Abstract CT061: Binimetinib in patients with tumors with NRAS mutations: NCI-MATCH ECOG-ACRIN Cancer Research Group subprotocol EAY131-Z1A

Background: NRAS-mutations are established oncologic drivers in many malignancies with no effective targeted therapy options. Preclinical and clinical data have suggested that downstream inhibition with a MEK inhibitor, such as binimetinib, might be efficacious for NRAS-mutated cancers. Methods: Patients who enrolled in the multicenter NCI-MATCH trial master protocol underwent tumor biopsy and molecular profiling by targeted next generation sequencing with a custom Oncomine AmpliSeq™ panel. Patients with refractory solid tumors harboring codon 12, 13, or 61 NRAS-mutations were enrolled in subprotocol Z1A, a single arm study of binimetinib 45 mg twice daily. Patients with melanoma were excluded. The primary endpoint was objective response rate (ORR). Secondary endpoints included progression-free survival (PFS) and overall survival (OS). A post-hoc analysis examined association of NRAS-mutation allele with outcome and histology. Results: 47 eligible patients with refractory solid tumors harboring codon 12, 13, or 61 NRAS-mutations were treated on this trial. The most common cancer types enrolled on this subprotocol were colorectal adenocarcinoma (24/47, 51%), cholangiocarcinoma (7/47, 15%), low-grade papillary serous carcinoma of the ovary (3/47, 6%), and endometrioid endometrial adenocarcinoma patients (3/47, 6%). Observed toxicity was moderate, similar to previous reports, and 27.7% (13 of 47) of eligible patients discontinued binimetinib because of adverse events. The ORR was 2.1% (1 of 47 patients), and the median PFS was 3.5 months. The sole confirmed partial response (PR) was observed in a codon 61 NRAS-mutated indolent malignant ameloblastoma. One patient with a colorectal cancer harboring a NRAS codon 61 mutation had an unconfirmed PR, and two others with NRAS codon 61 mutated colorectal cancer had stable disease for at least 12 months. In a post-hoc analysis, patients with cancers bearing a codon 61 NRAS-mutation (n=22) had a significantly longer OS (p=0.04) and PFS (p=0.006) than those with tumors harboring codon 12 or 13 NRAS-mutations (n=25). Similarly, colorectal cancer patients with NRAS codon 61 mutations treated with binimetinib (n=8) had a significantly longer OS (p=0.03) and PFS (p=0.007) than those with NRAS codon 12 or 13 mutated (n=16) tumors. Conclusions: Single-agent binimetinib did not demonstrate promising efficacy in NRAS-mutated solid tumors. Further studies are needed to clarify whether the increased OS and PFS observed in codon 61 NRAS-mutated cancers reflects a more favorable prognosis for this subtype.

Citation Format: James M. Cleary, Victoria Wang, Rebecca Heist, Scott Kopetz, Edith P. Mitchell, James Zwiebel, Helen X. Chen, Shuli Li, Robert Gray, Lisa McShane, Larry Rubinstein, David Patton, Funda Meric-Bernstam, Melissa Dillmon, Mickey Williams, Stanley Hamilton, Barbara Conley, Peter O'Dwyer, Lyndsay Harris, Carlos Arteaga, Alice Chen, Keith Flaherty. Binimetinib in patients with tumors with NRAS mutations: NCI-MATCH ECOG-ACRIN Cancer Research Group subprotocol EAY131-Z1A [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT061.

Dabrafenib and Trametinib in Patients With Tumors With BRAFV600E Mutations: Results of the NCI-MATCH Trial Subprotocol H

PURPOSE

BRAF^V600 mutations are commonly found in melanoma and thyroid cancers and to a lesser degree in other tumor types. Subprotocol H (EAY131-H) of the NCI-MATCH platform trial sought to investigate the selective BRAF inhibitor dabrafenib and the MEK1/2 inhibitor trametinib in patients with solid tumors, lymphomas, or multiple myeloma whose tumors harbored a BRAF^V600 mutation.

PATIENTS AND METHODS

EAY131-H is an open-label, single-arm study. Patients with melanoma, thyroid, or colorectal cancer were excluded; patients with non-small-cell lung cancer were later excluded in an amendment. Patients received dabrafenib 150 mg twice per day and trametinib 2 mg per day continuously until disease progression or intolerable toxicity. The primary end point was centrally assessed objective response rate (ORR); secondary end points included progression-free survival (PFS), 6-month PFS, and overall survival.

RESULTS

Thirty-five patients were enrolled, and 29 were included in the primary efficacy analysis as prespecified in the protocol. Median age was 59 years, and 45% of the patients had received ≥ 3 lines of therapy. The confirmed ORR was 38% (90% CI, 22.9% to 54.9%) with P < .0001 against a null rate of 5%, and PFS was 11.4 months (90% CI, 8.4 to 16.3 months); responses were seen in 7 distinct tumor types. Seven patients had a duration of response of > 12 months, including 4 patients with a duration of response of > 24 months. An additional 8 patients had a PFS > 6 months. The median overall survival was 28.6 months. Reported adverse events were comparable to those noted in previously reported profiles of dabrafenib and trametinib.

CONCLUSION

This study met its primary end point, with an ORR of 38% (P < .0001) in this mixed histology, pretreated cohort. This promising activity warrants additional investigations in BRAF^V600-mutated tumors outside of currently approved indications.

