Muralidhar Beeram

Phase I Study of Trastuzumab-DM1, an HER2 Antibody-Drug Conjugate, Given Every 3 Weeks to Patients With HER2-Positive Metastatic Breast Cancer

PURPOSE Trastuzumab-DM1 (T-DM1) is an antibody-drug conjugate that uses trastuzumab to specifically deliver the maytansinoid antimicrotubule agent DM1 to HER2-positive cells. This first-in-human study of T-DM1 evaluated safety, pharmacokinetics, and preliminary activity of T-DM1 in patients with advanced HER2-positive breast cancer. PATIENTS AND METHODS Successive cohorts of patients who had progressed on trastuzumab-based therapy received escalating doses of T-DM1. Outcomes were assessed by standard solid-tumor phase I methods. RESULTS Twenty-four patients who had received a median of four prior chemotherapeutic agents for metastatic disease received T-DM1 at 0.3 mg/kg to 4.8 mg/kg on an every-3-weeks schedule. Transient thrombocytopenia was dose-limiting at 4.8 mg/kg; the maximum-tolerated dose (MTD) was 3.6 mg/kg. The half-life of T-DM1 at the MTD was 3.5 days, with peak DM1 levels < 10 ng/mL. Clearance at doses < 1.2 mg/kg was faster than at higher doses. Common drug-related adverse events (AEs) included grade < or = 2 thrombocytopenia, elevated transaminases, fatigue, nausea, and anemia. No grade > 1 nausea, vomiting, alopecia, or neuropathy events and no cardiac effects requiring dose modification were reported. The clinical benefit rate (objective response plus stable disease at 6 months) among 15 patients treated at the MTD was 73%, including five objective responses. The confirmed response rate in patients with measurable disease at the MTD (n = 9) was 44%. CONCLUSION At the MTD of 3.6 mg/kg every 3 weeks, T-DM1 was associated with mild, reversible toxicity and substantial clinical activity in a heavily pretreated population. Phase II and III trials in patients with advanced HER2-positive breast cancer are under way.

The Clinical Effect of the Dual-Targeting Strategy Involving PI3K/AKT/mTOR and RAS/MEK/ERK Pathways in Patients with Advanced Cancer

Purpose: This study evaluated the clinical relevance of the dual-targeting strategy involving PI3K/AKT/mTOR and RAF/MEK/ERK pathways. Experimental Design: We investigated safety, efficacy, and correlations between tumor genetic alterations and clinical benefit in 236 patients with advanced cancers treated with phase I study drugs targeting phosphoinositide 3-kinase (PI3K) and/or mitogen-activated protein kinase (MAPK) pathways in our Phase I Clinical Trials Program. Results: Seventy-six (32.2%) patients received a PI3K pathway inhibitor in combination with a MAPK pathway inhibitor (D), whereas 124 (52.5%) and 36 (15.3%), respectively, received an inhibitor of either the PI3K or MAPK pathways (S). The rates of drug-related grade >III adverse events were 18.1% for (S) and 53.9% for (D; P < 0.001); the rates of dose-limiting toxicities were 9.4% for (S) and 18.4% for (D; P = 0.06). The most frequent grade >III adverse events were transaminase elevations, skin rash, and mucositis. In our comprehensive tumor genomic analysis, of 9 patients who harbored coactivation of both pathways (colorectal cancer, n = 7; melanoma, n = 2), all 5 patients treated with (D) had tumor regression ranging from 2% to 64%. Conclusions: These results suggest that dual inhibition of both pathways may potentially exhibit favorable efficacy compared with inhibition of either pathway, at the expense of greater toxicity. Furthermore, this parallel pathway targeting strategy may be especially important in patients with coexisting PI3K pathway genetic alterations and KRAS or BRAF mutations and suggests that molecular profiling and matching patients with combinations of these targeted drugs will need to be investigated in depth. Clin Cancer Res; 18(8); 2316–25. ©2012 AACR.

