Temozolomide is chemotherapy for selected brain cancers. This adult guide compares specific US and GB product information; other medicines, countries and off-label combinations need separate review.
- Follow your prescribed calendar.
- Manufacturer-supported trials are excluded from our independent outcome verdict.
- Follow country/product instructions.
Table of contents
- Evidence summary
- What it is and licensed uses
- How it works
- Specialist care and treatment choices
- Supplements and supportive care
- Trials and evidence limits
- Risks and urgent symptoms
- Interactions
- Pregnancy, breastfeeding and fertility
- Taking and handling it safely
- Animal and laboratory evidence
- Funding: follow the money
- Frequently asked questions
- Sources and funding notes
Evidence summary
Independent comparative outcome evidence remains unestablished in this review.
What it is and licensed uses
Modern WHO terminology distinguishes IDH-wildtype glioblastoma from IDH-mutant astrocytoma. Older trial/label names do not automatically establish the same molecular diagnosis.
How it works
Temozolomide forms an active compound that damages DNA through methylation. A mechanism cannot establish patient benefit.
Specialist care and treatment choices
NICE recommendations consider tumor type, MGMT methylation status, age and daily functioning for surgery, radiotherapy and chemotherapy choices. MGMT does not guarantee response; ask the team how your result affects your options.
Related guide: adult primary brain and CNS tumors. This article does not supply a personal dose or treatment calendar.
Supplements and supportive care
Ask oncology about anti-sickness treatment; report repeated vomiting.
No supplement is established as a replacement here. Bring supplement labels to the oncology pharmacist; an exhaustive supplement-interaction or anticancer review was not performed.
Trials and evidence limits
Stupp 2005: 573 patients randomized; eligibility was 18–70 with historical glioblastoma. Radiotherapy plus concurrent/adjuvant temozolomide was compared with radiotherapy. This treatment package does not represent every brand, molecular subtype or individual prognosis.
Perry 2017: 562 randomized patients aged at least 65, considered unsuitable for conventional six-week combined treatment; short-course radiotherapy with versus without temozolomide. Selected older patients do not represent every older adult.
CATNON 2021: 751 randomized patients in a factorial, open-label trial of concurrent and/or adjuvant temozolomide for historical non-codeleted anaplastic glioma. Molecular subgroup findings do not justify treating every glioma identically.
The 2026 final abstract reports longer follow-up of the same CATNON cohort, not independent replication. Safety data were not reported in that abstract; its full article was not reviewed.
Risks and urgent symptoms
Nausea, vomiting, fatigue and constipation occur; avoid driving if sleepy.
US: serious allergy to temozolomide, its ingredients or dacarbazine precludes treatment.
Interactions
Check every medicine/supplement with oncology; never change seizure treatment yourself.
Pregnancy, breastfeeding and fertility
Can harm unborn babies; discuss pregnancy/fertility before treatment.
Taking and handling it safely
US: take consistently with or without food.
Confirm capsule strengths/days; US infusion requires professionals.
US overdose: contact your provider or emergency help immediately.
Animal and laboratory evidence
Funding: follow the money
Research funding at a glance
22 disclosure entries. The counts below summarize independence tiers explicitly assigned in this article. They count disclosures, not studies, funding amounts or evidence quality.
Consult this article’s source and funding notes for named funders, countries, relationships and exceptions where available. Institutional backing, researcher interests and trial sponsorship are separate questions. Public funding alone does not establish independence; commercial ties alone do not prove a claim false. This overview is not a new financial audit.
The installed funding graphic summarizes these disclosures. Its counts describe sources, not research spending, trial quality or numbers of independent studies.
A–D are editorial independence ratings for this review. A is strongest; D includes commercial or manufacturer-supported sources. Official medicine safety instructions still apply. The infographic labels each funding tier.
| Documented route | Limits |
|---|---|
| Schering-Plough Holdings Limited → Merck Sharp & Dohme (UK) Limited | Recorded shares/votes ≥75% and director rights; notified 6 April 2016. A control band is not an exact stake. |
| Merck & Co., Inc. (US) → Schering-Plough Holdings Limited (UK) | Recorded shares/votes ≥75% and director rights; exact stake unknown. |
| Merck group finance | 2025 operating cash and debt finance support the group. Current group income does not identify historical trial grants or product-specific receipts. |
Historical trial grants are disclosed in the original papers below. Current institutional accounts do not audit those grants; sponsorship and author relationships are separate questions.
