Drug pipeline for September 2026

At Prime Therapeutics (Prime), we have positioned ourselves to best prepare our clients to manage new drugs. Our clinical and trade relations teams keep a keen eye on drugs awaiting approval by the Food and Drug Administration (FDA).

September 2026: condoliase (SI-6603)

Ferring Therapeutics and Seikagaku Corporation are awaiting an FDA decision for condoliase for lumbar disc herniation (LDH). Condoliase is a single-dose intradiscal enzyme therapy that reduces herniated disc material to alleviate nerve compression and associated radicular pain. This is the drug’s second FDA review following a Complete Response Letter (CRL) issued in March 2025 that primarily cited manufacturing-related deficiencies and did not raise concerns regarding efficacy and safety. Condoliase was evaluated in two double-blind clinical trials in patients who failed to achieve  resolution of pain despite at least six weeks of conservative therapy (e.g., nonsteroidal anti-inflammatory drugs, physical therapy).¹ Both trials reported significant improvement from baseline to Week 13 in worst leg pain during the past 24 hours, averaged over the previous seven days (primary endpoint), as measured by the Visual Analog Scale (least square mean [LSM] difference, -7.5 [P=0.0263] in Trial 1 and -15.2 [P=0.001] in Trial 2). If approved, condoliase would provide a less invasive option compared to surgery for patients with LDH.

For more information, see the condoliase Deep dive in the January 2025 edition of Prime’s Quarterly Drug Pipeline.

September 2026: omalizumab (ADL-018)

Kashiv BioSciences, soon to be acquired by Amneal Pharmaceuticals, is awaiting an FDA decision on ADL-018, its biosimilar candidate to Genentech and Novartis Pharmaceutical’s omalizumab (Xolair). Omalizumab is an anti-immunoglobulin E (IgE) antibody approved for multiple allergic and inflammatory conditions, including moderate-to-severe persistent asthma, chronic rhinosinusitis with nasal polyps, chronic spontaneous urticaria and IgE-mediated food allergy. If approved, ADL-018 will be the second omalizumab biosimilar in the United States, following Celltrion’s Omlyclo. Omlyclo is anticipated to be available in the second half of 2026 and ADL-018 could launch in 2026 or 2027.

September 2026: tavapadon

AbbVie has submitted tavapadon, an oral selective dopamine D1/D5 receptor partial agonist, to the FDA for the treatment of Parkinson’s disease (PD). The application is supported by data from three Phase 3, placebo-controlled trials: TEMPO-1, TEMPO-2 and TEMPO-3. TEMPO-1 and TEMPO-2 evaluated tavapadon as monotherapy in patients with early PD, with or without concurrent monoamine oxidase-B (MAO-B) inhibitor therapy. ² ³ Once-daily doses of tavapadon were administered as 5 mg and 15 mg in TEMPO-1 and were titrated to 15 mg in TEMPO-2. In both trials, tavapadon produced significant improvements in motor symptoms at Week 26, as measured by the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), compared with placebo (difference: TEMPO-1, -11.5 points and -12.1 points, respectively; P<0.001 for both doses; TEMPO-2, -9.1 points, P<0.0001). The TEMPO-3 trial evaluated flexible doses of tavapadon (5–15 mg once daily) as adjunctive therapy to oral levodopa in adults with PD experiencing motor fluctuations.⁴ At Week 26, tavapadon demonstrated a statistically significant improvement in the primary endpoint of total daily time without dyskinesia by 1.1 hours compared with placebo (1.7 hours versus 0.60 hours; P<0.001). Tavapadon may be associated with lower rates of somnolence, impulse control disorder and hypotension than currently available dopamine agonists that preferentially target D2 and D3 receptors, although direct comparative studies are lacking.⁵ If approved, tavapadon would be the first selective D1/D5 receptor partial agonist available for patients with PD and could serve as monotherapy in early PD and adjunctive therapy to oral levodopa for patients with advanced PD experiencing motor fluctuations. 

