizziness, maculo-papular rash, back pain and gastroesophageal reflux disease (all 7%), Frequent AEs (˃5%) considered at least possibly related to durvalumab were: anorexia (13%), arthritis, fatigue, back pain, pain in extremity and hot flashes (all 7%). No responses were observed in 14 evaluable patients during stage 1, therefore the pre-specified threshold for anti-tumor activity to proceed to stage 2 was not met. Disease control rate (complete response, partial response or stable disease ˃16 weeks in duration) was 7% (1/14). Conclusions: CFI-400945 and durvalumab was well tolerated, with no unexpected toxicities of the combination. However, in this heavily pretreated and PD-L1 unselected TNBC population, no responses were observed and the pre-specified threshold for anti-tumor activity for stage 2 was not met. The trial was closed to accrual on April 26, 2022. Final analysis and correlative analyses are ongoing. Acknowledgements: Coordinated by the CCTG. Funding supported by Astra Zeneca. CFI-400945 provided by Treadwell Therapeutics and durvalumab provided by Astra Zeneca.

Citation Format: John Hilton, David W. Cescon, Andrew Robinson, Sukhbinder Dhesy-Thind, Sara Taylor, Arif Awan, Terry L. Ng, Moira Rushton, Marie-France Savard, Lindsay Muyot, Marie Claude Reeves, Linda Hagerman, Hongbo Lui, Mark Bray, Dongsheng Tu, Lesley Seymour, Pierre-Olivier Gaudreau. CCTG IND.239: A phase 2 study of combined CFI-400945 and durvalumab in patients with advanced triple negative breast cancer (aTNBC) [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-07-18.

Brief Report: Canadian Cancer Trials Group IND.227: A Phase 2 Randomized Study of Pembrolizumab in Patients With Advanced Malignant Pleural Mesothelioma (NCT02784171)

Immune checkpoint inhibitors have activity in mesothelioma. IND.227 was a phase 2 trial (120 patients planned) comparing progression-free survival of standard platinum and pemetrexed (CP) versus CP + pembrolizumab (pembro) versus pembro. Accrual to the pembro arm was discontinued on the basis of interim analysis (IA-16 wk disease control rate). CP + pembro was tolerable, with progression-free survival similar between arms and median survival and overall response rate higher than those of CP alone (19.8 mo [95% confidence interval or CI: 8.4-41.36] versus 8.9 mo [95% CI: 5.3-12.8] and 47% [95% CI: 24%-71%] versus 19% [95% CI: 5%-42%], respectively). The subsequent phase 3 trial has completed accrual; results are expected in 2023.

Prospective ctDNA genotyping for treatment selection in metastatic castration-resistant prostate cancer (mCRPC): The Canadian Cancer Trials Group phase II PC-BETS umbrella study

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Background: Precision oncology trials in mCRPC rely on genomic profiling of tumor tissue but testing failure rates are 30-40%. Incorporating liquid biopsy screening into trial designs may address limitations of tissue-only genotyping. We report findings from the first 500 plasma samples screened on Prostate Cancer Biomarker Enrichment and Treatment Selection (PC-BETS), a phase II multicenter, eight-arm Canadian umbrella trial (NCT03385655) using circulating tumor DNA (ctDNA) to match mCRPC patients to biomarker (BM)-informed targeted therapies. Methods: mCRPC patients previously treated with novel androgen receptor inhibitor therapy were eligible after PSA and/or radiological progression. Plasma cell-free DNA and matched leukocyte DNA underwent deep targeted sequencing with an exon-limited panel (Feb 2017-Sep 2020), or an expanded panel integrating select introns and a genome-wide copy number grid (July 2020-present). A molecular tumor board (MTB) assigned patients to treatment arms based on prespecified BM criteria (BM+), or by randomization if BM negative (BM-). The primary endpoint was clinical benefit rate (PSA50 response; RECIST CR/PR; or SD ≥12 weeks). We report tumor content (ctDNA%), genomic alterations, and BM status for the whole cohort. Results: As of Nov 2021, 503 samples were screened from 444 patients, with 496 passing quality control. 345 samples (70%) had ctDNA ≥1% (ctDNA+), of which the median ctDNA fraction was 20% (IQR 6-44%). 72% of ctDNA+ samples were BM+ (52% of all screened samples). Driver alterations influencing BM status included AR (76%; 59% gain, 24% mutation), PI3K pathway (37%; PTEN 30%, PIK3CA 6%, AKT 3%), and DNA repair defects (26%: mismatch repair 5%, BRCA2 7%, ATM 6%, CDK12 7%, other 6%). The expanded panel detected additional intronic structural variants in baseline ctDNA+ samples ( PTEN 1% vs 25%; BRCA2 0.6% vs 5%; AR 16% vs 37%), and identified whole genome doubling and segmental deletion events. To date, 167 patients have been enrolled to a substudy (83 BM+, 84 BM-). Median time from blood draw to MTB decision improved over time (first vs second half of screening period: 28 vs 17d) with implementation of optimized lab workflows, standardized genomic reports, and hierarchical genomic eligibility assessment. As of Sep 2022, 485 patients have been screened (updated results will be presented). Conclusions: Prospective centralized screening of ctDNA is feasible for guiding precision oncology initiatives. Improvements to assay design, robust availability of targeted therapies and an adaptive approach to biomarker assessment allowed high detection of actionable tumor alterations. Our framework can be used in future trials to stratify patients according to genomic alteration status. Study accrual to PC-BETS is ongoing, with a screening target of 600 patients. Clinical trial information: NCT02905318, NCT03385655 .

Meta-Analysis of the Test-Retest Repeatability of [18F]-Fluorodeoxyglucose Standardized Uptake Values: Implications for Assessment of Tumor Response

PURPOSE

Currently, guidelines for PET with 18F-fluorodeoxyglucose (FDG-PET) interpretation for assessment of therapy response in oncology primarily involve visual evaluation of FDG-PET/CT scans. However, quantitative measurements of the metabolic activity in tumors may be even more useful in evaluating response to treatment. Guidelines based on such measurements, including the European Organization for Research and Treatment of Cancer Criteria and PET Response Criteria in Solid Tumors, have been proposed. However, more rigorous analysis of response criteria based on FDG-PET measurements is needed to adopt regular use in practice.

EXPERIMENTAL DESIGN

Well-defined boundaries of repeatability and reproducibility of quantitative measurements to discriminate noise from true signal changes are a needed initial step. An extension of the meta-analysis from de Langen and colleagues (2012) of the test-retest repeatability of quantitative FDG-PET measurements, including mean, maximum, and peak standardized uptake values (SUVmax, SUVmean, and SUVpeak, respectively), was performed. Data from 11 studies in the literature were used to estimate the relationship between the variance in test-retest measurements with uptake level and various study-level, patient-level, and lesion-level characteristics.

RESULTS

Test-retest repeatability of percentage fluctuations for all three types of SUV measurement (max, mean, and peak) improved with higher FDG uptake levels. Repeatability in all three SUV measurements varied for different lesion locations. Worse repeatability in SUVmean was also associated with higher tumor volumes.

CONCLUSIONS

On the basis of these results, recommendations regarding SUV measurements for assessing minimal detectable changes based on repeatability and reproducibility are proposed. These should be applied to differentiate between response categories for a future set of FDG-PET-based criteria that assess clinically significant changes in tumor response.

