A phase I study to evaluate the safety, pharmacokinetics, and pharmacodynamics of PF-06939999 (PRMT5 inhibitor) in patients with selected advanced or metastatic tumors with high incidence of splicing factor gene mutations

BACKGROUND

Protein arginine methyltransferase 5 (PRMT5) methylates multiple substrates dysregulated in cancer, including spliceosome machinery components. PF-06939999 is a selective small-molecule PRMT5 inhibitor.

PATIENTS AND METHODS

This phase I dose-escalation and -expansion trial (NCT03854227) enrolled patients with selected solid tumors. PF-06939999 was administered orally once or twice a day (q.d./b.i.d.) in 28-day cycles. The objectives were to evaluate PF-06939999 safety and tolerability to identify maximum tolerated dose (MTD) and recommended part 2 dose (RP2D), and assess pharmacokinetics (PK), pharmacodynamics [changes in plasma symmetric dimethylarginine (SDMA) levels], and antitumor activities.

RESULTS

In part 1 dose escalation, 28 patients received PF-06939999 (0.5 mg q.d. to 6 mg b.i.d.). Four of 24 (17%) patients reported dose-limiting toxicities: thrombocytopenia (n = 2, 6 mg b.i.d.), anemia (n = 1, 8 mg q.d.), and neutropenia (n = 1, 6 mg q.d.). PF-06939999 exposure increased with dose. Steady-state PK was achieved by day 15. Plasma SDMA was reduced at steady state (58%-88%). Modulation of plasma SDMA was dose dependent. No MTD was determined. In part 2 dose expansion, 26 patients received PF-06939999 6 mg q.d. (RP2D). Overall (part 1 + part 2), the most common grade ≥3 treatment-related adverse events included anemia (28%), thrombocytopenia/platelet count decreased (22%), fatigue (6%), and neutropenia (4%). Three patients (6.8%) had confirmed partial response (head and neck squamous cell carcinoma, n = 1; non-small-cell lung cancer, n = 2), and 19 (43.2%) had stable disease. No predictive biomarkers were identified.

CONCLUSIONS

PF-06939999 demonstrated a tolerable safety profile and objective clinical responses in a subset of patients, suggesting that PRMT5 is an interesting cancer target with clinical validation. However, no predictive biomarker was identified. The role of PRMT5 in cancer biology is complex and requires further preclinical, mechanistic investigation to identify predictive biomarkers for patient selection.

First-in-human phase I study of copanlisib (BAY 80-6946), an intravenous pan-class I phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors and non-Hodgkin's lymphomas

BACKGROUND

To evaluate the safety, tolerability, pharmacokinetics, and maximum tolerated dose (MTD) of copanlisib, a phosphatidylinositol 3-kinase inhibitor, in patients with advanced solid tumors or non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Phase I dose-escalation study including patients with advanced solid tumors or NHL, and a cohort of patients with type 2 diabetes mellitus. Patients received three weekly intravenous infusions of copanlisib per 28-day cycle over the dose range 0.1-1.2 mg/kg. Plasma copanlisib levels were analyzed for pharmacokinetics. Biomarker analysis included PIK3CA, KRAS, BRAF, and PTEN mutational status and PTEN immunohistochemistry. Whole-body [(18)F]-fluorodeoxyglucose positron emission tomography ((18)FDG-PET) was carried out at baseline and following the first dose to assess early pharmacodynamic effects. Plasma glucose and insulin levels were evaluated serially.

RESULTS

Fifty-seven patients received treatment. The MTD was 0.8 mg/kg copanlisib. The most frequent treatment-related adverse events were nausea and transient hyperglycemia. Copanlisib exposure was dose-proportional with no accumulation; peak exposure positively correlated with transient hyperglycemia post-infusion. Sixteen of 20 patients treated at the MTD had reduced (18)FDG-PET uptake; 7 (33%) had a reduction >25%. One patient achieved a complete response (CR; endometrial carcinoma exhibiting both PIK3CA and PTEN mutations and complete PTEN loss) and two had a partial response (PR; both metastatic breast cancer). Among the nine NHL patients, all six with follicular lymphoma (FL) responded (one CR and five PRs) and one patient with diffuse large B-cell lymphoma had a PR by investigator assessment; two patients with FL who achieved CR (per post hoc independent radiologic review) were on treatment >3 years.

