Targeted Drug Therapies for Craniopharyngioma: What Patients and Families Should Know

Table of Contents

• Key Points
• Background: Why This Research Matters
• What Are Craniopharyngiomas?
• The Two Types of Craniopharyngioma
• Molecular and Genetic Profiles
• Targeted Treatment for Papillary Craniopharyngioma (PCP)
• Targeted Treatment for Adamantinomatous Craniopharyngioma (ACP)
• Experimental Therapy: MAPK/ERK–MEK Pathway Inhibition
• Other Therapies Under Investigation
• Clinical Implications: What This Means for Patients
• Limitations: What the Research Could Not Prove
• Recommendations for Patients and Families
• Conclusions
• Frequently Asked Questions
• Source Information

Key Points

• Papillary craniopharyngioma (PCP) usually has a BRAF V600E mutation and responds well to combined BRAF and MEK inhibitor drugs.
• In early prospective studies, more than 90% of patients with BRAF V600E-mutant PCP showed tumor shrinkage with targeted therapy.
• Targeted treatment for adamantinomatous craniopharyngioma (ACP) remains mostly experimental; blocking IL-6 may help control cysts in some patients.
• Common side effects of targeted therapy include rash, fever, diarrhea, and elevated liver enzymes; some patients stop treatment due to toxicity.
• Long-term data on endocrine, hypothalamic, and neurocognitive outcomes are sparse; clinical trials should be considered when feasible.

Background: Why This Research Matters

Craniopharyngiomas are rare tumors that grow near critical brain structures. These structures include the optic nerves, the hypothalamus (the brain region that controls appetite, thirst, and hormones), and the pituitary gland. Because of this location, both the tumor itself and its treatment can cause lasting harm.

For many years, surgery has been the main treatment. Surgeons aimed to remove as much of the tumor as possible. More recently, the approach has shifted toward limited surgery that spares the hypothalamus, followed by radiation therapy when the hypothalamus is involved.

Even with these careful approaches, survivors of childhood-onset craniopharyngioma face high rates of severe obesity, metabolic disease, and reduced quality of life. These problems come from both the tumor and from treatment-related damage to the back part of the hypothalamus.

These limitations have driven interest in systemic therapies. Systemic therapies are drugs that travel through the bloodstream and can control tumor growth. The goal is to minimize further damage to critical hormone-regulating structures in the brain.

Recurrence still happens even after complete surgical removal or radiation therapy. Repeat surgery and repeat radiation carry substantial risks. Because of this, targeted drug therapies are increasingly used as salvage options that spare the hypothalamus.

BRAF/MEK inhibitor therapy has substantially changed the treatment landscape for papillary craniopharyngioma. Blocking the interleukin-6 pathway has shown promise for managing the cystic components of adamantinomatous craniopharyngioma. This review brings together current evidence for these targeted therapies.

What Are Craniopharyngiomas?

Craniopharyngiomas are rare epithelial tumors. They arise from remnants of Rathke's pouch, a structure present during early development. Rathke's pouch sits in the region of the sella turcica, the bony pocket that holds the pituitary gland, and above it.

These tumors account for 1–5% of all tumors inside the skull. Most published series report a range of 2–5%.

Although these tumors are histologically benign (meaning they are not cancerous and do not spread to other parts of the body), they are locally aggressive. Their proximity to and frequent involvement of the optic apparatus, hypothalamus, and pituitary gland creates a high risk of health problems. These problems come from both tumor progression and treatment.

The Two Types of Craniopharyngioma

Doctors recognize two biologically and clinically distinct tumor types. Each type has different genetic drivers, different typical patients, and different responses to treatment.

Papillary craniopharyngioma (PCP) predominates in adults. It harbors BRAF V600E mutations in approximately 95% of cases.

Adamantinomatous craniopharyngioma (ACP) more commonly affects children and young adults. It is characterized by CTNNB1 mutations in 69–100% of cases. These mutations affect the Wnt/beta-catenin signaling pathway. ACP also has a radiographically cystic growth pattern, meaning it often appears as fluid-filled sacs on imaging.

ACP demonstrates a bimodal age distribution. This means it has two peaks of occurrence: one at ages 5–15 years and another at ages 45–60 years. This makes ACP the predominant subtype in the pediatric population.

