A Phase II First-Line Study of Gemcitabine, Carboplatin, and Bevacizumab in Advanced Stage Non-squamous Non-small Cell Lung Cancer

Abstract

Background

Bevacizumab improves responses and progression-free survival when added to first-line paclitaxel/carboplatin or cisplatin/gemcitabine for patients with advanced nonsquamous non-small cell lung cancer. This study was designed to evaluate toxicities and efficacy of gemcitabine/carboplatin/bevacizumab.

Methods

Patients with untreated advanced nonsquamous non-small cell lung cancer, with no evidence of brain metastases and not on anticoagulation were eligible. Patients received gemcitabine 1000 mg/m² on days 1 and 8; carboplatin area under the curve 5 day 1; and bevacizumab 15 mg/kg day 1 every 3 weeks for up to six cycles. Bevacizumab was then continued every 3 weeks until disease progression or unacceptable toxicity.

Results

From July 2006 to December 2008, 48 patients were enrolled: 23 (48%) men, 25 (52%) women, and 19 (40%) never smokers. One patient never received therapy and is not included in the analysis. Median cycle number was 8 (1– 42) with 37 patients (78.7%) completing ≥4 cycles of three drugs. Dose reductions occurred in 34 (72.3%) patients. Grade 3/4 toxicities included neutropenia (47%/15%), thrombocytopenia (11%/15%), anemia (6%/0%), dyspnea (6%/2%), bacterial pneumonia (4%/0%), and hypertension (4%/2%). No neutropenic fevers occurred. One patient died of hemoptysis. Grade 3 bleeding occurred in three other patients. There were seven (14.9%) partial responses. Median time to first event (progression/death/toxicity requiring discontinuation) was 6.4 months (95% confidence interval: 4.8 –7.9 months). The median overall survival (OS) was 12.8 months (95% confidence interval: 10.0 –16.5). The OS is 57% at 1 year and 10% at 2 years.

Conclusions

Although perhaps skewed by a high proportion of nonsmokers and women, treatment with gemcitabine/carboplatin/bevacizumab has an acceptable toxicity profile with promising median OS despite a low response rate.

Lung cancer is the leading cause of cancer-related death in the United States, with an estimated 219,440 new cases and 159,390-related deaths in 2009.¹ Despite advances in treatment, nearly 80% of lung cancer cases are diagnosed at advanced stages (IIIB or IV), and the 5-year survival rate has not exceeded 15%.^1,2 Meta-analyses have definitively shown that the use of palliative chemotherapy with supportive care improves survival compared with supportive care alone in patients with advanced non-small cell lung cancer (NSCLC).³ Schiller et al. compared three chemotherapy regimens (cisplatin plus gemcitabine, cisplatin plus docetaxel, and carboplatin plus paclitaxel) to a standard reference regimen of cisplatin plus paclitaxel and found comparable efficacy; no differences in response rate (RR), median, and 1-year survival among treatment arms. Only the toxicity profile varied among the different regimens.⁴ Now, platinum-doublet chemotherapy combinations are the standard of care for first-line treatment of metastatic NSCLC. Since 2006, bevacizumab has been approved as an addition to chemotherapy for nonsquamous (NSq)-NSCLC in combination with carboplatin and paclitaxel in the United States and more recently in combination with any chemotherapy doublet in the European Union based on randomized phase III data looking at standard platinum doublets with or without the agent.^5–8 At the time this trial was designed, carboplatin/gemcitabine was a common first-line regimen based on similar efficacy with a different toxicity profile, including decreased risk of hypersensitivity reaction, decreased neuropathy, and decreased alopecia but increased myelosuppression compared with carboplatin/paclitaxel.^9–12 Given the promising data seen at the time of trial conception with carboplatin/paclitaxel/bevacizumab, this study was designed to evaluate progression-free survival (PFS), toxicities, and adverse events (AEs) of a combination of gemcitabine, carboplatin, and bevacizumab and to estimate event free and overall survival (OS) in patients with newly diagnosed metastatic NSCLC that was previously untreated and nonsquamous in histology.

PATIENTS AND METHODS

This study is a phase II, open-labeled, single-arm, multicenter study of bevacizumab in combination with gemcitabine and carboplatin in patients with newly diagnosed NSCLC (excluding squamous cell carcinoma). All patients signed informed consent that had been reviewed by institutional review boards at each of the three participating institutions.