Oncology phase I trial design and conduct: time for a change - MDICT Guidelines 2022

In 2021, the Food and Drug Administration Oncology Center of Excellence announced Project Optimus focusing on dose optimization for oncology drugs. The Methodology for the Development of Innovative Cancer Therapies (MDICT) Taskforce met to review and discuss the optimization of dosage for oncology trials and to develop a practical guide for oncology phase I trials. Defining a single recommended phase II dose based on toxicity may define doses that are neither the most effective nor the best tolerated. MDICT recommendations address the need for robust non-clinical data which are needed to inform trial design, as well as an expert team including statisticians and pharmacologists. The protocol must be flexible and adaptive, with clear definition of all endpoints. Health authorities should be consulted early and regularly. Strategies such as randomization, intrapatient dose escalation, and real-world eligibility criteria are encouraged whereas serial tumor sampling is discouraged in the absence of a strong rationale and appropriately validated assay. Endpoints should include consideration of all longitudinal toxicity. The phase I dose escalation trial should define the recommended dose range for later testing in randomized phase II trials, rather than a single recommended phase II dose, and consider scenarios where different populations may require different dosages. The adoption of these recommendations will improve dosage selection in early clinical trials of new anticancer treatments and ultimately, outcomes for patients.

Results of the phase I CCTG IND.231 trial of CX-5461 in patients with advanced solid tumors enriched for DNA-repair deficiencies

CX-5461 is a G-quadruplex stabilizer that exhibits synthetic lethality in homologous recombination-deficient models. In this multicentre phase I trial in patients with solid tumors, 40 patients are treated across 10 dose levels (50–650 mg/m²) to determine the recommended phase II dose (primary outcome), and evaluate safety, tolerability, pharmacokinetics (secondary outcomes). Defective homologous recombination is explored as a predictive biomarker of response. CX-5461 is generally well tolerated, with a recommended phase II dose of 475 mg/m² days 1, 8 and 15 every 4 weeks, and dose limiting phototoxicity. Responses are observed in 14% of patients, primarily in patients with defective homologous recombination. Reversion mutations in PALB2 and BRCA2 are detected on progression following initial response in germline carriers, confirming the underlying synthetic lethal mechanism. In vitro characterization of UV sensitization shows this toxicity is related to the CX-5461 chemotype, independent of G-quadruplex synthetic lethality. These results establish clinical proof-of-concept for this G-quadruplex stabilizer. Clinicaltrials.gov NCT02719977.

G-quadruplex stabilizers, including CX-5461, exhibit synthetic lethality with loss of BRCA1/2 in preclinical models. Here the authors report the results of a phase I study of CX-5461 in patients with solid tumors enriched for DNA-repair deficiencies.

iRECIST and atypical patterns of response to immuno-oncology drugs

With the advent of immunotherapy as one of the keystones of the treatment of our patients with cancer, a number of atypical patterns of response to these agents has been identified. These include pseudoprogression, where the tumor initially shows objective growth before decreasing in size, and hyperprogression, hypothesized to be a drug-induced acceleration of the tumor burden. Despite it being >10 years since the first immune-oncology drug was approved, neither the biology behind these paradoxical responses has been well understood, nor their incidence, identification criteria, predictive biomarkers, or clinical impact have been fully described. Immune-based Response Evaluation Criteria in Solid Tumors (iRECIST) guidelines have been published as a revision to the RECIST V.1.1 criteria for use in trials of immunotherapeutics, and the iRECIST subcommittee (of the RECIST Working Group) is working on elucidating these aspects, with data sharing a current major challenge to move forward with this unmet need in immuno-oncology.

OUP accepted manuscript

Background

Complementary medicines (CM) are frequently used by patients with cancer. Controversy exists over the effectiveness and risk that CM may add to conventional cancer therapy. The incidence of CM use among patients enrolled in phase III clinical trials is unknown.

Methods

Medication lists from 6 international phase III clinical trials were retrospectively reviewed to identify patients using CM. Patients had metastatic breast, colorectal, or lung cancers. Quality of life, adverse events, overall survival, and progression-free survival were compared between CM users and non-users. Baseline differences between groups were adjusted with propensity score matching groups.

Results

Seven hundred and six of 3446 patients (20.5%) used at least one CM. CM use was highest among patients with breast cancer (35.6%). CM users had more favorable baseline prognostic factors (ECOG 0-1, non-smoking status, younger age, and fewer metastases). CM use was associated with lower rates of adverse events (50% vs. 62%, P = .002) and quality of life was similar between both groups. After adjustment with propensity score matching, CM use was also associated with longer overall survival in patients with lung cancer (adjusted hazard ratio 0.80, 95%CI, 0.68-0.94, P =.0054). However, several key control variables like EGFR status were not available.

Conclusion

One in 5 patients in phase III clinical trials report using CM. CM was not associated with worse cancer-specific outcomes. However, CM users had more favorable baseline prognostic factors, and likely other confounders that may have contributed to improved outcomes observed in the lung cohort. Physicians should monitor for CM use and potential interactions with clinical trial drugs.

Prognostic and predictive effect of KRAS gene copy number and mutation status in early stage non-small cell lung cancer patients

Background

In the current analysis, we characterize the prognostic significance of KRAS mutations with concomitant copy number aberrations (CNA) in early stage non-small cell lung cancer (NSCLC), and evaluate the ability to predict survival benefit from adjuvant chemotherapy.

Methods

Clinical and genomic data from the LACE (Lung Adjuvant Cisplatin Evaluation)-Bio consortium was utilized. CNAs were categorized as Gain (CN ≥2) or Neutral (Neut)/Loss; KRAS status was defined as wild type (WT) or mutant (MUT). The following groups were compared in all patients and the adenocarcinoma subgroup, and were correlated to survival endpoints using a Cox proportional hazards model: WT + Neut/Loss (reference), WT + Gain, MUT + Gain and MUT + Neut/Loss. A treatment-by-variable interaction was added to evaluate predictive effect.

Results

Of the 946 (399 adenocarcinoma) NSCLC patients, 41 [30] had MUT + Gain, 145 [99] MUT + Neut/Loss, 125 [16] WT + Gain, and 635 [254] WT + Neut/Loss. A non-significant trend towards worse lung cancer-specific survival (LCSS; HR =1.34; 95% CI, 0.83-2.17, P=0.232), DFS (HR =1.34; 95% CI, 0.86-2.09, P=0.202) and OS (HR =1.59; 95% CI, 0.99-2.54, P=0.055) was seen in KRAS MUT + Gain patients relative to KRAS WT + Neut/Loss patients. A negative prognostic effect of KRAS MUT + Neut/Loss was observed for LCSS (HR =1.32; 95% CI, 1.01-1.71, P=0.038) relative to KRAS WT + Neut/Loss on univariable analysis, but to a lesser extent after adjusting for covariates (HR =1.28; 95% CI, 0.97-1.68, P=0.078). KRAS MUT + Gain was associated with a greater beneficial effect of chemotherapy on DFS compared to KRAS WT + Neut/Loss patients (rHR =0.33; 95% CI, 0.11-0.99, P=0.048), with a non-significant trend also seen for LCSS (rHR =0.41; 95% CI, 0.13-1.33, P=0.138) and OS (rHR =0.40; 95% CI, 0.13-1.26, P=0.116) in the adenocarcinoma subgroup.

Conclusions

A small prognostic effect of KRAS mutation was identified for LCSS, and a trend towards worse LCSS, DFS and OS was noted for KRAS MUT + Gain. A potential predictive effect of concomitant KRAS mutation and copy number gain was observed for DFS in adenocarcinoma patients. These results could be driven by the small number of patients and require validation.

Design and Conduct of Early Clinical Studies of Immunotherapy: Recommendations from the Task Force on Methodology for the Development of Innovative Cancer Therapies 2019 (MDICT)

PURPOSE

To review key aspects of the design and conduct of early clinical trials (ECT) of immunotherapy agents.