| Source and date | Country / jurisdiction | Funding / backers | Tier | Credibility / incentives / gaps |
|---|---|---|---|---|
| Temodar (2026) | Rahway, US | MSD LLC distributor; revenue/parent untraced. | Tier 4 | D. Regulatory/sales incentives; pediatric safety/benefit unestablished. |
| GB Temodal SmPC: July 2023 | London, UK | Merck Sharp & Dohme (UK) holder; commercial product information. Exact page payments unknown. | Tier 4 | D. Regulatory duties; commercial interest. |
| GB Temodal leaflet: August 2023 | UK / Netherlands | Merck Sharp & Dohme (UK) holder; MSD B.V. manufacturer, Haarlem. | Tier 4 | D. Safety duties/sales interest; Dutch parent unverified. |
| FDA Project Renewal: September 2023 | US | Public regulator; appropriations and industry user fees. Project payments unknown. | Tier 2 | B provisional. Legal accountability; possible regulatory framing. |
| Companies House: UK holder control | UK registry / England law | Public control filing; registry revenue not traced here. | Tier 2 | B provisional. Filing duties; submitted-record limits, not full ownership audit. |
| Companies House: UK parent control | UK registry / US parent | Public control filing; registry revenue not traced here. | Tier 2 | B provisional. Filing duties; submitted-record limits, not private cash flow. |
| CATNON: 2021 interim original | Multinational; Dutch-led | MSD grant/drug; NRG/NCI grants, CRUK, Australian public grants; molecular work: Brain Tumour Charity, Dutch Cancer Society, Strijd van Salland. | Tier 4 | D for independent outcomes. Randomization/disclosures enable scrutiny; author company ties remain. |
| CATNON: January 2026 final abstract | Multinational; Dutch-led | MSD funded; disclosed personal/institutional company relationships. | Tier 4 | D for independent outcomes. Same cohort; full body, safety reporting and disclosure forms unreviewed. |
| Merck 2025 Form 10-K | Rahway, US; New Jersey incorporation | Medicine sales, operating cash and debt finance; listed NYSE: MRK. | Tier 4 | D. Filing accountability; management framing. Shareholder/proxy audit incomplete. |
| FDA FY2026 operating plan | US | Budget authority and industry user fees, including human-drug activity. | Tier 2 | B provisional. Budget accountability; political/agency framing. |
| NCI temozolomide overview: September 2023 | Bethesda, US | Congressional funding; page-specific allocations untraced. | Tier 2 | B provisional. Public accountability; institutional framing and incomplete drug summary. |
| Stupp et al.: 2005 original | Multinational; Swiss/Canadian-led | NCI grant; Schering-Plough educational grant and drug. Disclosed Schering consulting/lecture ties; additional EMD, Oncomethylome and Novartis ties. | Tier 4 | D for independent outcomes. Randomization helps; industry support remains despite reported non-role. |
| Perry et al.: 2017 original | Canada / Europe / Australia–New Zealand | Canadian Cancer Society Research Institute grants; Schering (now Merck) unrestricted grant/drug; EORTC Cancer Research Fund. | Tier 4 | D for independent outcomes. Cooperative oversight; manufacturer reported non-role. Separate forms unread. |
| EORTC 2025 annual report | Brussels, Belgium; Belgian law | Academic grants, industry grants/sponsored work, royalties, services and subsidies; ECRF includes corporate/private support. | Tier 2 | B provisional. Reporting duties; institutional framing. Current income does not identify 2017 grant payments. |
| Canadian Cancer Society financial page | Canada | Charity registration 118829803RR0001; donations and corporate-giving routes. | Tier 2 | B provisional. Donor/public scrutiny; advocacy. CRA return and donor audit unreviewed. |
| Canadian Cancer Society 2025/26 accounts | Canada; Toronto auditor | Donation/fundraising, corporate sponsorship, government grants and other income; charity without share capital. | Tier 2 | B provisional. Qualified audit: fundraising-revenue completeness cannot be verified; not a fraud finding. |
| WHO CNS classification summary: 2021 | US-led; multinational authors | Paper reports no funding; COI statement is manuscript-limited. Institutional finances untraced. | Tier 2 | B provisional. Classification scrutiny; professional incentives. No treatment-outcome audit. |