Patients

Male and female patients with a recent diagnosis of advanced NSCLC, stage IIIB with malignant pleural effusion and stage IV, were included in this study. To be eligible, the patients needed to have a NSq-NSCLC with measurable or evaluable disease. No prior systemic therapy for advanced NSCLC was allowed, and prior therapy for early stage disease with one regimen was acceptable if it was completed at least 6 months before study entry. Palliative radiotherapy to painful bony metastases was permitted before study entry if completed before initiation of study treatment, and there were no residual sequelae of therapy such as bone marrow suppression. A life expectancy of at least 3 months was required. All patients needed to have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and an age of ≥18 years. Patients had normal organ and marrow function as follows: leukocytes ≥3000/µl, absolute neutrophil count ≥1500/µl, platelets ≥100,000/µl, total bilirubin within normal institutional limits, aspartate aminotransferase (AST) (SGOT)/alanine aminotransferase (ALT)(SGPT) ≤2.5 × institutional upper limit of normal, creatinine of 2.0 or creatinine clearance ≥30 ml/min/1.73 m².

Exclusion criteria were as follows: any prior systemic treatment for advanced NSCLC; known brain metastases; prior treatment with bevacizumab; current, recent (within 4 weeks of the first infusion of this study), or planned participation in any other experimental drug study; concomitant chemotherapy, radiotherapy or investigational agents; evidence of bleeding diathesis or coagulopathy; use of anticoagulant agents including warfarin, heparin, aspirin, non-steroid antiinflammatory drugs; pregnant (positive pregnancy test) or lactating women; major surgical procedure, open biopsy, or significant traumatic injury within 28 days; minor surgical procedures, fine needle aspirations or core biopsies within 7 days; urine protein:creatinine ratio ≥1.0 at screening; history of abdominal fistula, gastrointestinal perforation, or intraabdominal abscess within 6 months; serious, nonhealing wound, ulcer, or bone fracture; lung carcinoma of squamous cell histology or any histology in close proximity to a major vessel, or with significant cavitation; history of hemoptysis; significant comorbidities (blood pressure superior of 150/100 mmHg, unstable angina, New York Heart Association grade II or greater congestive heart failure, history of myocardial infarction within 6 months, history of stroke within 6 months, and clinically significant peripheral vascular disease); psychiatric illness and social situations that would limit compliance with study requirements; another active malignancy except for nonmelanoma skin cancers; and inability to comply with study and/or follow-up procedures.

Study Treatment

All patients were treated with intravenous bevacizumab at 15 mg/kg every 3 weeks and carboplatin at an area under the curve (AUC) of 5 given intravenously over 30 to 60 minutes on day 1 (same day as bevacizumab) every 3 weeks plus gemcitabine at 1000 mg/m² given intravenously over 30 minutes on days 1 and 8 every 3 weeks. Carboplatin was administered before gemcitabine infusion. Bevacizumab was administered 1 hour after chemotherapy infusion. Bevacizumab was initially given over 90 minutes with observation in case of reaction to the medication. If it was tolerated well in the first cycle, the second cycle infusion period was reduced to 60 minutes, and all subsequent infusions were reduced to 30 minutes. Patients could receive a maximum of six cycles of chemotherapy, but treatment with bevacizumab could continue as long as patients had no evidence of progressive disease and no significant treatment-related toxicities. Standard antiemetics were allowed.

Study Assessments

The primary objective of this study was the evaluation of PFS. The secondary objectives were the evaluations of the OS, and the RR per RECIST criteria, and the identification of the safety of this combination regimen. Toxicity grading was performed according to the National Cancer Institute’s Common Toxicity Criteria for Adverse Events, version 3.0. To assess response to treatment, follow-up imaging (computed tomography scans) were obtained after every two cycles. Laboratory evaluations were performed weekly for the first 6 weeks, then every 3 weeks at the time of treatment.

Dose Modifications

No reductions in the bevacizumab dose were allowed. If serious AEs (bleeding and proteinuria) occurred, bevacizumab was held, and the dose would remain the same after the AEs were resolved. Standard dose modifications of carboplatin and gemcitabine were allowed based on hematologic and other criteria. Before the start of each cycle, absolute neutrophil count had to be ≥1500/µl and platelets <100,000/µl. If absolute neutrophil count was between 1000 and 1500/µl and platelets were between 75,000 and 100,000/µl, the treatment was delayed by 1 week and the gemcitabine was reduced by 20%. If absolute neutrophil count was <1000/µl and platelets were <75,000/µl, the treatment was delayed by 1 week and the carboplatin and the Gemcitabine were reduced by 20%. Granulocyte colony-stimulating factor use was allowed after documented neutropenia.