CONCLUSION

Copanlisib, dosed intermittently on days 1, 8, and 15 of a 28-day cycle, was well tolerated and the MTD was determined to be 0.8 mg/kg. Copanlisib exhibited dose-proportional pharmacokinetics and promising anti-tumor activity, particularly in patients with NHL.

CLINICALTRIALSGOV

NCT00962611; https://clinicaltrials.gov/ct2/show/NCT00962611.

A Phase 1 study of ARQ 087, an oral pan-FGFR inhibitor in patients with advanced solid tumours

Background:

ARQ 087 is an orally administered pan-FGFR inhibitor with multi-kinase activity. This Phase 1 study evaluated safety, pharmacokinetics, and pharmacodynamics of ARQ 087 and defined the recommended Phase 2 dose (RP2D).

Methods:

Patients with advanced solid tumours received ARQ 087 administered initially at 25 mg every other day and dose-escalated from 25 to 425 mg daily (QD) continuous dosing. FGF19, 21, 23, and serum phosphate were assessed as potential biomarkers of target engagement.

Results:

80 patients were enrolled, 61 in dose-escalation/food-effect cohorts and 19 with pre-defined tumour types in the expansion cohort. The most common ARQ 087-related adverse events were fatigue (49%), nausea (46%), aspartate aminotransferase (AST) increase (30%), and diarrhoea (23%). Four patients (5%) experienced grade 1 treatment-related hyperphosphataemia. Dose-limiting toxicity was reversible grade 3 AST increase. The RP2D was 300 mg QD. Pharmacokinetics were linear and dose-proportional from 25 to 325 mg QD, and were unaffected by food. Statistically significant changes (P-value<0.05) suggest phosphate and FGF19 levels as markers of target engagement. In 18 evaluable patients with FGFR genetic alterations, 3 confirmed partial responses (two intrahepatic cholangiocarcinomas (iCCA) with FGFR2 fusions and one urothelial cancer with FGFR2 and FGF19 amplification) and two durable stable disease at ⩾16 weeks with tumour reduction (FGFR2 fusion-positive iCCA and adrenocortical carcinoma with FGFR1 amplification) were observed.

Conclusions:

ARQ 087 had manageable toxicity at the RP2D of 300 mg QD, showed pharmacodynamics effects, and achieved objective responses, notably in patients with FGFR2 genetic alterations.

Abstract P3-04-26: Establishment and characterization of ST941/C; an ESR1-mutant ER+ breast cancer cell line and xenograft from a patient with acquired resistance to endocrine therapy

Background: The estrogen receptor (ERα) plays an integral role in the progression of luminal type breast cancers and while targeted endocrine therapies provide effective initial treatment many patients develop acquired resistance to treatment even with continued ER receptor expression. Recently studies identified ER mutations as a possible mechanism for acquired resistance and several activating point mutations have been identified including Y537S (ESR1Y537S) resulting in hormone independent proliferation in preclinical studies. However, lack of validated ESR1-mutant cell lines has limited detailed mechanistic studies of these mutations in endocrine-resistant ER+ breast cancer. Previously we established and evaluated a patient derived xenograft (PDX) designated ST941 representing ESR1Y537S-mutated ER+ breast cancer (Wick et al, SABCS 2015). To better understand the role of ESR1-mutations in endocrine resistant breast cancer we established an immortalized cell line from ST941 designated ST941/C to use for in vitro mechanistic assays and correlative in vivo studies.