Sept. 19, 2026: rebisufligene etisparvovec (UX111)

Ultragenyx is seeking FDA Accelerated Approval for UX111 for the treatment of Sanfilippo syndrome type A (mucopolysaccharidosis type IIIA), a rare pediatric lysosomal storage disease caused by a mutation in the N-sulfoglucosamine sulfohydrolase (SGSH) gene. The disease is characterized by progressive neurodevelopmental decline, including intellectual and motor deterioration and behavioral disturbances. UX111 is an in vivo gene therapy that uses a self-complementary AAV9 vector to deliver a functional copy of the SGSH gene to cells via a one-time intravenous (IV) infusion. The therapy is being evaluated in the ongoing Phase 1/2/3 Transfer A trial.⁶ Updated clinical data demonstrated a 63.98% reduction in median cerebrospinal fluid heparin sulfate (CSF HS) exposure among patients included in the efficacy analysis who received UX111 (P<0.001). Treatment with UX111 was also associated with durable stabilization or improvement of developmental skills compared with the progressive decline typically seen in the natural history of the disease. This is the drug’s second FDA review following a CRL issued in July 2025 due to concerns specific to chemistry, manufacturing and controls, but not to safety or efficacy of UX111. The FDA has granted UX111 Fast Track, Orphan Drug, Regenerative Medicine Advanced Therapy (RMAT) and Rare Pediatric Disease (RPD) designations. If approved, UX111 will be the first disease-modifying treatment for Sanfilippo syndrome type A, addressing a significant unmet need for this pediatric disorder.

For more information, see the rebisufligene etisparvovec Deep dive in the April 2025 edition of Prime’s Quarterly Drug Pipeline.

Sept. 22, 2026: zilganersen

Ionis Pharmaceuticals has submitted zilganersen to the FDA for the treatment of Alexander disease (AxD), a rare neurological disease affecting the white matter of the brain. AxD is caused by mutations in the glial fibrillary acidic protein (GFAP) gene that result in abnormal deposits of Rosenthal fibers, which disrupt normal brain cell function. Zilganersen is an antisense oligonucleotide agent designed to reduce GFAP production. The FDA granted zilganersen a Priority Review, as well as Breakthrough Therapy, Orphan Drug and RPD designations. The drug is being evaluated in a Phase 1–3, multicenter, double-blind, placebo-controlled study (NCT04849741) in patients 2–65 years of age (median age, 11 years) with AxD.⁷ Zilganersen was administered via intrathecal bolus every 12 weeks. Based on interim results, patients receiving zilganersen 50 mg demonstrated significantly greater stabilization of gait function than those receiving placebo at Week 61, as measured by the primary endpoint of the 10-Meter Walk Test during the double-blind treatment period (LSM difference, 33.3%; P=0.0412). There is no cure for AxD; current treatment is symptomatic and supportive. If approved, zilganersen will be the first medicine available for patients with AxD that addresses the underlying cause of the disease.

For more information, see the zilganersen Deep dive in the July 2026 edition of Prime’s Quarterly Drug Pipeline.

Sept. 26, 2026: zilurgisertib 

Zilurgisertib is a once-daily, oral activin receptor-like kinase 2 (ALK2) inhibitor by Mirum Pharmaceuticals and Incyte. It is under Priority Review for the treatment of fibrodysplasia ossificans progressiva (FOP), an ultra-rare, progressive genetic disorder characterized by heterotopic ossification (HO), in which bone forms abnormally within soft tissues — including muscles, tendons and ligaments — leading to severe disability and loss of mobility. The FDA has granted zilurgisertib Fast Track and Orphan Drug designations. The application is supported by data from Cohort 1 of the Phase 2 PROGRESS study. Among patients 12 years of age and older, topline results demonstrated that zilurgisertib reduced the proportion of patients developing new HO lesions by 81% versus placebo at Week 24, although the result did not reach statistical significance (P=0.0986). Despite this, the therapy resulted in a 99% reduction in total volume of new HO lesions compared with placebo (nominal P<0.0001). Additionally, no new HO lesions were detected between Weeks 24 and 48 among patients receiving zilurgisertib, and total HO lesion volume continued to decline during this period.⁸ If approved, zilurgisertib could become the third agent in the United States for FOP, following the approval of the once-daily, oral retinoid palovarotene (Sohonos) in 2023 and the potential approval of the monthly, IV-administered investigational anti-Activin A monoclonal antibody garetosmab (FDA decision expected in August 2026).