EXPERIMENTAL DESIGN

The Methodology for the Development of Innovative Cancer Therapies Task Force 2019 included experts from academia, nonprofit organizations, industry, and regulatory agencies. The review focus was on methodology for ECTs testing immune-oncology therapies (IO) used in combination with other IO or chemotherapy.

RESULTS

Although early successes have been seen, the landscape continues to be very dynamic, and there are ongoing concerns regarding the capacity to test all new drugs and combinations in clinical trials.

CONCLUSIONS

Optimization of drug development methodology is required, taking into account early, late, and lower grade intolerable toxicities, novel response patterns, as well as pharmacodynamic data.

Role of the total mutation burden (TMB) and tumor-infiltrating lymphocytes (TILs) on the development of second primary cancer after complete resection of non-small cell lung cancer (NSCLC)

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Background: Risk of developing SPC after complete surgical resection of NSCLC has been reported to be 3-6% per person-year. We hypothesized that genomic instability, as assessed by high TMB, and the absence of TILs in the primary tumor might be associated with SPC. Methods: The LACE [Lung Adjuvant Cisplatin Evaluation])-BIO database was used, which includes 3 randomized trials. TMB and TILs were analyzed on FFPE specimens. TMB was categorized into tertiles (high > 7.8 mutations/MB, moderate i.e. > 4 and < = 7.8, low < 4) and TILs as marked vs. other. Associations on competing time-to-event endpoints (SPC, and death without developing SPC) were evaluated using the Fine and Gray model stratified by trail and adjusted on treatment, age, gender, tumor stage, nodal stage, histology, performance status and surgery type. Results: TMB and TILs assessments were available for 879 patients without missing clinical covariates; 85 patients had marked TILs. During follow-up, 47 SPCs had been observed and 392 deaths without developing SPC. Regarding TMB, a significant association was found between low TMB and death without SPC (sub-distribution hazard ratio SHR = 1.36(1.06-1.74), see Table), suggesting a higher risk of death without SPC among patient with low TMB compared to those with moderate TMB; no strong effect was observed for SPC. Regarding TILs, a trend was observed between marked TILS and a lower risk of death (SHR = 0.70 [0.47-1.04]) but to a lesser extent for SPC (SHR = 0.80 [0.28-2.28]). Conclusions: This is the first study of the effect of genomic instability (measured by TMB) and host immune response (measured by TILs) in completely resected NSCLC on competing events of SPC and death, suggesting associations between TMB, TILs and death-without-SPC . There was no statistically significant association with SPC. However, the number of SPCs was small; these findings requires validation in other early stage lung cancer cohorts. [Table: see text]

Prognostic and predictive effect of KRAS gene copy number and mutation status in early stage non-small cell lung cancer (NSCLC) patients

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Background: The prognostic and predictive role of KRAS mutations and gene copy number aberrations (CNA) in early stage NSCLC is unclear. In this study, we characterize the prognostic effect of KRAS mutation status and concomitant CN gain in early stage NSCLC, and determine the ability to predict survival benefit from adjuvant chemotherapy. We hypothesize that concomitant KRAS mutations and CN gain will be prognostic of worse survival compared to KRAS mutations alone. Methods: Clinical and genomic data from The LACE (Lung Adjuvant Cisplatin Evaluation)-BIO consortium was utilized. CNA were categorized as Gain or Neutral (Neut)/Loss; mutation status was defined as wild type (WT) or mutant (MUT). WT+Neut/Loss (reference), WT+Gain, MUT+Gain and MUT+Neut/Loss groups were compared in all patients and the adenocarcinoma subgroup. Primary endpoint was lung-cancer-specific survival (LCSS); secondary endpoints were DFS and OS. Survival curves were assessed using Kaplan-Meier and log-rank tests. Concomitant KRAS CNA and mutation status was correlated to endpoints using a Cox proportional hazards model stratified by trial and adjusted for treatment, age, gender, histology, WHO performance status, surgery type, tumor and nodal stage. A treatment-by-variable interaction was added to evaluate predictive effect. Results: 946 (399 adenocarcinoma) patients had complete KRAS mutation, CNA and clinical data: 41 (30) MUT+Gain, 145 (99) MUT+Neut/Loss, 125 (16) WT+Gain, 635 (254) WT+Neut/Loss. There was a negative prognostic effect of KRAS MUT+Neut/Loss for LCSS (HR = 1.32 [1.01-1.71]) on univariable analysis, and to a lesser extent after adjusting for covariates (HR = 1.28 [0.97-1.68]). A similar non-significant trend was observed in KRAS MUT+Gain patients for LCSS (HR = 1.34 [0.83-2.17]), DFS (HR = 1.34 [0.86-2.09]) and OS (HR = 1.59 [0.99-2.54]). There was no significant predictive effect in the overall population; however, a potential predictive effect of KRAS for OS was seen in the adenocarcinoma subgroup (interaction p = 0.046). KRAS MUT+Gain was associated with a beneficial effect of chemotherapy on DFS (HR = 0.33 [0.11-0.99], p = 0.048), with a non-significant trend also seen for LCSS (HR = 0.41 [0.13-1.33]) and OS (HR = 0.40 [0.13-1.26]). Conclusions: A small prognostic effect of KRAS mutation was identified for LCSS. A potential predictive effect of concomitant KRAS mutation status and CNA was observed for DFS in adenocarcinoma patients. These results could be driven by the small number of patients and require further validation.

Abstract PD4-02: Canadian cancer trials group trial IND.231: A phase 1 trial evaluating CX-5461, a novel first-in-class G-quadruplex stabilizer in patients with advanced solid tumors enriched for DNA-repair deficiencies

Background: G-quadruplexes are secondary DNA structures that reversibly form in guanine-rich regions within DNA. Our group has demonstrated that CX-5461 selectively binds and stabilizes G-quadruplex structures, causing replication fork collapse and double-stranded DNA breaks. In BRCA1/2 deficient cell lines and xenograft models, synthetic lethality was observed. We are conducting a phase I study of CX-5461, a first-in-class G-quadruplex stabilizer, in patients with advanced solid tumors enriching for patients with DNA-repair deficiencies. Methods: We conducted a phase I study of 10 dose levels of CX-5461. The initial 7 dose levels (50, 100, 150, 200, 250, 325, 475 mg/m2) were administered intravenously on days 1 and 8 of a 4-week cycle, while the final 3 dose levels (325, 475 and 650 mg/m2) were administered intravenously on days 1, 8 and 15 of a 4-week cycle. Escalation was performed using a 3+3 design. Eligible patients must have advanced disease, a PS 0-2 and adequate organ function. Patients were treated until disease progression. The primary objective was the determination of RP2D. The DLT evaluation period was cycle 1 and AEs needed to be maximally managed to be considered a DLT. Secondary objectives include ORR (RECIST 1.1), PK, and toxicity (CTCAEv4.0). Results: As of March 28th, 2019, 40 patients were registered on protocol with 39 patients evaluable for toxicity and 35 patients evaluable for response. 18 of the participants were diagnosed with metastatic breast cancer. Of the evaluable patients, the median age is 53 with 24 patients having 3 or more prior regimens for their disease. There have been no DLTs observed to date. There were 5 treatment-related non-DLT grade 3 photosensitivity events (DL0, DL4, DL7, DL8, DL9) that were reversible and were secondary to lack of photo-protective measures. 3 SAEs were considered related to CX-5461 (photosensitivity of the skin (n=2); photosensitivity of the eyes (n=1). Treatment-related AEs ≥10% were photosensitivity of the skin (59%), photosensitivity of the eyes (21%), mucositis (15%), nausea (44%), hand-foot syndrome (23%), headache (10%) and rash (10%). The RP2D was determined to be 475 mg/m2 on days, 1, 8 and 15 of a 4-week cycle. PK appears dose-proportional for Cmax and AUC24,∞. Of the 40 patients treated on protocol, 34 have discontinued from the study either due to objective progressive disease (n=29), symptomatic progression of disease (n=4) or withdrawal of consent (n=1). In terms of best response, 4 patients, including 3 with breast cancer, have a confirmed PR (2 germline BRCA2, 1 germline BRCA2 VUS, germline PALB2) with an additional 6 patients, including 2 with breast cancer, (4 germline BRCA2, 2 somatic BRCA1/2) with SD as best response for &gt;=4 cycles. Conclusion: CX-5461 is tolerable with preventable photosensitivity being the main toxicity. The RP2D is now identified at 475 mg/m2 on days 1, 8 and 15 of a 4-week cycle. Preliminary activity for CX-5461 has been observed in patients with HR-deficient tumors for both breast cancer and other tumor types. An expansion cohort, with mandatory tumor and skin biopsies, for patients with metastatic breast cancer with confirmed HR deficiency is currently open. Further updates will be provided.

