Sanofi requests removal of Tzield from CNPV program after Høeg gets involved

Sanofi Seeks Tzield Removal from CNPV Amid FDA Disagreement

Sanofi has reportedly requested the FDA remove its type 1 diabetes drug, teplizumab (Tzield), from the Commissioner’s National Priority Review (CNPV) program. This follows a high-level disagreement where acting CDER Director Tracy Beth Høeg reportedly opposed FDA staff's recommendation to expand Tzield's label to include adults and children aged 8 and older with stage 3 type 1 diabetes. Høeg raised concerns about the drug's risk-benefit profile, citing safety signals like seizures, blood clotting, and a death, as well as potential Epstein-Barr virus and cancer risks. The decision for the new indication was initially expected by April 21 but was delayed. Sanofi maintains its supplemental biologics application (sBLA) is robust, noting over 1,000 patients treated with no established causal link between the drug and reported malignancies or the single death.

• The core of the news revolves around a significant internal disagreement within the FDA regarding Tzield's label expansion. Acting CDER Director Tracy Beth Høeg reportedly challenged the consensus of FDA staff who favored approval, expressing concerns that the drug's benefits might not outweigh its risks. These concerns were specifically tied to detected safety signals, including two seizures, one episode of blood clotting, and one death, alongside potential risks of Epstein-Barr virus and cancer reactivation, which are already noted on the drug's label.
• Following this internal dispute, Sanofi has reportedly requested the removal of Tzield from the FDA's Commissioner’s National Priority Review (CNPV) program, which was designed to expedite reviews. The initial decision date for the supplemental biologics application (sBLA) was pushed back from April 21. Despite the regulatory hurdles, Sanofi has publicly affirmed its confidence in the sBLA, emphasizing that over 1,000 patients have been treated with teplizumab over 30 years of clinical development, and no causal relationship has been established between the drug and the reported malignancies or the single fatal outcome.
• This incident with Tzield is presented within a broader pattern of alleged interventions by senior FDA leaders in drug approval decisions. The press release highlights similar past instances, such as oncology chief Richard Pazdur's reported involvement in the rejection of Replimune’s melanoma drug RP1, and former CBER director Vinay Prasad's alleged role in the rebuff of Capricor Therapeutics’ deramiocel for Duchenne muscular dystrophy and the initial refusal to review Moderna’s flu vaccine mRNA-1010. This context suggests a recurring tension between political appointees and review teams at the agency.

Scrutinizing Teplizumab's Safety Profile: FDA's Concerns

Published safety and tolerability data for teplizumab reveals a complex profile characterized by manageable but statistically significant adverse effects across multiple organ systems. Recent meta-analyses demonstrate that while teplizumab does not increase serious adverse event risk, it consistently elevates the incidence of specific adverse effect categories compared to placebo.

• Dermatological and hematological effects represent the most prominent safety signals, with 2024 systematic review data showing dramatically increased risk of dermatological adverse effects (OR = 6.33, 95%CI: 4.05-9.88, P < 0.00001) and hematological adverse effects (OR = 19.03, 95%CI: 11.09-32.66, P < 0.00001), with rash being the most common clinical adverse event affecting 53% of teplizumab patients versus 20% of placebo patients

• Infectious disease risk is elevated, particularly for Epstein-Barr Virus reactivation, with teplizumab patients showing significantly higher likelihood of active EBV infection (OR = 3.16, 95%CI: 1.51-6.64, P < 0.002) compared to placebo controls

• Gastrointestinal adverse effects occur more frequently in teplizumab-treated patients (OR = 1.60, 95%CI: 1.01-2.52, P = 0.04), alongside expected immune-related effects including transient lymphopenia and mild cytokine release syndrome

• Overall serious adverse event rates remain comparable to placebo, with Phase 3 data showing 10% serious adverse events in teplizumab groups versus 9% in placebo groups, and 99% of patients in both groups experiencing some adverse events

• Real-world experience suggests manageable tolerability, with Italian compassionate use data in three adult patients showing one case of mild transient transaminase elevation and lymphopenia, one asymptomatic 40% lymphocyte reduction, and one treatment discontinuation due to anxiety following mild cytokine release syndrome

• Dose-response relationship affects tolerability, with clinical development revealing a narrow therapeutic window where low doses prove ineffective while higher pharmacologically active doses cause intolerable adverse effect levels, leading to dose reductions in confirmatory trials

Addressing Unmet Needs in Type 1 Diabetes with Teplizumab

Recent literature has identified several vulnerable populations and critical gaps in Type 1 diabetes care that require targeted interventions. The transition from pediatric to adult care emerges as a particularly high-risk period, while specific demographic groups face unique challenges that current standard care does not adequately address.