Phase II Study of AZD4547 in Patients With Tumors Harboring Aberrations in the FGFR Pathway: Results From the NCI-MATCH Trial (EAY131) Subprotocol W

PURPOSE

NCI-MATCH is a nationwide, histology-agnostic, signal-finding, molecular profile-driven trial for patients with refractory cancers, lymphomas, or myelomas. Patients with tumors harboring actionable aberration(s) in fibroblast growth factor receptor (FGFR) 1-3 were treated with AZD4547, an oral FGFR1-3 inhibitor.

METHODS

Patients' tumors were screened by next-generation sequencing for predefined FGFR amplification, activating mutations, or fusions. Patients were treated with AZD4547, 80 mg orally twice daily until progression of disease or drug intolerance. A response rate of 16% was considered promising.

RESULTS

Between July 2016 and June 2017, 70 patients were assigned and 48 received protocol therapy and are eligible for analysis. Patients' tumors harbored FGFR1 or FGFR2 amplification (n = 20), FGFR2 or FGFR3 single-nucleotide variants (n = 19), or FGFR1 or FGFR3 fusions (n = 9). The most common primary tumors were breast (33.3%), urothelial (12.5%), and cervical cancer (10.4%).Grade 3 adverse events were consistent with those described in previous clinical trials. Confirmed partial responses were seen in 8% (90% CI, 3% to 18%) and were observed only in patients whose tumors harbored FGFR1-3 point mutations or fusions. Stable disease was observed in 37.5% (90% CI, 25.8% to 50.4%). The median progression-free survival (PFS) was 3.4 months, and the 6-month PFS rate was 15% (90% CI, 8% to 31%). For patients with tumors harboring FGFR fusions, the response rate was 22% (90% CI, 4.1% to 55%), and 6-month PFS rate was 56% (90% CI, 31% to 100%).

CONCLUSION

Preliminary signals of activity appeared to be limited to cancers harboring FGFR activating mutations and fusions, although AZD4547 did not meet the primary end point. Different FGFR somatic alterations may confer different levels of signaling potency and/or oncogene dependence.

Associations between oncogenic risk markers and clinical outcomes among black and white colorectal cancer patients

e16078

Background: Blacks have a 25% higher incidence of colorectal cancer compared to their white societal counterparts1. Additionally, the overall mortality rate among black colorectal cancer patients is 50% higher than that of whites2. However, little is known about the biomarkers prevalent among blacks and their possible correlation to treatment response and patient outcomes. Objective: The objective of this study is to explore disease trends that may unveil a correlation between molecular markers, pathologic stage at presentation and poor clinical outcomes among black colorectal cancer patients. Methods: De-identified patient data was obtained from The Oncology Data Services Department (Cancer Registry) of TJUH. The population cohort (n = 836) included newly diagnosed colorectal cancer patients treated at TJUH from 2000-2019, & included information regarding patient race, sex, age at presentation, stage at presentation, histological code, tumor markers: KRAS, NRAS, BRAF, MS1, treatment received, surgical findings: tumor size, lymph node involvement, presence of distant metastases at first surgery, response to chemotherapy & disease-free survival. Results: Findings reveal a higher prevalence of BRAF mutations among whites compared to blacks within this population, while black patients were diagnosed later according to AJCC pathological stage at presentation. Future analysis of this cohort will further divide the population by age ( < 50, 50-65, & > 65). This facet of the study will explore relationships between age & stage at presentation among patients of different races. Conclusions: Both oncogenic risk markers and AJCC stage at presentation differ between black and white colorectal cancer patients within this population. Additional analysis regarding age at presentation will further inform us as to how these findings may contribute to the comparatively higher incidence and mortality rates among black colorectal cancer patients. Researchers should continue to explore possible etiologies for the prevalent racial disparities seen among black colorectal cancer patients.

Phase II study of copanlisib in patients with tumors with PIK3CA mutations (PTEN loss allowed): NCI MATCH EAY131-Z1F

3506

Background: The NCI-MATCH (EAY131) is a platform trial that enrolls patients (pts) with solid tumors, lymphomas, or multiple myeloma to targeted therapies based on matching genomic alterations of interest (NCT02465060). Arm Z1F evaluated copanlisib, a highly selective, pan-Class 1 PI3K inhibitor with predominant activity against both the δ and α isoforms in pts with PIK3CA mutations. Methods: Pts received copanlisib (60 mg IV) on days 1, 8, and 15 in 28-day cycles until progression/toxicity. Tumor assessment was every 2 cycles. The primary endpoint was objective response rate (ORR); secondary endpoints were PFS, 6-month PFS, and predictive biomarkers. Pts with KRAS mutations, HER2+ve breast cancers, lymphomas were excluded. Results: 35 pts were enrolled (from 8/2/18 to 12/27/18), of which, 28 pts were available for analysis (7 patients, not eligible or did not start therapy). Multiple histologies were enrolled with gynecologic (n = 7), gastrointestinal (n = 6), and genitourinary (n = 5) the most common tumors. Median age 61 (range 42-78). 75% of pts had ≥ 3 lines of prior therapy. 54% of PIK3CA mutations were located in the helical domain, 32% in kinase domain and 14% in other domains. Twenty-six pts had co-occurring gene alterations (median 3; range 1-9), with 9 patients having 4 or more gene alterations. The ORR was 11% (3/28, 90% CI: 3%-25%). Partial responses were seen in uterine cancer, clear cell carcinoma of anterior abdominal wall, and liposarcoma. 6 pts had > 6 months of stable disease and clinical benefit rate was 32% (9/28). Two pts are still on treatment. The most common reason for protocol discontinuation was disease progression (n = 18, 69%). Thirty pts were included for toxicity analysis. Ten pts (33%) had grade 1 or 2 toxicities, 16 pts (53%) had grade 3 toxicities, and one patient (3%) had grade 4 toxicity (CTCAE v5.0). Most common toxicities include hyperglycemia (n = 19), fatigue (n = 11), hypertension (n = 10), diarrhea (n = 10), and nausea (n = 9). Total of 5 deaths were reported, none related to treatment. Conclusions: Copanlisib showed meaningful clinical activity across various tumors with PIK3CA mutation in the late-line refractory setting. Further study either alone or in combinations in select tumors is warranted. G3/4 toxicities observed were consistent with reported toxicities for PI3K pathway inhibition. Clinical trial information: NCT02465060 .