Citation Format: John Hilton, Karen Gelmon, David Cescon, Anna Tinker, Derek Jonker, Rachel Goodwin, Scott Laurie, Aaron Hansen, Samuel Aparicio, John Soong, Linda Hagerman, Hongbo Lui, Philippe Bedard, Kathleen Pritchard, Dongsheng Tu, Lesley Seymour. Canadian cancer trials group trial IND.231: A phase 1 trial evaluating CX-5461, a novel first-in-class G-quadruplex stabilizer in patients with advanced solid tumors enriched for DNA-repair deficiencies [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD4-02.

A Canadian cancer trials group phase IB study of durvalumab (anti-PD-L1) plus tremelimumab (anti-CTLA-4) given concurrently or sequentially in patients with advanced, incurable solid malignancies

Background The IND.226 study was a phase Ib study to determine the recommended phase II dose of durvalumab + tremelimumab in combination with standard platinum-doublet chemotherapy. Sequential administration of multiple agents increases total chair time adding costs overall and inconvenience for patients. This cohort of the IND.226 study evaluated the safety and tolerability of durvalumab + tremelimumab given either sequentially (SEQ) or concurrently (CON). Methods Patients with advanced solid tumours were enrolled and randomised to either SEQ tremelimumab 75 mg IV over 1 h followed by durvalumab 1500 mg IV over 1 h q4wks on the same day, or CON administration over 1 h. The serum pharmacokinetic profile of SEQ versus CON of durvalumab and tremelimumab administration was also evaluated. Results 14 patients either received SEQ (n = 7pts) or CON (n = 7 pts). There were no infusion related reactions. Drug related adverse events (AEs) were mainly low grade and manageable, and comparable in frequency between SEQ/CON- fatigue (43%/57%), rash (43%/43%), pruritus (43%/29%) and nausea (14%/29%). One patient in each cohort discontinued treatment due to toxicity. The PK profiles of durvalumab and tremelimumab were similar between CON and SEQ, and to historical reference data. Conclusions Concurrent administration of durvalumab and tremelimumab over 1 h is safe with a comparable PK profile to sequential administration.

Design and conduct of early clinical studies of immunotherapy agent combinations: recommendations from the task force on Methodology for the Development of Innovative Cancer Therapies

The Methodology for the Development of Innovative Cancer Therapies task force considered aspects of the design and conduct of early studies of combinations of immunotherapy agents during their 2018 meeting. The task force defined the relevant data to justify combination clinical trials, which includes a robust hypothesis for the combination, pre-clinical data with evidence of efficacy and an understanding of the pharmacodynamics effects of each agent, and ideally evidence of single agent activity. Evaluation of pharmacodynamic biomarkers is critical in early phase combination trials, and should be incorporated into trial objectives and go/no-go decisions. The task force also identified the need to develop assessment tools and end points that capture the unique patterns of tumour responses to immunotherapy, including pseudoprogression and hyperprogression. At least one additional tumour measurement before baseline and an early CT scan (at 4 weeks for example) would help define the incidence of hyperprogression, although a common definition is needed. Finally, the task force highlighted substantial redundancy and inefficiency in the combination immunotherapy space, and recommended the adoption of innovative trial designs.

A phase I study of vistusertib (dual mTORC1/2 inhibitor) in patients with previously treated glioblastoma multiforme: a CCTG study

The PI3K/AKT/mTOR pathway activation plays a central role in glioblastoma multiforme (GBM) development and progression, and in resistance to anti-cancer therapies. Inhibition of the PI3K pathway has been shown to sensitize cultured glioma cells and tumor xenografts to the effects of temozolomide (TMZ) and radiation. Vistusertib is an oral inhibitor of mTORC1/2 complexes. The primary objective of this Canadian Cancer Trials Group phase I study was to determine the recommended phase II dose (RP2D) of vistusertib in patients with GBM receiving TMZ at first progression following primary treatment. Vistusertib was administered at a starting dose of 100 mg bid 2 days on/5 days off weekly with TMZ 150 mg/m² daily for 5 days/28-days cycle. Dose escalation was according to a 3 + 3 design. Secondary objectives included assessment of vistusertib safety and toxicity profile, and preliminary efficacy. 15 patients were enrolled in the study (median age 66 (range 51-77), females 8). Vistusertib 125 mg BID in combination with TMZ 150 mg/m² daily for 5 days was well tolerated. Vistusertib treatment-related adverse events were generally grade 1-2, with the most frequently reported being fatigue, gastrointestinal symptoms, and rash. Of 13 response evaluable patients, 1 patient (8%) had a partial response ongoing at 7.6 months of follow-up, and 5 patients had stable disease (38%) as best response (median duration 9.6 months, range 3.7-not yet reached). Six-month progression-free survival (PFS) rate was 26.6%. Combination of vistusertib with TMZ in GBM patients at first recurrence demonstrated a favorable safety profile at the tested dose levels.

A phase Ib study of a PI3Kinase inhibitor BKM120 in combination with panitumumab in patients with KRAS wild-type advanced colorectal cancer

Background Resistance to Epidermal Growth Factor inhibition (EGFRi) in patients with KRAS wild-type (wt) Colorectal Cancer (CRC) may occur as a result of PI3K/AKT/mTOR signaling. We conducted a study to establish the recommended phase II dose (RP2D) and response rate of panitumumab, an EGFRi, plus BKM120, a PI3K inhibitor, in advanced CRC. Methods Patients with chemotherapy refractory KRAS wt CRC, who were EGFRi naive were enrolled. A 3 + 3 dose escalation design was utilized. The starting dose of panitumumab was 6 mg/kg iv every 2 weeks with BKM120 at 60 mg oral daily. Results Nineteen patients were treated and 17 were evaluable for response. The starting dose was not tolerable (mucositis, fatigue). At dose level (DL) 1, three of six patients discontinued treatment due to toxicity, DL - 1 had no significant toxicity. Panitumumab 6 mg/kg iv q 2 weeks with BKM120 60 mg given 5 out of 7 days per week was declared the RP2D. One patient (5.9%) who was PTEN and PIK3CA negative by IHC had a partial response, seven had stable disease, and nine had disease progression. Conclusion Panitumumab (6 mg/kg iv q 2 weeks) with BKM120 60 mg given 5 out of 7 days per week was declared the RP2D. Toxicities including fatigue, rash and mucositis. There was little evidence of activity in this biomarker unselected cohort.

A Phase Ib Trial of Durvalumab in Combination with Trastuzumab in HER2-Positive Metastatic Breast Cancer (CCTG IND.229)

BACKGROUND

Immune checkpoint inhibitors are active in a broad range of cancers, including programmed death ligand 1 (PD-L1)-positive, triple-negative, metastatic breast cancer (MBC). Antibody-dependent cell-mediated cytotoxicity is a mechanism of action of trastuzumab. We performed a phase Ib trial of durvalumab and trastuzumab in HER2-positive MBC previously treated with chemotherapy and anti-HER2 antibodies to assess safety, efficacy, and correlative endpoints.