• Adolescents and young adults transitioning from pediatric to adult care (ages 18-25) face a mean gap of 6.9±5.8 months between last pediatric and first adult visits, with glycated hemoglobin levels remaining suboptimal throughout transition (8.92±1.84% at last pediatric visit, 9.03±1.84% at first adult visit)

• Black young adults with T1D (ages 18-30) experience diabetes distress that contributes to disparities compared to White patients, with few interventions designed to center their specific experiences and cultural needs

• Pediatric populations represent a key target for stem-cell therapy research and personalized medicine approaches, as advancements in immune-shielding strategies may pave the way for clinical success in younger patients

• Elderly patients with multiple comorbidities present significant management challenges due to persistent glycemic variability, severe hypoglycemia, hypoglycemia unawareness, and limited data on advanced diabetes technology in this population

• Females with childhood-onset T1D show elevated risk of anorexia nervosa with 10-year incidence rates of 74.7 per 100,000 person-years compared to 45.2 per 100,000 in controls, requiring routine screening protocols

• Diabetes distress management remains inadequately addressed across all populations, as this negative emotional impact correlates with higher HbA1c, poorer self-management, and reduced quality of life without current interventions targeting this specific need

• Comprehensive transition support programs are critically lacking, with adolescents highly valuing peer support opportunities and age-appropriate, interactive learning experiences that current care models do not systematically provide

Safety Concerns Challenge Teplizumab's Stage 3 T1D Expansion

Teplizumab has already marked a significant milestone in type 1 diabetes (T1D) care, becoming the first FDA-approved disease-modifying therapy to delay the onset of clinical T1D in at-risk individuals. This breakthrough has opened a new era, shifting focus from merely managing symptoms to actively preserving pancreatic beta-cell function. The ambition to expand teplizumab's label to include adults and children aged 8 and older with newly diagnosed (stage 3) T1D was a logical next step, promising to extend these benefits to a broader patient population by mitigating the ongoing autoimmune destruction and potentially reducing the lifelong burden of exogenous insulin.

However, this strategic expansion has encountered a significant regulatory hurdle. Sanofi's recent decision to withdraw its supplemental biologics application from the Commissioner’s National Priority Review program, following high-level disagreement within the FDA, underscores the intense scrutiny applied to immunomodulatory therapies. Concerns raised by the acting CDER Director regarding safety signals, including seizures, blood clotting, a death, and potential Epstein-Barr virus and cancer risks, highlight the complex risk-benefit assessment inherent in such treatments. While Sanofi maintains the robustness of its data, asserting no established causal link between the drug and these severe events, the regulatory body's caution reflects the need for unequivocal long-term safety assurances, especially for a chronic condition affecting a young population.

The clinical literature consistently demonstrates teplizumab's efficacy in preserving C-peptide levels and reducing exogenous insulin requirements in newly diagnosed T1D patients. Yet, some studies also indicate that these benefits do not always translate into significant improvements in key secondary clinical endpoints like HbA1c levels or a reduction in hypoglycemic events. This nuanced efficacy profile, when weighed against the raised safety concerns, creates a challenging path for regulatory approval. For Sanofi, this means a likely delay in market expansion and potentially the need for further data to address the FDA's specific safety questions. For the broader T1D community, it reinforces the ongoing challenge of developing disease-modifying therapies that offer clear, sustained clinical benefits with an acceptable long-term safety profile. Future immunotherapies will undoubtedly face similar rigorous evaluation, emphasizing the critical need for robust evidence that extends beyond surrogate markers to demonstrate tangible improvements in patient quality of life and long-term health outcomes.