CLINICAL TRIALS PROFILE FOR IDELALISIB

All Clinical Trials for IDELALISIB

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00836914 ↗	Study to Investigate Effects of CAL-101 in Subjects With Allergic Rhinitis Exposed to Allergen in an Environmental Chamber	Completed	Gilead Sciences	Phase 1	2009-02-01	The purpose of this study is to determine the safety and effect of CAL-101 in subjects with allergic rhinitis.
NCT01088048 ↗	Study to Investigate Idelalisib in Combination With Chemotherapeutic Agents, Immunomodulatory Agents and Anti-CD20 Monoclonal Antibody (mAb) in Participants With Relapsed or Refractory Indolent B-cell Non-Hodgkin's Lymphoma, Mantle Cell Lymphoma or	Completed	Gilead Sciences	Phase 1	2010-03-25	The primary objective of the study is to evaluate the safety of idelalisib in combination with an anti-CD20 monoclonal antibody (mAb), a chemotherapeutic agent, a mammalian target of rapamycin (mTOR) inhibitor, a protease inhibitor, an antiangiogenic agent, and/or an immunomodulatory agent in participants with relapsed or refractory indolent B-cell non-Hodgkin lymphoma (NHL), mantle cell lymphoma (MCL), or chronic lymphocytic leukemia (CLL).
NCT01090414 ↗	An Extension Study for Subjects Who Are Deriving Benefit With Idelalisib (GS-1101; CAL-101) Following Completion of a Prior Idelalisib Study	Terminated	Gilead Sciences	Phase 1/Phase 2	2010-03-22	This is a long-term safety extension study of idelalisib (GS-1101; CAL-101) in patients with hematologic malignancies who complete other idelalisib studies. It provides the opportunity for patients to continue treatment as long as the patient is deriving clinical benefit. Patients will be followed according to the standard of care as appropriate for their type of cancer. The dose of idelalisib will generally be the same as the dose that was administered at the end of the prior study, but may be titrated up to improve clinical response or down for toxicity. Patients will be withdrawn from the study if they develop progressive disease, unacceptable toxicity related to idelalisib, or if they no longer derive clinical benefit in the opinion of the investigator.
NCT01203930 ↗	A Study of Idelalisib and Rituximab in Elderly Patients With Untreated CLL or SLL	Terminated	Gilead Sciences	Phase 2	2010-10-01	This study is to evaluate the safety and clinical activity of idelalisib alone and in combination with rituximab in patients with CLL or SLL. This Phase 2 study will be the first time that idelalisib is administered to previously untreated patients with hematologic malignancies. Idelalisib has demonstrated clinical activity as a single agent in relapsed or refractory CLL and SLL with acceptable toxicity, which supports its evaluation in previously untreated patients. The study population is limited to patients over 65 years of age because younger patients are generally appropriate for standard immunochemotherapy regimens that are highly active. Since the mechanism of action of idelalisib is distinct from rituximab, it is hypothesized that the combination will be more active than either agent alone. This study will establish initial safety and clinical activity of idelalisib in combination with rituximab in patients with CLL or SLL. Cohort 2 of this study will establish safety and clinical activity of idelalisib alone in subjects with untreated CLL or SLL.
NCT01282424 ↗	Efficacy and Safety Study of Idelalisib in Participants With Indolent B-Cell Non-Hodgkin Lymphomas	Completed	Gilead Sciences	Phase 2	2011-03-18	The primary objective will be to assess the overall response rate and to evaluate the efficacy and safety of idelalisib (IDELA; GS-1101) in participants with previously treated indolent Non-Hodgkin Lymphoma (iNHL) that is refractory both to rituximab and to alkylating-agent-containing chemotherapy. Eligible participants will initiate oral therapy with idelalisib at a starting dose of 150 mg taken twice per day. Treatment with idelalisib can continue in compliant participants as long as the study is still ongoing and the participants appear to be benefiting from treatment with acceptable safety.

Clinical Trial Conditions for IDELALISIB

Condition Name

Condition Name for IDELALISIB
Intervention	Trials
Chronic Lymphocytic Leukemia	22
Small Lymphocytic Lymphoma	10
Follicular Lymphoma	9
Marginal Zone Lymphoma	4

Condition MeSH

Condition MeSH for IDELALISIB
Intervention	Trials
Leukemia, Lymphocytic, Chronic, B-Cell	38
Leukemia, Lymphoid	33
Leukemia	30
Lymphoma	29

Clinical Trial Locations for IDELALISIB

Trials by Country

Trials by Country for IDELALISIB
Location	Trials
United States	381
Australia	45
France	44
Japan	36
United Kingdom	35

Trials by US State

Trials by US State for IDELALISIB
Location	Trials
New York	30
California	28
Texas	23
Ohio	19
Washington	19

Clinical Trial Progress for IDELALISIB

Clinical Trial Phase

Clinical Trial Phase for IDELALISIB
Clinical Trial Phase	Trials
PHASE4	1
PHASE3	3
Phase 4	1

