Sarina Anne Piha-Paul

Personalized Medicine in a Phase I Clinical Trials Program: The MD Anderson Cancer Center Initiative

Purpose: We initiated a personalized medicine program in the context of early clinical trials, using targeted agents matched with tumor molecular aberrations. Herein, we report our observations. Patient and Methods: Patients with advanced cancer were treated in the Clinical Center for Targeted Therapy. Molecular analysis was conducted in the MD Anderson Clinical Laboratory Improvement Amendments (CLIA)–certified laboratory. Patients whose tumors had an aberration were treated with matched targeted therapy, when available. Treatment assignment was not randomized. The clinical outcomes of patients with molecular aberrations treated with matched targeted therapy were compared with those of consecutive patients who were not treated with matched targeted therapy. Results: Of 1,144 patients analyzed, 460 (40.2%) had 1 or more aberration. In patients with 1 molecular aberration, matched therapy (n = 175) compared with treatment without matching (n = 116) was associated with a higher overall response rate (27% vs. 5%; P < 0.0001), longer time-to-treatment failure (TTF; median, 5.2 vs. 2.2 months; P < 0.0001), and longer survival (median, 13.4 vs. 9.0 months; P = 0.017). Matched targeted therapy was associated with longer TTF compared with their prior systemic therapy in patients with 1 mutation (5.2 vs. 3.1 months, respectively; P < 0.0001). In multivariate analysis in patients with 1 molecular aberration, matched therapy was an independent factor predicting response (P = 0.001) and TTF (P = 0.0001). Conclusion: Keeping in mind that the study was not randomized and patients had diverse tumor types and a median of 5 prior therapies, our results suggest that identifying specific molecular abnormalities and choosing therapy based on these abnormalities is relevant in phase I clinical trials. Clin Cancer Res; 18(22); 6373–83. ©2012 AACR.

PIK3CA mutations in patients with advanced cancers treated with PI3K/AKT/mTOR axis inhibitors

Preclinical data suggest that PIK3CA mutations predict response to PI3K/AKT/mTOR inhibitors. Concomitant KRAS or BRAF mutations may mediate resistance. Therefore, tumors from patients referred to the phase I program for targeted therapy starting in October 2008 were analyzed for PIK3CA mutations using PCR-based DNA sequencing of exons 9 and 20. Consecutive patients with diverse tumor types and PIK3CA mutation were treated whenever possible with agents targeting the PI3K/AKT/mTOR pathway. Overall, PIK3CA mutations were detected in 25 of 217 patients (11.5%; exon 9, n = 11; exon 20, n = 14). In tumor types with more than 10 patients tested, PIK3CA mutations were most frequent in endometrial (3 of 14, 21%), ovarian (5 of 30, 17%), colorectal (9 of 54, 17%), breast (2 of 14, 14%), cervical (2 of 15, 13%), and squamous cell cancer of the head and neck (1 of 11, 9%). Of the 25 patients with PIK3CA mutations, 17 (68%) were treated on a protocol that included a PI3K/AKT/mTOR pathway inhibitor, and 6 (35%) achieved a partial response. In contrast, only 15 of 241 patients (6%) without documented PIK3CA mutations treated on the same protocols responded (P = 0.001). Of the 17 patients with PIK3CA mutations, 6 (35%) had simultaneous KRAS or BRAF mutations (colorectal, n = 4; ovarian, n = 2). Colorectal cancer patients with PIK3CA and KRAS mutations did not respond to therapy, whereas both ovarian cancer patients with PIK3CA and KRAS or BRAF mutations did. In conclusion, PIK3CA mutations were detected in 11.5% of patients with diverse solid tumors. The response rate was significantly higher for patients with PIK3CA mutations treated with PI3K/AKT/mTOR pathway inhibitors than for those without documented mutations. Mol Cancer Ther; 10(3); 558–65. ©2011 AACR.

PIK3CA mutation H1047R is associated with response to PI3K/AKT/mTOR signaling pathway inhibitors in early-phase clinical trials.