PATIENTS AND METHODS

Patients with HER2-positive MBC were enrolled on a standard 3 + 3 design. Dose level 1 was durvalumab (1,125 mg intravenously day 1) and trastuzumab (8 mg/kg intravenously loading, then 6 mg/kg day 1) on a q3 weekly cycle. An expansion cohort at the recommended phase II dose (RP2D) performed tumor biopsies at baseline and after cycle 1. The primary endpoint was to establish the RP2D.

RESULTS

Fifteen patients were accrued from April to December 2016, of which 14 were evaluable for response. Median age was 54 years (range 40-86); the majority had visceral disease (87%) and at least three prior (adjuvant and/or metastatic) lines of chemotherapy (73%), including trastuzumab (93%), pertuzumab (60%), and trastuzumab-emtansine (93%) for MBC. No dose-limiting toxicities were observed at dose level 1 (n = 6) or dose expansion (n = 9) during cycle 1. One patient developed a grade ≥3 immune-related adverse event (grade 4 diabetes mellitus). No responses by RECIST were seen, with 4 of 14 patients (29%) demonstrating stable disease as best response at week 6 (median duration, 2.7 months). All patients had <1% PD-L1 expression on either archival tissue (7/15) or prestudy biopsy (8/15). In the dose expansion cohort, evaluable pretreatment and on-treatment tumor biopsies (n = 5) showed minimal CD8 cell infiltration.

CONCLUSION

The RP2D of durvalumab and trastuzumab is standard full doses of both agents. No significant clinical activity was observed in patients with heavily pretreated HER2-positive PD-L1-negative MBC.

IMPLICATIONS FOR PRACTICE

This phase Ib trial with associated correlative endpoints provides insights into the lack of activity of the combination of durvalumab and trastuzumab in heavily pretreated HER2-positive metastatic breast cancer (MBC). No significant clinical activity was observed in patients with heavily pretreated HER2-positive programmed death ligand 1 (PD-L1)-negative MBC with evidence of cytotoxic T-cell exhaustion. Furthermore, all patients had no expression of PD-L1 in the tumor cells. These data support the importance of PD-L1 as an important selection biomarker and the need to assess the tumor microenvironment for immune regulatory cells. Further work is needed to understand how to activate the "cold" tumors to be able to combine current immune-oncology agents.

Dose-Ranging and Cohort-Expansion Study of Monalizumab (IPH2201) in Patients with Advanced Gynecologic Malignancies: A Trial of the Canadian Cancer Trials Group (CCTG): IND221

PURPOSE

Monalizumab binds CD94/NKG2A, preventing HLA-E inhibition of tumor lymphocytes. A dose-ranging/cohort expansion trial of monalizumab for recurrent gynecologic malignancies was conducted to determine the recommended phase II dose (RP2D) and to explore clinical activity, pharmacokinetics, pharmacodynamics, safety, and immunogenicity.

PATIENTS AND METHODS

Participants (and part 2 expansion cohorts) included (i) platinum-sensitive ovarian, (ii) platinum-resistant ovarian, (iii) squamous cervical (CX), and (iv) epithelial endometrial (END) carcinomas. Part 1 assessed monalizumab at 1, 4, or 10 mg/kg every 2 weeks. In part 2, ≥4 patients/cohort underwent pre- and on-treatment tumor biopsies. Preset criteria determined cohort expansion.

RESULTS

A total of 58 participants were evaluable. The RP2D was 10 mg/kg i.v. every 2 weeks. Dose proportionality and 100% NKG2A saturation were observed. Related adverse events were mild: headache, abdominal pain, fatigue, nausea, and vomiting. Grade 3 related adverse events were nausea (1), vomiting (1), dehydration (1), fatigue (2), anorexia (1), dyspnea (1), and proctitis (1). Dose-limiting toxicities were not observed. Hematologic and biochemical changes were mild and not dose related. Best response was SD: part 1, 7 of 18 (39%) [3.4 months (1.4-5.5)], and part 2, 7 of 39 (18%) [1.7 months (CX) to 14.8 months (END)]. Neither a predictive biomarker for SD nor evidence of pharmacodynamic effects was identified. There was a trend to significance between a reduction in lymphocyte HLA-E total score and pharmacodynamics.

CONCLUSIONS

Monalizumab 10 mg/kg i.v. every 2 week is well tolerated in patients with pretreated gynecologic cancers. Short-term disease stabilization was observed. Future studies should assess combinations with other agents, including immunotherapeutics.

Selumetinib in patients receiving standard pemetrexed and platinum-based chemotherapy for advanced or metastatic KRAS wildtype or unknown non-squamous non-small cell lung cancer: A randomized, multicenter, phase II study. Canadian Cancer Trials Group (CCTG) IND.219

INTRODUCTION

Activation of the RAS/RAF/MEK/ERK pathway may confer resistance to chemotherapy in non-small cell lung cancer (NSCLC). Selumetinib (AZD6244, ARRY142886), a MEK1/2 inhibitor combined with chemotherapy in patients with NSCLC was evaluated in two schedules to evaluate efficacy and toxicity.

METHODS

IND.219 was a three-arm study of first line pemetrexed/platinum chemotherapy with two schedules of selumetinib (Arm A: intermittent given on days 2-19; Arm B: continuous given on days 1-21) versus chemotherapy alone (Arm C). The primary endpoint was objective response rate (ORR); secondary objectives were tolerability, progression-free survival (PFS), overall survival (OS). The trial was stopped at the planned interim analysis.

RESULTS

Arms A/B/C enrolled 20/21/21 patients, ORR was 35% (95% CI 15-59% median duration 3.8 months), 62% (95% CI 38-82%; median duration 6.3 months), 24% (95% CI 8-47%; median duration 11.6 months) respectively. The PFS (months Arm A, B, C) was 7.5, 6.7, 4.0 respectively (hazard ratio (HR) PFS Arm A over Arm C: 0.76 [95% CI, 0.38-1.51, 2-sided p = 0.42]; Arm B over Arm C 0.75 [95% CI 0.37-1.54, p = 0.43]. Skin and gastrointestinal adverse events were more common with the addition of selumetinib. A high incidence of venous thromboembolism was seen in all arms.

CONCLUSIONS

Selumetinib combined with chemotherapy was associated with a higher response rate. Continuous selumetinib appeared to be superior to an intermittent schedule. PFS was prolonged with the addition of selumetinib, however this was not statistically significant.

A Phase II Study of PX-866 in Patients With Recurrent or Metastatic Castration-resistant Prostate Cancer: Canadian Cancer Trials Group Study IND205

BACKGROUND

In PTEN-loss models, the phosphatidylinositol 3-kinase (PI3K)/AKT and androgen receptor signaling pathways cross-regulate by reciprocal feedback whereby inhibition of one activates the other, creating a rationale for co-targeting. We studied the irreversible, pan-isoform inhibitor of Class I PI-3K PX-866 singly (part A) and with abiraterone acetate (AA) in patients on AA with rising prostate-specific antigen (PSA) (part B).

PATIENTS AND METHODS

The primary endpoint was lack of progression at 12 weeks. Exploratory endpoints included changes in circulating tumor cells (CTC), pharmacodynamic studies on platelets (part A), and archival tumor exploration of PTEN as predictor of response (part B).

