An Innovative Phase I Trial Design Allowing for the Identification of Multiple Potential Maximum Tolerated Doses with Combination Therapy of Targeted Agents

Treatment for cancer often involves combination therapies used both in medical practice and clinical trials. Korn and Simon listed three reasons for the utility of combinations: 1) biochemical synergism, 2) differential susceptibility of tumor cells to different agents, and 3) higher achievable dose intensity by exploiting non-overlapping toxicities to the host. Even if the toxicity profile of each agent of a given combination is known, the toxicity profile of the agents used in combination must be established. Thus, caution is required when designing and evaluating trials with combination therapies. Traditional clinical design is based on the consideration of a single drug. However, a trial of drugs in combination requires a dose-selection procedure that is vastly different than that needed for a single-drug trial. When two drugs are combined in a phase I trial, an important trial objective is to determine the maximum tolerated dose (MTD). The MTD is defined as the dose level below the dose at which two of six patients experience drug-related dose-limiting toxicity (DLT). In phase I trials that combine two agents, more than one MTD generally exists, although all are rarely determined. For example, there may be an MTD that includes high doses of drug A with lower doses of drug B, another one for high doses of drug B with lower doses of drug A, and yet another for intermediate doses of both drugs administered together. With classic phase I trial designs, only one MTD is identified. Our new trial design allows identification of more than one MTD efficiently, within the context of a single protocol. The two drugs combined in our phase I trial are temsirolimus and bevacizumab. Bevacizumab is a monoclonal antibody targeting the vascular endothelial growth factor (VEGF) pathway which is fundamental for tumor growth and metastasis. One mechanism of tumor resistance to antiangiogenic therapy is upregulation of hypoxia inducible factor 1α (HIF-1α) which mediates responses to hypoxic conditions. Temsirolimus has resulted in reduced levels of HIF-1α making this an ideal combination therapy. Dr. Donald Berry developed a trial design schema for evaluating low, intermediate and high dose levels of two drugs given in combination as illustrated in a recently published paper in Biometrics entitled “A Parallel Phase I/II Clinical Trial Design for Combination Therapies.” His trial design utilized cytotoxic chemotherapy. We adapted this design schema by incorporating greater numbers of dose levels for each drug. Additional dose levels are being examined because it has been the experience of phase I trials that targeted agents, when given in combination, are often effective at dosing levels lower than the FDA-approved dose of said drugs. A total of thirteen dose levels including representative high, intermediate and low dose levels of temsirolimus with representative high, intermediate, and low dose levels of bevacizumab will be evaluated. We hypothesize that our new trial design will facilitate identification of more than one MTD, if they exist, efficiently and within the context of a single protocol. Doses gleaned from this approach could potentially allow for a more personalized approach in dose selection from among the MTDs obtained that can be based upon a patient’s specific co-morbid conditions or anticipated toxicities

Safety and Antitumor Activity of the Anti–Programmed Death-1 Antibody Pembrolizumab in Patients With Advanced Esophageal Carcinoma

Purpose The anti–programmed death-1 antibody pembrolizumab was evaluated in KEYNOTE-028, a multicohort, phase IB study of patients with programmed death ligand-1 (PD-L1)–positive advanced solid tumors. Results from the esophageal carcinoma cohort are reported herein. Patients and Methods Eligible patients with squamous cell carcinoma or adenocarcinoma of the esophagus or gastroesophageal junction in whom standard therapy failed and who had PD-L1–positive tumors received pembrolizumab 10 mg/kg every 2 weeks for up to 2 years or until confirmed disease progression or intolerable toxicity. Response was assessed every 8 weeks up to 6 months and every 12 weeks thereafter. Primary end points were safety and overall response rate, determined by investigator review per Response Evaluation Criteria in Solid Tumors (version 1.1). Results Among 83 patients with esophageal carcinoma and samples evaluable for PD-L1 expression, 37 (45%) had PD-L1–positive tumors, and 23 were enrolled. Median age was 65 years; 78% had squamous histology; and 87% received ≥ two prior therapies for advanced/metastatic disease. As of the data cutoff (February 20, 2017), median follow-up was 7 months (range, 1 to 33 months). Nine patients (39%) experienced treatment-related adverse events, most commonly decreased appetite, decreased lymphocyte count, generalized rash, and rash (two patients [9%] each). No grade 4 adverse events or deaths were attributed to pembrolizumab. Overall response rate was 30% (95% CI, 13% to 53%); median duration of response was 15 months (range, 6 to 26 months). A six-gene interferon-γ gene expression signature analysis suggested that delayed progression and increased response occur among pembrolizumab-treated patients with higher interferon-γ composite scores. Conclusion Pembrolizumab demonstrated manageable toxicity and durable antitumor activity in patients with heavily pretreated, PD-L1–positive advanced esophageal carcinoma

