Exploring FDA-approved biosimilar insulin products

Semglee (insulin glargine-yfgn)

Developed by Biocon Biologics and distributed by Viatris, Semglee was approved by the FDA on July 28, 2021. It is a long-acting insulin biosimilar to Lantus (insulin glargine) and became the first biosimilar insulin to receive interchangeability designation, meaning it can be substituted for Lantus without prescriber approval. The interchangeable version of Semglee is available alongside a non-interchangeable version, allowing for greater flexibility in pricing and distribution.

Rezvoglar (insulin glargine-aglr)

Manufactured by Eli Lilly, Rezvoglar received FDA approval on December 17, 2021, as a long-acting biosimilar to Lantus. On November 16, 2022, the FDA granted Rezvoglar interchangeable status, making it the second interchangeable biosimilar insulin in the U.S. Like Semglee, this designation allows pharmacists to substitute Rezvoglar for Lantus without requiring physician approval.

Merilog (insulin aspart-szjj)

Sanofi-Aventis developed Merilog, which the FDA approved on Feb. 14, 2025. It is the first rapid-acting biosimilar insulin approved in the U.S., offering an alternative to NovoLog (insulin aspart). Unlike Semglee and Rezvoglar, Merilog has not received interchangeable status. However, its approval marks a significant expansion of biosimilar insulin options, particularly for patients requiring mealtime insulin.

Pricing and cost savings

Between 2012 and 2021, insulin prices for a 30-day supply in the U.S. rose by 184%, contributing to affordability concerns and prompting regulatory interventions. The introduction of biosimilar insulins has led to price stabilization and, in some cases, reductions. In European markets, biosimilars have resulted in median price reductions of 21.6%, with some biosimilar insulins priced up to 22% lower than their reference products in the U.S.

Despite these reductions, the insulin market remains influenced by rebate-driven pricing models. Pharmacy benefit managers (PBMs), which negotiate drug prices on behalf of insurers, have been criticized for favoring higher-rebate branded insulins over lower-cost biosimilars, restricting patient access to more affordable options. In response to these concerns, the Federal Trade Commission has launched investigations into PBMs, alleging that their practices contribute to artificially high prices.

Adoption and market uptake

The adoption of biosimilar insulins in the U.S. has been slower than that of other biosimilars, such as oncology treatments, which have reached uptake rates of 82%. Several factors contribute to this discrepancy. Formulary restrictions, rebate agreements and limited prescriber awareness have all played a role in slowing adoption rates. Medicare Advantage plans have shown 1.1­–2.3 times higher biosimilar uptake compared to traditional Medicare, largely due to plan-driven cost-containment strategies, according to a JAMA research letter.

Although the $35 monthly insulin price cap implemented in 2023 has provided relief for Medicare beneficiaries, many still face significant cost barriers. For instance, privately insured patients and those without coverage experience still struggle to afford access.

Future market outlook

According to a market report, the biosimilar insulin market is poised for substantial growth. Projections estimate an expansion from $3.04 billion in 2023 to $9.69 billion by 2032, reflecting a 13.9% compound annual growth rate. This growth is driven by several factors, including the rising prevalence of diabetes, an increasing focus on cost-effective treatment options and regulatory efforts to streamline biosimilar approvals.

Despite several hurdles, biosimilars are expected to play an increasingly vital role in expanding patient access to insulin therapy. The Biosimilar User Fee Amendments, which help fund regulatory review processes, have supported the efficient approval of biosimilars and kept the market competitive.

Moving forward, healthcare stakeholders -- such as manufacturers, insurers and policymakers -- will need to balance pricing strategies, formulary positioning and regulatory compliance to ensure widespread adoption and affordability. If barriers to uptake are effectively addressed, biosimilar insulins could significantly affect the U.S. diabetes treatment market, making essential medications more accessible to millions of patients.

With the addition of more FDA-approved biosimilar insulins like Semglee, Rezvoglar and Merilog, the market could experience increased competition, while patients could experience reduced insulin costs. However, as noted, adoption challenges, regulatory hurdles and pricing dynamics continue to negatively impact the biosimilar insulin market. While rebate structures and payer negotiations present significant obstacles, the continued expansion of biosimilars is expected to drive long-term improvements.

As biosimilars continue to gain momentum, their potential to disrupt traditional insulin pricing models and expand treatment access will depend on regulatory policies, payer incentives and continued innovation.

Alivia Kaylor is a scientist and the senior site editor of Pharma Life Sciences.