Phase I and Pharmacokinetic Study of XRP6258 (RPR 116258A), a Novel Taxane, Administered as a 1-Hour Infusion Every 3 Weeks in Patients with Advanced Solid Tumors

Purpose: To assess the feasibility of administering XRP6258, a new taxane with a low affinity for the multidrug resistance 1 protein, as a 1-hour i.v. infusion every 3 weeks. The study also sought to determine the maximum tolerated dose and the recommended dose, to describe the pharmacokinetic (PK) behavior of the compound, and to seek preliminary evidence of anticancer activity. Experimental Design: Twenty-five patients with advanced solid malignancies were treated with 102 courses of XRP6258 at four dose levels ranging from 10 to 25 mg/m2. Dose escalation was based on the occurrence of dose-limiting toxicity (DLT) at each dose level, provided that PK variables were favorable. The maximum tolerated dose was defined as the dose at which at least two patients developed a DLT at the first course. Results: Neutropenia was the principal DLT, with one patient experiencing febrile neutropenia and two others showing prolonged grade 4 neutropenia at the 25 mg/m2 dose level. Nonhematologic toxicities, including nausea, vomiting, diarrhea, neurotoxicity, and fatigue, were generally mild to moderate in severity. XRP6258 exhibited dose-proportional PK, a triphasic elimination profile, a long terminal half-life (77.3 hours), a high clearance (mean CL, 53.5 L/h), and a large volume of distribution (mean Vss, 2,034 L/m2). Objective antitumor activity included partial responses in two patients with metastatic prostate carcinoma, one unconfirmed partial response, and two minor responses. Conclusion: The recommended phase II dose of XRP6258 on this schedule is 20 mg/m2. The general tolerability and encouraging antitumor activity in taxane-refractory patients warrant further evaluations of XRP6258.

Raf: A Strategic Target for Therapeutic Development Against Cancer

The mitogen-activated protein kinase (MAPK) signaling pathway plays a critical role in transmitting proliferative signals generated by cell surface receptors and cytoplasmic signaling elements to the nucleus. Several important signaling elements of the MAPK pathway, particularly Ras and Raf, are encoded by oncogenes, and as such, their structures and functions can be modified, rendering them constitutively active. Because the MAPK pathway is dysregulated in a notable proportion of human malignancies, many of its aberrant and critical components represent strategic targets for therapeutic development against cancer. Raf, which is an essential serine/threonine kinase constituent of the MAPK pathway and a downstream effector of the central signal transduction mediator Ras, is activated in a wide range of human malignancies by aberrant signaling upstream of the protein (eg, growth factor receptors and mutant Ras) and activating mutations of the protein itself, both of which confer a proliferative advantage. Three isoforms of Raf have been identified, and therapeutics targeting Raf, including small-molecule inhibitors and antisense oligodeoxyribonucleotides (ASON), are undergoing clinical evaluation. The outcomes of these investigations may have far-reaching implications in the management of many types of human cancer. This review outlines the structure and diverse functions of Raf, the rationale for targeting Raf as a therapeutic strategy against cancer, and the present status of various therapeutic approaches including ASONs and small molecules, particularly sorafenib (BAY 43-9006).

Double-Blind Randomized Phase II Study of the Combination of Sorafenib and Dacarbazine in Patients With Advanced Melanoma: A Report From the 11715 Study Group

PURPOSE This phase II study evaluated the efficacy and safety of sorafenib plus dacarbazine in patients with advanced melanoma. PATIENTS AND METHODS This randomized, double-blind, placebo-controlled, multicenter study enrolled chemotherapy-naive patients with stage III (unresectable) or IV melanoma. A total of 101 patients received placebo plus dacarbazine (n = 50) or sorafenib plus dacarbazine (n = 51). On day 1 of a 21-day cycle, patients received intravenous dacarbazine 1,000 mg/m(2) for a maximum of 16 cycles. Oral sorafenib 400 mg or placebo was administered twice a day continuously. The primary end point was progression-free survival (PFS) by independent assessment. Secondary and tertiary end points included time to progression (TTP), response rate, and overall survival (OS). RESULTS Median PFS in the sorafenib plus dacarbazine arm was 21.1 weeks versus 11.7 weeks in the placebo plus dacarbazine arm (hazard ratio [HR], 0.665; P = .068). There were statistically significant improvements in PFS rates at 6 and 9 months, and in TTP (median, 21.1 v 11.7 weeks; HR, 0.619) in favor of the sorafenib plus dacarbazine arm. No difference in OS was observed (median, 51.3 v 45.6 weeks in the placebo plus dacarbazine and sorafenib plus dacarbazine arms, respectively; HR, 1.022). The regimen was well tolerated and had a manageable toxicity profile. CONCLUSION Sorafenib plus dacarbazine was well tolerated in patients with advanced melanoma and yielded an encouraging improvement in PFS. Based on these findings, additional studies with the combination are warranted in this patient population.