Advanced gynecologic malignancies treated with a combination of the VEGF inhibitor bevacizumab and the mTOR inhibitor temsirolimus.

BackgroundBevacizumab and temsirolimus are active agents in gynecologic tumors. Temsirolimus attenuates upregulation of HIF-1α levels, a resistance mechanism for antiangiogenics, and targets the PI3-kinase/AKT/mTOR axis, commonly aberrant in these tumors.Patients and methodsWe analyzed safety and responses in 41 patients with gynecologic cancers treated as part of a Phase I study of bevacizumab and temsirolimus.ResultsMedian age of the 41 women was 60 years (range, 33-80 years); median number of prior systemic therapies was 4 (1-11). Grade 3 or 4 treatment-related toxicities included: thrombocytopenia (10%), mucositis (2%), hypertension (2%), hypercholesterolemia (2%), fatigue (7%), elevated aspartate aminotransferase (2%), and neutropenia (2%). Twenty-nine patients (71%) experienced no treatment-related toxicity greater than grade 2. Full FDA-approved doses of both drugs (bevacizumab 15mg/kg IV Q3weeks and temsirolimus 25mg IV weekly) were administered without dose-limiting toxicity. Eight patients (20%) achieved stable disease (SD) > 6 months and 7 patients (17%), a partial response (PR) [total = 15/41 patients (37%)]. Eight of 13 patients (62%) with high-grade serous histology (ovarian or primary peritoneal) achieved SD > 6 months/PR.ConclusionBevacizumab and temsirolimus was well tolerated. Thirty-seven percent of heavily-pretreated patients achieved SD > 6 months/PR, suggesting that this combination warrants further study

Dual EGFR inhibition in combination with anti-VEGF treatment in colorectal cancer.

Preclinical studies demonstrate that epidermal growth factor receptor (EGFR) signals through both kinase-dependent and independent pathways and that combining a small-molecule EGFR inhibitor, EGFR antibody, and/or anti-angiogenic agent is synergistic. We conducted a dose-escalation, phase I study combining erlotinib, cetuximab, and bevacizumab. The subset of patients with metastatic colorectal cancer was analyzed for safety and antitumor activity. Forty-one patients with heavily pretreated metastatic colorectal cancer received treatment on a range of dose levels. The most common treatment-related grade ≥2 adverse events were rash (68%), hypomagnesemia (37%), and fatigue (15%). Thirty of 34 patients (88%) treated at the full FDA-approved doses of all three drugs tolerated treatment without drug-related dose-limiting effects. Eleven patients (27%) achieved stable disease (SD) ≥6 months and three (7%) achieved a partial response (PR) (total SD>6 months/PR= 14 (34%)). Of the 14 patients with SD≥6 months/PR, eight (57%) had received prior sequential bevacizumab and cetuximab, two (5%) had received bevacizumab and cetuximab concurrently, and four (29%) had received prior bevacizumab but not cetuximab or erlotinib (though three had received prior panitumumab). The combination of bevacizumab, cetuximab, and erlotinib was well tolerated and demonstrated antitumor activity in heavily pretreated patients with metastatic colorectal cancer

Dual EGFR inhibition in combination with anti-VEGF treatment: a phase I clinical trial in non-small cell lung cancer.