In contrast, PCP is most frequently observed in adults. It primarily occurs in the fifth and sixth decades of life.

PCP was historically considered exclusively an adult disease. However, sporadic pediatric cases with confirmed BRAF V600E mutations have been reported since 2018. These pediatric cases remain rare, accounting for approximately 3% of all PCP cases.

Molecular and Genetic Profiles

The two tumor types of craniopharyngioma harbor mutually exclusive genetic alterations. These alterations define how each tumor develops at the molecular level.

ACP is driven by somatic mutations in CTNNB1, the gene that encodes beta-catenin. These mutations predominantly occur in exon 3. The mutations result in pathologic stabilization of beta-catenin and constitutive activation of the Wnt/beta-catenin signaling pathway. Some evidence suggests that mutations at a specific location called Thr41 may correlate with worse event-free survival.

Importantly, next-generation sequencing studies have not identified other recurrent mutations in ACP beyond CTNNB1. This indicates that CTNNB1 is the crucial pathogenetic driver for ACP.

PCP is characterized by BRAF V600E mutations in 94–95% of cases. These mutations activate the RAS/RAF/MEK/ERK (MAPK) pathway. This mutation is clonal, meaning it is present in all tumor cells, and represents the primary oncogenic driver. No other recurrent genomic alterations have been identified in PCP.

The presence of BRAF V600E has critical therapeutic implications. These tumors demonstrate remarkable responsiveness to combined BRAF and MEK inhibitor therapy.

Recent multi-omics analyses (studies that examine multiple types of molecular data at once) have suggested additional molecular heterogeneity within ACP. Researchers have identified three possible molecular subgroups:

• Wnt subgroup: characterized by high Wnt/beta-catenin pathway activity
• ImA subgroup: with activated inflammatory pathways and MEK/MAPK signaling
• ImB subgroup: showing elevated Interleukin-6 (IL-6) expression and epithelial–mesenchymal transition markers

These subgroups correlate with different imaging features, histological characteristics, and clinical outcomes. The Wnt subgroup demonstrates longer event-free survival compared to the ImB subgroup.

Genomic analysis has shown that most PCP tumors and a subset of ACP tumors have stable genomes. Other ACP cases demonstrate focal chromosomal gains or losses in specific regions such as Xq28.

Targeted Treatment for Papillary Craniopharyngioma (PCP)

In BRAF V600E–mutant PCP, dual BRAF/MEK inhibition has shown high objective response rates in early prospective studies. This is the most striking finding in the field.

The landmark Alliance A071601 phase II trial tested neoadjuvant therapy with vemurafenib (an inhibitor of mutated BRAF V600E kinase) plus cobimetinib (a MEK1 and MEK2 inhibitor). In this trial, 15 of 16 patients (94%; 95% confidence interval, 70–100) achieved an objective partial or better response at 4 months. This was measured by centrally reviewed volumetric MRI. The median tumor-volume reduction was 91% (range, 68–99).

The French multicenter cohort tested dabrafenib (a competitive inhibitor of BRAF kinase, specifically the V600E, V600K, and V600D BRAF proteins) plus trametinib (another MEK1 and MEK2 inhibitor). This cohort included 16 patients across neoadjuvant, adjuvant, and palliative settings. In this group, 94% demonstrated partial or better response.

Follow-up responses in the French cohort were categorized as:

• Subtotal response: 12 of 16 patients
• Partial response: 3 of 16 patients
• Stable disease: 1 of 16 patients

Mean volume reduction was 88.9% in the neoadjuvant setting, 73.3% in the adjuvant setting, and 91.8% in the palliative setting.

A recent systematic review of 21 studies, including 54 patients, reported a median tumor volume reduction of 89% overall. This broke down to 90% in the neoadjuvant setting, 85% in the adjuvant setting, and 88% in the palliative setting. Volumetric response rates were as high as 94% in the Alliance trial and 93% in the French cohort.

Disease control appears closely linked to therapy compliance. Follow-up from Alliance A071601 indicated that progression-free survival was 87% at 12 months and 58% at 24 months. Importantly, no patient progressed while receiving per-protocol vemurafenib–cobimetinib. Among patients who discontinued protocol therapy, 6 of 7 had no evidence of progression at a median 23-month follow-up.