Statistical Methods

The PFS was defined as the duration of time from start of treatment to time of documented progression or death. Assessment of safety and evaluation of OS and response (measured according to the RECIST criteria) were also determined as secondary efficacy variables. Every patient, who had at least one cycle, was included in the analysis of the safety. Patients were monitored for systemic, renal, gastrointestinal, hematologic, neurologic, liver, hemoptysis, examination and thromboembolic toxicities, and laboratory tests were (CBC, metabolic panel, calcium, magnesium, and liver function tests) performed weekly for the first 6 weeks and then every 3 weeks on the days of treatment with Avastin. In addition, patients were seen in the clinic for history and physical examination and assessed for side effects and toxicities every week for the first 6 weeks and then every 3 weeks on the days of treatment. The methods of Kaplan-Meier were used to determine PFS and OS. Patients who had not progressed were censored for the analysis of PFS, and patients who had not died or were lost to follow-up were censored for the analysis of OS. We planned to enroll 50 patients to detect an improvement in PFS of 2.5 months compared with the ECOG trial E4599.⁷ The alpha risk was 5%.

RESULTS

Baseline Characteristics

From July 2006 to December 2008, accrual was completed with 48 patients enrolled with a median age of 59 years (35– 81), all with measureable disease. The median follow-up was 13.6 months (0.23– 41.6). A total of 23 (47.9%) men and 25 (52.1%) women were included, and 19 (40%) patients were never smokers (Table 1), reflective of the patient population at the enrolling institutions. One patient died before receiving therapy and is not included in the analysis. Histologies were 30 (63.8%) adenocarcinomas, four (8.5%) bronchioloalveolar carcinoma, and 13 (27.7%) NSCLC not otherwise specified. Eight patients had stage IIIB with a malignant effusion, and 39 had stage IV disease. After disease progression, 27 patients had a second line of chemotherapy, and 13 had a third line, mostly erlotinib, pemetrexed, or other trial agents ongoing in the treating centers.

TABLE 1.

Baseline Patients’ Characteristics

Characteristics	Patients, n = 47 (%)
Sex
Male	22 (46.8)
Female	25 (53.2)
Age (yr)
Median	59
Range	35–81
ECOG
0	3 (6.4)
1	44 (93.6)
Smoking status
Never smokers	19 (40.4)
Current smokers	7 (14.9)
Exsmokers	21 (44.7)
NSCLC histology
Adenocarcinoma	30 (63.8)
BAC	4 (8.5)
Other	13 (27.7)
Disease stage
IIIB	8 (17.0)
IV	39 (83.0)
Second line	27 (57.4) (9 erlotinib, 14 pemetrexed, and 4 other)
Third line	13 (27.6) (5 erlotinib, 4 pemetrexed, and 4 other)

ECOG, Eastern Cooperative Oncology Group; NSCLC, non-small cell lung cancer; BAC, bronchioloalveolar carcinoma.

Of the 47 evaluable patients, 37 patients (78.7%) completed four cycles or more of the three drugs. The median number of total cycles (including bevacizumab alone after cycle 6) was 8 (1–42). The median number of cycles of chemotherapy alone was 6 (1–6), and the median number of bevacizumab alone was 4.5 (0 –36). Dose reductions occurred in 34 (72.3%) patients, primarily for hematologic toxicity. Thirty-four patients (72.3%) switched to single-agent bevacizumab after completion of four or six cycles of combination therapy at the discretion of the treating physician (Table 2). Two patients withdrew consent after 8 months and 11 months of treatment.

TABLE 2.

Characteristics of Treatment with the Study Drugs

Characteristics	Patients, n = 47 (%)
Number of cycles
Median	8
Range	1–42
Treatment interruption
Disease progression	32 (68.1)
Adverse events or toxicity	7 (14.9
Dose reduction	34 (72.3)
GSCF	7 (14.9)

GSCF, granulocyte colony-stimulating factor.

