CLINICAL TRIALS PROFILE FOR TELITHROMYCIN

All Clinical Trials for telithromycin

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00132938 ↗	PERSPECTIVE: Telithromycin - Acute Exacerbation of Chronic Bronchitis	Completed	Sanofi	Phase 4	2004-01-01	Primary Objective: - The primary objective of the study is to demonstrate the superiority of telithromycin over azithromycin and over cefuroxime axetil in the reduction of Streptococcus pneumoniae (Sp) strains resistant to beta-lactams or macrolides at the Test of Cure (TOC) visit in the sputum of patients with Sp detected at the start of the study (Visit 1). Secondary Objectives: The secondary objectives of the study are: - To demonstrate the superiority of telithromycin over azithromycin and over cefuroxime axetil in achieving clinical cure and Sp eradication success at the Test of Cure visit in patients with Sp detected in sputum specimen at the start of the study (Visit 1); - To compare the clinical cure rates achieved by each treatment group in the penicillin or erythromycin resistant Sp (PERSp) population with the cure rates in the sensitive Sp (SSp) population at the End of Therapy (EOT) and Test of Cure visits; - To compare the effect of telithromycin, azithromycin and cefuroxime axetil at the End of Therapy visit on the presence of Streptococcus pneumoniae strains resistant to beta-lactams or macrolides in the sputum of patients with Sp detected at the start of the study (Visit 1); - To compare the clinical efficacy at the End of Therapy visit and safety at the Test of Cure visit of telithromycin, azithromycin and cefuroxime axetil in the "global" randomized population.
NCT00132951 ↗	KEYS: Study Comparing Clinical Health Outcomes of Telithromycin Versus Azithromycin in Outpatients With Community-acquired Lower Respiratory Tract Infections	Terminated	Sanofi	Phase 4	2004-10-01	The purpose of this study is to determine if 1 course of antibiotic treatment with telithromycin is superior to azithromycin in the treatment of lower respiratory tract infections (LRTIs), acute exacerbations of chronic bronchitis (AECBs) and community-acquired pneumonia (CAP) in the community setting.
NCT00164112 ↗	Comparative Effects of Azithromycin, Telithromycin and Levofloxacin on Drug Metabolizing Enzymes	Completed	PriCara, Unit of Ortho-McNeil, Inc.	Phase 4	2004-11-01	Studies have previously shown that a broad drug interaction screening can be performed using enzyme specific probes such as oral caffeine for CYP1A2, N-acetyltrasferase-2 (NAT-2), and xanthine oxidase (XO), warfarin plus vitamin K for CYP2C9, omeprazole for CYP 2C19, dextromethorphan for CYP2D6, and midazolam for CYP3A4/5. This combination of probes has been validated in the Cooperstown 5+1 Cocktail (5+1).1 The use of the 5+1 cocktail provides information on the drug metabolizing enzymes that metabolize 90% of hepatically eliminated drugs for a fraction of the costs of the individual studies. Using a cocktail of biomarkers reduces the overall cost of drug interaction screening. The purpose of this study is to evaluate the effects of three Food and Drug Administration (FDA) approved oral antibiotics (azithromycin, telithromycin, and levofloxacin) on metabolism of other medications when taken together. This will be determined by the measuring the activity of drug metabolizing enzymes following administration of certain drug probes (caffeine, dextromethorphan, omeprazole, midazolam, and warfarin with vitamin K). A total of 16 subjects will complete four phases of the study: 1) Cooperstown 5+1 alone, 2) Azithromycin plus Cooperstown 5+1, 3) Telithromycin plus Cooperstown 5+1, and 4) Levofloxacin plus Cooperstown 5+1.
NCT00164112 ↗	Comparative Effects of Azithromycin, Telithromycin and Levofloxacin on Drug Metabolizing Enzymes	Completed	Bassett Healthcare	Phase 4	2004-11-01	Studies have previously shown that a broad drug interaction screening can be performed using enzyme specific probes such as oral caffeine for CYP1A2, N-acetyltrasferase-2 (NAT-2), and xanthine oxidase (XO), warfarin plus vitamin K for CYP2C9, omeprazole for CYP 2C19, dextromethorphan for CYP2D6, and midazolam for CYP3A4/5. This combination of probes has been validated in the Cooperstown 5+1 Cocktail (5+1).1 The use of the 5+1 cocktail provides information on the drug metabolizing enzymes that metabolize 90% of hepatically eliminated drugs for a fraction of the costs of the individual studies. Using a cocktail of biomarkers reduces the overall cost of drug interaction screening. The purpose of this study is to evaluate the effects of three Food and Drug Administration (FDA) approved oral antibiotics (azithromycin, telithromycin, and levofloxacin) on metabolism of other medications when taken together. This will be determined by the measuring the activity of drug metabolizing enzymes following administration of certain drug probes (caffeine, dextromethorphan, omeprazole, midazolam, and warfarin with vitamin K). A total of 16 subjects will complete four phases of the study: 1) Cooperstown 5+1 alone, 2) Azithromycin plus Cooperstown 5+1, 3) Telithromycin plus Cooperstown 5+1, and 4) Levofloxacin plus Cooperstown 5+1.
NCT00174694 ↗	CHOOSE : Telithromycin, Acute Bacterial Sinusitis	Completed	Sanofi	Phase 4	2004-11-01	Primary objective: - To demonstrate that the clinical efficacy of telithromycin (800 mg od for 5 days) is non-inferior to amoxicillin-clavulanic acid (875/125 mg bid for 10 days) at the test-of-cure (TOC) visit (Day 17-21) in subjects with acute bacterial sinusitis (ABS). Secondary objective(s): - To assess the time to resolution of signs and symptoms between the baseline (Day 1) and TOC (Day 17-21) visits, - To assess the rate of clinical relapse at the follow-up visit (Day 41-49), - To assess health economic outcome until follow-up visit (Day 41-49), - To assess quality of life up to the follow-up visit (Day 41-49), - To compare the safety of telithromycin and amoxicillin-clavulanic acid, - To compare the bacteriologic outcome of both treatments as observed at TOC (Day 17-21) and at follow-up visit (Day 41-49),in subjects with ABS.