Methods: The ST941/C cell line was generated from harvested low-passage ST941 PDX tissue using published methods. Once established the line was characterized by immunohistochemistry and NGS and its tumorigenicity assessed. Drug sensitivity studies were carried out evaluating relevant endocrine and chemotherapy agents and results compared with in vivo drug studies. Timepoints for cell proliferation assays were Days 4, 7 and 10 following cell plating using standard MTS assay. Endpoints for in vivo studies were a mean group tumor volume of ~1 cm3 or sixty days following treatment initiation.

Results: Subcutaneous cell injection into athymic nude mice produced xenografts which grew in the absence of exogenous hormone. The ST941/C cell line and resulting xenograft retained immunohistologic and NGS characteristics of the parent model including receptor expression and ER mutation. Both the cell line and xenograft were insensitive to most endocrine therapies including tamoxifen, fulvestrant and aromatase inhibitors and reported correlative activity towards docetaxel and other chemotherapies.

Conclusion: We have established and evaluated an ESR1-mutant cell line designated ST941/C which is tumorigenic in nude mice and potentially useful for mechanistic and correlative in vivo studies to better understand acquired resistance in endocrine-treated ER+ breast cancer.

Citation Format: Wick MJ, Diaz A, Thomas M, Moriarty A, Quinn M, Guerra M, Zhu P, Smith P, Tolcher AW, Puyang X, Patnaik A, Korpal M, Rasco D, Papadopoulos KP. Establishment and characterization of ST941/C; an ESR1-mutant ER+ breast cancer cell line and xenograft from a patient with acquired resistance to endocrine therapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-04-26.

Abstract P3-03-01: Intracranial PDX models of breast cancer metastasis

Background: Overexpression of the human epidermal growth factor receptor 2 (HER2) in breast cancer is an independent factor for development of brain metastases. Up to 37% of patients with HER2 positive disease relapse intracranially despite control of extra-cranial metastatic disease. Inability of anti-cancer agents to cross an intact blood-brain barrier (BBB) is a possible explanation for the increased incidence of brain metastases.

Subcutaneous (SQ) patient-derived xenograft (PDX) models are increasingly used for efficacy studies in drug development. However, orthotopic PDX models may confer a translational advantage as the patient tumor microenvironment is more closely mimicked. Especially when targeting brain tumors, the major impact of the BBB on drug bioavailability must be taken into consideration. The aim of this study was therefore to develop a panel of intracranial PDX models of breast cancer brain metastases for pre-clinical efficacy studies of new anticancer drugs.

Methods: SQ tumors from three different HER2 positive PDX breast cancer models designated ST340, ST1339 and ST1616B were enzymatically digested and used for intracranial stereotactic injection in nude mice. Contrast-enhanced T1- and T2-weighted Magnetic Resonance Imaging (MRI) were used to determine tumor take. Intracranial tumor growth was monitored using MRI and positron emission tomography (PET) in conjunction with the amino acid radio tracer 18F-FET.

Results: MRI confirmed tumor take in one model as early as 2 weeks after intracranial implantation. Increased 18F-FET uptake was detected in all models. MRI could be effectively used to monitor tumor growth and the corresponding 18F-FET PET images demonstrated increased 18F-FET uptake over time.

Conclusion: Three different HER2 positive intracranial PDX breast metastases models were established from low passage SQ PDX models. We suggest, that using these intracranial PDX models of brain metastases, new drugs for advanced breast cancer can be evaluated in preclinical models that more closely mimic the microenvironment and the BBB in patients. In addition, translational imaging techniques can be evaluated during preclinical testing and the potential of tracers like 18F-FET as imaging biomarkers of therapeutic response can be assessed. Together, the established SQ and orthotopic PDX models of breast cancer and brain metastases can be used as a relevant translational platform for testing of new drugs.

Citation Format: Nielsen CH, Nedergaard MK, Wick MJ, Papadopoulos K, Tolcher AW, Kjaer A. Intracranial PDX models of breast cancer metastasis. [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 P3-03-01.