Malignant cell-specific pro-tumorigenic role of type I interferon receptor in breast cancers

Within the microenvironment of solid tumors, stress associated with deficit of nutrients and oxygen as well as tumor-derived factors triggers the phosphorylation-dependent degradation of the IFNAR1 chain of type I interferon (IFN1) receptor and ensuing suppression of the IFN1 pathway. Here we sought to examine the importance of these events in malignant mammary cells. Expression of non-degradable IFNAR1^S526A mutant in mouse mammary adenocarcinoma cells stimulated the IFN1 pathway yet did not affect growth of these cells in vitro or ability to form subcutaneous tumors in the syngeneic mice. Remarkably, these cells exhibited a notably accelerated growth when transplanted orthotopically into mammary glands. Importantly, in human patients with either ER+ or ER- breast cancers, high levels of IFNAR1 were associated with poor prognosis. We discuss the putative mechanisms underlying the pro-tumorigenic role of IFNAR1 in malignant breast cells.

Trametinib Activity in Patients with Solid Tumors and Lymphomas Harboring BRAF Non-V600 Mutations or Fusions: Results from NCI-MATCH (EAY131)

PURPOSE

Substantial preclinical evidence and case reports suggest that MEK inhibition is an active approach in tumors with BRAF mutations outside the V600 locus, and in BRAF fusions. Thus, Subprotocol R of the NCI-MATCH study tested the MEK inhibitor trametinib in this population.

PATIENTS AND METHODS

The NCI-MATCH study performed genomic profiling on tumor samples from patients with solid tumors and lymphomas progressing on standard therapies or with no standard treatments. Patients with prespecified fusions and non-V600 mutations in BRAF were assigned to Subprotocol R using the NCI-MATCHBOX algorithm. The primary endpoint was objective response rate (ORR).

RESULTS

Among 50 patients assigned, 32 were eligible and received therapy with trametinib. Of these, 1 had a BRAF fusion and 31 had BRAF mutations (13 and 19 with class 2 and 3 mutations, respectively). There were no complete responses; 1 patient (3%) had a confirmed partial response (patient with breast ductal adenocarcinoma with BRAF G469E mutation) and 10 patients had stable disease as best response (clinical benefit rate 34%). Median progression-free survival (PFS) was 1.8 months, and median overall survival was 5.7 months. Exploratory subgroup analyses showed that patients with colorectal adenocarcinoma (n = 8) had particularly poor PFS. No new toxicity signals were identified.

CONCLUSIONS

Trametinib did not show promising clinical activity in patients with tumors harboring non-V600 BRAF mutations, and the subprotocol did not meet its primary endpoint.

Nivolumab Is Effective in Mismatch Repair-Deficient Noncolorectal Cancers: Results From Arm Z1D-A Subprotocol of the NCI-MATCH (EAY131) Study

PURPOSE

The National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH) trial, the largest national precision oncology study to date (> 1,100 sites) of patients with relapsed or refractory malignancies, assigned patients to targeted therapy in parallel phase II studies based on tumor molecular alterations. The anti-programmed death receptor 1 inhibitor nivolumab previously showed activity in mismatch repair (MMR)-deficient colon cancer. We hypothesized that nivolumab would have activity in patients with MMR-deficient, noncolorectal tumors.

PATIENTS AND METHODS

Eligible patients with relapsed or refractory tumors, good end-organ function, and Eastern Cooperative Oncology Group performance status of ≤ 1 underwent tumor biopsy for centralized screening of molecular alterations. MMR deficiency was defined by complete loss of nuclear expression of MLH1 or MSH2 MMR gene products by immunohistochemistry (IHC). Patients with MMR-deficient colorectal cancer were excluded. Nivolumab, 3 mg/kg every 2 weeks (28-day cycles) and 480 mg every 4 weeks after cycle 4, was administered intravenously. Disease reassessment was performed every 2 cycles. The primary end point was RECIST 1.1 objective response rate (ORR).

RESULTS

Two percent of 4,902 screened patients had an MMR-deficient cancer by IHC. Forty-two evaluable patients were enrolled, with a median age of 60 years and a median of 3 prior therapies. The most common histologies were endometrioid endometrial adenocarcinoma (n = 13), prostate adenocarcinoma (n = 5), and uterine carcinosarcoma (n = 4). ORR was 36% (15 of 42 patients). An additional 21% of patients had stable disease. The estimated 6-, 12-, and 18-month progression-free survival rates were 51.3% (90% CI, 38.2% to 64.5%), 46.2% (90% CI, 33.1% to 59.3%), and 31.4% (90% CI, 18.7% to 44.2%), respectively. Median overall survival was 17.3 months. Toxicity was predominantly low grade.

