Study Purpose: IG-001, utilizes biodegradable di-block copolymers composed of methoxy poly (ethylene glycol)-poly (lactide) to form nanoparticle (NP) with paclitaxel and is being developed as the next generation NP Paclitaxel. IG-001 was launched as Genexol-PM in Korea in 2007 and the post-marketing surveillance (PMS) for breast cancer has been completed. This was a PMS study of IG-001 in patients with locally recurrent or metastatic breast cancer conducted to investigate the incidences & types of adverse events (AEs) including unexpected and serious AEs in clinical use. The study was also intended to monitor changes in the incidences and types of AEs, to assess clinical factors affecting safety and efficacy in this setting.

Methods: The study was conducted at 12 medical institutions in Korea from 2007 to 2010. 186 subjects were enrolled and surveillance data was collected during this period. The starting dose of IG-001 was 300 mg/m2 with possible dose reductions in 2 stages based on hematological and non-hematological toxicities (except alopecia) to 240 mg/m2 and 190 mg/m2. IG-001 was administered as an IV infusion over 3 hours.

Results: In subjects with measurable disease at enrollment, subject responses were determined by comparing the tumor dimensions before & after treatment using either the WHO standard or RECIST criteria. In subjects with no measurable tumors at enrollment, response was determined by assessing the clinical condition of the subject. The “best overall response” was used to categorize response. For subjects with measurable disease, complete response (CR) and partial response (PR) were classified as efficacious while stable disease (SD), progressive disease (PD) & not assessable disease were classified as inefficacious. The results showed that 36/148 evaluable subjects (24.32%) responded to study drug treatment with PR and were judged efficacious. SD occurred in 53 subjects (35.81%) and PD observed in 58 subjects (39.19%). 1 subject (0.68%) was not assessable and no CR observed. The background factors analyzed for possible correlations with efficacy included age, illness duration, disease stage, concurrent disease, medical history, total number of treatment cycles, mean dose of study drug per cycle and concomitant anticancer therapy. One factor correlated with efficacy was the total number of drug treatment cycles (p < 0.0001). The efficacy was 0% in the 53 subjects who received 3 or fewer cycles of treatment and 42.47% in the 73 subjects who received 6 or more cycles (31/73). 21 subjects (11.29%) reported a total of 34 serious AEs. The most frequent were neutropenia (1.61%), febrile neutropenia (1.61%), headache (1.61%), vomiting (1.08%), fever (1.08%), dyspnea (1.08%) and tachycardia (1.08%). Most of these were secondary to expected toxicities of the study drug.

Conclusions: In this PMS study of IG-001 in patients with breast cancer, the study drug was well tolerated with an excellent safety profile even though most of these patients had extensive prior chemotherapy.

Citation Format: Larn Hwang, Caleigh Douglass, David Nam, Vuong Trieu. IG-001 phase 4 data in Korea: Safety and efficacy. [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 CT316. doi:10.1158/1538-7445.AM2014-CT316