Rapid recurrence within 3 months is typical following treatment discontinuation. However, tumors remain responsive to therapy reinitiation without evidence of acquired resistance, even after multiple treatment courses. Case reports further describe and confirm tumor regrowth after interruption and renewed response upon rechallenge. This suggests persistent oncogenic dependence on MAPK signaling.

Tumor morphology also influences response. Mixed-type tumors demonstrate significantly faster and more robust responses than purely solid or cystic lesions. This may reflect differential drug penetration. Enhancing components show greater volume reduction (96%) than cystic components (82%).

Symptom improvement tends to correlate with radiographic shrinkage. In the French cohort, targeted therapy resolved headaches in 5 of 5 patients and improved visual impairment in 6 of 9 patients. Endocrine recovery was reported in 2 of 14 patients.

Across published reports, many patients begin targeted therapy with pre-existing pituitary hormone dysfunction following prior surgery and/or radiotherapy. Recovery of established deficits appears uncommon despite marked tumor regression.

A major practical value of neoadjuvant BRAF/MEK therapy is facilitation of less extensive local therapy. Multiple series describe profound volumetric shrinkage that enables limited resection and/or de-escalation of radiotherapy planning, including smaller target volumes. The goal is to minimize additional hypothalamic injury.

In neoadjuvant paradigms, tumor-volume reductions of approximately 85–90% within several months (about 3–6 months) have enabled less aggressive surgical approaches. In selected cases, this has allowed deferral of surgery. Conceptually, "medical debulking" aligns with hypothalamus-preservation principles by reducing the need for extensive dissection in anatomically constrained tumors.

However, whether this strategy translates into improved long-term hypothalamic outcomes (such as obesity risk) remains insufficiently reported. This should be evaluated prospectively.

Adverse events warrant careful monitoring. Across recent series, treatment discontinuation due to toxicity occurred in 14.5–18.8% of patients. Common adverse events include:

• Rash
• Fever (pyrexia)
• Diarrhea
• Elevated liver enzymes
• Occasional cardiotoxicity (heart-related side effects)

The 2025 NCCN Pediatric CNS Cancer Guidelines now list dabrafenib/trametinib and vemurafenib as preferred targeted therapies for BRAF V600E-mutated tumors in both adjuvant and recurrent/progressive settings. This highlights both the efficacy and widespread adoption of this treatment.

Despite these promising results, critical questions remain. These include the optimal duration of targeted therapy, the ideal sequencing with surgery and radiotherapy, and whether all patients require consolidative local treatment following medical debulking.

The Alliance A071601 trial originally proposed four cycles of therapy followed by definitive treatment. Yet many patients continued beyond this timeframe with acceptable toxicity. Some avoided radiation entirely without progression. This highlights the need for prospective studies to establish standardized protocols. Lack of long-term follow-up in this patient population limits conclusions regarding the long-term efficacy of these treatments.

Targeted Treatment for Adamantinomatous Craniopharyngioma (ACP)

Targeted treatment for ACP remains primarily investigational. Unlike PCP, ACP does not have a single routinely actionable oncogenic driver analogous to BRAF V600E. Most systemic strategies are supported by small clinical reports and early translational data rather than prospective efficacy trials.

Prior studies sampling ACP cystic fluid have demonstrated high levels of IL-6. These levels can be up to 50,000 times that in cerebrospinal fluid. As a driver of pro-inflammatory signaling pathways, IL-6 is associated with cyst formation, tumor progression, and local tissue invasion.

The robust inflammatory response driven by IL-6 is a suspected contributor to ACP's tendency to adhere to adjacent structures such as the optic chiasm and hypothalamus. Targeting IL-6 with IL-6/IL-6 receptor blockade (tocilizumab with or without bevacizumab) has generated the most reproducible published systemic signal to date in ACP. This works largely through cyst control rather than durable eradication of solid tumor.

Grob and colleagues described two pediatric patients with recurrent cystic disease who were treated with tocilizumab (with or without bevacizumab). Both experienced meaningful reductions in cyst burden.

Another report described prolonged stabilization of cystic progression with biweekly intravenous tocilizumab in a pediatric patient. de Vos-Kerkhof and colleagues reported a case of a fifth cystic progression of ACP treated with tocilizumab IV 800 mg every 2 weeks. This treatment showed a good response at approximately 9 months, with clinical stability maintained off therapy (reported follow-up approaching 3 years).