CONCLUSION

A variety of refractory cancers (2.0% of those screened) had MMR deficiency as defined in NCI-MATCH. Nivolumab has promising activity in MMR-deficient noncolorectal cancers of a wide variety of histopathologic types.

Intergroup Randomized Phase III Study of Postoperative Oxaliplatin, 5-Fluorouracil, and Leucovorin Versus Oxaliplatin, 5-Fluorouracil, Leucovorin, and Bevacizumab for Patients with Stage II or III Rectal Cancer Receiving Preoperative Chemoradiation: A Trial of the ECOG-ACRIN Research Group (E5204)

BACKGROUND

The addition of bevacizumab to chemotherapy improved outcomes for patients with metastatic colon cancer. E5204 was designed to test whether the addition of bevacizumab to mFOLFOX6, following neoadjuvant chemoradiation and definitive surgery, could improve overall survival (OS) in patients with stage II/III adenocarcinoma of the rectum.

SUBJECTS, MATERIALS, AND METHODS

Patients with stage II/III rectal cancer who had completed neoadjuvant 5-fluorouracil-based chemoradiation and had undergone complete resection were enrolled. Patients were randomized to mFOLFOX6 (Arm A) or mFOLFOX6 with bevacizumab (Arm B) administered every 2 weeks for 12 cycles.

RESULTS

E5204 registered only 355 patients (17% of planned accrual goal) as it was terminated prematurely owing to poor accrual. At a median follow-up of 72 months, there was no difference in 5-year overall survival (88.3% vs. 83.7%) or 5-year disease-free survival (71.2% vs. 76.5%) between the two arms. The rate of treatment-related grade ≥ 3 adverse events (AEs) was 68.8% on Arm A and 70.7% on Arm B. Arm B had a higher proportion of patients who discontinued therapy early as a result of AEs and patient withdrawal than did Arm A (32.4% vs. 21.5%, p = .029).The most common grade 3-4 treatment-related AEs were neutropenia, leukopenia, neuropathy, diarrhea (without prior colostomy), and fatigue.

CONCLUSION

At 17% of its planned accrual, E5204 did not meet its primary endpoint. The addition of bevacizumab to FOLFOX6 in the adjuvant setting did not significantly improve OS in patients with stage II/III rectal cancer.

IMPLICATIONS FOR PRACTICE

At 17% of its planned accrual, E5204 was terminated early owing to poor accrual. At a median follow-up of 72 months, there was no significant difference in 5-year overall survival (88.3% vs. 83.7%) or in 5-year disease-free survival (71.2% vs. 76.5%) between the two arms. Despite significant advances in the treatment of rectal cancer, especially in improving local control rates, the risk of distant metastases and the need to further improve quality of life remain a challenge. Strategies combining novel agents with chemoradiation to improve both distant and local control are needed.

Abstract A089: Adolescent and young adult (AYA) cohort of the NCI MATCH clinical trial (EAY131)

Background: Over the last 30 years, adolescent and young adult (AYA, 15-39 years of age) patients (pts) with cancer have experienced smaller improvements in 5-year survival compared to younger and older pts. One reason is their historically lower rate of participation in clinical trials (~3% AYA vs. 10% in pts &gt; 40 years of age in adult cancer centers). A histology-agnostic trial provides greater opportunity for the AYA population and may improve accrual. The National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH; NCT0246506), a phase II precision medicine trial evaluating targeted therapy in adult pts (3 18 years old) based on molecular abnormalities in a tumor-agnostic fashion, has been open since 2015. Jointly developed and coordinated by NCI and ECOG-ACRIN and open through the NCI National Clinical Trials Network and the NCI Community Oncology Research Program at more than 1100 academic and community sites, this trial screened 6801 pts for 39 independently-accruing targeted treatment subprotocols. We reviewed the AYA data from the NCI-MATCH trial, which, due to eligibility criteria, does not include pts age 15-17. Materials and Methods: AYA pts age 18-39 with treatment-refractory malignancies (solid tumor, lymphoma, or myeloma) who were (a) eligible for a screening biopsy on the NCI-MATCH trial (screening cohort [SC]) or (b) had an actionable mutation previously identified through clinically indicated sequencing at a CLIA-approved and NCI-MATCH–accepted laboratory (outside assay cohort [OAC]) were eligible for MATCH AYA analysis. Results: Of the 6801 pts screened for NCI-MATCH, 373 were AYA pts age 18-39 (5.5%). Within the SC, 93.5% (300/321) of AYA pts were successfully biopsied, vs. 92.9% of those age 40+ (5240/5640); 35.7% of the SC AYA vs. 39.6% of the 40+ pts had a study-eligible actionable mutation, and 17% (51/300) of AYA pts vs. 17.8% (934/5240) of those 40+ were subsequently assigned to treatment. Of the 401 pts in the OAC, 30 (7.1%) were AYA; 24/30 (80.0%) of AYA OAC pts were assigned to treatment vs. 87.6% (332/379) of OAC pts age 40+. Screening enrollment data show that at Lead Academic Participating Sites (LAPS), a higher percentage of AYA pts were enrolled compared to pts age 40+ (32.8% [113/344] vs. 24.3% [1472/6047], respectively). In contrast, at NCORP sites, a higher percentage of 40+ pts was enrolled relative to AYA pts (43.8% [2647/6047] vs. 35.8% [123/344], respectively). Among the top histologies enrolled (aside from colon, breast, ovarian) were soft tissue sarcoma other than rhabdomyosarcoma, primary CNS tumors, and liver and hepatobiliary, cervical, and neuroendocrine cancers. Conclusions: There were no statistically significant differences between AYA and older (40+) pts in the number who underwent successful biopsies, the prevalence of tumor actionable mutations, or the number of pts assigned to or who received study treatment. AYA pts were more likely to have been enrolled at a LAPS than a NCORP site, consistent with the AYA population being referred to LAPS upon progression from first-line treatment. Enrollment of the AYA in adult cancer centers in the NCI-MATCH trial was higher than the historical 3%: 5.5% in the SC and 7.1% in the OAC. As more tissue-agnostic studies become available in nationwide trials, AYA participation in clinical trials may increase.