| NICE NG99: January 2021 recommendations | UK | DHSC/NHS contracts and appraisal/advice fees; VPAG investment-facility funding via DHSC. NG99 allocation unknown. | Tier 2 | B provisional. Published recommendations; institutional/committee bias. Underlying trial sponsorship not fully screened. |
| NICE 2025/26 annual accounts | Manchester / London, UK | DHSC/public funding, NHS contracts, appraisal/advice fees; £3m VPAG investment-facility funding via DHSC. | Tier 2 | B provisional. Financial accountability; institutional presentation. |
| NCI budget: May 2026 | Bethesda, US | Congressional appropriation; enacted funding separate from requests. | Tier 2 | B provisional. Budget accountability; political framing. |
| Macmillan temozolomide: June 2025 | London, UK | Charity donations, legacies, corporate support, grants and trading; page allocation untraced. | Tier 2 | B provisional. Expert/patient review; advocacy and donor influence possible. eMC references, not independently screened outcomes. |
| Macmillan 2025 financial overview | London, UK; England/Wales guarantee company | Donations, legacies, corporate income, grants and trading; guarantee company. | Tier 2 | B provisional. Public/donor accountability; fundraising framing. Full accounts failed to open; donor/page audit incomplete. |
Frequently asked questions
Are Temodar/Temodal temozolomide?
Yes. Follow the correct product instructions.
Are the pivotal trials independent?
Stupp and Perry had manufacturer grant/drug support. They are excluded from our independent outcome verdict.
Does the 2026 CATNON report provide independent replication?
No. It follows the same manufacturer-supported cohort.
Missed or vomited dose?
Does MGMT guarantee temozolomide will work?
No. It informs specialist choices alongside age, diagnosis and daily functioning.
Sources and funding notes
Only the stated source sections were reviewed. Unread supplements, author forms, donor allocations and private contracts remain gaps. This is a selected adult product guide, not exhaustive global coverage.
- US Temodar: February 2026 — Selected label; patient information September 2023.
- GB Temodal SmPC: July 2023 — Displayed clinical/legal text; underlying trials not fully audited.
- GB Temodal leaflet: August 2023 — Complete displayed GB patient leaflet.
- FDA Project Renewal: September 2023 — Label update announcement, not independent comparative evidence.
- Companies House: UK holder control — Active control bands notified 6 April 2016.
- Companies House: UK parent control — Active control bands; Merck incorporated under New Jersey law.
- CATNON: 2021 interim original — Selected methods/results; complete main funding/COI, not supplements.
- CATNON: January 2026 final abstract — Complete indexed abstract and displayed declarations only.
- Merck 2025 Form 10-K — Selected identity/finance; no Temodar-specific revenue or grant allocation.
- FDA FY2026 operating plan — Plan as of 12 November 2025, not actual spending or FY2027.
- NCI temozolomide overview: September 2023 — Complete displayed overview; linked trials not independently audited.
- Stupp et al.: 2005 original — Selected publisher-version repository text; full main funding/COI, not supplements.
- Perry et al.: 2017 original — Indexed publisher abstract/methods/funding; direct full-body access failed.
- EORTC 2025 annual report — Selected governance/finance; donor/project audit and chart pixels incomplete.
- Canadian Cancer Society financial page — Current national financial-report landing page.
- Canadian Cancer Society 2025/26 accounts — Year ended 31 January 2026; selected accounts/opinion, not historical grant allocations.
- WHO CNS classification summary: 2021 — Selected taxonomy, affiliations and declarations; not the complete WHO book.
- NICE NG99: January 2021 recommendations — Selected brain-tumour recommendations, not every section.
- NICE 2025/26 annual accounts — Selected original pages/tables; not NG99 payments or a personal-benefit audit.
- NCI budget: May 2026 — FY2026 institution figures; no page/trial allocations or FY2027 claim.
- Macmillan temozolomide: June 2025 — Complete displayed clinical body; urgent guidance, not an outcome review.
- Macmillan 2025 financial overview — Current annual-report landing HTML, not the full 2025 PDF or chart pixels.
Educational research reviewed 6 October 2026. Follow your clinician’s urgent safety instructions and your exact medicine leaflet. Diagnosis and treatment require a qualified clinician.
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