BackgroundPreclinical data indicate EGFR signals through both kinase-dependent and independent pathways and that combining a small-molecule EGFR inhibitor, EGFR antibody, and/or anti-angiogenic agent is synergistic in animal models.MethodsWe conducted a dose-escalation, phase I study combining erlotinib, cetuximab, and bevacizumab. The subset of patients with non-small cell lung cancer (NSCLC) was analyzed for safety and response.ResultsThirty-four patients with NSCLC (median four prior therapies) received treatment on a range of dose levels. The most common treatment-related grade ≥2 adverse events were rash (n=14, 41%), hypomagnesemia (n=9, 27%), and fatigue (n=5, 15%). Seven patients (21%) achieved stable disease (SD) ≥6 months, two achieved a partial response (PR) (6%), and two achieved an unconfirmed partial response (uPR) (6%) (total=32%). We observed SD≥6 months/PR/uPR in patients who had received prior erlotinib and/or bevacizumab, those with brain metastases, smokers, and patients treated at lower dose levels. Five of 16 patients (31%) with wild-type EGFR experienced SD≥6 months or uPR. Correlation between grade of rash and rate of SD≥6 months/PR was observed (p less than 0.01).ConclusionThe combination of erlotinib, cetuximab, and bevacizumab was well-tolerated and demonstrated antitumor activity in heavily pretreated patients with NSCLC

PIK3CA mutations in advanced cancers: characteristics and outcomes.

PIK3CA mutations are frequently diagnosed in diverse cancers and may predict response to PI3K/AKT/mTOR inhibitors. It remains unclear whether they are associated with other characteristics. We analyzed characteristics and outcome of 90 consecutive patients with diverse advanced tumors and PIK3CA mutations and 180 wild-type PIK3CA controls matched by tumor type, gender, and age referred to the Clinical Center for Targeted Therapy. PIK3CA and MAPK mutations (KRAS, NRAS, and BRAF) were analyzed using polymerase chain reaction-based DNA sequencing. The most frequent PIK3CA mutations were E545K (31/90, 34%), E542K (16/90, 18%) in exon 9, and H1047R (20/90, 22%) in exon 20. PIK3CA mutations compared to wild-type PIK3CA were associated with simultaneous KRAS (p=0.047) and MAPK mutations (p=0.03), but only MAPK mutations were confirmed as having an independent association in multivariate analysis. Rates of lung, bone, liver and brain metastases were similar in PIK3CA-mutant and wild-type patients. Patients with PIK3CA mutations treated on trials with PI3K/AKT/mTOR inhibitors had a higher partial/complete response (PR/CR) rate than wild-type PIK3CA patients treated with their best phase I therapy (10/56, 18% vs. 12/152, 8%; p=0.045), but not a prolonged progression-free survival. Patients with H1047R PIK3CA mutations had higher PR/CR rate with PI3K/AKT/mTOR inhibitors compared to wild-type PIK3CA patients treated with their best phase I therapy (6/16, 38% vs. 12/152, 8%; p=0.003). In conclusion, PIK3CA mutations in diverse cancers were not associated with clinical characteristics, but were correlated with MAPK mutations. PIK3CA mutations, especially, H1047R, were associated with attaining a PR/CR to PI3K/AKT/mTOR pathway inhibitors

Anastrozole and everolimus in advanced gynecologic and breast malignancies: activity and molecular alterations in the PI3K/AKT/mTOR pathway.

BackgroundSince PI3K/AKT/mTOR pathway activation diminishes the effects of hormone therapy, combining aromatase inhibitors (anatrozole) with mTOR inhibitors (everolimus) was investigated.Patients and methodsWe evaluated anastrozole and everolimus in 55 patients with metastatic estrogen (ER) and/or progesterone receptor (PR)-positive breast and gynecologic tumors. Endpoints were safety, antitumor activity and molecular correlates.ResultsFull doses of anastrozole (1 mg PO daily) and everolimus (10 mg PO daily) were well tolerated. Twelve of 50 evaluable patients (24%) (median = 3 prior therapies) achieved stable disease (SD) ≥ 6 months/partial response (PR)/complete response (CR) (n = 5 (10%) with PR/CR): 9 of 32 (28%) with breast cancer (n=5 (16%) with PR/CR); 2 of 10 (20%), ovarian cancer; and 1 of 6 (17%), endometrial cancer. Six of 22 patients (27%) with molecular alterations in the PI3K/AKT/mTOR pathway achieved SD ≥ 6 months/PR/CR. Six of 8 patients (75%) with SD ≥ 6 months/PR/CR with molecular testing demonstrated at least one alteration in the PI3K/AKT/mTOR pathway: mutations in PIK3CA (n=3) and AKT1 (n=1) or PTEN loss (n=3). All three responders (CR (n = 1); PR (n=2)) who had next generation sequencing demonstrated additional alterations: amplifications in CCNE1, IRS2, MCL1, CCND1, FGFR1 and MYC and a rearrangement in PRKDC.ConclusionsCombination anastrozole and everolimus is well tolerated at full approved doses, and is active in heavily-pretreated patients with ER and/or PR-positive breast, ovarian and endometrial cancers. Responses were observed in patients with multiple molecular aberrations. CLINICAL TRAILS INCLUDED: NCT01197170