PIK3CA mutations may predict response to PI3K/AKT/mTOR inhibitors in patients with advanced cancers, but the relevance of mutation subtype has not been investigated. Patients with diverse cancers referred to the Clinical Center for Targeted Therapy were analyzed for PIK3CA and, if possible, KRAS mutations. Patients with PIK3CA mutations were treated, whenever possible, with agents targeting the PI3K/AKT/mTOR pathway. Overall, 105 (10%) of 1,012 patients tested harbored PIK3CA mutations. Sixty-six (median 3 prior therapies) of the 105 PIK3CA-mutant patients, including 16 individuals (of 55 PIK3CA-mutant patients tested) with simultaneous KRAS mutations, were treated on a protocol that included a PI3K/AKT/mTOR pathway inhibitor; 17% (11/66) achieved a partial response (PR). Patients with a PIK3CA H1047R mutation compared with patients who had other PIK3CA mutations or patients with wild-type PIK3CA treated on the same protocols had a higher PR rate (6/16, 38% vs. 5/50; 10% vs. 23/174, 13%, respectively; all P ≤ 0.02). None of the 16 patients with coexisting PIK3CA and KRAS mutations in codon 12 or 13 attained a PR (0/16, 0%). Patients treated with combination therapy versus single-agent therapies had a higher PR rate (11/38, 29% vs. 0/28, 0%; P = 0.002). Multivariate analysis showed that H1047R was the only independent factor predicting response [OR 6.6, 95% confidence interval (CI), 1.02-43.0, P = 0.047). Our data suggest that interaction between PIK3CA mutation H1047R versus other aberrations and response to PI3K/AKT/mTOR axis inhibitors warrants further exploration.

Feasibility of Large-Scale Genomic Testing to Facilitate Enrollment Onto Genomically Matched Clinical Trials

PURPOSE We report the experience with 2,000 consecutive patients with advanced cancer who underwent testing on a genomic testing protocol, including the frequency of actionable alterations across tumor types, subsequent enrollment onto clinical trials, and the challenges for trial enrollment. PATIENTS AND METHODS Standardized hotspot mutation analysis was performed in 2,000 patients, using either an 11-gene (251 patients) or a 46- or 50-gene (1,749 patients) multiplex platform. Thirty-five genes were considered potentially actionable based on their potential to be targeted with approved or investigational therapies. RESULTS Seven hundred eighty-nine patients (39%) had at least one mutation in potentially actionable genes. Eighty-three patients (11%) with potentially actionable mutations went on genotype-matched trials targeting these alterations. Of 230 patients with PIK3CA/AKT1/PTEN/BRAF mutations that returned for therapy, 116 (50%) received a genotype-matched drug. Forty patients (17%) were treated on a genotype-selected trial requiring a mutation for eligibility, 16 (7%) were treated on a genotype-relevant trial targeting a genomic alteration without biomarker selection, and 40 (17%) received a genotype-relevant drug off trial. Challenges to trial accrual included patient preference of noninvestigational treatment or local treatment, poor performance status or other reasons for trial ineligibility, lack of trials/slots, and insurance denial. CONCLUSION Broad implementation of multiplex hotspot testing is feasible; however, only a small portion of patients with actionable alterations were actually enrolled onto genotype-matched trials. Increased awareness of therapeutic implications and access to novel therapeutics are needed to optimally leverage results from broad-based genomic testing.

Assessing PIK3CA and PTEN in early-phase trials with PI3K/AKT/mTOR inhibitors

Despite a wealth of preclinical studies, it is unclear whether PIK3CA or phosphatase and tensin homolog (PTEN) gene aberrations are actionable in the clinical setting. Of 1,656 patients with advanced, refractory cancers tested for PIK3CA or PTEN abnormalities, PIK3CA mutations were found in 9% (146/1,589), and PTEN loss and/or mutation was found in 13% (149/1,157). In multicovariable analysis, treatment with a phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) inhibitor was the only independent factor predicting response to therapy in individuals harboring a PIK3CA or PTEN aberration. The rate of stable disease ≥6 months/partial response reached 45% in a subgroup of individuals with H1047R PIK3CA mutations. Aberrations in the PI3K/AKT/mTOR pathway are common and potentially actionable in patients with diverse advanced cancers. This work provides further important clinical validation for continued and accelerated use of biomarker-driven trials incorporating rational drug combinations.

IFN-γ–related mRNA profile predicts clinical response to PD-1 blockade

Programmed death-1–directed (PD-1–directed) immune checkpoint blockade results in durable antitumor activity in many advanced malignancies. Recent studies suggest that IFN-&ggr; is a critical driver of programmed death ligand-1 (PD-L1) expression in cancer and host cells, and baseline intratumoral T cell infiltration may improve response likelihood to anti–PD-1 therapies, including pembrolizumab. However, whether quantifying T cell–inflamed microenvironment is a useful pan-tumor determinant of PD-1–directed therapy response has not been rigorously evaluated. Here, we analyzed gene expression profiles (GEPs) using RNA from baseline tumor samples of pembrolizumab-treated patients. We identified immune-related signatures correlating with clinical benefit using a learn-and-confirm paradigm based on data from different clinical studies of pembrolizumab, starting with a small pilot of 19 melanoma patients and eventually defining a pan-tumor T cell–inflamed GEP in 220 patients with 9 cancers. Predictive value was independently confirmed and compared with that of PD-L1 immunohistochemistry in 96 patients with head and neck squamous cell carcinoma. The T cell–inflamed GEP contained IFN-&ggr;–responsive genes related to antigen presentation, chemokine expression, cytotoxic activity, and adaptive immune resistance, and these features were necessary, but not always sufficient, for clinical benefit. The T cell–inflamed GEP has been developed into a clinical-grade assay that is currently being evaluated in ongoing pembrolizumab trials.