Sept. 27, 2026: lirafugratinib 

Elevar Therapeutics is seeking FDA Accelerated Approval for lirafugratinib, a selective oral fibroblast growth factor receptor 2 (FGFR2) inhibitor, for the treatment of cholangiocarcinoma (CCA) harboring FGFR2 fusions or rearrangements in patients who have received prior therapy. The FDA has granted lirafugratinib Breakthrough Therapy, Fast Track and Orphan Drug designations. The application is supported by results from the open-label, Phase 1/2 ReFocus trial, which included a cohort of patients with advanced or metastatic CCA with FGFR2 fusions/rearrangements who had received at least one prior systemic therapy but had not received prior treatment with an FGFR inhibitor.⁹ Among evaluable patients, once-daily lirafugratinib demonstrated an objective response rate of 47%, as assessed by an independent review committee (IRC). The median duration of response was 11.8 months, the median progression-free survival was 11.3 months, the median overall survival was 22.8 months and the disease control rate was 96.5%. CCA is a rare and aggressive malignancy with limited treatment options following disease progression on standard therapies. If approved, lirafugratinib would provide an additional targeted treatment option for patients with FGFR2 fusion- or rearrangement-positive disease.

Sept. 28, 2026: tiratricol (Emcitate)

Tiratricol, by Egetis Therapeutics, is undergoing FDA Priority Review for the treatment of monocarboxylate transporter 8 (MCT8) deficiency, also known as Allan-Herndon-Dudley syndrome, a rare, X-linked disorder caused by mutations in the solute carrier family 16 member 2 (SLC16A2) gene. These mutations impair the function of the MCT8 transport protein, limiting thyroid hormone uptake into the brain and resulting in abnormal neurodevelopment, intellectual disability, motor impairment, seizures, hypotonia, spasticity and characteristic thyroid hormone abnormalities. The FDA has granted tiratricol Breakthrough Therapy, Fast Track, Orphan Drug and RPD designations. Tiratricol is a thyroid hormone analog that mimics the activity of endogenous triiodothyronine (T3) and is administered daily, either orally or via a percutaneous endoscopic gastrostomy (PEG) tube. Interim data from the Phase 2 Triac Trial II study revealed that tiratricol did not result in a statistically significant improvement in neurocognitive development compared with historical controls in boys with MCT8 deficiency.¹⁰ However, published data from the Phase 2 Triac Trial I showed significant improvements in thyroid hormone parameters, including serum concentrations of T3, thyroxine (T4), total T4 and reverse T3 (all P<0.0001) at Month 12. In addition, 78% of patients achieved serum T3 levels within the normal range by Month 4 of treatment.¹¹ Notably, the Phase 3 ReTRIACt withdrawal trial demonstrated a return of elevated serum T3 levels after discontinuation of tiratricol.¹² Current pharmacotherapy for MCT8 deficiency is directed toward symptomatic and supportive care. If approved, tiratricol will be the only medicine in the United States indicated for patients with MCT8 deficiency.

For more information, see the tiratricol (Emcitate) Deep dive in the July 2026 edition of Prime’s Quarterly Drug Pipeline.

Sept. 30, 2026: apitegromab

Scholar Rock is awaiting an FDA decision for its selective latent myostatin inhibitor, apitegromab, for the treatment of spinal muscular atrophy (SMA). Apitegromab is designed to promote muscle growth and improve muscle strength by inhibiting latent myostatin. This is the second FDA review of the drug, after the FDA issued a CRL in September 2025 related to observations identified during a routine inspection of a third-party, fill-finish facility that were unrelated to apitegromab. The FDA has granted apitegromab Fast Track, Orphan Drug and RPD designations. In clinical trials, apitegromab was administered as an IV infusion every four weeks. Published results from the Phase 3 SAPPHIRE trial demonstrated that apitegromab added to standard of care (SOC; nusinersen or risdiplam) significantly improved motor function at Week 52, compared with placebo plus SOC, in nonambulatory patients 2–12 years of age with type 2 or type 3 SMA, as assessed by the Hammersmith Functional Motor Scale Expanded (HFMSE). Approximately 30.4% of patients who received apitegromab had >3-point improvement in HFMSE compared with 12.5% of patients who received placebo.¹³ If approved, apitegromab will provide a new mechanism of action to treat SMA. Notably, the Institute for Clinical and Economic Review (ICER) released their final evidence report in September 2025 assessing the comparative clinical effectiveness and value of treatments for SMA, including apitegromab. ICER stated that the addition of apitegromab to SOC in patients 2–12 years of age with type 2 or type 3 SMA likely provides comparable or incremental benefits compared with no additional therapy, but that there is some possibility of substantial benefit with long-term use, as well as some possibility of net harm.

For more information, see the apitegromab Deep dive in the July 2025 edition of Prime’s Quarterly Drug Pipeline.

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