Josina C. Reddy

Inhibition of the hedgehog pathway in advanced basal-cell carcinoma.

BACKGROUND Mutations in hedgehog pathway genes, primarily genes encoding patched homologue 1 (PTCH1) and smoothened homologue (SMO), occur in basal-cell carcinoma. In a phase 1 clinical trial, we assessed the safety and pharmacokinetics of GDC-0449, a small-molecule inhibitor of SMO, and responses of metastatic or locally advanced basal-cell carcinoma to the drug. METHODS We selected 33 patients with metastatic or locally advanced basal-cell carcinoma to receive oral GDC-0449 at one of three doses; 17 patients received 150 mg per day, 15 patients received 270 mg per day, and 1 patient received 540 mg per day. We assessed tumor responses with the use of Response Evaluation Criteria in Solid Tumors (RECIST), physical examination, or both. Molecular aspects of the tumors were examined. RESULTS The median duration of the study treatment was 9.8 months. Of the 33 patients, 18 had an objective response to GDC-0449, according to assessment on imaging (7 patients), physical examination (10 patients), or both (1 patient). Of the patients who had a response, 2 had a complete response and 16 had a partial response. The other 15 patients had either stable disease (11 patients) or progressive disease (4 patients). Eight grade 3 adverse events that were deemed to be possibly related to the study drug were reported in six patients, including four with fatigue, two with hyponatremia, one with muscle spasm, and one with atrial fibrillation. One grade 4 event, asymptomatic hyponatremia, was judged to be unrelated to GDC-0449. One patient withdrew from the study because of adverse events. We found evidence of hedgehog signaling in tumors that responded to the treatment. CONCLUSIONS GDC-0449, an orally active small molecule that targets the hedgehog pathway, appears to have antitumor activity in locally advanced or metastatic basal-cell carcinoma. (ClinicalTrials.gov number, NCT00607724.)

Efficacy and Safety of Vismodegib in Advanced Basal-Cell Carcinoma

BACKGROUND Alterations in hedgehog signaling are implicated in the pathogenesis of basal-cell carcinoma. Although most basal-cell carcinomas are treated surgically, no effective therapy exists for locally advanced or metastatic basal-cell carcinoma. A phase 1 study of vismodegib (GDC-0449), a first-in-class, small-molecule inhibitor of the hedgehog pathway, showed a 58% response rate among patients with advanced basal-cell carcinoma. METHODS In this multicenter, international, two-cohort, nonrandomized study, we enrolled patients with metastatic basal-cell carcinoma and those with locally advanced basal-cell carcinoma who had inoperable disease or for whom surgery was inappropriate (because of multiple recurrences and a low likelihood of surgical cure, or substantial anticipated disfigurement). All patients received 150 mg of oral vismodegib daily. The primary end point was the independently assessed objective response rate; the primary hypotheses were that the response rate would be greater than 20% for patients with locally advanced basal-cell carcinoma and greater than 10% for those with metastatic basal-cell carcinoma. RESULTS In 33 patients with metastatic basal-cell carcinoma, the independently assessed response rate was 30% (95% confidence interval [CI], 16 to 48; P=0.001). In 63 patients with locally advanced basal-cell carcinoma, the independently assessed response rate was 43% (95% CI, 31 to 56; P<0.001), with complete responses in 13 patients (21%). The median duration of response was 7.6 months in both cohorts. Adverse events occurring in more than 30% of patients were muscle spasms, alopecia, dysgeusia (taste disturbance), weight loss, and fatigue. Serious adverse events were reported in 25% of patients; seven deaths due to adverse events were noted. CONCLUSIONS Vismodegib is associated with tumor responses in patients with locally advanced or metastatic basal-cell carcinoma. (Funded by Genentech; Erivance BCC ClinicalTrials.gov number, NCT00833417.).

Phase I Trial of Hedgehog Pathway Inhibitor Vismodegib (GDC-0449) in Patients with Refractory, Locally Advanced or Metastatic Solid Tumors

Purpose: The hedgehog (Hh) signaling pathway, a key regulator of cell growth and differentiation during development is implicated in pathogenesis of certain cancers. Vismodegib (GDC-0449) is a small-molecule inhibitor of smoothened, a key component of Hh signaling. This phase I trial assessed GDC-0449 treatment in patients with solid tumors refractory to current therapies or for which no standard therapy existed. Experimental Design: Sixty-eight patients received GDC-0449 at 150 mg/d (n = 41), 270 mg/d (n = 23), or 540 mg/d (n = 4). Adverse events, tumor responses, pharmacokinetics, and pharmacodynamic down-modulation of GLI1 expression in noninvolved skin were assessed. Results: Thirty-three of 68 patients had advanced basal cell carcinoma (BCC), 8 had pancreatic cancer, 1 had medulloblastoma; 17 other types of cancer were also represented. GDC-0449 was generally well-tolerated. Six patients (8.8%) experienced 7 grade 4 events (hyponatremia, fatigue, pyelonephritis, presyncope, resectable pancreatic adenocarcinoma, and paranoia with hyperglycemia), and 27.9% of patients experienced a grade 3 event [most commonly hyponatremia (10.3%), abdominal pain (7.4%), and fatigue (5.9%)]. No maximum tolerated dose was reached. The recommended phase II dose was 150 mg/d, based on achievement of maximal plasma concentration and pharmacodynamic response at this dose. Tumor responses were observed in 20 patients (19 with BCC and 1 unconfirmed response in medulloblastoma), 14 patients had stable disease as best response, and 28 had progressive disease. Evidence of GLI1 down-modulation was observed in noninvolved skin. Conclusions: GDC-0449 has an acceptable safety profile and encouraging anti-tumor activity in advanced BCC and medulloblastoma. Further study in these and other cancer types is warranted. Clin Cancer Res; 17(8); 2502–11. ©2011 AACR.

Pharmacokinetics of Hedgehog Pathway Inhibitor Vismodegib (GDC-0449) in Patients with Locally Advanced or Metastatic Solid Tumors: the Role of Alpha-1-Acid Glycoprotein Binding

Purpose: In a phase I trial for patients with refractory solid tumors, hedgehog pathway inhibitor vismodegib (GDC-0449) showed little decline in plasma concentrations over 7 days after a single oral dose and nonlinearity with respect to dose and time after single and multiple dosing. We studied the role of GDC-0449 binding to plasma protein alpha-1-acid glycoprotein (AAG) to better understand these unusual pharmacokinetics. Experimental Design: Sixty-eight patients received GDC-0449 at 150 (n = 41), 270 (n = 23), or 540 (n = 4) mg/d, with pharmacokinetic (PK) sampling at multiple time points. Total and unbound (dialyzed) GDC-0449 plasma concentrations were assessed by liquid chromatography/tandem mass spectrometry, binding kinetics by surface plasmon resonance–based microsensor, and AAG levels by ELISA. Results: A linear relationship between total GDC-0449 and AAG plasma concentrations was observed across dose groups (R2 = 0.73). In several patients, GDC-0449 levels varied with fluctuations in AAG levels over time. Steady-state, unbound GDC-0449 levels were less than 1% of total, independent of dose or total plasma concentration. In vitro, GDC-0449 binds AAG strongly and reversibly (KD = 13 μmol/L) and human serum albumin less strongly (KD = 120 μmol/L). Simulations from a derived mechanistic PK model suggest that GDC-0449 pharmacokinetics are mediated by AAG binding, solubility-limited absorption, and slow metabolic elimination. Conclusions: GDC-0449 levels strongly correlated with AAG levels, showing parallel fluctuations of AAG and total drug over time and consistently low, unbound drug levels, different from previously reported AAG-binding drugs. This PK profile is due to high-affinity, reversible binding to AAG and binding to albumin, in addition to solubility-limited absorption and slow metabolic elimination properties. Clin Cancer Res; 17(8); 2512–20. ©2011 AACR.