Webb and colleagues published a recent case demonstrating cyst control with tocilizumab plus bevacizumab in recurrent ACP.

Overall, IL-6/IL-6R blockade appears to be a promising non-surgical strategy to manage cyst accumulation. Although solid nodules commonly persist, this may potentially defer higher-risk local interventions in well-selected patients.

The CONNECT 1905 trial (NCT05233397) is a phase II clinical trial currently enrolling patients aged 1 to 25 years. This trial evaluates the effects of tocilizumab on progressive or recurrent ACP.

Safety data remain limited. Reported adverse events were class-expected, including grade 3 neutropenia (a severe drop in a type of white blood cell). This underscores the need for systematic prospective monitoring.

Experimental Therapy: MAPK/ERK–MEK Pathway Inhibition

In contrast to PCP, ACP treatment with MAPK/ERK targeting has not yet demonstrated consistent clinical benefit. Molecular profiling and compartment-level studies show MAPK/ERK pathway activation in ACP, particularly in recurrent disease. This provides a biologic rationale for MEK inhibition even without BRAF V600E mutations.

In explant models (tumor tissue grown outside the body), MEK inhibition with drugs such as trametinib reduced proliferation and increased apoptosis (programmed cell death). This supports translational interest.

The CONNECT 2108 trial (NCT05286788) is an active phase 2 clinical study evaluating binimetinib, an oral MEK1/2 inhibitor, in pediatric ACP.

Another trial is the CONNECT 2103 trial (NCT05465174). This trial is currently enrolling pediatric patients with recurrent ACP, stratified by prior radiotherapy status. Participants receive binimetinib with radiological response as the primary endpoint.

While clinical trials evaluating MEK inhibitors are underway, clinical experience remains very limited. There are potential safety concerns in patients with fragile hypothalamic-pituitary physiology.

Notably, a pediatric patient with ACP and central diabetes insipidus developed severe hyponatremia (low blood sodium) with reduced desmopressin requirements shortly after initiating trametinib. Rapid rebound effects upon trametinib cessation prevented evaluation of tumor response.

Similar hyponatremia has been reported in pediatric low-grade glioma patients with diabetes insipidus receiving trametinib. This may be related to MEK inhibitor effects on aquaporin channel physiology (channels that regulate water movement in cells).

A case report describing use of binimetinib for recurrent ACP with Wnt mutation demonstrated good radiographic and clinical response. However, this required frequent dose adjustments due to side effects including:

• Furuncles (boils) and papulopustular rash
• Hyponatremia
• Poor wound healing
• Weight gain

Given sparse efficacy data and potential toxicity with a variable side effect profile, MEK inhibitor monotherapy should be considered experimental. It should preferentially be pursued within clinical trials.

Other Therapies Under Investigation

Investigation into the immune microenvironment of craniopharyngioma has revealed potential immunotherapeutic targets. Immunohistochemical studies demonstrate frequent expression of immune-related targets in craniopharyngioma. These include programed cell death (PD)-L1 and high B7-H3 expression. This suggests an immunologically active and potentially targetable microenvironment.

B7-H3 overexpression has been independently reported. Organoid models (miniature tumor models grown in the laboratory) support the tractability of B7-H3-directed strategies. Therapeutic effects vary by modality, providing a rationale for further development.

The Pediatric Neuro-oncology Consortium trial (PNOC029) is evaluating tovorafenib (a pan-RAF inhibitor) monotherapy and in combination with nivolumab (a PD-1 receptor inhibitor). This trial enrolls patients up to 39 years of age with newly diagnosed or recurrent ACP. The composite primary endpoint is progression-free survival and quality of life at 12 months, with extended follow-up continuing for 3 years after treatment completion.

Nevertheless, ACP-specific prospective clinical efficacy data for checkpoint inhibitors remain limited. These agents remain under investigation.

When considering treatment, clinicians must weigh immune-related endocrinopathies. These include hypophysitis (inflammation of the pituitary gland) and other endocrine toxicities. These could compound baseline hypothalamic–pituitary morbidity in this population.