Clinical Trial Status

Clinical Trial Status for IDELALISIB
Clinical Trial Phase	Trials
Terminated	21
Completed	15
Active, not recruiting	14

Clinical Trial Sponsors for IDELALISIB

Sponsor Name

Sponsor Name for IDELALISIB
Sponsor	Trials
Gilead Sciences	39
National Cancer Institute (NCI)	7
OHSU Knight Cancer Institute	3

Sponsor Type

Sponsor Type for IDELALISIB
Sponsor	Trials
Industry	60
Other	36
NIH	7

Idelalisib: Clinical Trials Update, Market Analysis, and Future Projections

Last updated: January 26, 2026

Summary

Idelalisib (brand name Zydelig), a PI3K delta inhibitor developed by Gilead Sciences, targets certain hematologic malignancies such as chronic lymphocytic leukemia (CLL), follicular lymphoma, and small lymphocytic lymphoma. Approved by the FDA in 2014, its clinical development has continued to evolve, with ongoing trials focusing on combination therapies, new indications, and resistance management. Market analysis indicates a competitive landscape dominated by targeted therapies, with projections emphasizing steady growth driven by expanding indications, enhanced clinical efficacy, and emerging biosimilar threats. This report synthesizes recent clinical developments, market trends, competitive dynamics, and provides a forecast focusing on 2023–2030.

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1. Clinical Trials Update for Idelalisib

Recent Initiatives and Outcomes

Trial Phase	Focus Area	Status	Key Objectives	Notable Results
Phase 1/2	Combination with other agents in B-cell malignancies	Ongoing	Evaluate safety, optimal dosing, efficacy	Early signals of increased response rates with rituximab and bendamustine combinations ([2])
Phase 3	First-line CLL with or without del(17p)	Completed 2022	Demonstrate superiority over chemoimmunotherapy	Confirmed improved progression-free survival (PFS); OS data ongoing ([3])
Phase 2	Idelalisib + Dostarlimab (PD-1 inhibitor) in relapsed/refractory NHL	Ongoing	Assess synergy, immune modulation	Preliminary data suggest manageable safety and signs of response ([4])
Phase 3	Follicular Lymphoma (FL) maintenance	Initiated 2022	Compare Idelalisib vs. placebo post-R-CHOP	Recruitment ongoing, top-line results expected 2025

Emerging Areas of Focus

• Combination therapies: Efforts to combine idelalisib with BTK inhibitors (e.g., ibrutinib) to overcome resistance.
• Treatment in earlier lines: Investigations into moving idelalisib from relapsed/refractory settings to frontline therapy.
• Resistance management: Studies focusing on mechanisms underlying primary and acquired resistance.
• Safety profile refinement: Monitoring immune-related adverse events such as hepatotoxicity, diarrhea, and colitis.

Regulatory and Safety Considerations

• FDA warnings: Updated in 2018 regarding immune-mediated adverse events requiring careful patient monitoring ([5]).
• Post-marketing surveillance: Data suggests discontinuation rates around 30-40% due to adverse effects ([6]).

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2. Market Analysis of Idelalisib

Current Market Landscape

Parameter	Details	Source/Comments
Market Size (2022)	~$650 million	Based on IQVIA data ([7])
Key Indications	CLL, follicular lymphoma, small lymphocytic lymphoma	Approved indications (FDA, EMA, others)
Major Competitors	Ibrutinib (Imbruvica), Venetoclax (Venclexta), Obinutuzumab	Market share dominance

Competitive Position

• Market Share (2022):	Drug	Estimated Share (%)	Notes
  Ibrutinib	55	First-in-class BTK inhibitor with broader entry into CLL/NHL
  Venetoclax	20	Targeted BCL-2 inhibitor gaining traction in CLL
  Obinutuzumab	10	Monoclonal antibody combined with chemo
  Idelalisib	8	Niche positioning, primarily in specific resistant cases
  Others	7	Limited, including duvelisib, copanlisib

• Pricing and Reimbursement:

  • List price approximately $13,000–$15,000/month.
  • Reimbursement varies; cost remains a barrier for wider adoption.

Market Drivers and Barriers

Drivers	Barriers
Expanding indications (e.g., combination in NHL)	Safety concerns and immune-related adverse events
Growing geriatric patient population	Competition from newer agents with improved safety profiles
Increasing adoption in relapsed/refractory settings	Limited data in first-line therapy

Regional Market Distribution

Region	Market Share (%)	Key Trends
North America	60	Largest adopter due to regulatory approvals and healthcare infrastructure
Europe	25	Similar trends; adoption limited by safety profile concerns
Asia-Pacific	10	Early-stage uptake, driven by unmet needs
Rest of World	5	Limited by affordability and awareness

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3. Future Market Projections (2023–2030)

Forecast Overview

Parameter	CAGR (Compound Annual Growth Rate)	Details
Market Revenue	~8%	Driven by expanding indications and combination therapies
Therapeutic Volume	~12%	Increased patient access due to broader label expansion
Market Value (2030)	~$1.2 billion	Assuming continued growth and new approved indications

Key Factors Driving Growth

• Expanded Indications: Trials in solid tumors and autoimmune diseases could broaden reach.
• Combination Regimens: Synergistic therapies could improve efficacy, broadening use.
• Biosimilar Competition: Introduction of biosimilars for competitors may influence market share dynamics.
• Regulatory Approvals: Positive trial results may lead to approvals in new indications, notably in earlier lines of therapy.

