Biosimilar CT-P43: Psoriasis Treatment as Effective as Ustekinumab

A biosimilar version of the drug ustekinumab, known as CT-P43, has demonstrated effectiveness comparable to the original medication in treating moderate to severe plaque psoriasis, according to the results of a phase 3 clinical trial. This finding offers potential for increased access and affordability for patients managing this chronic skin condition. The study, detailed in publications from AJMC and Dermatology Times, assessed the efficacy, safety, and immunogenicity of CT-P43 over a 52-week period.

Understanding Psoriasis and Ustekinumab

Plaque psoriasis is a common dermatological condition characterized by raised, red, scaly patches on the skin. It’s an autoimmune disease, meaning the body’s immune system mistakenly attacks healthy skin cells. Ustekinumab is a biologic drug that works by targeting specific proteins in the immune system – interleukin-12 and interleukin-23 – that contribute to inflammation and the development of psoriatic plaques. It’s administered via injection and is typically used when other treatments, like topical creams or light therapy, haven’t provided sufficient relief.

What Does ‘Biosimilar’ Indicate?

Biosimilars are not identical copies of the original biologic drug (the “originator”). Because biologics are complex molecules made from living cells, it’s impossible to create an exact replica. Instead, biosimilars are highly similar to the originator, with no clinically meaningful differences in safety, purity, and potency. The development of biosimilars is a rigorous process overseen by regulatory agencies like the Food and Drug Administration (FDA) in the United States and the European Medicines Agency (EMA). The goal is to provide more treatment options and potentially lower healthcare costs.

The Phase 3 Trial: Design and Findings

The phase 3 trial, a double-blind, randomized controlled study, involved 509 patients with moderate to severe plaque psoriasis. Participants were randomly assigned to receive either CT-P43 or the originator ustekinumab. The primary endpoint of the study was the mean percentage improvement in the Psoriasis Area and Severity Index (PASI) score at week 12. The PASI is a commonly used tool to measure the severity of psoriasis, taking into account the area of skin affected and the characteristics of the lesions (redness, scaling, thickness).

Results showed that CT-P43 achieved equivalence to the originator ustekinumab based on two different statistical approaches – one used by the FDA and another by the EMA. Specifically, the mean PASI improvement at week 12 was 77.93% for CT-P43 and 75.89% for originator ustekinumab (FDA approach), with a treatment difference of 2.05. Using the EMA approach, the corresponding values were 78.26% and 77.33%, with a treatment difference of 0.94. The study, detailed in an abstract available on PubMed, too evaluated pharmacokinetic properties, safety, and immunogenicity through week 52, with results continuing to demonstrate comparability between the two drugs.

What Does Equivalence Mean in Practice?

Equivalence doesn’t necessarily mean the drugs are performing identically in every individual. It means that any differences observed between CT-P43 and ustekinumab are small enough that they are unlikely to have a clinically significant impact on patients. The pre-defined equivalence margins – ±10% (FDA) or ±15% (EMA) – set the boundaries within which the treatment difference had to fall to conclude equivalence. This is a crucial distinction from demonstrating “superiority,” where one drug must show a statistically significant and clinically meaningful improvement over the other.

Safety and Immunogenicity

The trial also assessed the safety and immunogenicity of CT-P43. Immunogenicity refers to the potential for a drug to trigger an immune response in the body, which could potentially reduce its effectiveness or cause adverse effects. The study found no clinically meaningful differences in safety or immunogenicity between CT-P43 and the originator ustekinumab. This is a critical aspect of biosimilar development, as regulators require evidence that the biosimilar does not pose any new or increased safety risks compared to the original drug.

Limitations and Further Research

While the results are promising, it’s significant to acknowledge the study’s limitations. The trial population was relatively homogenous, and further research may be needed to assess the effectiveness and safety of CT-P43 in more diverse patient populations. The study followed patients for 52 weeks, and longer-term data will be valuable to confirm the sustained comparability of the two drugs. Ongoing research will also focus on real-world evidence, examining how CT-P43 performs in clinical practice outside of the controlled environment of a clinical trial.

What’s Next for CT-P43 and Biosimilars?

The successful completion of this phase 3 trial represents a significant step towards the potential approval of CT-P43 as a biosimilar to ustekinumab. The next step typically involves submitting the trial data to regulatory agencies like the FDA and EMA for review. If approved, CT-P43 could become available to patients, potentially offering a more affordable treatment option for moderate to severe plaque psoriasis. The increasing availability of biosimilars is expected to play a crucial role in lowering healthcare costs and improving access to essential medications. Further studies are planned to continue monitoring the long-term effects and real-world performance of CT-P43, contributing to a growing body of evidence supporting the use of biosimilars.

Patients currently using ustekinumab should continue their prescribed treatment and discuss any questions or concerns with their healthcare provider. Switching between the originator biologic and a biosimilar is a decision that should be made in consultation with a qualified clinician.