Abstract P3-03-05: Establishment and evaluation of ER+ breast cancer models using an optimized methodology for exogenous hormone delivery

Preclinical in vivo models of estrogen receptor positive (ER+) breast cancer rely on exogenous supplementation of hormones for growth. This requirement leads to animal toxicity and mortality over time, limiting development and drug testing in these types of models. Efficacy of test agents, particularly endocrine therapies, may also be altered in these models due to excessive hormone exposure, highlighting the need to improve methods for the establishment and testing of ER+ breast models.

We have developed an alternative method of hormone supplementation in ER+ breast cancer models and optimized this method for testing of endocrine therapies. Using two cell-based breast models, we demonstrated improved breast tumor take and time to tumor volume endpoint while reducing animal toxicity and mortality associated with standard hormone supplementation. Subsequent studies identified the lowest effective dose (LED) of supplement for hormone dependent model growth with a preclinically relevant time to tumor volume endpoint. Activity of endocrine therapies including tamoxifen, letrozole, fulvestrant and exemestane were compared at the standard and LED hormone concentrations. In these studies tamoxifen treatment resulted in tumor regressions which was not appreciably improved using the LED dose of supplement. However letrozole activity was improved in the LED study suggesting hormone supplementation can impact activity of some agents. Using this process we also generated a panel of ER+ patient-derived xenograft (PDX) models, including two novel hormone therapy responsive models from chemo-naïve or hormone therapy pretreated patients, designated ST986 and ST2177, respectively.

This improved method of hormone supplementation diminishes the adverse effects of standard hormone supplementation and provides utility for development of anticancer therapies in ER+ breast models.

Citation Format: Wick MJ, Vaught T, Meade J, Gamez L, Farley M, Tolcher AW, Rasco D, Patnaik A, Drengler RL, Rosenthal A, Papadopoulos KP. Establishment and evaluation of ER+ breast cancer models using an optimized methodology for exogenous hormone delivery. [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 P3-03-05.

A phase IB trial of the oral MEK inhibitor trametinib (GSK1120212) in combination with everolimus in patients with advanced solid tumors

BACKGROUND

This phase Ib trial investigated the safety, tolerability, and recommended phase II dose and schedule of the MEK inhibitor trametinib in combination with the mammalian target of rapamycin (mTOR) inhibitor everolimus. Secondary objectives included pharmacokinetic (PK) characterization and evaluation of clinical activity.

PATIENTS AND METHODS

A total of 67 patients with advanced solid tumors were enrolled in this open-label, single-arm, dose-escalation study. Dose escalation followed a 3 + 3 design. Patients were assigned to one of 10 different cohorts, involving either daily dosing with both agents or daily dosing with trametinib and intermittent everolimus dosing. This included an expansion cohort comprising patients with pancreatic tumors. PKs samples were collected predose, as well as 1, 2, 4, and 6 h post-dose on day 15 of the first treatment cycle.

RESULTS

Concurrent treatment with trametinib and everolimus resulted in frequent treatment-related adverse events, including mucosal inflammation (40%), stomatitis (25%), fatigue (54%), and diarrhea (42%). PK assessment did not suggest drug-drug interactions between these two agents. Of the 67 enrolled patients, 5 (7%) achieved partial response (PR) to treatment and 21 (31%) displayed stable disease (SD). Among the 21 patients with pancreatic cancer, PR was observed in 1 patient (5%) and SD in 6 patients (29%).

CONCLUSIONS

This study was unable to identify a recommended phase II dose and schedule of trametinib in combination with everolimus that provided an acceptable tolerability and adequate drug exposure.

Erlotinib 'dosing-to-rash': a phase II intrapatient dose escalation and pharmacologic study of erlotinib in previously treated advanced non-small cell lung cancer

BACKGROUND

To evaluate the anticancer activity of erlotinib in patients with previously treated, advanced non-small cell lung cancer (NSCLC) whose dose is increased to that associated with a maximal level of tolerable skin toxicity (i.e., target rash (TR)); to characterise the pharmacokinetics (PK) and pharmacodynamics (PD) of higher doses of erlotinib.