RESULTS

A total of 43 and 25 patients accrued to parts A and B, respectively. In part A, 14 (33%) patients were progression-free at 12 weeks, with 2 partial objective responses and 1 confirmed PSA response. Favorable CTC conversion (< 5 CTC/7.5 mL) occurred in 6 (24%) of 25 evaluable patients. In part B, 11 of 25 patients had measurable disease. Six (24%) patients were progression-free at 12 weeks. No objective or PSA responses were observed. For all 68 patients, the most common toxicities were diarrhea (53 patients), nausea (36), anorexia (24), fatigue (22), and vomiting (20). Among 17 patients for whom PTEN testing was possible, 3 had PTEN homozygous deletion and 14 had no change. No correlation between PTEN status and response was seen.

CONCLUSIONS

PX-866 had modest single agent activity. Adding AA to PX-866 showed no evidence of resistance reversal. Strategies to combine PI3K inhibition with androgen receptor-targeted therapies could consider initiation earlier, combination with other agents, and/or recruiting a selected population.

RECIST 1.1 for Response Evaluation Apply Not Only to Chemotherapy-Treated Patients But Also to Targeted Cancer Agents: A Pooled Database Analysis

PURPOSE

The mode of action of targeted cancer agents (TCAs) differs from classic chemotherapy, which leads to concerns about the role of RECIST in evaluating tumor response in trials with TCAs. We investigated the performance of RECIST using a pooled database from 50 clinical trials with at least one TCA.

METHODS

We examined the impact of the number of target lesions (TLs) on within-patient variability of tumor response. The prognostic effect of TL response (at 12 weeks or on study on the basis of a maximum five TLs) on survival was studied through landmark and time-dependent Cox models adjusted for baseline tumor load, occurrence of new lesions, or unequivocal progression of nontarget disease.

RESULTS

Data were obtained from 23,259 patients with cancer (36% lung, 28% colorectal, 11% breast, and 25% other); 15,620 received TCAs, predominantly transduction or angiogenesis inhibitors, as a single agent (37%), combined with other TCAs (7%), or as chemotherapy (56%); 28% received chemotherapy only; and 5% received best supportive care or placebo. A total of 17,222 patients contributed to the analyses. Within-patient variability decreased with increasing number of TLs, similarly for TCAs (with/without chemotherapy) and chemotherapy only. Mixed responses occurred proportionally in all treatment classes. Landmark analyses showed an ordinal relationship between percentage change from baseline to 12 weeks and overall survival, and demonstrated a clear distinction between tumor shrinkage and progressive disease according to RECIST. Time-dependent analysis showed no marked improvement in the ability to predict survival on the basis of TL tumor growth compared with nontarget progression or new lesion occurrence, regardless of treatment. Similar results were seen for major tumor types and different classes of TCAs.

CONCLUSION

This work reinforces that RECIST version 1.1 perform well for response assessment of TCAs.

Phase I study of vinblastine and temsirolimus in pediatric patients with recurrent or refractory solid tumors: Canadian Cancer Trials Group Study IND.218

Combining mammalian target of rapamycin (mTOR) inhibitors and vinca alkaloids has shown therapeutic synergy in xenograft models of pediatric cancers. This phase I study assessed safety and toxicity of temsirolimus in combination with vinblastine in children.

PROCEDURE

Patients ≥ 1 and ≤ 18 years with recurrent/refractory solid or CNS tumors were eligible. Vinblastine (4 mg/m² ) and temsirolimus (15 mg/m² ) were administered i.v. weekly, with planned dose escalation of vinblastine using a rolling six phase I design. Pharmacokinetic and pharmacodynamic data were collected.

RESULTS

Seven patients with median age 12 years (range, 8-18 years) were enrolled; all were evaluable for toxicity and six for response. At dose level 1, four of six patients developed grade 3 mucositis, of which one met duration criteria for dose-limiting toxicity (DLT). Four patients required dose omissions for grade 3 or 4 hematologic toxicity, including one prolonged neutropenia DLT. A subsequent patient was enrolled on dose level -2 (temsirolimus 10 mg/m² , vinblastine 4 mg/m² ) with no protocol-related toxicity > grade 1, except grade 2 neutropenia. Two serious adverse events (SAE) occurred-an allergic reaction to temsirolimus (grade 2) and an intracranial hemorrhage in a CNS tumor patient (grade 3)-unlikely related to study therapy. Soluble VEGFR2 was reduced at cycle 1, day 36 in keeping with inhibition of angiogenesis. Four patients achieved prolonged stable disease for a median of 5.0 months (range, 3.1-8.3 months).

CONCLUSION

The combination of weekly temsirolimus (15 mg/m² ) and vinblastine (4 mg/m² ) exceeds the maximum tolerated dose in children, with frequent oral mucositis and hematologic toxicity.

Tumor Mutation Burden as a Biomarker in Resected Non-Small-Cell Lung Cancer

PURPOSE

The survival benefit with adjuvant chemotherapy for patients with resected stage II-III non-small-cell lung cancer (NSCLC) is modest. Efforts to develop prognostic or predictive biomarkers in these patients have not yielded clinically useful tests. We report findings from the Lung Adjuvant Cisplatin Evaluation (LACE)-Bio-II study, in which we analyzed next-generation sequencing and long-term outcomes data from > 900 patients with early-stage NSCLC treated prospectively in adjuvant landmark clinical trials. We used a targeted gene panel to assess the prognostic and predictive effect of mutations in individual genes, DNA repair pathways, and tumor mutation burden (TMB).

METHODS

A total of 908 unmatched, formalin-fixed, paraffin-embedded, resected lung cancer tumor specimens were sequenced using a targeted panel of 1,538 genes. Stringent filtering criteria were applied to exclude germline variants and artifacts related to formalin fixation. Disease-free survival, overall survival, and lung cancer-specific survival (LCSS) were assessed in Cox models stratified by trial and adjusted for treatment, age, sex, performance score, histology, type of surgery, and stage.

RESULTS

Nonsynonymous mutations were identified in 1,515 genes in 908 tumor samples. High nonsynonymous TMB (> 8 mutations/Mb) was prognostic for favorable outcomes (ie, overall survival, disease-free survival, and LCSS) in patients with resected NSCLC. LCSS benefit with adjuvant chemotherapy was more pronounced in patients with low nonsynonymous TMBs (≤ 4 mutations/Mb). Presence of mutations in DNA repair pathways, tumor-infiltrating lymphocytes, TP53 alteration subtype, and intratumor heterogeneity was neither prognostic nor predictive. Statistically significant effect of mutations in individual genes was difficult to determine due to high false-discovery rates.

CONCLUSION

High nonsynonymous TMB was associated with a better prognosis in patients with resected NSCLC. In addition, the benefit of adjuvant chemotherapy on LCSS was more pronounced in patients with low nonsynonymous TMBs. Studies are warranted to confirm these findings.

Developing a standard approach to immune checkpoint inhibitor toxicity management in Ontario

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Background: The use of immune checkpoint inhibitor medications (ICIs) in the province of Ontario, Canada has increased in volume by almost 4 fold between 2015/16 to 2017/18 and has expanded from use primarily in melanoma to lung, genitourinary, and other cancers. Lack of widespread clinical experience with ICIs and provincial variation in the management of the potentially life-threatening immune-related adverse effects (irAEs) was identified as a safety and quality gap. Cancer Care Ontario (CCO) set out to develop user-friendly health care provider and patient resources to facilitate a standard approach to ICI toxicity management in Ontario. Methods: A multidisciplinary working group of oncology clinicians with ICI experience reviewed available literature and current approaches to ICI toxicity management. An iterative consensus-building process was used to develop a practical guideline. This was circulated to an external expert review panel for content validity. Complementary patient/caregiver information was created based on best practices in health literacy and input from patient and family advisors. All resources were made publicly available via the CCO website and disseminated broadly to relevant stakeholders. Results: A user-friendly clinical practice guideline was created. It contains a description of irAEs associated with ICIs, guidance on the general management of irAEs, detailed algorithms describing the assessment and management of ten specific irAEs, and general considerations for patients on ICIs. A toolkit was developed with direct links to the algorithms, a customizable wallet card, a “Dear Healthcare Professional” letter template, and a patient information sheet. The guideline and toolkit webpages were accessed over 1500 times in the first month, suggesting that broad dissemination has been successful. Informal reports of guideline implementation were received from several Ontario hospitals. Conclusions: Careful analysis of the available literature and application of oncology professionals’ expertise resulted in evidence-informed, consensus-based practical resources to help facilitate safe, standardized ICI toxicity management across the Ontario health care system.