Clinical Trial Conditions for telithromycin

Condition Name

Condition Name for telithromycin
Intervention	Trials
Pneumonia	4
Bronchitis, Chronic	3
Respiratory Tract Infections	2
Healthy	2

Condition MeSH

Condition MeSH for telithromycin
Intervention	Trials
Pneumonia	7
Bronchitis	6
Bronchitis, Chronic	6
Respiratory Tract Infections	3

Clinical Trial Locations for telithromycin

Trials by Country

Trials by Country for telithromycin
Location	Trials
United States	14
Chile	3
Argentina	3
Costa Rica	3
Japan	3

Trials by US State

Trials by US State for telithromycin
Location	Trials
New Jersey	8
Arizona	1
Massachusetts	1
Louisiana	1
Kentucky	1

Clinical Trial Progress for telithromycin

Clinical Trial Phase

Clinical Trial Phase for telithromycin
Clinical Trial Phase	Trials
Phase 4	14
Phase 3	11
Phase 2	1

Clinical Trial Status

Clinical Trial Status for telithromycin
Clinical Trial Phase	Trials
Completed	16
Terminated	9
Unknown status	2

Clinical Trial Sponsors for telithromycin

Sponsor Name

Sponsor Name for telithromycin
Sponsor	Trials
Sanofi	21
CPL Associates	2
Bayer	1

Sponsor Type

Sponsor Type for telithromycin
Sponsor	Trials
Industry	25
Other	12

Telithromycin Clinical Trials Update, Market Analysis, and Exclusivity Outlook (2026)

Last updated: May 20, 2026

Telithromycin (Ketek) has limited active late-stage clinical development and no ongoing large-scale registrational program in major jurisdictions. Commercially, the branded US market has been constrained since generic entry and regulatory risk remains tied to the drug’s boxed warning and label restrictions. Most current “clinical trials” activity is incremental, such as small mechanistic or formulation studies, and much of the global market is concentrated in legacy channels rather than broad new uptake.

What is telithromycin’s current clinical trials status (ongoing, recruiting, completed)?

Featured answer: Telithromycin’s current clinical footprint is thin in major phase 3 registrational categories; activity is mostly small, non-registrational studies, with low visibility of late-stage trials in public registries.

Where do telithromycin trials show up now (typical patterns)?

Public trial listings for telithromycin historically cluster into:

• Antibacterial activity and resistance surveillance studies
• Dose, food effect, pharmacokinetic (PK), and tolerability studies
• Formulation or analytical method validation (niche)
• Subgroup or comparative studies versus other antibiotics (often post-approval)

How does telithromycin’s regulatory label affect trial designs?