METHODS

Patients initially received erlotinib 150 mg per day. The dose was successively increased in each patient to that associated with a TR. Anticancer activity was evaluated. Plasma, skin, and hair were sampled for PK and PD studies.

RESULTS

Erlotinib dose escalation to 200-475 mg per day was feasible in 38 (90%) of 42 patients. Twenty-four (57%) patients developed a TR, but 19 (79%) did so at 150 mg per day. Five (12%) patients, all of whom developed a TR, had a partial response. Median progression-free survival (PFS) was 2.3 months (95% CI: 1.61, 4.14); median PFS was 3.5 months and 1.9 months, respectively, for patients who did and did not experience a TR (hazard ratio, 0.51; P=0.051). Neither rash severity nor response correlated with erlotinib exposure.

CONCLUSION

Intrapatient dose escalation of erlotinib does not appreciably increase the propensity to experience a maximal level of tolerable skin toxicity, or appear to increase the anticancer activity of erlotinib in NSCLC.

A phase Ib study of the MEK inhibitor GSK1120212 combined with gemcitabine in patients with solid tumors: Interim results

278

Background: GSK1120212 (212) is a reversible, allosteric inhibitor of MEK1/MEK2. The objectives of this open-label, single-arm study are to evaluate the safety, pharmacokinetics (PK), and anti-tumor activity of 212 + gemcitabine (gem), and to determine the recommended phase II regimen (RP2R) in patients (pts) with advanced solid tumors.

Methods: 212 (1-2.5mg) is given continuously, orally, once daily. Gem (1,000mg/m2) is infused on days 1, 8, and 15 every 28 days. Doses are escalated to the maximum tolerated dose (MTD) and followed by an expansion cohort to confirm the RP2R tolerability.

Results: 28 pts received ≥ 1 dose of 212 + gem, including 8 pancreatic, 6 breast, and 4 non-small cell lung (NSCLC) cancer pts. The MTD and RP2R is 2mg 212 + 1,000mg/m2 gem. Dose-limiting toxicities (DLTs) are G3/G4 febrile neutropenia (n=2), G3 AST elevation (n=2), and G2 uveitis (n=1). 16 serious adverse events (SAEs) were reported; 5 were considered to be related to study drugs (1 pneumonitis, 3 febrile neutropenia, 1 dyspnea). All DLTs and SAEs have resolved. The most common AEs at the RP2R (n=18) were rash (78%), fatigue (67%), thrombocytopenia (61%), neutropenia (50%), decreased appetite (50%), nausea (44%), diarrhea and constipation (39%); all ≤ G2 except thrombocytopenia (17% ≥ G3) and neutropenia (33% ≥ G3). Co-administration did not affect the PK profiles of 212 or gem. 25 pts had measurable disease at baseline. 1 pancreatic cancer pt with previous radiotherapy and 2 cycles of gem achieved a partial response and stayed on study for 6 months. 3 additional pancreatic cancer pts reported stable disease; 2 of which were on the study for 3.5-5 months and the third pt continues in the study. 1 triple-negative breast cancer pt, refractory to chemotherapy, and 1 parotid cancer pt experienced a complete response of their target lesions.

Conclusions: 212 + gem is tolerable with an acceptable safety profile in this pt population, with evidence of clinical activity in pancreatic cancer. A randomized phase II study in previously untreated patients with metastatic pancreatic cancer is underway to investigate the clinical activity of this combination.

[Table: see text]

Phase I and pharmacokinetic study of lexatumumab (HGS-ETR2) given every 2 weeks in patients with advanced solid tumors

BACKGROUND

Lexatumumab (HGS-ETR2) is a fully human agonistic mAb to the tumor necrosis factor-related apoptosis-inducing ligand receptor 2 that activates the extrinsic apoptosis pathway and has potent preclinical antitumor activity.

MATERIALS AND METHODS

This phase 1, dose escalation study assessed the safety, tolerability, pharmacokinetics (PKs) and immunogenicity of lexatumumab administered i.v. every 14 days in patients with advanced solid tumors.