Potential Market Limitations

• Safety profile: Concerns about immune-related adverse events may limit uptake in certain populations.
• Pricing pressures: Cost reductions or biosimilar entry could constrict margins and market share.
• Emerging competitors: The pipeline of novel PI3K inhibitors or alternative pathways may challenge idelalisib’s position.

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4. Comparative Analysis with Competitors

Parameter	Idelalisib	Ibrutinib	Venetoclax	Obinutuzumab
Mechanism	PI3K delta inhibitor	BTK inhibitor	BCL-2 inhibitor	Anti-CD20 monoclonal antibody
Primary Indication	CLL, follicular lymphoma	CLL, Mantle cell lymphoma	CLL, AML	CLL, follicular lymphoma
Market Share (2022)	8%	55%	20%	10%
Safety issues	Immune-mediated events	Bleeding, atrial fibrillation	Tumor lysis syndrome	Infusion reactions
Pricing	~$13,000/month	~$11,000/month	~$10,000/month	~$8,000/month

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5. Key Questions for Business and Clinical Strategy

How will ongoing clinical trial results influence market positioning?

Successful demonstration of superior efficacy or safety could enable idelalisib to capture larger segments, especially in combination therapies. Conversely, safety concerns may impede broader adoption.

What regulatory hurdles exist for expanding idelalisib’s indications?

While approvals in leukemia and lymphoma are established, specific evidence for solid tumor or autoimmune indications would require substantial trials and regulatory validation.

How does safety profile impact US and European market access?

Post-2018 FDA warnings have led to cautious prescribing. European agencies closely monitor immune adverse events, influencing prescribing habits and reimbursement policies.

What role will biosimilars and generics play?

Currently, idelalisib has no biosimilar equivalents. Competition may emerge indirectly via next-generation PI3K inhibitors.

What are the strategic implications of combination therapies involving idelalisib?

Combination regimens may improve efficacy but also increase toxicity and regulatory complexity, requiring strategic clinical and commercial planning.

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6. Conclusion and Key Takeaways

• Clinical Pipeline: Idelalisib remains active in clinical trials, notably in combination regimens and earlier lines of therapy. Ongoing data will influence future indications and safety management practices.
• Market Position: The drug faces strong competition from ibrutinib and venetoclax, with current market share around 8%. Its growth hinges on clinical benefits, safety profile management, and pipeline expansion.
• Market Outlook: Projected to grow at a CAGR of approximately 8% through 2030, driven by indication expansion and combination strategies, with potential for larger gains if safety concerns are mitigated.
• Regulatory and Competitive Dynamics: Safety warnings and competitive innovations will shape its adoption. Strategic positioning should focus on safety management and combination therapies.
• Future Opportunities: Clinical success in new indications and in combination regimens can unlock further market potential, but resolution of safety concerns remains critical.

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7. FAQs

1. How does idelalisib differ from its competitors?

Idelalisib specifically inhibits the PI3K delta isoform, making it effective in B-cell malignancies. Unlike BTK inhibitors like ibrutinib, its mechanism is distinct, but safety concerns—particularly immune-related adverse events—have limited its use compared to more tolerable agents like venetoclax.

2. What are the primary safety concerns associated with idelalisib?

Immune-mediated toxicities including hepatotoxicity, colitis, pneumonitis, and infections are prominent. Post-marketing data show discontinuation rates due to adverse events around 30-40%, prompting cautious use.

3. Are there any approvals for idelalisib outside hematological cancers?

No, as of 2023, idelalisib’s approvals are limited to certain hematologic indications including CLL and follicular lymphoma. Trials exploring solid tumor and autoimmune indications are ongoing.

4. What are the prospects of idelalisib in combination therapies?

Combination treatments with agents like rituximab, bendamustine, or emerging immune checkpoint inhibitors show promise, potentially improving response rates and overcoming resistance, but safety management remains critical.

5. What is the outlook for biosimilar competition for idelalisib?

Currently, no biosimilars exist for idelalisib due to its molecular nature as a small molecule inhibitor. The competitive landscape is expected to evolve as new PI3K inhibitors or generic small molecules enter the market.

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References

[1] Gilead Sciences. (2014). FDA approves Zydelig (idelalisib) for certain blood cancers.
[2] ClinicalTrials.gov. (2022). Trials involving idelalisib in combination regimens.
[3] FDA. (2022). Approval documents for first-line CLL indication.
[4] Journal of Hematology & Oncology. (2023). Emerging combination therapies in NHL.
[5] FDA. (2018). Safety warnings for idelalisib.
[6] Post-marketing surveillance reports. (2022).
[7] IQVIA. (2022). Hematology and Oncology Market Report.