Targeted therapy of advanced gallbladder cancer and cholangiocarcinoma with aggressive biology: eliciting early response signals from phase 1 trials.

PurposePatients with advanced cholangiocarcinoma (CC) and gallbladder carcinoma (GC) have few therapeutic options for relapsed disease. methods: Given the overall poor prognosis in this population and the availability of novel targeted therapies, we systematically analyzed the characteristics and outcomes for GC and CC patients treated on phase I trials with an emphasis on targeted agents and locoregional therapies.ResultsOf 40 treated patients (GC=6; CC=34; median age, 60 years), 8 (20%) had stable disease (SD) > 6 months, 3 (8%) partial response (PR), on protocols with hepatic arterial drug infusion and anti-angiogenic, anti-HER-2/neu or novel MAPK/ERK kinase (MEK) inhibitors. Median progression-free survival (PFS) on phase I trials was 2.0 months (95% CI 1.7, 2.8) versus 3.0 months (95% CI 2.4, 5.0), 3.0 months (95% CI 2.3, 4.6), and 3.0 months (95% CI 2.4, 3.9) for their first-, second-, and last-line FDA-approved therapy. In univariate analysis, >3 metastatic sites, elevated alanine aminotransferase (ALT) (>56IU/L), serum creatinine (>1.6mg/dL), and CA19-9 (>35U/mL) were associated with a shorter PFS. Mutational analysis revealed mutation in the KRAS oncogene in 2 of 11 patients (18%). The SD >6 months/PR rate of 28% was seen with hepatic arterial infusion of oxaliplatin, and inhibitors of angiogenesis, HER-2/neu or MEK.ConclusionsThe PFS in phase I trials was similar to that of the first, second, and last-line therapy (P=0.95, 0.98, 0.76, respectively) with FDA-approved agents given in the advanced setting, emphasizing a role for targeted agents in a clinical trials setting as potentially valuable therapeutic options for these patients

Outcomes of patients with advanced cancer and KRAS mutations in phase I clinical trials.

BackgroundKRAS mutation is common in human cancer. We assessed the clinical factors, including type of KRAS mutation and treatment, of patients with advanced cancer and tumor KRAS mutations and their association with treatment outcomes.MethodsPatients referred to the Phase I Clinic for treatment who underwent testing for KRAS mutations were analyzed.ResultsOf 1,781 patients, 365 (21%) had a KRAS mutation. The G12D mutation was the most common mutation (29%). PIK3CA mutations were found in 24% and 10% of patients with and without KRAS mutations (p<0.0001). Of 223 patients with a KRAS mutation who were evaluable for response, 56 were treated with a MEK inhibitor-containing therapy and 167 with other therapies. The clinical benefit (partial response and stable disease lasting ≥6 months) rates were 23% and 9%, respectively, for the MEK inhibitor versus other therapies (p=0.005). The median progression-free survival (PFS) was 3.3 and 2.2 months, respectively (p=0.09). The respective median overall survival was 8.4 and 7.0 months (p=0.38). Of 66 patients with a KRAS mutation and additional alterations, higher rates of clinical benefit (p=0.04), PFS (p=0.045), and overall survival (p=0.02) were noted in patients treated with MEK inhibitor-containing therapy (n=9) compared to those treated with targeted therapy matched to the additional alterations (n=24) or other therapy (n=33).ConclusionsMEK inhibitors in patients with KRAS-mutated advanced cancer were associated with higher clinical benefit rates compared to other therapies. Therapeutic strategies that include MEK inhibitors or novel agents combined with other targeted therapies or chemotherapy need further investigation