Product Profile:

Rituximab-arrx (Riabni) 

Drug Category: Monoclonal anti-CD20 antibody

Target Indications:  Treatment of adult patients with relapsed or refractory, low-grade or  follicular B-cell non-Hodgkin’s lymphoma who are CD20-positive and have failed prior treatments; patients who have nonprogressing, low-grade, CD20-positive B-cell non-Hodgkin’s lymphoma and who are stable after receiving a prior chemotherapy regimen containing cyclophosphamide, vincristine and prednisone;  patients with CD20-positive follicular lymphoma who are therapy naïve in combination with chemotherapy or who had responded to previous rituximab therapy; patients with CD20-positive chronic lymphocytic leukemia in combination with fludarabine and cyclophosphamide; and granulomatosis with polyangiitis in adult patients in combination with glucocorticoids

Developed and marketed by Amgen

Summary: Riabni® is the third FDA-approved version of rituximab (reference product, Rituxan) manufactured by Genentech.

The product was originally designated as ABP798. Amgen submitted a biologic license application for approval via the 351(k) biosimilar pathway in December 2019. The Food and Drug Administration (FDA) approved the application on December 17, 2020.

Like the other two approved rituximab biosimilars (Truxima® and Ruxience®), Riabni was not approved for the reference product’s autoimmune indication (rheumatoid arthritis). Amgen did submit a clinical study for rheumatoid arthritis, in which the company stated there was no clinically meaningful difference in outcomes between their product and the reference product Rituxan®. This drug was launched in January 2021.

About the Manufacturer

Amgen, based in Thousand Oak, California, is a leading global biotechnology company. The company focuses on six therapeutic areas: cardiovascular disease, oncology, bone health, neuroscience, nephrology and inflammation. Amgen Biosimilars is the division responsible for biosimilar commercialization. Riabni is the fifth Amgen biosimilar approved by the FDA. Amgen and Allergan have worked together on four oncology products together, with two of the products being FDA approved, Kanjinti® (trastuzumab) and Mvasi® (bevacizumab). Other products approved include Amjevita® (adalimumab) and Avasola® (infliximab). Additionally, Amgen has three biosimilar products in the pipeline: aflibercept, eculizumab, and ustekinumab. Amgen also has reference products that currently face biosimilar competition (filgrastim and pegfilgrastim).

News, Commentary, and Intelligence

Competitor Products and Manufacturer Analysis

Riabni was the third and perhaps last rituximab biosimilar to be approved by the FDA, owing to other potential biosimilar candidates being derailed in recent years.  This product was launched in January 2021, and biosimilar rituximab has now captured about 50% of the marketshare for its oncology indications. Boehringer Ingelheim, Sandoz, Viatris, and Samsung Bioepis/AstraZeneca (partners in a joint venture called Archigen) have run into either business roadblocks or regulatory problems in bringing their products to market. None of these agents will likely move towards FDA application.

Riabni was approved for the non-automimmune indications only. Truxima was approved for rheumatoid arthritis and Wegener’s granulomatosis indications in December 2019, and launched these two indications in May 2020. However, it is not clear as to whether payers will exclude Ruxience coverage for the nonapproved indications.

Rituximab Biosimilar(s) Approved by the FDA

Company Name Product Name FDA Filing Approval Date



December 20, 2019

FDA approved December 17, 2020



June 30, 2017/May 29, 2018

Approved December 14, 2018



December 2018

Approved July 23, 2018


Here Are Some of the Big Cost Takeaways From the Latest US Biosimilar Data

(September 29, 2021) The data emphasize one key trend: Biosimilar competition drives down the average sales price (ASP) of the category; this happens quickly for many categories, even those with modest discounts at launch.

Amgen Receives FDA Approval for Rituximab Biosimilar Riabni

(December 22, 2020) Amgen added another notch on its biosimilar belt last week, receiving approval from the Food and Drug Administration (FDA) to market ABP798, its biosimilar version of Rituxan®. The drug, dubbed Riabni™ (rituximab-arrx), is the third biosimilar rituximab available in the US.

Archigen Closes Its Doors After Failing to Introduce Rituximab Biosimilar

(November 20, 2020) Samsung Biologics announced in its third quarter earnings report that they and partner Astra Zeneca have agreed to shut down their joint venture Archigen Biotech. Archigen was created in 2014 with the hope of developing a biosimilar to reference product Rituxan/MabThera for the treatment of follicular lymphoma.

Truxima Now Available With Autoimmune Indications

(May 4, 2020) Partners Teva and Celltrion announced the launch of their biosimilar Truxima for two autoimmune indications (rhematoid arthritis and Wegener’s granulomatosis).

Pfizer Launches Ruxience, Announces Pricing for Upcoming Trazimera

(January 27, 2020) In December, the company launched its bevacizumab biosimilar Zirabev®, and on January 23, Pfizer announced the availability of its rituximab biosimilar Ruxience®. Ruxience is the second launched biosimilar to the reference product Rituxan®.