Telithromycin’s US label includes important safety restrictions and a boxed warning for severe adverse reactions (including hepatotoxicity, QT prolongation, and potential myasthenia gravis exacerbation). This drives contemporary clinical practice toward:

• Narrower indication framing
• Stronger exclusion criteria for neurological or cardiac risk
• Lower willingness to enroll in new efficacy trials unless a clear unmet need and a strong monitoring plan are built in

(Clinical trial activity remains possible, but the drug’s safety profile and reduced commercial incentive reduce phase 3 recruitment and sponsor interest.)

---

What do telithromycin late-stage clinical trial results show (efficacy vs safety trade-offs)?

Featured answer: Prior phase 3 efficacy established telithromycin as a potent oral ketolide for respiratory infections, but post-approval safety events changed prescriber behavior and regulatory handling in key markets.

Typical historical endpoints used in telithromycin development

• Clinical response rates in acute bacterial exacerbations of chronic bronchitis and community-acquired bacterial pneumonia
• Microbiological eradication
• Safety and tolerability (GI events and class-related events)
• ECG monitoring for QT-related concerns

Why safety has continued to shape clinical outcomes

Telithromycin’s risk profile has been the central determinant of uptake:

• Boxed warning and label restrictions reduced prescribing velocity.
• Regulatory authorities required additional warnings and restricted use in some indications.
• The patient population most likely to be treated (respiratory infection cohorts with comorbidities) often overlaps with populations that carry higher risk for hepatic and cardiac adverse events.

---

When does telithromycin lose exclusivity (patent expiration and regulatory exclusivity)?

Featured answer: Telithromycin’s core exclusivity and patent protection has long since expired in major markets; the current commercial reality is legacy brand use after generic availability.

Exclusivity levers for telithromycin to check (how they generally behave)

For a legacy small molecule:

• Composition-of-matter patents typically expire first
• Formulation patents (if any) expire later
• Use patents are often narrower and expire with fewer enforcement routes
• Regulatory exclusivity (New Chemical Entity) applies around approval timing, which is not current

Because telithromycin is an established marketed antibiotic, the exclusivity timeline is no longer a primary gating factor for competitive entry.

---

What is the Orange Book status of telithromycin (US FDA listed patents)?

Featured answer: Telithromycin is not generally protected by a strong, active patent stack that would block generic entry; Orange Book coverage, if present, is largely historical and does not reflect meaningful ongoing exclusivity for broad market control.

How Orange Book listings typically impact generic entry

For an orally administered small molecule like telithromycin:

• If listed patents are expired, generic entry is straightforward.
• If a use or formulation patent remains, Paragraph IV challenges and forfeiture or settlement can affect launch timing.
• In telithromycin’s case, public market behavior indicates that generics are already available and widely accessible.

---

How many patents cover telithromycin and what do they protect (composition, formulations, methods of use)?

Featured answer: Remaining patent coverage for telithromycin is limited in practical enforcement terms and does not appear to create broad, durable barriers against generics across key markets.

Patent estate categories that mattered historically

• Composition-of-matter: ketolide chemical series claims
• Crystalline forms / solid state: polymorph, hydrate/solvate, particle size
• Formulations: tablets and controlled release (if claimed)
• Methods of use: specific respiratory infection indications or patient subgroups
• Manufacturing methods: intermediates or specific synthesis routes

Given telithromycin’s commercial history, the composition estate is expected to be expired, with any surviving claims being narrow.

---

What formulations are protected for telithromycin (tablet composition, dosing strengths, stability patents)?

Featured answer: No active, broad formulation IP is expected to materially block generic oral tablets; telithromycin’s branded commercial footprint is therefore limited to legacy branding and channel preference rather than formulation exclusivity.

What matters for generic formulation risk

Generic telithromycin typically faces:

• Bioequivalence and dissolution matching requirements
• Stability testing to ensure shelf life
• Ingredient sourcing control and manufacturing controls

These are execution barriers, not IP barriers, once key patents expire.

---

What generic entry risks exist for telithromycin (Paragraph IV, settlements, launch blockers)?

Featured answer: Telithromycin has already faced generic competition; incremental launch risk is low because the market is not structured around ongoing patent blocking.

How Paragraph IV dynamics typically play out

• If any narrow patents remained, Paragraph IV filers could seek 30-month stay or resolve via settlement.
• Once patents expire, generic entry can occur without further litigation leverage.

The current market indicates the stay/settlement era has effectively passed.

---

What patent litigation affects telithromycin (major cases, settlement trends)?

Featured answer: Telithromycin’s litigation and settlements largely belong to the earlier generic-entry period; they do not appear to be a current driver of market access in 2026.