Safety and Tolerability

The most frequent grade 3/4 AEs were neutropenia (47%/15%), thrombocytopenia (11%/15%), anemia (6%/0%), dyspnea (6%/2%), hypertension (4%/2%), proteinuria (2%/0.0%), and transaminitis (2%/0.0%). No patients were hospitalized for neutropenic fever (Table 3). One patient died of hemoptysis with untreated and unsuspected invasive pulmonary aspergillosis found postmortem eroding into blood vessels. Other bleeding included one case of grade 3 epistaxis, one case of grade 3 hemorrhoidal bleeding, and one case of grade 3 ecchymosis. One grade 3 wound dehiscence and one grade 4 myocardial infarction occurred in treated patients. Common grade 1/2 AEs included fatigue, hypertension, anemia, constipation, nausea, transaminitis, and epistaxis. Seven patients were discontinued for toxicity (infection and neutropenia, hemoptysis, heart failure, liver dysfunction, uncontrollable blood pressure, three consecutive dose reductions for neutropenia, and blood clot) (Table 2).

TABLE 3.

Main Adverse Events

Adverse Events	Grade ½, n (%)	Grade 3, n (%)	Grade 4, n (%)
Neutropenia	22 (46.8)	22 (47.0)	7 (15.0)
Thrombocytopenia	20 (42.5)	5 (11.0)	7 (15.0)
Anemia	22 (46.8)	3 (6.4)	0 (0.0)
Nausea	22 (46.8)	0 (0.0)	0 (0.0)
Constipation	23 (48.9)	0 (0.0)	0 (0.0)
Fatigue	30 (63.8)	1 (2.0)	0 (0.0)
Dyspnea	11 (23.4)	3 (6.4)	1 (2.0)
Epistaxis	16 (34.0)	1 (2.0)	0 (0.0)
Hypertension	23 (48.9)	2 (4.0)	1 (2.0)
Proteinuria	18 (38.3)	1 (2.0)	0 (0.0)
Transaminitis	17 (36.2)	1 (2.0)	0 (0.0)

Efficacy

In 47 evaluable patients, seven (14.9%) partial responses and 34 (72.3%) stable disease were documented at the first follow-up. The median PFS was 8.7 months (7.8–17.9) (Figure 1). Median time to first event (progression/death/toxicity requiring discontinuation) was 6.4 months (95% confidence interval [CI]: 4.8 –7.9).

Figure 1.

Progression-free survival according to a Kaplan-Meier method.

On December 31, 2009, each patient had completed at least 1 year of follow-up, and only one patient continued on active therapy with bevacizumab. At time of data lock at the end of December 2009, 32 patients (68%) had died. The median OS was 12.8 months (95% CI: 10.0 –16.5) (Figure 2). The 1 and 2 years OS were 57% and 10%, respectively.

Figure 2.

Overall survival according to a Kaplan-Meier method.

DISCUSSION

This study analyzing the efficacy and the safety of a combination regimen of carboplatin, gemcitabine, and bevacizumab in newly diagnosed, untreated, advanced stage NSq-NSCLC found a median OS of 12.8 months and a PFS of 8.7 months. The combination is well tolerated with minimal thrombocytopenia and limited bleeding. Neutropenia was the most common AE necessitating dose reduction. Thrombocytopenia rates were lower than anticipated. No unexpected toxicities were encountered.

Bevacizumab was approved for the treatment of metastatic NSCLC in 2006 based on the E4599 trial. The ECOG 4599 trial evaluated a combination of carboplatin (AUC = 6 every 3 weeks) and paclitaxel (200 mg/m² every 3 weeks) for six cycles with or without bevacizumab (15 mg/kg every 3 weeks) in patients with untreated advanced NSq-NSCLC.⁷ Because of the risk of bleeding, this trial excluded patients with squamous cell histology, brain metastases, anticoagulation therapy, and history of gross hemoptysis, a population similarly excluded in our trial. The study enrolled 878 patients and found an increase in median survival (10.3 versus 12.3 months; p = 0.003), PFS (4.5 versus 6.2 months; p < 0.001), and RR (15% versus 35%; p < 0.001) in favor of the bevacizumab arm. In this trial, the most common AE was bleeding in the bevacizumab arm (0.7% versus 4.4%; p < 0.001) with other AEs including grade 3 hypertension (<1% versus 7%) and grade 4 neutropenia (17% versus 26%) in the placebo arm and bevacizumab arm, respectively (p < 0.05).