Clinical Implications: What This Means for Patients

This review highlights BRAF-/MEK-targeted therapy as an increasingly utilized option in both neoadjuvant and salvage treatment for PCP. The role of targeted therapies in ACP remains under investigation.

In clinical practice, adult patients with BRAF-mutant PCP who present with recurrent or unresectable disease should be considered for treatment with combined BRAF/MEK inhibition. In selected cases, neoadjuvant administration can result in substantial tumor reduction. This can facilitate surgical resection and, in some instances, eliminate the need for adjuvant radiotherapy.

For patients with ACP, especially those with symptomatic cystic recurrences, use of tocilizumab may be considered. In this context, the therapeutic objective is disease stabilization and symptomatic improvement rather than complete tumor eradication.

Given the absence of established systemic therapies targeting the solid component of ACP, enrollment in clinical trials should be pursued whenever feasible. Multiple clinical trials are currently investigating targeted therapies for both craniopharyngioma tumor types.

For ACP, active clinical trials are mainly exploring:

• MEK inhibition
• PD-1 blockade
• Wnt pathway targeting
• IL-6 inhibition

For PCP, ongoing studies are focused on investigating BRAF V600E and MEK inhibition as single-agent or combination strategies. Other targets have been reported and represent an ongoing area of study. Notably, most current trials in ACP are limited to children and young adults.

This applies across both craniopharyngioma tumor types. Systematic and longitudinal assessment is essential during and after therapy. This assessment covers visual function, endocrine status, and hypothalamic regulation of appetite and thirst. It also covers cognitive performance and quality of life.

As targeted treatments transition from isolated case reports to broader clinical application, close collaboration between treating physicians, endocrinologists, and neuropsychologists is warranted. This ensures comprehensive outcome documentation.

Clinicians should maintain vigilant surveillance for established treatment-related toxicities, particularly dermatologic and febrile reactions. These should be managed proactively, as therapy can often be safely continued with appropriate supportive measures and dose adjustments.

Future comparative trials are essential. They must define treatment duration, determine which patients may safely defer or avoid surgery and radiotherapy after targeted therapy, and optimize integration of these modalities. The goal is to maximize tumor control while minimizing long-term morbidity.

Limitations: What the Research Could Not Prove

Several important limitations affect the conclusions of this review. Understanding these limitations helps patients and families interpret the findings appropriately.

First, data on long-term endocrine, hypothalamic, and neurocognitive outcomes are sparse. Most studies report tumor response on imaging, but few follow patients long enough to know whether targeted therapy improves long-term quality of life.

Second, whether neoadjuvant targeted therapy translates into improved long-term hypothalamic outcomes (such as reduced obesity risk) remains insufficiently reported. This should be evaluated prospectively.

Third, critical questions remain regarding the optimal duration of targeted therapy for PCP. The ideal sequencing with surgery and radiotherapy is also unknown. It is unclear whether all patients require consolidative local treatment following medical debulking.

Fourth, for ACP, most systemic strategies are supported by small clinical reports and early translational data rather than prospective efficacy trials. Evidence remains limited to small case series.

Fifth, safety data for IL-6/IL-6R blockade remain limited. Reported adverse events were class-expected, including grade 3 neutropenia, underscoring the need for systematic prospective monitoring.

Sixth, clinical experience with MEK inhibitors for ACP remains very limited. There are potential safety concerns in patients with fragile hypothalamic-pituitary physiology.

Seventh, ACP-specific prospective clinical efficacy data for checkpoint inhibitors remain limited. These agents remain under investigation.

Finally, most current trials in ACP are limited to children and young adults. This limits generalizability to older adults with ACP.

Recommendations for Patients and Families

Based on this review, the following recommendations may help guide discussions with your medical team:

1. For patients with PCP: Ask your doctor whether your tumor has been tested for the BRAF V600E mutation. If it is present and your tumor is recurrent or cannot be fully removed by surgery, combined BRAF/MEK inhibitor therapy should be discussed as a treatment option.
2. For patients with ACP and symptomatic cysts: Ask whether tocilizumab (with or without bevacizumab) might be appropriate. Understand that the goal is disease stabilization and symptom improvement, not complete tumor eradication.
3. Ask about clinical trials: Given the absence of established systemic therapies targeting the solid component of ACP, enrollment in clinical trials should be pursued whenever feasible. Multiple trials are currently investigating targeted therapies.
4. Monitor for side effects: Common side effects of targeted therapies include rash, fever, diarrhea, and elevated liver enzymes. Report these promptly to your medical team, as therapy can often be safely continued with supportive measures and dose adjustments.
5. Request comprehensive monitoring: Ask for regular assessment of visual function, hormone levels, appetite and thirst regulation, cognitive performance, and quality of life during and after therapy.
6. Work with a multidisciplinary team: Close collaboration between treating physicians, endocrinologists, and neuropsychologists helps ensure comprehensive care.