Personalized Medicine for Patients with Advanced Cancer in the Phase I Program at MD Anderson: Validation and Landmark Analyses

Purpose: The purpose of this study was to confirm our previous results that targeted agents matched with tumor molecular alterations were associated with improved outcomes compared with nonmatched therapy in patients with advanced cancer. Experimental Design: Outcomes of patients who were referred for treatment on phase I clinical trials at The University of Texas MD Anderson Cancer Center (Houston, TX) from March 2011 to January 2012 were compared between those who had received targeted therapy and those for whom no targeted therapy was available. Two-month landmark analyses for overall and progression-free survival (PFS) combining previously published and validation cohort patient data were performed. Results: In patients with one alteration, matched therapy (n = 143) compared with treatment without matching (n = 236) was associated with a higher objective response rate (12% vs. 5%; P < 0.0001), longer PFS (median, 3.9 vs. 2.2 months; P = 0.001), and longer survival (median, 11.4 vs. 8.6 months; P = 0.04). In multivariate analysis, matched therapy was an independent factor predicting response (P < 0.015) and PFS (P < 0.004). Two-month landmark analyses in the matched therapy group demonstrated that the median survival of responders was 30.5 months compared with 11.3 months for nonresponders (P = 0.01); and the median PFS was 38.7 months compared with 5.9 months, respectively (P < 0.0001). The respective values in the nonmatched therapy group were 9.8 and 9.4 months (P = 0.46) and 8.5 and 4.2 months (P = 0.18). Conclusion: This validation analysis confirms our previous observations. In the matched therapy group, 2-month landmark analyses demonstrated that responders have longer survival and PFS than nonresponders. Clin Cancer Res; 20(18); 4827–36. ©2014 AACR.

AZD9150, a next-generation antisense oligonucleotide inhibitor of STAT3 with early evidence of clinical activity in lymphoma and lung cancer

Systemically administered antisense oligonucleotide AZD9150 inhibits STAT3 and shows anticancer activity in preclinical models and patients. Blocking transcription in tumors, STAT STAT3 is a transcription factor that plays an oncogenic role in many cancers, which has proven very difficult to target with chemical inhibitors. Now, Hong et al. have demonstrated that antisense technology is a feasible alternative to small-molecule inhibitors for targeting STAT3. The authors used high-affinity next-generation antisense oligonucleotides, which have higher potency than previous generations and can be systemically administered without a lipid vehicle. One of these new antisense oligonucleotides, AZD9150, demonstrated activity in a variety of preclinical cancer models, as well as in cancer patients who have failed one or more previous treatments, paving the way for additional clinical testing of this therapy. Next-generation sequencing technologies have greatly expanded our understanding of cancer genetics. Antisense technology is an attractive platform with the potential to translate these advances into improved cancer therapeutics, because antisense oligonucleotide (ASO) inhibitors can be designed on the basis of gene sequence information alone. Recent human clinical data have demonstrated the potent activity of systemically administered ASOs targeted to genes expressed in the liver. We describe the preclinical activity and initial clinical evaluation of a class of ASOs containing constrained ethyl modifications for targeting the gene encoding the transcription factor STAT3, a notoriously difficult protein to inhibit therapeutically. Systemic delivery of the unformulated ASO, AZD9150, decreased STAT3 expression in a broad range of preclinical cancer models and showed antitumor activity in lymphoma and lung cancer models. AZD9150 preclinical activity translated into single-agent antitumor activity in patients with highly treatment-refractory lymphoma and non–small cell lung cancer in a phase 1 dose-escalation study.

MABp1, a first-in-class true human antibody targeting interleukin-1α in refractory cancers: An open-label, phase 1 dose-escalation and expansion study