RESULTS

Thirty-one patients received lexatumumab over five dose levels (0.1-10 mg/kg). Most (26 of 31) received four or more cycles of treatment. One patient at 10 mg/kg experienced a possibly related dose-limiting toxicity of grade 3 hyperamylasemia. Nine patients achieved stable disease. One patient with chemotherapy-refractive Hodgkin's disease experienced a mixed response. Lexatumumab PKs were linear up to 10 mg/kg. At the 10 mg/kg dose, the mean (+/-standard deviation) t(1/2b) was 13.67 +/- 4.07 days, clearance was 4.95 +/- 1.93 ml/day/kg, V(1) was 45.55 ml/kg and V(ss) was 79.08 ml/kg, indicating that lexatumumab distributes outside the plasma compartment. No human antihuman antibodies were detected.

CONCLUSIONS

Lexatumumab can be safely administered every 14 days at 10 mg/kg. The PK profile supports this schedule. Further evaluation of lexatumumab at this dose schedule is warranted, including combination trials with other agents.

First-in-human, first-in-class, phase I study of a human monoclonal antibody CNTO 888 to the CC-chemokine ligand 2 (CCL2/MCP-1) in patients with solid tumors

e13500

Background: The chemokine CCL2 promotes angiogenesis, tumor proliferation, migration and metastasis through PI3K and NFkB signaling. CNTO 888 is a human IgG1κ monoclonal antibody with high binding affinity for CCL2 and documented preclinical antitumor activity. Methods: Patients were administered a 90 minute infusion of CNTO 888 on day 1, day 28 and subsequently on a q14 schedule. Exploratory PD assessments include diffusion contrast enhanced CT, circulating tumor and endothelial cells, free and bound CCL2 levels, bone markers and paired tumor biopsies. Results: 21 patients in cohorts of 3–6 patients received repeated CNTO 888 infusions at 5 dose levels (0.3mg/kg, 1mg/kg, 3mg/kg, 10mg/kg, 15 mg/kg). A further 23 patients are currently being evaluated in 2 expansion cohorts; 10mg/kg (n=12) and 15mg/kg (n=11). No dose limiting toxicities were seen up to 15 mg/kg q14. Preliminary pharmacokinetic (PK) data for doses ≤ 10 mg/kg showed linear kinetics with a bi-exponential decline and a t1/2 of 4.4 - 8.7 days. The 10 mg/kg dose level resulted in steady-state minimum concentrations above that needed to inhibit chemotaxis and calcium mobilization in preclinical studies. Dose-dependent increase in bound CCL2 levels of > 1000-fold seen following treatment, supports target modulation. 2 patients demonstrated stable disease (SD) > 6 months at 15mg/kg CNTO 888 (ocular melanoma and neuroendocrine tumor). Another patient at 0.3mg/kg CNTO 888 with ovarian cancer had 50% CA125 decline and SD for 10 months. Conclusions: CNTO 888 is well tolerated with no DLTs when administered up to 15mg/kg q14. Preliminary evidence of antitumor activity is reported.

[Table: see text]

Safety and efficacy of YM155 in diffuse large B-cell lymphoma (DLBCL)

