The purpose of this study is to evaluate safety and pharmacokinetic of GP2013 in Japanese patients with CD20 positive low tumor burden indolent B-cell NHL under weekly dosing schedule.

Inclusion Criteria:

• Patient with CD20 positive low tumor burden indolent B-cell non- Hodgkin's lymphoma.
• Patient with at least one measurable lesion.
• Patient with ECOG performance status 0 or 1.

Exclusion Criteria:

• Patient who has received radiotherapy within the last 28 days prior to administration, or are not recovered from previous radiotherapy.
• Patient who has received immunotherapy, chemotherapy, antibodies and experimental treatment within the last 28 days prior to administration, or are not recovered from previous therapy.
• Patient who has mAb therapy other than rituximab as prior line of therapy.
• Patient with evidence of any uncontrolled, acute or chronic active infection (viral, bacterial or fungal).
• Patient with any other malignancy within 5 years prior to date of screening, with the exception of adequately treated in situ carcinoma of the cervix uteri, basal or squamous cell carcinoma or nonmelanomatous skin cancer.

Other protocol-defined inclusion/exclusion criteria may apply.