Conclusions

BRAF/MEK inhibitor therapy has substantially altered the therapeutic landscape for PCP. Inhibition of the interleukin-6 pathway has shown promise in the management of cystic components of ACP.

However, the extent to which these targeted strategies translate into sustained improvements in long-term endocrine and neurocognitive outcomes remains uncertain. These considerations underscore the need for prospective studies incorporating extended follow-up and patient-centered outcome measures.

Frequently Asked Questions

What are craniopharyngiomas and why are they serious?

Craniopharyngiomas are rare, benign brain tumors that grow near the optic nerves, hypothalamus, and pituitary gland. Although they do not spread, their location means the tumor and its treatment can cause lasting problems, including hormone issues, obesity, and reduced quality of life.

How well does targeted therapy work for papillary craniopharyngioma?

In early prospective studies, combined BRAF and MEK inhibitor drugs shrank tumors in more than 90% of patients with BRAF V600E-mutant PCP. For example, in one trial of 16 patients, 15 had a partial or better response at 4 months, with a median tumor-volume reduction of 91%.

What side effects should I watch for during targeted therapy?

Common side effects include rash, fever, diarrhea, and elevated liver enzymes. Less often, heart-related effects can occur. In recent series, 14.5–18.8% of patients stopped treatment because of toxicity. Report any side effects promptly, as therapy can often continue with supportive measures and dose adjustments.

Is there targeted treatment for adamantinomatous craniopharyngioma?

Targeted treatment for ACP remains mostly experimental. Blocking the IL-6 pathway with tocilizumab, sometimes with bevacizumab, may help control cysts in some patients, based on small case reports. For the solid part of the tumor, no established systemic therapy exists, so clinical trials should be considered.

What does it mean if my tumor has the BRAF V600E mutation?

If your tumor has the BRAF V600E mutation, it may respond well to combined BRAF and MEK inhibitor therapy. This mutation is found in about 94–95% of papillary craniopharyngiomas. Ask your doctor whether your tumor has been tested for it, especially if the tumor is recurrent or cannot be fully removed.

When should a patient with papillary craniopharyngioma seek a second opinion before starting BRAF/MEK inhibitor therapy?

A second opinion is worth seeking when a papillary craniopharyngioma has not been tested for the BRAF V600E mutation, which is present in roughly 94–95% of these tumors and determines whether combined BRAF/MEK inhibitor therapy is an option. It is also reasonable when the tumor is recurrent or cannot be fully removed, or when neoadjuvant therapy is proposed to shrink the tumor before surgery or radiation. Because questions about optimal treatment duration and sequencing with surgery and radiotherapy remain unresolved, an independent review can help clarify the plan. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: Systemic Molecularly Targeted Therapies for Neoadjuvant and Salvage Craniopharyngioma: A Contemporary Narrative Review.

Authors: Neubecker JJ, Griepp DW, Turnbull JP, Caskey J, Desai S, Mansour A, Ahmed R, Beggs A, Griepp ATK, Heitkotter H, Claus CF, Richards BF, Kelkar PS.

Author affiliation: Division of Neurosurgery, Henry Ford Health System Providence Hospital, College of Human Medicine, Michigan State University, Southfield, MI 48075, USA

Journal: Biomedicines 2026, 14, 499

Publication details: Received: 31 January 2026; Revised: 20 February 2026; Accepted: 24 February 2026; Published: 25 February 2026

DOI: https://doi.org/10.3390/biomedicines14030499

Note: This patient-friendly article is based on peer-reviewed research. It is intended for educational purposes and should not replace consultation with qualified healthcare professionals. Patients should discuss their individual treatment options with their medical team.