Genome-wide copy number analyses of samples from LACE-Bio project identify novel prognostic and predictive markers in early stage non-small cell lung cancer

Background

Adjuvant chemotherapy (ACT) provides modest benefit in resected non-small cell lung cancer (NSCLC) patients. Genome-wide studies have identified gene copy number aberrations (CNA), but their prognostic implication is unknown.

Methods

DNA from 1,013 FFPE tumor samples from three pivotal multicenter randomized trials (ACT vs. control) in the LACE-Bio consortium (median follow-up: 5.2 years) was successfully extracted, profiled using a molecular inversion probe SNP assay, normalized relative to a pool of normal tissues and segmented. Minimally recurrent regions were identified. P values were adjusted to control the false discovery rate (Q values).

Results

A total of 976 samples successfully profiled, 414 (42%) adenocarcinoma (ADC), 430 (44%) squamous cell carcinoma (SCC) and 132 (14%) other NSCLC; 710 (73%) males. We identified 431 recurrent regions, with on average 51 gains and 43 losses; 253 regions (59%) were ≤3 Mb. Most frequent gains (up to 48%) were on chr1, 3q, 5p, 6p, 8q, 22q; most frequent losses (up to 40%) on chr3p, 8p, 9p. CNA frequency of 195 regions was significantly different (Q≤0.05) between ADC and SCC. Fourteen regions (7p11-12, 9p21, 18q12, and 19p11-13) were associated with disease-free survival (DFS) (univariate P≤0.005, Q<0.142), with poorer DFS for losses of regions including CDKN2A/B [hazard ratio (HR) for 2-fold lower CN: 1.5 (95% CI: 1.2-1.9), P<0.001, Q=0.020] and STK11 [HR =2.4 (1.3-4.3), P=0.005, Q=0.15]. Chromosomal instability was associated with poorer DFS (HR =1.5, P=0.015), OS (HR =1.2, P=0.189) and lung-cancer specific survival (HR =1.7, P=0.003).

Conclusions

These large-scale genome-wide analyses of gene CNA provide new candidate prognostic markers for stage I-III NSCLC.

A Randomized Phase II Study of FOLFOX6/Bevacizumab With or Without Pelareorep in Patients With Metastatic Colorectal Cancer: IND.210, a Canadian Cancer Trials Group Trial

BACKGROUND

Oncolytic reovirus pelareorep might preferentially infect and destroy rat sarcoma (RAS)-activated cells, and has preclinical and early clinical activity against colorectal cancer (CRC).

PATIENTS AND METHODS

After a 6-patient safety run-in, 103 patients with metastatic CRC were randomly assigned to standard first-line leucovorin/5-FU/oxaliplatin (FOLFOX6)/bevacizumab (FOLFOX/BEV) every 2 weeks with (n = 51) or without (n = 52) pelareorep 3 × 10¹⁰ tissue culture infective dose 50 on days 1 to 5 (cycles 1, 2, 4, and alternate cycles thereafter). The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), objective response rate (ORR), quality of life, and correlative analyses.

RESULTS

At 13 months' median follow-up, PFS was inferior in the pelareorep arm (median 7 vs. 9 months; hazard ratio [HR], 1.59 [80% confidence interval (CI), 1.18-2.15]; P = .046). There was no statistical difference in OS (median, 19.2 vs. 20.1 months; HR, 1.22; P = .38). An increased ORR was observed with pelareorep (adjusted odds ratio, 2.52 [80% CI, 1.44-4.41]; P = .03), but with a shorter median duration of response (5 vs. 9 months; P = .028). Pelareorep patients experienced more hypertension and proteinuria, and were more likely to omit bevacizumab before progression. A trend to lower dose intensity and shorter oxaliplatin and bevacizumab treatment duration was observed with pelareorep.

CONCLUSION

Combination pelareorep with FOLFOX/BEV was tolerable with an increased ORR, but PFS was inferior. Subgroup analysis of baseline variables including Kirsten rat sarcoma oncogene did not identify subgroups with PFS benefit. Decreased treatment intensity with standard agents likely contributed to the lack of benefit with pelareorep. Future studies might consider alternate pelareorep/chemotherapy strategies or combination therapy with novel agents.

A randomized phase II study of pelareorep and docetaxel or docetaxel alone in men with metastatic castration resistant prostate cancer: CCTG study IND 209

BACKGROUND

Pelareorep is an oncolytic virus with activity in many cancers including prostate. It has in vitro synergism with microtubule-targeted agents. We undertook a clinical trial evaluating pelareorep in mCRPC patients receiving docetaxel.

PATIENTS AND METHODS

In this randomized, open-label phase II study, patients received docetaxel 75mg/m2 on day 1 of a 21-day cycle and prednisone 5mg twice daily, in combination with pelareorep (arm A) or alone (arm B). The primary endpoint was 12 weeks lack of disease progression rate (LPD).

RESULTS

Eighty-five pts were randomized. Median age was 69, ECOG performance status was 0/1/2 in 31%/66%/3% of patients. Bone/regional lymph node/liver metastases were present in 98%/24%/6%. The median prognostic score was slightly higher in Arm A (144 vs. 129 p= 0.005). Adverse events were as expected but more prevalent in arm A. The 12-week LPD rate was 61% and 52.4% in arms A/B (p=0.51). Median survival was 19.1 on Arm A and 21.1 months on Arm B (HR 1.83; 95% CI 0.96 to 3.52; p=0.06). No survival benefit of pelareorep was found.

CONCLUSION

Pelareorep with docetaxel was tolerable with comparable LPD in both arms but response and survival were inferior and so this combination does not merit further study.

Abstract A100: Seamless phase I/II clinical trials in oncology: retrospective analysis of the last 7 years

Introduction: Drug development has evolved from the conventional sequence of three-phase clinical trial process to a seamless approach of adding cohorts to first-in-human trials to investigate both safety and efficacy in various cancers. In this retrospective study, we evaluated the prevalence of large early-phase studies in adult cancer patients; described the clinical characteristics, design, and statistical plan of these studies; and identified which investigational drugs using this seamless strategy were included in the accelerated approval program by the Food and Drug Administration (FDA).

Methods: All abstracts presented at the American Society of Clinical Oncology (ASCO) annual meetings from 2010 to 2017 were reviewed. Clinical studies conducted in the pediatric population as well as abstracts reporting trials in progress were excluded. Seamless clinical trials were defined as any phase I/II studies with a sample size of 100 or more patients. The Center for Drug Evaluation and Research (CDER) drug approvals report was used to access the list of drugs included in the accelerated approval program by FDA.