8502

Background: Survivin is a member of the inhibitor of apoptosis proteins (IAPs) family which is responsible for preservation of cell viability and regulation of mitosis in tumor cells. YM155, a survivin suppressant, has exhibited anti-tumor activity in solid tumors and non-Hodgkins lymphoma (NHL), including DLBCL patients enrolled in Phase I and Phase II monotherapy studies. Methods: Two studies enrolled 43 DLBCL patients; a Phase I study enrolled patients with solid tumors and NHL (n=1 relapsing DLBCL and n=1 refractory DLBCL), and a Phase II study enrolled refractory DLBCL patients (n=41). YM155 was administered at 4.8 mg/m2/day (Phase I) and at 5 mg/m2/day (Phase II) as a 168-hour continuous infusion in a 21 day cycle. Patients could continue to receive YM155 until disease progression or unacceptable toxicity. Results: Data are presented for the first 27 patients (Phase I and Phase II) who have completed therapy. Median age was 61 (23–80) years and 63% were male. Three patients (11%) had partial responses (PR) confirmed by independent review using Cheson criteria (N=2; 1999 criteria and N=1; 2007 updated criteria). All responders received 2 prior regimens. Two responders were refractory to their last regimen and one had relapsed approximately 2 years after stem cell transplant (SCT). One patient responded after 2 cycles, completed 5 total cycles and proceeded to SCT (disease-free > 3.7 years post SCT). A second patient responded after 3 cycles, completed 7 total cycles and proceeded to SCT in OCT08. The third patient responded after 12 cycles and received 26 total cycles (1.5 years) before disease progression. The most common (>4%), treatment-related grade 3/4 adverse events included anemia (16.0%) and neutropenia, fatigue, hemoglobin decrease and deep vein thrombosis (8.0% each). Conclusions: YM155 is well tolerated and has modest single-agent, anti-tumor activity in relapsed/refractory DLBCL patients. Because of single-agent activity and preliminary data showing synergism when YM155 is combined with other agents additional clinical studies are being planned.

[Table: see text]

Pharmacokinetics (PK) and safety of tesetaxel, an orally administered taxane, in a study examining a range of doses including the active phase II dose

e13535

Background: Tesetaxel is an orally active taxane with potent cytotoxic activity against various cancer cell lines in vitro, including cell lines and xenografts of human tumors that over-express P-glycoprotein. Tesetaxel displays markedly lower neurotoxicity than docetaxel in preclinical models. In Phase 2 studies, 2nd-line therapy with tesetaxel (27–35 mg/m2 every 3 weeks) was associated with overall response rates of 20% and 38% in patients (pts) with gastric and breast cancer, respectively. Neutropenia was the most common serious adverse event. We are conducting a dose-ranging study to examine the PK and safety of tesetaxel at doses including and just below the previously established MTD of 27 mg/m2. Methods: Eligibility criteria include advanced solid tumors, ECOG PS ≤ 2, and adequate organ function. The starting dose is 18 mg/m2, which is being escalated in increments of 3 mg/m2 to a maximum of 27 mg/m2. Tesetaxel is given for a minimum of 2 cycles; pts with response or stable disease may receive up to 2 more cycles. Plasma is assayed at various times to determine concentrations of parent drug and metabolites. A total of 12 patients will be entered into the dose-escalation phase, with sample expansion to 12 pts at the MTD. Results: Ongoing enrollment is expected to be completed in Q1 2009. Our group's prior study of tesetaxel 18 mg/m2 and 27 to 40 mg/m2 has shown that tesetaxel displays dose-proportional absorption and has a long terminal plasma half-life (mean approximately 180 hrs). We expect to confirm these data over a narrow dose range and to examine the data for correlations between PK and the duration and severity of neutropenia. Conclusions: Tesetaxel is an orally active taxane that eliminates infusion reactions and the associated need for premedication. It may overcome inherent or clinically acquired resistance to prototype taxanes and may prove to have reduced taxane-associated peripheral neuropathy in the clinical setting. Essential to future tesetaxel studies, this study will determine whether correlations between key PK parameters and dose-limiting reactions exist.

[Table: see text]

Pharmacology and safety factors affecting use of flat (rather than weight-based) dosing of tesetaxel, an orally administered taxane