What to expect from older telithromycin litigation

Historically, antibiotic IP disputes usually focus on:

• Validity and infringement of composition or formulation claims
• Carve-outs tied to method-of-use claims
• Settlement terms that delay launch relative to filers’ intended dates

Current competitive reality implies these effects have resolved.

---

How strong is the patent estate for telithromycin compared with other ketolides/antibiotics?

Featured answer: Compared with newer respiratory antibiotics with robust late-stage patent estates, telithromycin’s patent strength is weak for ongoing commercial differentiation.

Competitive implications

• Newer agents with ongoing line extensions and reformulations can maintain exclusivity longer.
• Telithromycin’s label restrictions and safety warnings reduce competitive share even when IP is weak.

---

How does telithromycin compare with macrolides (azithromycin, clarithromycin) in market share and regulatory behavior?

Featured answer: Market uptake for macrolides has generally persisted due to broader label acceptance and fewer severe boxed-warning constraints, leaving telithromycin with a smaller addressable segment.

Key differentiators that influence prescribing

• Safety profile and boxed warning impact
• Guideline positioning for respiratory infections
• Local resistance patterns and preferred empiric therapy
• Availability of alternatives with better tolerability or fewer severe risks

---

What is the biosimilar risk for telithromycin (and is it relevant)?

Featured answer: Biosimilar risk is not relevant because telithromycin is a small-molecule antibiotic, not a biologic.

---

What is the global commercial landscape for telithromycin (volume, pricing, major geographies)?

Featured answer: Telithromycin’s commercial activity is largely legacy and geographically uneven, with the US brand representing a constrained market due to safety label restrictions and generic availability.

Where demand concentrates

• Markets where brand retention persists through channel inertia
• Prescriber segments that still use telithromycin for specific respiratory indications despite restrictions
• Countries with less aggressive generic substitution or where brand discounting maintains shelf presence

Pricing dynamics

• Branded pricing is compressed by generic reference pricing.
• Where generic penetration is high, brand pricing loses relevance and shelf presence becomes the key differentiator.

---

Market projections for telithromycin through 2030 (base, bull, bear scenarios)

Featured answer: Through 2030, telithromycin market value is likely to remain on a declining or flat-to-down trajectory, driven by mature generic competition and fixed label constraints.

Base case (most likely)

• Gradual decline in branded units in the US and other mature markets
• Stabilization in select geographies where brand channels persist
• Limited reacceleration due to the absence of new registrational evidence and weak sponsor incentives

Bull case

• Minor stabilization from guideline-driven niche use in settings with specific susceptibility patterns
• Local brand campaigns offset generic substitution in limited geographies

Bear case

• Further erosion from safety-driven prescribing shifts to alternative antibiotics
• Tighter restrictions from regulators or hospital formulary changes
• Accelerated generic price declines and further channel loss

Projection drivers

• Safety perception tied to boxed warning and label restrictions
• Replacement by newer respiratory antibiotics and stewardship preferences
• Generic penetration and ongoing price compression

---

What is the competitive landscape for telithromycin (key substitutes and overlap)?

Featured answer: Substitution pressure comes primarily from macrolides, fluoroquinolones, and newer respiratory antibiotics with broader label acceptance.

Common overlap categories

• Community-acquired bacterial pneumonia
• Acute bacterial exacerbations of chronic bronchitis
• Other respiratory tract bacterial infections where ketolides are historically used

Substitution behavior

• When stewardship selects preferred first-line agents, telithromycin use typically declines
• Safety-sensitive populations accelerate switching away from ketolides

---

Key Takeaways

• Telithromycin’s clinical pipeline visibility is limited, with activity skewed toward small studies rather than new phase 3 registrational programs.
• The market is shaped more by boxed-warning label restrictions and generic competition than by active exclusivity.
• Exclusivity and patent-driven barriers have largely resolved; Orange Book and litigation effects from earlier generic entry do not appear to be active market levers in 2026.
• Through 2030, branded telithromycin is more likely to face continued decline or flat-to-down performance unless a narrow niche expands.

FAQs

1. Are there any recruiting phase 3 trials for telithromycin in 2026?
2. Does telithromycin have ongoing formulation patents that block generics?
3. What FDA label restrictions limit telithromycin use in the US?
4. How does telithromycin compare with azithromycin in safety and prescribing patterns?
5. Is telithromycin still sold in major EU markets, and how does generic penetration differ by country?

References (APA)

1. U.S. Food and Drug Administration. (n.d.). Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm
2. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: FDA Approved Drug Products. https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm