Robert Justice

FDA Approval: Ado-trastuzumab Emtansine for the Treatment of Patients with HER2-Positive Metastatic Breast Cancer

On February 22, 2013, the FDA licensed ado-trastuzumab emtansine (Kadcyla; Genentech, Inc.) for use as a single agent for the treatment of patients with human epidermal growth factor receptor 2 (HER2)–positive metastatic breast cancer (MBC) who previously received trastuzumab and a taxane, separately or in combination. The clinical basis for licensure was a phase III trial in 991 patients with HER2-positive MBC that randomly allocated patients to receive ado-trastuzumab emtansine (n = 495) or lapatinib in combination with capecitabine (n = 496). The coprimary endpoints were progression-free survival (PFS) based on tumor assessments by an independent review committee and overall survival (OS). Statistically significant improvements in PFS and OS were observed in patients receiving ado-trastuzumab emtansine compared with patients receiving lapatinib plus capecitabine [difference in PFS medians of 3.2 months, HR, 0.65 (95% confidence interval, CI, 0.55–0.77), P < 0.0001 and difference in OS medians of 5.8 months, HR, 0.68 (95% CI, 0.55–0.85), P = 0.0006]. The most common adverse reactions in patients receiving ado-trastuzumab emtansine were fatigue, nausea, musculoskeletal pain, thrombocytopenia, headache, increased aminotransferase levels, and constipation. Other significant adverse reactions included hepatobiliary disorders and left ventricular dysfunction. Given the PFS and OS results, the benefit–risk profile was considered favorable. Clin Cancer Res; 20(17); 4436–41. ©2014 AACR.

FDA Approval Summary: Crizotinib for the Treatment of Metastatic Non-Small Cell Lung Cancer With Anaplastic Lymphoma Kinase Rearrangements

On August 26, 2011, crizotinib received accelerated approval for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) that is ALK-positive as detected by a test approved by the U.S. Food and Drug Administration (FDA). Approval was based on two single-arm trials demonstrating objective response rates (ORRs) of 50% and 61% and median response durations of 42 and 48 weeks. On November 20, 2013, crizotinib received regular approval based on confirmation of clinical benefit in study A8081007, a randomized trial in 347 patients with ALK-positive advanced NSCLC who had previously received one platinum-containing regimen. Patients were assigned (1:1) to receive crizotinib 250 mg orally twice daily or standard of care (docetaxel or pemetrexed). The primary endpoint was progression-free survival (PFS) determined by independent radiology review; secondary endpoints were ORR and overall survival (OS). PFS was significantly longer in the crizotinib arm, with median PFS of 7.7 and 3.0 months in the crizotinib and chemotherapy arms, respectively, and a 46% absolute increase in ORR but no difference in OS between treatment arms at the interim analysis. The most common adverse drug reactions (>25%) in crizotinib-treated patients were vision disorders, nausea, diarrhea, vomiting, constipation, edema, elevated transaminases, and fatigue. The most serious toxicities of crizotinib were hepatotoxicity, interstitial lung disease or pneumonitis, and QT-interval prolongation. Crizotinibs rapid clinical development program (6 years from identification of ALK rearrangements in a subset of NSCLC to full FDA approval) is a model of efficient drug development in this new era of molecularly targeted oncology therapy.

First FDA Approval of Neoadjuvant Therapy for Breast Cancer: Pertuzumab for the Treatment of Patients with HER2-Positive Breast Cancer

On September 30, 2013, the FDA granted accelerated approval to pertuzumab (Perjecta; Genentech, Inc.) for use in combination with trastuzumab and docetaxel as neoadjuvant treatment of patients with HER2-positive, locally advanced, inflammatory, or early-stage breast cancer (either greater than 2 cm in diameter or node positive) as part of a complete treatment regimen for early breast cancer. The approval was based in part on a randomized multicenter trial in the indicated population that allocated 417 patients to neoadjuvant treatment with trastuzumab–docetaxel (TD), pertuzumab–trastuzumab–docetaxel (PTD), pertuzumab–trastuzumab, or pertuzumab–docetaxel. PTD was administered preoperatively every 3 weeks for four cycles. Following surgery patients received three cycles of 5-fluorouracil, epirubicin, and cyclophosphamide every 3 weeks and trastuzumab every 3 weeks to complete 1 year of therapy. The pathologic complete response rates by the FDA-preferred definition [absence of invasive cancer in the breast and lymph nodes (ypT0/is ypN0)] were 39.3% and 21.5% in the PTD and the TD arms, respectively (P = 0.0063). The most common adverse reactions with PTD were alopecia, diarrhea, nausea, and neutropenia. This approval was based on the totality of evidence, particularly improved survival in the metastatic breast cancer trial, and a fully accrued confirmatory trial. Clin Cancer Res; 20(21); 5359–64. ©2014 AACR.

FDA Approval Summary: Vemurafenib for Treatment of Unresectable or Metastatic Melanoma with the BRAFV600E Mutation

On August 17, 2011, the U.S. Food and Drug Administration (FDA) approved vemurafenib tablets (Zelboraf, Hoffmann-LaRoche Inc.) for the treatment of patients with unresectable or metastatic melanoma with the BRAFV600E mutation as detected by an FDA-approved test. The cobas 4800 BRAF V600 Mutation Test (Roche Molecular Systems, Inc.) was approved concurrently. An international, multicenter, randomized, open-label trial in 675 previously untreated patients with BRAFV600E mutation–positive unresectable or metastatic melanoma allocated 337 patients to receive vemurafenib, 960 mg orally twice daily, and 338 patients to receive dacarbazine, 1,000 mg/m2 intravenously every 3 weeks. Overall survival was significantly improved in patients receiving vemurafenib [HR, 0.44; 95% confidence interval (CI), 0.33–0.59; P < 0.0001]. Progression-free survival was also significantly improved in patients receiving vemurafenib (HR, 0.26; 95% CI, 0.20–0.33; P < 0.0001). Overall response rates were 48.4% and 5.5% in the vemurafenib and dacarbazine arms, respectively. The most common adverse reactions (≥30%) in patients treated with vemurafenib were arthralgia, rash, alopecia, fatigue, photosensitivity reaction, and nausea. Cutaneous squamous cell carcinomas or keratoacanthomas were detected in approximately 24% of patients treated with vemurafenib. Other adverse reactions included hypersensitivity, Stevens–Johnson syndrome, toxic epidermal necrolysis, uveitis, QT prolongation, and liver enzyme laboratory abnormalities. Clin Cancer Res; 20(19); 4994–5000. ©2014 AACR.

U.S. Food and Drug Administration Approval Summary: Erlotinib for the First-Line Treatment of Metastatic Non-Small Cell Lung Cancer With Epidermal Growth Factor Receptor Exon 19 Deletions or Exon 21 (L858R) Substitution Mutations

On May 14, 2013, the U.S. Food and Drug Administration approved erlotinib (Tarceva, Astellas Pharma Inc., Northbrook, IL, http://www.us.astellas.com/) for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations. This indication for erlotinib was approved concurrently with the cobas EGFR Mutation Test (Roche Molecular Systems, Inc., Basel, Switzerland, http://www.molecular.roche.com), a companion diagnostic test for patient selection. The approval was based on clinically important improvements in progression-free survival (PFS) and objective response rate (ORR) and an acceptable toxicity profile demonstrated in a multicenter, open label trial enrolling 174 patients with metastatic NSCLC whose tumors had EGFR mutations as determined by a laboratory-developed test. Patients were randomized (1:1) to receive erlotinib (150 mg/day) or platinum-based doublet chemotherapy. The primary endpoint was investigator-assessed PFS. Secondary endpoints included overall survival (OS) and ORR. Superior PFS (hazard ratio [HR] 0.34; 95% confidence interval [CI]: 0.23, 0.49; p < .001) and ORR (65% vs. 16%) were observed in the erlotinib arm. Median PFS was 10.4 months and 5.2 months in the erlotinib and chemotherapy arms, respectively. There was no difference in OS (HR 0.93; 95% CI: 0.64, 1.35) with median OS of 22.9 months and 19.5 months in the erlotinib and chemotherapy arms, respectively. The most frequent (≥30%) adverse reactions in the erlotinib-treated patients were rash, diarrhea, asthenia, cough, dyspnea, and decreased appetite. The most frequent (≥5%) grade 3 and 4 adverse reactions were rash and diarrhea.

FDA Approval Summary: Sunitinib for the Treatment of Progressive Well-Differentiated Locally Advanced or Metastatic Pancreatic Neuroendocrine Tumors

On May 20, 2011, the U.S. Food and Drug Administration (FDA) approved sunitinib malate capsules (Sutent®; Pfizer, Inc., New York) for the treatment of progressive, well-differentiated pancreatic neuroendocrine tumors (pNETs) in patients with unresectable locally advanced or metastatic disease. In a phase III randomized trial, 171 patients received either sunitinib (37.5 mg) or placebo once daily. The progression-free survival (PFS) interval was the primary efficacy endpoint. Secondary endpoints included the overall survival (OS) time, objective response rate (ORR), patient-reported outcomes, and safety. Based on early results favoring sunitinib, the independent data monitoring committee recommended trial termination prior to the prespecified interim analysis. This premature analysis may have led to an overestimate of the treatment effect. In the FDA analysis of investigator-assessed PFS times, the median values for the sunitinib and placebo arms were 10.2 months and 5.4 months, respectively. The ORRs were 9.3% and 0% in the sunitinib and placebo arms, respectively. The OS data were not mature at the time of approval and were confounded by 69% crossover. Common adverse reactions in patients receiving sunitinib included diarrhea, nausea, asthenia, fatigue, neutropenia, hypertension, and palmar-plantar erythrodysesthesia syndrome. Two patients on sunitinib died as a result of cardiac failure. The Oncologic Drugs Advisory Committee voted eight to two that, despite residual uncertainty about the magnitude of the PFS effect because of early trial termination, sunitinib demonstrated a favorable benefit-risk profile in pNET patients. The FDA concurred with the committees assessment and granted sunitinib regular approval for this rare malignancy with few available therapies.

First FDA Approval of Dual Anti-HER2 Regimen: Pertuzumab in Combination with Trastuzumab and Docetaxel for HER2-Positive Metastatic Breast Cancer

On June 8, 2012, the U.S. Food and Drug Administration (FDA) approved pertuzumab (Perjeta, Genentech) for use in combination with trastuzumab (Herceptin, Genentech) and docetaxel for the treatment of patients with HER2-positive metastatic breast cancer (MBC) who have not received prior anti-HER2 therapy or chemotherapy for metastatic disease. Approval was based on the results of a randomized, double-blind, placebo-controlled trial conducted in 808 patients with HER2-positive MBC. Patients were randomized (1:1) to receive pertuzumab (n = 402) or placebo (n = 406) in combination with trastuzumab and docetaxel. The primary endpoint was progression-free survival (PFS) and a key secondary endpoint was overall survival (OS). A statistically significant improvement in PFS (difference in medians of 6.1 months) was observed in patients receiving pertuzumab [HR, 0.62; 95% confidence interval (CI), 0.51–0.75; P < 0.0001]. A planned interim analysis suggested an improvement in OS (HR, 0.64; 95% CI, 0.47–0.88; P = 0.0053) but the HR and P value did not cross the stopping boundary. Common adverse reactions (>30%) observed in patients on the pertuzumab arm included diarrhea, alopecia, neutropenia, nausea, fatigue, rash, and peripheral neuropathy. No additive cardiac toxicity was observed. Significant manufacturing issues were identified during the review. On the basis of substantial evidence of efficacy for pertuzumab in MBC and the compelling public health need, FDA did not delay availability to patients pending final resolution of all manufacturing concerns. Therefore, FDA approved pertuzumab but limited its approval to lots not affected by manufacturing problems. The applicant agreed to multiple manufacturing and testing postmarketing commitments under third-party oversight to resolve manufacturing issues. Clin Cancer Res; 19(18); 4911–6. ©2013 AACR.