Citation Format: Alice P Chen, Shuli Li, Brent Coffey, James V Tricoli, Stanley R Hamilton, Mickey P Williams, Edith P Mitchell, David Patton, Robert J Gray, Lisa M McShane, Lawrence V Rubinstein, Carlos L Arteaga, Peter J O'Dwyer, Lyndsay N Harris, Barbara A Conley, Keith T Flaherty. Adolescent and young adult (AYA) cohort of the NCI MATCH clinical trial (EAY131) [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A089. doi:10.1158/1535-7163.TARG-19-A089

Abstract A079: National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH): A successful precision medicine signal-seeking trial in patients (pts) with rare variants and refractory malignancies

Introduction: NCI-MATCH, developed by ECOG-ACRIN & NCI, is the largest precision medicine study for pts with refractory malignancy. Over 1100 clinical sites in the National Clinical Trials Network enrolled pts. The purpose of the study is to identify potentially beneficial targeted treatments across tumor types with similar molecular abnormalities. Methods: The NCI Central IRB approved NCI-MATCH. Pts with refractory/no treatment available solid tumors, lymphomas or myelomas had a fresh biopsy profiled by next generation sequencing (143 genes, &gt; 4000 single nucleotide variants, indels, amplifications & targeted fusions). Pts are assigned by a defined algorithm to treatments with evidence of activity against tumors with the relevant molecular alteration. Pts are excluded if a treatment is FDA approved or known to be ineffective for their malignancy. After successfully sequencing fresh biopsies from 5540 pts, subprotocols with extremely rare variants lacked sufficient accrual. To address actionable variants with a prevalence of &lt; 1.5%, we decided to accept clinical sequencing results from 30 commercial and academic laboratories vetted by NCI-MATCH to address relevant variants. These labs notify clinicians participating in NCI-MATCH if their pt’s tumor contains an actionable variant. Treatment continues until tumors became refractory, pt intolerance or withdrawal of consent. An objective response rate (ORR by RECIST) of &gt; 16% among 31 eligible patients is considered a positive signal. Results: After screening 5540 pts, 37.6% had an actionable variant. After histology and treatment-specific exclusions, 17.8% were assigned and 69.5% enrolled on the assigned subprotocol. 11 of the initial 30 subprotocols reached completion with adequate follow-up. Of the first 11 evaluable subprotocols, 3 addressing rare variants had a positive signal: Nivolumab in pts with loss of expression of MLH1 or MSH2 (ORR 36%), capivasertib in pts with AKT mutations (ORR 23%), and dabrafenib + trametinib in pts with BRAF V600 mutations (ORR 33%). These molecular variants were found in 2%, 1.2% and 1.9% respectively, of screened pts. Two other subprotcocols (afatinib in ERBB2 mutations and AZD4547 in FGFR abnormalities) showed responses in rare tumors or specific variant subsets, respectively. As of July 15, 2019, an additional 378 of 432 (88%) pts have been assigned to a treatment with a clinical sequencing assay; 83% of these pts enrolled to 1 of 24 subprotocols, allowing completion of an additional 9 of the original 30 subprotocols and complete accrual to 2 of 5 recently added subprotocols. Four of 35 subprotocols closed for lack of accrual, 10 continue accruing and 4 are planned. Conclusions: Platform precision medicine trials can identify potentially useful targeted treatments for diverse malignancies in pts with uncommon tumors & rare actionable variants, an unmet need. In a population of pts with refractory cancers, lymphomas and myelomas, 30-40% will have an actionable variant for targeted treatment (investigational or standard). Of the first 11 subprotocols with adequate follow-up, 3 (27%) showed a positive signal and an additional 2 showed responses in rare tumors or in a molecular subset, suggesting that the NCI-MATCH trial approach identifies useful targets for further exploration.

Citation Format: Lyndsay N Harris, Robert J Gray, Barbara A Conley, Alice P Chen, Keith T Flaherty, Stanley R Hamilton, Paul M Williams, Chris Karlovich, David Patton, Shuli Li, Lisa M McShane, Larry V Rubinstein, Edith P Mitchell, James V Tricoli, Richard F Little, Carlos L Arteaga, Peter J O'Dwyer, NCI-MATCH team. National Cancer Institute Molecular Analysis for Therapy Choice (NCI-MATCH): A successful precision medicine signal-seeking trial in patients (pts) with rare variants and refractory malignancies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A079. doi:10.1158/1535-7163.TARG-19-A079

Ado-trastuzumab emtansine (T-DM1) in patients with HER2-amplified tumors excluding breast and gastric/gastroesophageal junction (GEJ) adenocarcinomas: results from the NCI-MATCH trial (EAY131) subprotocol Q

BACKGROUND

The National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH) is a national precision medicine study incorporating centralized genomic testing to direct refractory cancer patients to molecularly targeted treatment subprotocols. This treatment subprotocol was designed to screen for potential signals of efficacy of ado-trastuzumab emtansine (T-DM1) in HER2-amplified histologies other than breast and gastroesophageal tumors.