BACKGROUND Inflammation is an important feature of the malignant phenotype and promotes angiogenesis, tumour invasiveness, metastases, and cachexia. We used a first-in-class, monoclonal antibody (MABp1) cloned from a human being to target interleukin-1α, a mediator of chronic inflammation. We aimed to assess the safety and tolerability of MABp1 for interleukin-1α blockade in a refractory cancer population. METHODS We did an open-label, dose-escalation, and phase 1 study of MABp1 in adults with metastatic cancer at the MD Anderson Clinical Center for Targeted Therapy (Houston, TX, USA). We used a standard 3+3 design to identify the maximum tolerated dose. Patients received MABp1 intravenously once every 3 weeks through four dose levels: 0.25 mg/kg, 0.75 mg/kg, 1.25 mg/kg, and 3.75 mg/kg. After the dose-escalation phase, a second dosing arm was started with dosing every 2 weeks at the maximum tolerated dose. The primary objectives were safety, tolerability, characterisation of the pharmacokinetic profile, and identification of the recommended phase 2 dose. Secondary endpoints included pharmacodynamic effects and antitumour activity. All patients who received at least one dose of MABp1 were included in the safety analyses. This trial is registered with ClinicalTrials.gov, NCT01021072. FINDINGS Between March 15, 2010, and July 30, 2012, 52 patients with metastatic cancer (18 tumour types) received anti-interleukin-1α monotherapy in dose-escalation and expansion groups. MABp1 was well tolerated, with no dose-limiting toxicities or immunogenicity. Thus, the recommended phase 2 dose was concluded to be 3.75 mg/kg every 2 weeks. Pharmacokinetic data were consistent at all dose levels and showed no evidence of accumulation or increased clearance of MABp1 at increasing doses. For 42 assessable patients, median plasma interleukin-6 concentrations had decreased from baseline to week 8 by a median of 2.7 pg/mL (IQR -12.6 to 3.0; p=0.08). Of the 34 patients restaged, one patient had a partial response and ten had stable disease. 30 patients were assessable for change in lean body mass, which increased by a mean of 1.02 kg (SD 2.24; p=0.02) between baseline and week 8. The most common adverse events possibly related to the study drug were proteinuria (n=11; 21%), nausea (7; 13%), and fatigue (7; 13%). The most frequent grade 3-4 adverse events (regardless of relation to treatment) were fatigue (3; 6%), dyspnoea (2; 4%), and headache (2; 4%). Two patients (4%) had grade 5 events (death due to disease progression), which were unrelated to treatment. INTERPRETATION MABp1 was well tolerated, no dose-limiting toxicities were experienced in this study, and disease control was observed. Further study of MABp1 anti-interleukin-1α antibody therapy for advanced stage cancer is warranted.

Abstract S5-07: Preliminary efficacy and safety of pembrolizumab (MK-3475) in patients with PD-L1–positive, estrogen receptor-positive (ER+)/HER2-negative advanced breast cancer enrolled in KEYNOTE-028

Background: The programmed cell death 1 (PD-1) pathway is used by tumors to evade immune surveillance. Pembrolizumab is a humanized anti–PD-1 monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2. Pembrolizumab has shown robust antitumor activity against several advanced malignancies, including triple-negative breast cancer. We assessed the safety and efficacy of pembrolizumab in patients with PD-L1–positive, ER+/HER2-negative advanced breast cancer. Methods: KEYNOTE-028 (ClinicalTrials.gov, NCT02054806) is an ongoing multicohort, open-label phase 1b study evaluating the safety and efficacy of pembrolizumab in patients with PD-L1–positive advanced solid tumors. Key eligibility criteria for this cohort include ER+ and HER2-negative tumor status defined by institutional standards, locally advanced or metastatic disease, ECOG performance status of 0 or 1, failure of or inability to receive standard therapy, and PD-L1 expression in stroma or in ≥1% of tumor cells as assessed at a central laboratory using a prototype immunohistochemistry assay with the 22C3 antibody (Merck). Pembrolizumab was administered at a dose of 10 mg/kg every 2 weeks for up to 24 months or until confirmed progression or intolerable toxicity. Response is based on RECIST v1.1 as assessed by investigator review every 8 weeks for the first 6 months and every 12 weeks thereafter. Primary efficacy end point is overall response rate (ORR). Results: Of the 248 patients with ER+/HER2-negative breast cancer who had evaluable tumor samples screened for PD-L1 expression, 48 (19%) had PD-L1–positive tumors. Of these, 25 patients were enrolled. Median age was 53 years (range, 36-79), and 44% of patients had an ECOG performance status of 1. Patients were heavily pretreated, with 76% having received ≥3 prior lines of therapy for advanced disease, including 48.0% who received ≥5 prior lines. Analyses of ORR, duration of response, and adverse events are ongoing and will be completed by September 4, 2015. Conclusion: Data from this KEYNOTE-028 cohort will provide information on the antitumor activity and safety of pembrolizumab in patients with heavily pretreated, PD-L1–positive, ER+/HER2-negative advanced breast cancer. Citation Format: Rugo HS, Delord J-P, Im S-A, Ott PA, Piha-Paul SA, Bedard PL, Sachdev J, Le Tourneau C, van Brummelen E, Varga A, Saraf S, Pietrangelo D, Karantza V, Tan A. Preliminary efficacy and safety of pembrolizumab (MK-3475) in patients with PD-L1–positive, estrogen receptor-positive (ER+)/HER2-negative advanced breast cancer enrolled in KEYNOTE-028. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S5-07.