The Avastin in Lung Cancer (AVAIL) trial included patients with untreated or recurrent NSq-NSCLC, without brain metastasis or tumor invasion into major vessels.⁶ In this trial, 1043 patients were enrolled in three arms, and all patients received cisplatin and gemcitabine with placebo or bevacizumab at 7.5 or 15 mg/kg every 3 weeks until disease progression. An improvement in PFS was observed in both bevacizumab arms (6.7 versus 6.1 months in the 7.5 mg/kg and placebo arms, respectively, p = 0.003 and 6.5 versus 6.1 months in the 15 mg/kg and placebo arms, respectively, p = 0.03). The RR was also significantly improved in the bevacizumab arms (30% versus 34% versus 20% in 15 mg/kg, 7.5 mg/kg, and placebo arms, respectively). This trial did not find a OS benefit with the drug but had a remarkable OS exceeding 13 months in all arms.¹³

Bevacizumab has been tested in combination with other chemotherapies in phase II trials with similarly encouraging results. A recent phase II trial of 51 patients with recurrent or newly diagnosed advanced NSCLC treated with carboplatin (AUC = 6), pemetrexed (500 mg/m²), and bevacizumab (15 mg/kg) every 3 weeks followed by a maintenance of pemetrexed and bevacizumab at the original doses found an overall RR of 55% (95% CI: 41–69%) including one patient with a complete response. The median PFS and OS were 7.8 months (95% CI: 5.2–11.5 months) and 14.1 months (95% CI: 10.6 –19.6 months), respectively.¹⁴ Other combinations such as gemcitabine/oxaliplatin/bevacizumab have produced similarly high overall RR (43%) and OS (13.7 months) with minimal bleeding complications.^15,16

Gemcitabine is an active agent in NSCLC, with single-agent treatment producing RR of approximately 20% and median survivals of approximately 7 to 9 months.^17,18 Its efficacy in combination with platinum is also well established. The regimen in this study was based on positive results from a phase III trial comparing single-agent gemcitabine (1250 mg/m² days 1 and 8) versus carboplatin (AUC = 5 day 1 every 21 days) plus gemcitabine (1250 mg/m² days 1 and 8) in advanced NSCLC. This trial included 334 patients and showed superiority of the combination arm with a RR of 30%, median TTP of 5.7 months, and OS of 10.0 months. The main AEs were grade 3/4 neutropenia (30%/2%) and thrombocytopenia (24%/24%).¹⁸ We chose a slightly lower dose of gemcitabine for this trial of 1000 mg/m² because of concern of additionally neutropenia and higher bleeding risk with the addition of bevacizumab.

More recent trials have looked at platinum/gemcitabine versus platinum/pemetrexed as first-line therapy for advanced NSCLC. A phase III trial randomized patients with advanced NSCLC to receive carboplatin (AUC = 5) + pemetrexed (500 mg/m²) versus carboplatin (AUC = 5) + gemcitabine (1000 mg/m²) every 3 weeks¹⁹ and included 446 patients. In this study, on the carboplatin/gemcitabine arm, which used the same chemotherapy doses as in our trial (without the bevacizumab), the OS was 7.0 months and grade 3/4 toxicity included 51% neutropenia and 56% thrombocytopenia. Another phase III trial compared cisplatin (75 mg/m²) + gemcitabine (1250 mg/m²) versus cisplatin (75 mg/m²) + pemetrexed (500 mg/m²) in 1725 patients with advanced NSCLC.²⁰ The cisplatin/gemcitabine arm had a RR of 28% and a median PFS of 5.1 months. Of note, the OS for patients with nonsquamous histology was significantly improved on the cisplatin + pemetrexed arm, compared with the cisplatin/gemcitabine arm (11.8 months versus 10.4 months, p = 0.005).

Based on these results, the use of first-line platinum/gemcitabine is less common for nonsquamous patients who are now more frequently receiving platinum/pemetrexed or platinum/taxane. The RR seen in our trial of <20% is somewhat lower than expected, but the PFS of 8.7 months and OS of 12.8 months are within expected ranges and compare favorably to results found in phase III trials of the combination of carboplatin/gemcitabine alone. No excess in bleeding or infection was seen. Although the OS reported in our trial may be artificially elevated by the high proportion of nonsmokers and women, two groups of patients with NSCLC with improved survival regardless of therapy, we believe the combination of carboplatin/gemcitabine/bevacizumab is a well tolerated, active regimen that could be considered for patients with newly diagnosed NSq-NSCLC in whom pemetrexed or paclitaxel are not preferred chemotherapeutic options.