METHODS

Eligible patients had HER2 amplification at a copy number (CN) >7 based on targeted next-generation sequencing (NGS) with a custom Oncomine AmpliSeq™ (ThermoFisher Scientific) panel. Patients with prior trastuzumab, pertuzumab or T-DM1 treatment were excluded. Patients received T-DM1 at 3.6 mg/kg i.v. every 3 weeks until toxicity or disease progression. Tumor assessments occurred every three cycles. The primary end point was centrally assessed objective response rate (ORR). Exploratory end points included correlating response with HER2 CN by NGS. The impact of co-occurring genomic alterations and PTEN loss by immunohistochemistry were also assessed.

RESULTS

Thirty-eight patients were enrolled and 36 included in efficacy analysis. Median prior therapies in the metastatic setting was 3 (range 0-9; unknown in one patient). Median HER2 CN was 17 (range 7-139). Partial responses were observed in two (5.6%) patients: one mucoepidermoid carcinoma of parotid gland and one parotid gland squamous cell cancer. Seventeen patients (47%) had stable disease including 8/10 (80%) with ovarian and uterine carcinomas, with median duration of 4.6 months. The 6-month progression-free survival rate was 23.6% [90% confidence interval 14.2% to 39.2%]. Common toxicities included fatigue, anemia, fever and thrombocytopenia with no new safety signals. There was a trend for tumor shrinkage with higher levels of gene CN as determined by the NGS assay.

CONCLUSION

T-DM1 was well tolerated. While this subprotocol did not meet the primary end point for ORR in this heavily pre-treated diverse patient population, clinical activity was seen in salivary gland tumors warranting further study in this tumor type in dedicated trials.

Abstract 2257: Phase II study of dual immune checkpoint blockade (ICB) with durvalumab (Durva) plus tremelimumab (T) following palliative hypofractionated radiotherapy (SBRT) in patients (pts) with microsatellite-stable (MSS) metastatic colorectal cancer (mCRC) progressing on chemotherapy: NSABP FC-9

Background

Monotherapy with ICB has not been effective in MSS mCRC. Preclinical data demonstrate that immunomodulators synergize with radiotherapy (RT) resulting in tumor regression at irradiated sites and rarely at non-irradiated sites. Anecdotal reports in pts have confirmed an abscopal effect of RT and ICB. This phase II, open-label, single-arm study is testing dual ICBs following SBRT in pts with MSS mCRC who have progressed on chemotherapy. We report here efficacy and safety results.

Methods

Eligible pts have: MSS mCRC, progressed on prior oxaliplatin and irinotecan-based regimens, measurable lesions with at least one amenable to SBRT and another for core biopsy, and performance status &lt;2. Following 3 doses of SBRT at 9 Gy daily (D −2, −1, and D 0 prior to Cycle 1), pts received the combination of T (75 mg IV infusion) and Durva (1500 mg IV infusion) on D 1 of Cycles 1-4. Beginning with Cycles 5-12, pts received Durva alone on D 1 q 28d. Pts were considered evaluable using RECIST 1.1 if a tumor response at non-irradiated target lesions was measured at baseline and after 2 cycles. Subsequent scans were performed every 8 wks. Toxicity was graded according to NCI CTCAE v4.0. Primary aim is to determine overall objective response rate (ORR) in non-irradiated metastasis. Secondary aims are clinical benefit rate, duration of response, tolerability, and correlates of response. Archived and fresh tumor biopsies were obtained at study entry and after cycle 2, blood samples were collected before treatment, at cycle 1 D 15, and on D 1 of cycles 2, 4, and 6.

Results

FC-9 is open at six academic centers. From October 2017 to November 1, 2018, 33 pts enrolled with 20 pts evaluable. Median age was 58 y (range, 37-71). Toxicity was assessed without regard to attribution. One pt had grade 5 unexplained sudden death (3%); two had grade 4 (6%, colitis, dehydration, pneumonitis); and 12 had grade 3 (38%, primarily GI, other than colitis, and nutrition). Partial responses were seen in 2 pts lasting 44 wks and 44+ wks; two pts had stable disease of 12 and 16 wks duration. Correlative studies will be presented including PD-L-1 expression, CD8+ T cell infiltration into tumor tissues, and gene expression of immune pathways.

Conclusions

The combination of SBRT and dual immunotherapy was safe and well tolerated following immunotherapy standard guidelines. In this refractory group of MSS mCRC pts, we observed 2 partial responses of 44 and 44+ wks among 20 evaluable pts. Correlative analyses will be presented.

Support: Astra-Zeneca; NSABP Foundation, Inc.

Citation Format: James J. Lee, Greg Yothers, Thomas J. George, Marwan G. Fakih, Atrayee Basu Mallick, Edith P. Mitchell, James L. Wade, John C. Krauss, Omar R. Kayaleh, Dwight E. Heron, Carmen J. Allegra, Corey Lipchik, Huichen Feng, Marion Joy, Ashok Srinivasan, Katherine L. Pogue-Geile, Peter C. Lucas, Sarah E. Warren, Alessandra Cesano, Samuel A. Jacobs. Phase II study of dual immune checkpoint blockade (ICB) with durvalumab (Durva) plus tremelimumab (T) following palliative hypofractionated radiotherapy (SBRT) in patients (pts) with microsatellite-stable (MSS) metastatic colorectal cancer (mCRC) progressing on chemotherapy: NSABP FC-9 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2257.