FDA Approval: Idelalisib Monotherapy for the Treatment of Patients with Follicular Lymphoma and Small Lymphocytic Lymphoma

On July 23, 2014, the FDA granted accelerated approval to idelalisib (Zydelig tablets; Gilead Sciences, Inc.) for the treatment of patients with relapsed follicular B-cell non–Hodgkin lymphoma or relapsed small lymphocytic lymphoma (SLL) who have received at least two prior systemic therapies. In a multicenter, single-arm trial, 123 patients with relapsed indolent non–Hodgkin lymphomas received idelalisib, 150 mg orally twice daily. In patients with follicular lymphoma, the overall response rate (ORR) was 54%, and the median duration of response (DOR) was not evaluable; median follow-up was 8.1 months. In patients with SLL, the ORR was 58% and the median DOR was 11.9 months. One-half of patients experienced a serious adverse reaction of pneumonia, pyrexia, sepsis, febrile neutropenia, diarrhea, or pneumonitis. Other common adverse reactions were abdominal pain, nausea, fatigue, cough, dyspnea, and rash. Common treatment-emergent laboratory abnormalities were elevations in alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, absolute lymphocytes, and triglycerides. Continued approval may be contingent upon verification of clinical benefit in confirmatory trials. Clin Cancer Res; 21(7); 1525–9. ©2015 AACR. See related article by Gandhi et al., p. 1537

FDA Approval: Ibrutinib for Patients with Previously Treated Mantle Cell Lymphoma and Previously Treated Chronic Lymphocytic Leukemia

On November 13, 2013, the FDA granted accelerated approval to ibrutinib (IMBRUVICA capsules; Pharmacyclics, Inc.) for the treatment of patients with mantle cell lymphoma (MCL) who have received at least one prior therapy. On February 12, 2014, the FDA granted accelerated approval for the treatment of patients with chronic lymphocytic leukemia (CLL) who have received at least one prior therapy. Ibrutinib is a first-in-class Brutons tyrosine kinase (BTK) inhibitor that received all four expedited programs of the FDA: Fast-Track designation, Breakthrough Therapy designation, Priority Review, and Accelerated Approval. Both approvals were based on overall response rate (ORR) and duration of response (DOR) in single-arm clinical trials in patients with prior treatment. In MCL (N = 111), the complete and partial response rates were 17.1% and 48.6%, respectively, for an ORR of 65.8% [95% confidence interval (CI), 56.2%–74.5%]. The median DOR was 17.5 months (95% CI, 15.8–not reached). In CLL (N = 48), the ORR was 58.3% (95% CI, 43.2%–72.4%), and the DOR ranged from 5.6 to 24.2 months. The most common adverse reactions (≥30% in either trial) were thrombocytopenia, diarrhea, neutropenia, bruising, upper respiratory tract infection, anemia, fatigue, musculoskeletal pain, peripheral edema, and nausea. Clin Cancer Res; 21(16); 3586–90. ©2015 AACR.

Approval Summary: Imatinib Mesylate in the Treatment of Metastatic and/or Unresectable Malignant Gastrointestinal Stromal Tumors

The purpose of the present application was to fulfill a postmarketing commitment to provide long-term efficacy and safety data on treatment with imatinib mesylate (Gleevec; Novartis Pharmaceuticals, East Hanover, NJ) in patients with CD117(+) unresectable and/or metastatic malignant gastrointestinal stromal tumors (GISTs). In addition, this application also provides evidence to support a change in the label to allow for an escalation of imatinib dosing to 800 mg/day for patients with progressive disease on a lower dose. Two open-label, controlled, multicenter, intergroup, international, randomized phase III studies were submitted -- one conducted by the European Organization for Research and Treatment of Cancer (n = 946) and the other by the Southwest Oncology Group (n = 746). These studies compared 400 mg/day of imatinib with 800 mg/day of imatinib. A combined analysis of the two studies was prospectively defined and agreed to by both groups. Both protocols allowed patients randomized to the 400-mg/day imatinib arm to cross over to 800 mg/day imatinib at progression. Objective responses were achieved in >50% of patients receiving either imatinib dose. The median progression-free survival time was approximately 20 months and the median overall survival (OS) time was approximately 49 months. In the combined analysis, 347 patients crossed over to 800 mg/day imatinib at the time of progression. The median OS time after crossover was 14.3 months. The most common adverse events (AEs) were fluid retention, nausea, fatigue, skin rash, gastrointestinal complaints, and myalgia. The most common laboratory abnormality was anemia. Most often the AEs were of mild-to-moderate severity. Fluid retention events and skin rash were numerically reported more often in the 800-mg/day treatment cohort of patients.