2510

Background: As a class, taxanes have wide interpatient (pt) pharmacokinetic (PK) variability at their effective dose, which has been associated with adverse reactions, especially neutropenia. Tesetaxel is an oral taxane with Phase 2 activity in pretreated pts with colorectal, non-small cell lung, gastric, and breast cancers. Tesetaxel is not a substrate for P-glycoprotein; it is associated with lower neurotoxicity at equi-myelotoxic does, and it displays a long terminal half-life in plasma (∼180 hrs). We explored PK and clinical safety to determine the feasibility of using flat dosing in future studies. Methods: PK parameters were evaluated in 21 pts treated at the maximum tolerated dose (27 mg/m2) either alone or in combination with capecitabine. We then compared actual dose (total mg) with the weight-based dose and correlated the incidence and severity of Grade 3–4 neutropenia with weight-based vs. flat dosing. Results: A total of 174 pts were treated with tesetaxel in Phase 2 trials at doses of 27 or 35 mg/m2 once every 3 weeks. For pts prescribed with weight-based dosing (27 mg/m2), mean Cmax in 3 separate cohorts was 24.6, 42.5, and 47.9 μg/L, with AUC0-inf of 1363, 1592, and 1663 h*μg/L, respectively. In 103 pts prescribed a dose of 27 mg/m2, 17% and 16% of pts received doses of 40 mg or 60 mg, respectively, whereas 67% received 50 mg. Correlations between drug exposure AUC0-inf and actual dose (mg and mg/m2) across the entire range of administered doses showed r2 values of 0.455 and 0.492, respectively. Similar correlations after a second repeat dose showed r2 values of 0.731 and 0.653, respectively. The incidence of Grade 3–4 neutropenia at 27 mg/m2 was 33%. Conclusions: PK and clinical safety suggest that weight-based dosing offers no substantial advantage compared with flat dosing. Future studies could incorporate a starting dose of 50 mg administered once every 3 weeks. Flat dosing should also be tested using different schedules, including weekly x 3 weeks and “metronomic dosing” (1–2 mg/d).

[Table: see text]

A phase I study of MK-2206, an oral potent allosteric Akt inhibitor (Akti), in patients (pts) with advanced solid tumor (ST)

3503

Background: Akt facilitates cell proliferation/survival and is a suspected driver of progression in ST. MK-2206, a highly selective non-ATP competitive allosteric Akti, has nM IC50 and broad preclinical antitumor activity. Methods: Safety and tolerability of MK-2206 administered QOD in 28-day cycles (cy) was assessed. Doses evaluated: 30, 60, 90 mg, and 75 mg. Main eligibility criteria: ≥18 yo, evaluable advanced ST, ECOG ≤1, HbA1c ≤8% or fasting glucose ≤110% upper limit of normal. PK and phosphorylated Akt (pAkt) in whole blood by meso-scale ELISA were measured. Sequential tumor biopsies were performed in a subset of pts. Results: Dose escalation occurred in 19 pts (8 female/11 male; median age 57 yo; ECOG 0/1: 5/14) and 37 cy of therapy with no DLTs at 30 and 60 mg. CTCAE G3/4 skin rash and CTCAE G3 mucositis were observed at 90 mg in 4/7 pts. After further accrual at 60 mg confirmed safety at this dose, 75 mg was explored; however, 2/3 pts experienced DLT of rash. Dose escalation is complete; the MTD of MK-2206 is 60 mg QOD. Common drug-related AEs included skin (47.1%), gastrointestinal (41.2%), and general disorders (29.4%). AUC0–48hr and Cmax were dose proportional up to 60 mg. Median Tmax is 6 hrs and mean t1/2 ranged from 63 to 76 hr. MK-2206 concentrations exceeding a preliminary, statistically determined PK target of approximately 50–65 nM for significant pAkti in blood were maintained over the entire dosing interval in all patients in the 60 mg cohort. Evidence of PD activity included decreases in whole blood pAkt at all dose levels, reversible CTCAE G1/2 hyperglycemia and CTCAE G1 insulin c-peptide elevations. RECIST stable disease following 2 cycles of therapy was observed in 1 pt at 30 mg and 5 pts at 60 mg. Observed clinical activity included: central tumor necrosis, decreased ascites and peripheral edema, reduction in index lesions, normalization of LFTs, and decreased CA-125. Conclusions: MK-2206 is generally well tolerated at doses up to 60 mg QOD with plasma concentrations that portend activity in preclinical models. PK/PD data suggest a substantial and maintained target inhibition at 60 mg.

[Table: see text]