Efficacy and Safety of Abemaciclib, an Inhibitor of CDK4 and CDK6, for Patients with Breast Cancer, Non-Small Cell Lung Cancer, and Other Solid Tumors.

UNLABELLED We evaluated the safety, pharmacokinetic profile, pharmacodynamic effects, and antitumor activity of abemaciclib, an orally bioavailable inhibitor of cyclin-dependent kinases (CDK) 4 and 6, in a multicenter study including phase I dose escalation followed by tumor-specific cohorts for breast cancer, non-small cell lung cancer (NSCLC), glioblastoma, melanoma, and colorectal cancer. A total of 225 patients were enrolled: 33 in dose escalation and 192 in tumor-specific cohorts. Dose-limiting toxicity was grade 3 fatigue. The maximum tolerated dose was 200 mg every 12 hours. The most common possibly related treatment-emergent adverse events involved fatigue and the gastrointestinal, renal, or hematopoietic systems. Plasma concentrations increased with dose, and pharmacodynamic effects were observed in proliferating keratinocytes and tumors. Radiographic responses were achieved in previously treated patients with breast cancer, NSCLC, and melanoma. For hormone receptor-positive breast cancer, the overall response rate was 31%; moreover, 61% of patients achieved either response or stable disease lasting ≥6 months. SIGNIFICANCE Abemaciclib represents the first selective inhibitor of CDK4 and CDK6 with a safety profile allowing continuous dosing to achieve sustained target inhibition. This first-in-human experience demonstrates single-agent activity for patients with advanced breast cancer, NSCLC, and other solid tumors. Cancer Discov; 6(7); 740-53. ©2016 AACR.See related commentary by Lim et al., p. 697This article is highlighted in the In This Issue feature, p. 681.

A phase 1 study of weekly dosing of trastuzumab emtansine (T-DM1) in patients with advanced human epidermal growth factor 2–positive breast cancer†‡

We conducted a phase 1, multicenter, open‐label, dose‐escalation study (TDM3569g) to assess the safety, tolerability, and pharmacokinetics of single‐agent trastuzumab emtansine (T‐DM1) administered weekly and once every 3 weeks in patients with HER2‐positive metastatic breast cancer previously treated with trastuzumab. The weekly dose results are described here.

Clinical Implications of Pathophysiological and Demographic Covariates on the Population Pharmacokinetics of Trastuzumab Emtansine, a HER2‐Targeted Antibody‐Drug Conjugate, in Patients With HER2‐Positive Metastatic Breast Cancer

Trastuzumab emtansine (T‐DM1) is a HER2‐targeted antibody‐drug conjugate in development for treatment of HER2‐positive cancers. T‐DM1 has been tested as a single agent in a phase I and 2 phase II studies of patients with heavily pretreated metastatic breast cancer (MBC), with the maximum tolerated dose established at 3.6 mg/kg intravenously for every‐3‐week dosing. The authors present results from the population pharmacokinetics analysis for T‐DM1. Population pharmacokinetics for T‐DM1 were characterized using a clinical database of 273 patients from the 3 studies. Pharmacokinetics was best described by a linear 2‐compartment model. Population estimates (interindividual variability [IIV]) for pharmacokinetic parameters were clearance, 0.7 L/d (21.0%); central compartment volume (Vc), 3.33 L (13.2%); peripheral compartment volume (Vp), 0.89 L (50.4%); and intercompartmental clearance, 0.78 L/d. Body weight, albumin, tumor burden, and aspartate aminotransferase levels were identified as statistically significant covariates accounting for interindividual variability in T‐DM1 pharmacokinetics, with body weight having a greater effect on IIV of clearance and Vc than other covariates. T‐DM1 exposure was relatively consistent across the weight range following body weight‐based dosing. This analysis suggests no further T‐DM1 dose adjustments are necessary in heavily pretreated patients with MBC.