Partners Teva/Celltrion Seek the Jump on Pfizer, Launch Their Rituximab Biosimilar Next Week

(November 8, 2019) When Pfizer announced its intention just more than a week ago to begin marketing its rituximab biosimilar Ruxience® in January 2020, industry watchers wondered when we might hear a response from its sole approved competitor. The wait was over quickly: Teva and Celltrion will begin shipping their own rituximab biosimilar Truxima® on November 11.

The Biosimilar Mabs Have It: FDA Approves Biosimilars for Adalimumab and Rituxumab

(July 24, 2019) On July 22, 2019, the Food and Drug Administration (FDA) announced the approval of Pfizer’s Ruxience, a biosimilar of rituximab. Compared with reference agent MabThera, this biosimilar proved to produce equivalent efficacy and safety in a phase 3 trial.

Pfizer Signs Patent Settlement With Roche on Rituximab Biosimilar

(March 25, 2019) An agreement was announced between Pfizer and Roche (Genentech), which concludes litigation over a key patent for Rixutan. This may affect when Pfizer decides on marketing the product.

Amgen and Allergan Announce Top-Line Results of Phase 1/3 Rituximab Biosimilar Trial

(January 24, 2019) The results demonstrate that the study met its primary endpoint of pharmacokinetic (PK) similarity. Additionally, equivalent efficacy was established and a similar safety profile was demonstrated.

Rituximab Biosimilar Approved by FDA for Cancer Treatment

(November 28, 2018) On November 28, 2018, the Food and Drug Administration (FDA) announced the approval of rituximab-abbs (Truxima™), produced by Celltrion and marketed by Teva. Approval for this rituximab biosimilar was overwhelmingly recommended by the FDA’s Oncology Drug Advisory Committee by a vote of 16-0 in October.

Sandoz Decides Against Marketing Rituximab Biosimilar in US

(October 30, 2018) Sandoz announced that it would halt its efforts to obtain approval for its biosimilar version of rituximab from the US Food and Drug Administration (FDA).

Celltrion's Rituximab Biosimilar Earns Positive FDA Review

(October 8, 2018) The information package released by reviewers for the Food and Drug Administration (FDA) indicates that a positive recommendation for Celltrion’s rituximab biosimilar is likely at the Advisory Committee meeting on October 10.

Celltrion Bounces Back, Resubmits for FDA Approval of Rituximab Biosimilar

(May 30, 2018) Anticipating that its issues with the Incheon, South Korea, manufacturing plant will be resolved, Celltrion has resubmitted its biologic license application for a rituximab biosimilar (CT-P10).

FDA Hands Sandoz a Rejection on Its Rituximab Biosimilar

(May 2, 2018) Sandoz announced today that the Food and Drug Administration (FDA) has decided not to approve its biosimilar version of the oncology biosimilar rituximab.

Teva and Celltrion Receive Rejections on Trastuzumab and Rituximab Biosimilars

(April 5, 2018) Celltrion and its partner Teva were dealt a significant blow today, as the Korean manufacturer announced that the latest two biosimilar candidates were rejected by the Food and Drug Administration.

Biosimilar Rituximab Under FDA Review

(July 5, 2017) Celltrion announced June 30, 2017 that it has submitted its 351(k) application to the Food and Drug Administration for approval of its biosimilar version of rituximab. This represents the first biosimilar application for rituximab, a monoclonal antibody to CD20..

Celltrion’s Rituximab Recommended for Approval in Europe

(January 3, 2017) Just weeks after Celltrion presented data at the American College of Rheumatology meeting demonstrating that its product CT-P10 is as safe and effective as Rituxan®for the treatment of rheumatoid arthritis (RA), the European Medicines Agency (EMA) received the recommendation to approve the product for use in the EU.

CT-P10 Rituximab Biosimilar Phase 3 Clinical Trial Results Announced

(September 28, 2016) The results of a phase 3 trial presented at the American College of Rheumatology meeting proved that a biosimilar version of Rituxan provided equivalent results over a 24-week study period compared with the originator product.

Prognosis of Patients with B-Cell non-Hodgkins Lymphoma

Will Biosimilar Rituximab Replace the Originator Product?

Clinical Trials of Riabni

Riabni was tested in two phase 3 studies, one for B-cell non-Hodgkin lymphoma (NHL) and one for moderate-to-severe rheumatoid arthritis. The indication for rheumatoid arthritis was not pursued by Amgen.

Follicular B-cell non-Hodgkin’s Lymphoma

Efficacy and safety of ABP 798: Results from the JASMINE trial in patients with follicular lymphoma in comparison with rituximab reference product

A total of 256 patients diagnosed with grade 1, 2, or 3a  (Stage II-IV) follicular B-cell NH expressing CD20 that were asymptomatic were enrolled in a randomized, double-blind, active-controlled two-arm study. Patients were excluded if they had received previous treatment for NHL including the reference product rituximab or a biosimilar rituximab. The patients (128 patients in each group) received either the reference product or ABP 798 (dose 375 mg/m2) as an intravenous infusion every week for four weeks with the same dose at weeks 12 and 20.