Dabrafenib and trametinib in patients with tumors with BRAF V600E/K mutations: Results from the molecular analysis for therapy choice (MATCH) Arm H

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Background: The NCI-MATCH precision medicine trial assigns patients (pts) with solid tumors, lymphomas, or multiple myeloma with progression on prior treatment to a targeted therapy based on genetic alterations identified in pre-treatment biopsies. Arm H (EAY131-H) evaluated the combination of the BRAF inhibitor (inh) dabrafenib (DAB), and the MEK inh, trametinib (TRM), in pts with BRAF V600E/K mutations. Methods: Pts with melanoma, thyroid, or colorectal cancer were excluded. Pts with NSCLC were excluded after the U.S. Food and Drug Administration (FDA) approved DAB/TRM for this indication. Pts received DAB 150 mg po BID and TRM 2 mg PO daily on 28 day cycles until disease progression or intolerable toxicity; restaging was performed every 2 cycles. The primary endpoint was objective response rate (ORR); secondary endpoints included progression-free survival (PFS), 6-month PFS, and overall survival (OS). Results: A total of 35 pts were enrolled from 1/2016-2/2018; 2 were ineligible (CrCl below criteria; labs out of window). Over 17 distinct tumor histologies were represented. 58% of pts were female, median age was 63 (range 21-85), 94% were Caucasian, and 48% of pts had received at least 3 prior therapies (range 1- 8). The confirmed ORR was 33.3% (90% CI 19.9%, 49.1%), with a median duration of response (DoR) of 12 months (mon). Varied histologies had a DoR of > 12 mon: histiocytic sarcoma, cholangiocarcinoma and mixed adenoneuroendocrine carcinoma of unknown primary, among others. Median PFS was 9.4 mon; the 6 mon PFS rate was 70.6% (90% CI 58.2%-85.5%), and an additional 10 pts had a PFS > 5.5 mon. Median OS has not been reached. At the time of data cutoff (12/2018) 11 pts continue on treatment. Adverse events (AE) were comparable to previously reported profiles of DAB/TRM; no new AEs were identified. The most frequent grade 3 AEs were fatigue, neutropenia, hyponatremia, hypophosphatemia, and urinary tract infection; there was 1 grade 4 sepsis; no grade 5 AEs. Conclusions: In this pre-treated, mixed histology cohort, DAB and TRM showed promising activity outside of currently approved FDA indications warranting further investigations. Correlative analyses are planned. Clinical trial information: NCT02465060.

Stage of disease and initial surgical intervention in colon cancer patients: An exploratory analysis of the SEER database

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Background: Colorectal cancer (CRC) is the third-leading cause of cancer-related deaths in the United States. CRC’s decreasing mortality rate has been attributed to increased screening and early detection. This study explored the association between stage at diagnosis with initial surgical intervention for patients (pts) with colon cancer (CC), using data extracted from the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) data. Methods: Retrospective cohort study using the SEER database from 1998-2015. Included were pts with CC, aged 18 or older, and with disease in either the proximal or distal colon. Pts with rectal cancer were excluded. Stage was defined as local, regional versus distant, and initial treatment was defined as none versus any surgery. Multivariable logistic regression was used to describe the association between stage and initial surgical intervention, controlling for pts and tumor characteristics. Results: 354,640 CC pts were included in this analysis: 46%(localized), 36%(regional), 18%(distant), and 92.45%(received surgery). Multivariable analysis indicated that pts with regional disease were more likely to receive initial surgical intervention compared to those with localized disease (OR = 4.49,95% CI = 4.24,4.77). Pts with distant stage of disease were less likely to receive surgery compared to those with localized disease (OR = 0.11,CI = 0.11,0.12). Other factors significantly associated with an increased likelihood of initial surgical intervention included mucinous adenocarcinoma histology, papillary adenocarcinoma histology, having a partner relationship, adenomatous polyps on histology, white race, female sex, and lesion location in the proximal colon. Additionally, African American pts were significantly less likely than white pts to receive surgery as an initial intervention for colon cancer (OR = 0.76,CI = 0.73,0.79). Conclusions: We conclude that distant stage at diagnosis was associated with reduced odds of initial surgical intervention. This highlights the importance of screening and early detection to identify pts with operable disease and as a method of decreasing mortality.

Histology and stage at presentation among patients with rare pancreatic tumors: An exploratory analysis of the SEER database

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Background: Rare pancreatic tumors account for approximately 15% of all pancreatic cancers (PCs) and 8,300 new cases diagnosed within the United States annually, while 85% of PCs diagnosed are classified as adenocarcinomas. Comparatively little research exists to analyze differences in diagnosis between rare PCs and the more common adenocarcinoma given greater clinical interest in the latter. The purpose of this study was to analyze the relationship between PC histology and stage at presentation with a focus on rare histologies. Methods: This study employed a retrospective cohort model using the NCI’s Surveillance, Epidemiology, and End Results (SEER) 1990-2015 database. We included patients diagnosed with PC aged 18+, with the comparator group being patients diagnosed with adenocarcinoma, and “rare” tumors defined as one of the following histologies: ductal, carcinoid, mucinous adenocarcinoma, and undetermined neoplasm. Stage was dichotomized (locoregional versus distant). Multivariable logistic regression was used to describe the association between tumor histology with initial stage at diagnosis, controlling for patient and tumor characteristics. Results: 90,764 PC patients were analyzed: 66.3% adenocarcinoma, 9.6% ductal carcinomas, 4.5% carcinoid, 3.8% mucinous, and 15.8% undetermined neoplasm. 54.7% of all cases were distantly metastasized at diagnosis. In multivariable analysis, pancreatic cancer patients with mucinous histology had greater odds of presenting at late-stage compared to those with adenocarcinoma: OR = 1.41, 95% CI = [1.31, 1.52]. Carcinoid and undetermined neoplasm odds for late stage presentation were not significant compared to adenocarcinoma: OR = 0.99, 95% CI = [0.92, 1.07] and OR = 1.01, 95% Cl = [0.97, 1.05] respectively. Ductal carcinoma was less likely than adenocarcinoma to present with late stage: OR = 0.38, CI = [0.36, 0.40]. Conclusions: We observed that mucinous histology had greater odds of late-stage diagnosis compared to those with adenocarcinoma. Patients with ductal carcinoma was less likely than those with adenocarcinoma to present with late stage. Further investigation is needed to explore the reasons for these differences.