Phase I and Pharmacokinetic Study of Pemetrexed with High-Dose Folic Acid Supplementation or Multivitamin Supplementation in Patients with Locally Advanced or Metastatic Cancer

Purpose: This phase I study evaluated the effect of folate supplementation on the toxicity, tolerability, and pharmacokinetics of pemetrexed in patients with locally advanced or metastatic cancer. It also examined two different types of vitamin supplementation and whether the extent of prior myelosuppressive therapy affected pemetrexed tolerability. Patients and Methods: Patients received a 10-min infusion of 600 to 14,00 mg/m2 pemetrexed every 3 weeks. Patients were stratified into cohorts by pretreatment status [lightly pretreated (LPT) or heavily pretreated (HPT)] and were supplemented with intermittent high-dose folic acid (HDFA) or with continuous daily multivitamins (MVI) containing nutritional doses of folic acid. Pemetrexed plasma pharmacokinetics were evaluated for cycle 1. Results: Sixty-two HDFA patients (28 HPT and 34 LPT) were treated with 204 cycles of pemetrexed, and 43 MVI patients (20 HPT and 23 LPT) were treated with 182 cycles. Hematologic dose-limiting toxicities included grade 4 neutropenia (5 of 105 patients), grade 4 thrombocytopenia (4 of 105 patients), and febrile neutropenia (3 of 105 patients). Nonhematologic toxicities included fatigue, vomiting, diarrhea, and nausea. Pemetrexed doses of 800 and 1,050 mg/m2 were well tolerated when administered with vitamin supplementation to HPT and LPT patients, respectively. There were no clinically relevant differences in toxicities or pemetrexed pharmacokinetics for LPT versus HPT patients or for patients receiving HDFA versus daily MVI supplementation. Conclusions: The pemetrexed doses tolerated in this study with vitamin supplementation were significantly higher than those tolerated in earlier studies without supplementation, and toxicities were independent of the type of vitamin supplementation or prior myelosuppressive treatment. The recommended dose of pemetrexed is 1,050 mg/m2 in LPT patients and 800 mg/m2 in HPT patients, irrespective of the type of vitamin supplementation.

Abstract CT232: Clinical activity of LY2835219, a novel cell cycle inhibitor selective for CDK4 and CDK6, in patients with metastatic breast cancer

LY2835219 is a novel cell cycle inhibitor selective for the cyclin-dependent kinases CDK4 and CDK6 (CDK4/6), which act in a protein complex with D-type cyclins to enable G1 to S cell cycle progression. Preclinical models indicate this complex plays a critical role in breast cancer. We conducted a phase I study with expansion cohorts to evaluate the safety, pharmacokinetics, and antitumor activity of LY2835219 in 5 different tumor types: glioblastoma; melanoma; and cancers of the lung, colon/rectum and breast. In the expansion cohorts, LY2835219 was administered continuously at 150-200mg orally every 12 hours on Days 1-28 of a 28-day cycle. RECIST v1.1 was used to assess tumor response. The most common possibly related treatment-emergent adverse events across the expansion cohorts (n=132) included diarrhea (5% G3/4), nausea (3% G3/4), fatigue (2% G3/4), vomiting (2% G3/4) and neutropenia (11% G3/4). In the metastatic breast cancer (MBC) cohort, 47 patients with a median of 7 prior systemic regimens received therapy with LY2835219. Across all MBC patients, 9 achieved a best overall response of confirmed partial response (PR), 24 achieved stable disease (SD), 11 had progressive disease (PD), and 3 were not evaluable for response. Among the 36 HR+ patients, there were 9 confirmed partial responses for an ORR of 25%. In addition, 20 of these 36 HR+ patients (56%) had SD: 7 patients had SD Citation Format: Amita Patnaik, Lee S. Rosen, Sara M. Tolaney, Anthony W. Tolcher, Jonathan W. Goldman, Leena Gandhi, Kyriakos P. Papadopoulos, Muralidhar Beeram, Drew W. Rasco, Scott P. Myrand, Palaniappan Kulanthaivel, Lily Li, Martin Frenzel, Damien M. Cronier, Edward M. Chan, Keith T. Flaherty, Patrick Y. Wen, Geoffrey I. Shapiro. Clinical activity of LY2835219, a novel cell cycle inhibitor selective for CDK4 and CDK6, in patients with metastatic breast cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr CT232. doi:10.1158/1538-7445.AM2014-CT232