Results: We identified a total of 1786 early-phase trials enrolling more than 57,500 patients with malignant neoplasms. More frequently these studies included patients with advanced solid tumors (87%) and targeted therapy and immunotherapy agents were investigated in 64% and 15% of the cases, respectively. Of the 1786 trials, 51 were identified as seamless phase I/II with a sample size of 100 or more patients, representing only 3% of the total number of trials (n=1786) but 15% of the total number of patients (n=57,559). These seamless trials had a median number of 3 (1-13) expansion cohorts and a higher fraction (65%) were presented in the last 3 years (2014-2017), compared with 35% of the studies with results presented between 2010-2013. Fifty active investigational new drugs (67% targeted therapy, 18% immunotherapy, 10% antibody-drug conjugate, 2.0% chemotherapy, 3.9% other) were studied as single agents (53%) or in combination with other therapies (47%). Of the 51 identified large seamless phase I/II trials, only 29 (57%) studies had published results. Further, of these 29 studies, a planned statistical analysis for the calculation of the expansion cohorts’ sample-size was not available in 69% of the cases. The overall rate of significant (grade 3-4) adverse events was 49% (range, 0-100%), and at least one toxic death was reported in 5 of these studies. The pooled response rate (CR+PR) per study was 20% (range, 0.9-77). Considering the group of drugs studied in the 51-seamless phase I/II trials identified here, the FDA granted accelerated approval to 8 drugs and 1 other agent was given priority review.

Conclusions: Approximately two-thirds of the studies identified were presented after the year 2014, suggesting an increased use of the seamless approach. While the high rate of accelerated approvals granted by the FDA endorses the observed preliminary clinical benefit of these drugs, the absence of a prespecified statistical plan is a weakness of most of the published studies.

Citation Format: Pedro Barata, Brian Hobbs, Brian Rini, Channing Paller, Dan Normolle, Elizabeth Garrett-Mayer, Eric Rubin, Gary Rosner, Greg Pond, Jane Perlmutter, Lesley Seymour, Lillian Siu, Nolan Wages, Percy Ivy, Tatiana Prowell, Timothy Yap, David Hong. Seamless phase I/II clinical trials in oncology: retrospective analysis of the last 7 years [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A100.

A randomized phase II study of weekly paclitaxel with or without pelareorep in patients with metastatic breast cancer: final analysis of Canadian Cancer Trials Group IND.213

BACKGROUND

Pelareorep, a serotype 3 reovirus, has demonstrated preclinical and early clinical activity in breast cancer and synergistic cytotoxic activity with microtubule targeting agents. This multicentre, randomized, phase II trial was undertaken to evaluate the efficacy and safety of adding pelareorep to paclitaxel for patients with metastatic breast cancer (mBC).

METHODS

Following a safety run-in of 7 patients, 74 women with previously treated mBC were randomized either to paclitaxel 80 mg/m² intravenously on days 1, 8, and 15 every 4 weeks plus pelareorep 3 × 10¹⁰ TCID₅₀ intravenously on days 1, 2, 8, 9, 15, and 16 every 4 weeks (Arm A) or to paclitaxel alone (Arm B). Primary endpoint was progression-free survival (PFS). Secondary endpoints were objective response rate, overall survival (OS), circulating tumour cell counts, safety, and exploratory correlative analyses. All comparisons used a two-sided test at an alpha level of 20%. Survival analyses were adjusted for prior paclitaxel.

RESULTS

Final analysis was performed after a median follow-up of 29.5 months. Pelareorep was well tolerated. Patients in Arm A had more favourable baseline prognostic variables. Median adjusted PFS (Arm A vs B) was 3.78 mo vs 3.38 mo (HR 1.04, 80% CI 0.76-1.43, P = 0.87). There was no difference in response rate between arms (P = 0.87). Median OS (Arm A vs B) was 17.4 mo vs 10.4 mo (HR 0.65, 80% CI 0.46-0.91, P = 0.1).

CONCLUSIONS

This first, phase II, randomized study of pelareorep and paclitaxel in previously treated mBC did not show a difference in PFS (the primary endpoint) or RR. However, there was a significantly longer OS for the combination. Further exploration of this regimen in mBC may be of interest.

Abstract CT131: A randomized (RCT) phase II study of oncolytic reovirus (pelareorep ) plus standard weekly paclitaxel (P) as therapy for metastatic breast cancer (mBC)

Background: Pelareorep is a Dearing strain of reovirus serotype 3, with demonstrated in vitro and in vivo activity in many cancers and synergistic cytotoxic activity with microtubule targeting agents, including taxanes. This study was designed to determine the efficacy and safety of pelareorep + P compared to P alone in mBC. Materials and Methods: This randomized, open-label, phase II study enrolled subjects who had mBC previously exposed to chemotherapy (CT). Subjects were randomized 1:1 between Arm A (P 80 mg/m2 day 1, 8 and 15 q 28 days plus pelareorep 3 x 1010 TCID50 day 1,2,8,9,15,16 q 28 days) and Arm B (P 80 mg/m2 day 1, 8 and 15 q 28 days). Treatment was continued until disease progression (PD) or unacceptable toxicity. Objective response was assessed every 8 weeks. Primary endpoint was progression free survival (PFS). The study had 90% power to detect an improvement of PFS from 4 to 7.5 months (HR 0.5, two-sided α=0.2). All p-values are two-sided. Results: Between July 2012 and April 2016, 81 subjects were accrued: 7 to the safety run-in for arm A, 36 to Arm A and 38 to Arm B. All had received prior CT, 59 as adjuvant treatment and 48 for mBC. Patients in Arm A had more favorable prognostic features, including lower LDH and less prior therapy. The median cumulative dose of P was 960 mg/m2 for arm A vs. 828 mg/m2 for arm B. Similar numbers of subjects in both arms required dose reductions, predominantly for myelosuppression. The median duration of treatment was 16.1 weeks for pelareorep and P in arm A and 14.1 weeks for P in arm B. With a median follow-up of 29.5 months, the median PFS was 3.78 mo for arm A and 3.38 mo for arm B (HR 1.04, 80% CI 0.76-1.43, p=0.87). Median OS was 17.4 mo for arm A and 10.4 mo for arm B (HR 0.65, 80% CI 0.46-0.91, p=0.1). Response rates (RR) were 25% for arm A and 23.7% for arm B (p=0.87). Pre-specified subset analysis found statistically significant differences in OS in patients with ECOG 1 or 2, aged &lt; 65 yr, and no prior P treatment. Exploratory analysis of biomarkers found significant differences in OS in patients with wild type PIK3CA, KIT, APC, PTEN, ATM, AKT1, mutated TP53, and both wild type and mutated MET, although the number of pts was small. When grade 3 or higher adverse events (AE) were considered, only the incidence of fatigue was found in ≥10% (16% on Arm A vs 13%, arm B, p=0.76). Hematologic grade 3 or higher effects observed in ≥10% patients included lymphopenia (5% arm A vs 18% arm B, p=0.08), and neutropenia (23% arm A vs 26% arm B; p=0.8). There was a statistically significant difference in grade 3 or higher LDH (0% arm A vs 13% arm B, p=0.03). There were no treatment related deaths. Conclusions: This first, phase II, randomized study of pelareorep + P vs P in mBC previously exposed to CT, did not meet its primary endpoint of PFS. Despite similar PFS and RR there was a statistically significant improvement in OS for pelareorep + P pts. Given these data, further exploration of the role of pelareorep + P in mBC may be of interest.

Citation Format: Vanessa Bernstein, Susan Ellard, Susan F. Dent, Karen A. Gelmon, Sukhbinder K. Dhesy-Thind, Mihaela Mates, Muhammed Salim, Lawrence Panasci, Xinni Song, Mark Clemons, Dongsheng Tu, Linda J. Hagerman, Lesley Seymour. A randomized (RCT) phase II study of oncolytic reovirus (pelareorep ) plus standard weekly paclitaxel (P) as therapy for metastatic breast cancer (mBC) [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 CT131. doi:10.1158/1538-7445.AM2017-CT131