Impact of cancer in pulmonary embolism presentation and outcomes: A large academic center study

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Background: The risk of venous thromboembolism is increased 4- to 7-fold in patients with malignancy, emphasizing the need to identify and treat these patients early to improve outcomes. We aimed to study the clinical presentation and outcomes of pulmonary embolism (PE) in patients with and without cancer. Methods: We performed a retrospective analysis of consecutive patients diagnosed with PE via CT scan from 2014-2016 at Jefferson Hospital. We compared patient characteristics, presentation, PE characteristics and mortality of patients with and without cancer. Cox proportional regression hazards model was used for survival-time analysis. Results: Our study included 581 patients, of which 187 (32.1%) had active cancer. Cancer patients were less likely to have chest pain (18.2% vs 37.4% p < 0.01), syncope (2.7% vs 6.6% p = 0.05), bilateral PEs (50% vs 60% p = 0.025), and right heart strain (RHS) (48% vs 58% p = 0.024). Indwelling catheters (IC) were present in 41.2% (n = 77) of cancer patients. However, presence of IC was not associated finding of incidental PEs (26% vs 18.2% p = 0.201). There was no difference in hospital length of stay (8.9 vs 9.4 days p = 0.61) or intensive care unit admission (31.9% vs 33.3% p = 0.75). There were fewer massive PE (3.2% vs 7.1% p = 0.06) in patients with cancer, but this difference was not statistically significant. Cancer patients elected comfort care at higher rates (15.2% vs 5.4% p = 0.01). Cancer patients had higher 1-year mortality as compared to non-cancer (adj HR 6.9, 95% CI 3.3- 14.7, p < 0.01). Among cancer patients, 52.7% had metastasis with a higher 1-year mortality (adj HR 2.5, 95% CI 1.8- 4.9, p < 0.1) and 35.8% were on active chemotherapy with no difference in 1-year survival (adj HR 1.1, 95% CI 0.6-1.8, p = 0.79). The most represented cancers were genitourinary, lung and head and neck (35.3%, 23.0%, 13.4%, respectively). Conclusions: Cancer patients presented with less severe pulmonary emboli which may be due to increased health care contact and pre-clinical suspicion. The presence of IC did not affect the size, location of PE or incidental PEs among cancer patients. Although cancer patients have higher 1-year mortality, PE may not be as large as a contributor as previously perceived.

Urban/rural disparities in stage at presentation of colorectal cancer among young adults in the United States, 2007-2015

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Background: The overall incidence rate of colorectal cancer (CRC) has declined in recent decades but is rising in young adults (YA). Disparities also exist in CRC presentation and geographical residence. We examined associations between urban/rural residence and CRC stage at presentation among YA 18-50 years old, using the Surveillance, Epidemiology, and End Results (SEER) 1973-2015 registry. Methods: Retrospective cohort study using SEER patients (pts) diagnosed with CRC between 2007-2015, aged 18-50. Urban/rural status was defined at the county level as large metro, small metro, urban non-metro, and rural. Pts were grouped by age: 18-30, 31-40, and 41-50 years old. Stage was defined as in-situ/localized and regional/distant. We used multivariable logistic regression to describe associations between urban/rural status with stage at presentation, adjusting for tumor location, histology, grade, and patient attributes (e.g. insurance status). Results: 27,198 CRC pts were analyzed: 62.2% large metro, 27.4% small metro, 9.4% urban non-metro, and 67.1% regional/distant stage. In multivariable analysis, YA in urban non-metro counties had lower odds of regional/distant stage at presentation compared to YA in large metro counties (OR = 0.87, 95% CI = 0.79-0.97). Associations between small metro and rural status with stage at presentation were not significant (OR = 0.94, 95% CI = 0.89-1.01 and OR = 0.84, 95% CI = 0.64-1.10, respectively). YA with Medicaid or no insurance had higher odds of regional/distant CRC (OR = 1.28, 95% CI = 1.17-1.39 and OR = 1.34, 95% CI = 1.20-1.51, respectively) compared to YA privately insured. Other factors in YA associated with higher odds of regional/distant CRC included signet-ring histology, poorly-, moderately-, and undifferentiated grade, and younger age (18-30 and 31-40 years old). Conclusions: YA in urban non-metro areas had lower odds of regional/distant CRC at presentation compared to YA in large metro areas. YA with Medicaid, no insurance, signet-ring histology, poorly-, moderately-, and undifferentiated grade, and younger age had higher odds of regional/distant CRC at presentation. Further research is needed to explore the etiology of these differences.