Primary efficacy assessments included overall response rate (ORR), complete response (CR), unconfirmed complete response (Cru), and partial response (PR), all of which were determined at week 28. The secondary efficacy endpoint was the ORR at week 12. Safety endpoints and antidrug antibody assessments were also reported.

Based on the prespecified benchmarks of equivalent efficacy established by the investigators, they determined that the biosimilar’s clinical outcomes were equivalent to the reference product.

Variable (Efficacy)


(N = 123)


(N = 124)

ORR (n %) 96 (78%) 87 (70.2%)
CR 29 (23.6%) 32 (25.8%)
PR 67 (54.5%) 52 (41.9%)
Stable disease 23 (18.7%) 35 (28.2%)


Variable (Safety) Riabni
(N = 128)
(N =126)
≥ 1 adverse event 107 (83.6%) 95 (75.4%)
Any treatment-emergent adverse event 63 (49.2%) 57 (45.2%)
Adverse event grade 3 or 4 14 (10.9%) 13 (10.3%)
Serious adverse events 5 (3.9%) 5 (4.0%)


The percentage of patients with an adverse event ≥3 was similar in both study groups as were the total number of serious adverse events. The types of treatment-emergent adverse events and adverse events of interest observed in both groups were similar.

All patients in each group had at least one on-study antidrug antibody (ADA) result. During the 28 weeks of the study, three patients in the Riabni group tested positive for the development of binding ADAs, whereas 1 patient in the reference product group tested positive. At the conclusion of the study, one patient in each study group had a positive ADA result. Each study group had one patient that tested positive neutralizing antibodies.

The investigators concluded that the study supported similarity in efficacy and safety/tolerability for the biosimilar compared with the reference product in patients with follicular lymphoma.


Rheumatoid Arthritis

Efficacy and safety results from a randomized double-blind study comparing proposed biosimilar ABP 798 with rituximab reference product in subjects with moderate-to-severe rheumatoid arthritis.

A total of 311 patients with moderate-to-severe rheumatoid arthritis were enrolled in a randomized, double-blind, active-controlled 48-week study (a series of 2 doses administered 24 weeks apart). All patients in the study had been diagnosed with rheumatoid arthritis for at least 6 months and had an inadequate response or intolerance to other disease-modifying anti-rheumatic drugs (DMARDs), including intolerance or inadequate response to one or more TNF inhibitor therapies. The patients had to have received stable-dose methotrexate for ≥ 8 weeks prior to the study. Those taking oral corticosteroids were required to take a stable dose for ≥ 4 weeks prior to the study and those receiving nonsteroidal anti-inflammatory drugs (NSAIDs) or low- potency analgesic need to have been taking a stable dose for ≥ 2 weeks.

The 311 patients were assigned to one of three study groups (ABP 798, 104 patients; EU-sourced Rituxan, 104 patients; and US-sourced Rituxan, 103 patients). Each group received 1000 mg intravenously for two doses administered two weeks apart. At week 24, those in the Riabni or EU-sourced rituximab groups received the second dose of the same treatment whereas those in in US-sourced Rituxan group received Riabni for their second dose. The final study assessment was conducted at 48 weeks. The primary efficacy endpoint was the change from baseline in Disease Activity Score 28-joint C-reactive protein (DAS28-CRP) at week 24. Secondary endpoints included the DAS28-CRP at other time points, and American College of Rheumatology (ACR) measurements [20%, 50%, and 70%] at several points during the study.

The mean change in DAS28-CRP was similar between groups and was within the prespecified equivalence margin at week 24. Results at 48 weeks were similar, as were results for the secondary endpoints.

Mean ± SE Change in DAS29-CRP at 28 Weeks

ABP 798

(N = 104)

Rituxan US

(N = 103)

Rituxan EU

(N = 104)

–2.197 ± 1.369 –2.081 ± 1.305 –2.168 ± 1.349


Adverse events were similar among the groups. The most commonly observed treatment adverse events were upper respiratory tract infections, nasopharyngitis, nausea, bronchitis, and additional rheumatoid arthritis symptoms. The presence of neutralizing antibodies was similar among the groups; 8 (8.2%) in the Riabni/Riabni group, 4 (4.3%) in the Rituxan EU/Rituxan EU group, and 10 (10.3%) in the Rituxan US/Riabni group, with the results being transient for 7 (7.2%), 2 (2.1%), and 5 (5.2%) of the study participants, respectively.


Variable (Safety) at 48 Weeks


(N = 104)

Rituxan EU/Rituxan EU

(N = 104)

Rituxan US/Riabni

(N = 103)

Any adverse event 67 (64.4%) 54 (51.9%) 56 (54.4%)
Any adverse event, grades 3–4 5 (4.8%) 9 (8.7%) 9 (8.7%)
Any serious adverse event 8 (7.7%) 8 (7.7%) 8 (7.8%)


The study investigators concluded that Riabni demonstrated similar efficacy and safety results in patients with active moderate-to-severe rheumatoid arthritis compared with the reference product sourced from either the US or EU.

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