A Phase II, Randomized, Placebo-Controlled Study of Vismodegib as Maintenance Therapy in Patients with Ovarian Cancer in Second or Third Complete Remission

Purpose: Hedgehog pathway inhibition has been suggested as a potential maintenance treatment approach in ovarian cancer through disruption of tumor–stromal interactions. Vismodegib is an orally available Hedgehog pathway inhibitor with clinical activity in advanced basal cell carcinoma and medulloblastoma. This phase II, randomized, double-blind, placebo-controlled trial was designed to provide a preliminary estimate of efficacy in patients with ovarian cancer in second or third complete remission (CR). Experimental Design: Patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer in second or third CR were randomized 1:1 to vismodegib (GDC-0449; 150 mg daily) or placebo three to 14 weeks after completing chemotherapy. Treatment continued until radiographic progression or toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS). Results: One hundred four patients were randomized to vismodegib (n = 52) or placebo (n = 52); median PFS was 7.5 months and 5.8 months, respectively [HR 0.79; 95% confidence interval (CI), 0.46–1.35]. The HR was 0.66 (95% CI, 0.36–1.20) for second CR patients (n = 84) and 1.79 (95% CI, 0.50–6.48) for third CR patients (n = 20). The most common adverse events in the vismodegib arm were dysgeusia/ageusia, muscle spasms, and alopecia. Grade 3/4 adverse events occurred in 12 patients (23.1%) with vismodegib and six (11.5%) with placebo. Hedgehog expression was detected in 13.5% of archival tissues. Conclusions: In this study, the sought magnitude of increase in PFS was not achieved for vismodegib maintenance versus placebo in patients with ovarian cancer in second or third CR. The frequency of Hedgehog ligand expression was lower than expected. Clin Cancer Res; 18(23); 6509–18. ©2012 AACR.

Efficacy of Trastuzumab

To the Editor: We read with interest the article by Adams et al. [(1)][1], which describes the efficacy of an yttrium-90-labeled anti-HER2 diabody in a mouse xenograft model of HER2-positive breast cancer. Women with HER2-positive breast cancer have a distinctly worse prognosis than those whose

Abstract A44: Predictive biomarkers of efficacy to the hedgehog pathway inhibitor, GDC‐0449, in advanced basal cell carcinoma and medulloblastoma in phase I studies

The Hedgehog (Hh) signaling pathway has been directly implicated in the pathogenesis of basal cell carcinoma (BCC) and medulloblastoma (MB). Constitutive Hh signaling, most often due to underlying loss of function mutations in the inhibitory receptor Patched1 (PTCH1), has been demonstrated in a majority of common localized BCCs and approximately 25–30% of sporadic MB cases. In this study, we examined molecular correlatives of clinical efficacy in locally‐advanced / metastatic BCC and MB patients treated with GDC‐0449, an inhibitor of the Hh pathway that targets the serpentine receptor Smoothened (SMO). An analysis of Hh pathway transcriptional target gene expression in archival tissue biopsies provided evidence for active Hh signaling in patients exhibiting clinical benefit (objective response or disease stabilization) on therapy. This was further supported by the identification of either loss of function or activating mutations in PTCH1 or SMO, respectively. We were unable to provide evidence for active Hh signaling in 2 patients with progressive disease as best response, potentially underlying the reason for lack of efficacy in these patients. In addition to providing molecular support for Hh pathway activity in patients exhibiting treatment benefit, this is the first evidence for Hh pathway dysregulation in the previously uncharacterized, advanced BCC setting. Furthermore, the results begin to support the utility of transcriptional‐based tests as a strategy to potentially select the subset of MB patients with Hh‐driven disease that would likely benefit on GDC‐0449. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):A44.