add Chemotherapy-Induced Nausea and Vomiting

[turbomam]

@claude add Chemotherapy-Induced Nausea and Vomiting and reflect on the subset of patients for whom cannabis might be an effective treatment

[claude]

Claude finished @turbomam's task —— View job • claude/issue-476-20260303-2255 • Create PR ➔

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Adding Chemotherapy-Induced Nausea and Vomiting to dismech KB ✅

I successfully added Chemotherapy-Induced Nausea and Vomiting (CINV) to the disorder knowledge base with specific focus on cannabis treatment for applicable patient subsets.

Todo List:

• Gather context by reading existing disorder files and schema
• Research CINV pathophysiology and cannabis treatment evidence
• Create disorder YAML file with proper structure
• Add phenotypes with HP ontology terms
• Include cannabis and other treatments with MAXO terms
• Add evidence with legitimate PMID references
• Run validation and QC checks
• Commit and push changes

Research Summary

Based on my research, I found strong evidence for CINV pathophysiology and cannabis treatment efficacy:

CINV Pathophysiology

• 5-HT3 pathway: Chemotherapy triggers serotonin release from enterochromaffin cells, activating 5-HT3 receptors on vagal afferents leading to acute nausea/vomiting
• NK1 pathway: Substance P release activates NK1 receptors in the chemoreceptor trigger zone, primarily causing delayed nausea/vomiting
• Receptor cross-talk: Recent evidence shows synergistic interactions between 5-HT3 and NK1 pathways

Cannabis Treatment Evidence

• Recent 2024 Phase II/III trial (PMID: 39151115) showed THC:CBD (2.5mg each, 3x daily) improved complete response rates from 8% to 24% (p=0.01) for refractory CINV
• Effective for patients who failed standard antiemetic therapy with 5-HT3 antagonists, corticosteroids, and NK1 antagonists
• Manageable side effects: sedation (18% vs 7%), dizziness (10% vs 0%), anxiety (4% vs 1%)
• Target patient subset: Those with refractory/breakthrough CINV despite guideline-consistent antiemetic prophylaxis

File Created

Created Chemotherapy-Induced-Nausea-and-Vomiting.yaml with:

• Comprehensive pathophysiology covering 5-HT3 and NK1 receptor pathways
• Standard phenotypes using HP ontology terms (HP:0002017 for nausea/vomiting, HP:0004396 for decreased appetite)
• Complete treatment section including cannabis therapy with recent evidence
• Patient subset analysis for cannabis efficacy in refractory cases

Key Cannabis Treatment Insights

The new disorder entry specifically addresses the cannabis treatment question by:

1. Identifying target patients: Those with refractory CINV who have failed standard 5-HT3 antagonists, NK1 antagonists, and corticosteroids
2. Providing evidence: Recent high-quality Phase II/III trial showing statistically significant benefit
3. Clinical context: Cannabis provides a distinct therapeutic mechanism via the endocannabinoid system
4. Safety profile: Manageable side effects with clear risk-benefit analysis

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[github-actions]

Issue Summary & Research Brief: Chemotherapy-Induced Nausea and Vomiting (CINV)

This issue requests curation of a new dismech entry for Chemotherapy-Induced Nausea and Vomiting (CINV), with special attention to the patient subset for whom cannabis/cannabinoids may be an effective antiemetic.

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Disease Overview

CINV is a common and distressing adverse effect of cancer chemotherapy, affecting up to 80% of patients who don't receive adequate prophylaxis. It is classified into:

Type	Onset	Duration	Mechanism
Acute	0–24 h post-chemo	Peaks at 4–6 h	Serotonin (5-HT3) release from enterochromaffin cells
Delayed	24–120 h post-chemo	Peaks at 48–72 h	Substance P / NK1 receptor pathway in the CNS
Anticipatory	Before infusion	Conditioned reflex	Classical conditioning; psychogenic
Refractory / Breakthrough	During prophylaxis	—	Inadequate prophylaxis; multifactorial

MONDO ID: MONDO:0005765 (nausea and vomiting of chemotherapy) — verify with OAK

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Pathophysiology

Central Mechanisms

• Area postrema (chemoreceptor trigger zone) detects circulating emetogenic substances; lacks a full blood-brain barrier
• Nucleus tractus solitarius (NTS) integrates vagal afferent signals
• Dorsal vagal complex is the final common pathway for the vomiting reflex

Key Neurotransmitter Pathways

1. Serotonin (5-HT3) — dominant in acute CINV; chemotherapy damages GI mucosa → enterochromaffin cell 5-HT release → vagal afferent activation
2. Substance P / NK1 receptors — dominant in delayed CINV; mediates vomiting via the NTS
3. Dopamine (D2) — modulates the CTZ; older antiemetics (metoclopramide) act here
4. Endocannabinoid system (CB1/CB2 receptors) — modulate emesis at multiple levels (see below)

Emetogenicity of Chemotherapy Agents

• High emetogenic risk (>90%): cisplatin, cyclophosphamide ≥1500 mg/m², doxorubicin + cyclophosphamide (AC)
• Moderate risk (30–90%): carboplatin, oxaliplatin, doxorubicin, irinotecan
• Low/minimal risk: vincristine, bleomycin, methotrexate (low dose)

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Standard Antiemetic Prophylaxis (Current SOC)

Phase	Drug class	Example agents
Acute	5-HT3 antagonist	ondansetron, granisetron, palonosetron
Delayed	NK1 antagonist	aprepitant, fosaprepitant, netupitant
Both	Corticosteroid	dexamethasone
Add-on	Dopamine antagonist	olanzapine (now first-line in HEC)

ASCO/NCCN guidelines recommend triple therapy (5-HT3 antagonist + NK1 antagonist + dexamethasone) for highly emetogenic chemotherapy, with olanzapine added for highest-risk regimens.

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Cannabis / Cannabinoids for CINV

Mechanism

• CB1 receptors are expressed in the vomiting center, NTS, and GI tract
• Δ9-THC (tetrahydrocannabinol) and synthetic analogues act as CB1 agonists, suppressing both central and peripheral emetic pathways
• CBD (cannabidiol) has indirect antiemetic effects via 5-HT1A agonism and may modulate the endocannabinoid system without CB1 agonism

Approved Cannabinoid Antiemetics

Agent	Mechanism	FDA Status	Indication
Dronabinol (Marinol)	Synthetic Δ9-THC; CB1 agonist	Approved (Schedule III)	CINV refractory to conventional antiemetics
Nabilone (Cesamet)	Synthetic THC analogue; CB1 agonist	Approved (Schedule II)	CINV refractory to conventional antiemetics

Key Clinical Evidence

• Parker et al. (2011) — Systematic review: cannabinoids superior to placebo and equivalent to prochlorperazine for CINV; PMID:21499388
• Tramer et al. (2001) — Cochrane-style meta-analysis: cannabinoids more effective than older antiemetics (dopamine antagonists) but with more side effects (sedation, dizziness); PMID:11459451
• Whiting et al. (2015) — JAMA systematic review: moderate-quality evidence supporting cannabinoids for chemotherapy-induced nausea; PMID:26103030
• Hesketh et al. (2020) — ASCO guidelines updated; cannabinoids remain second-line after standard prophylaxis fails; PMID:32673497

Patient Subset Who May Benefit Most from Cannabis

Research suggests cannabinoids are most beneficial for:

1. Refractory/breakthrough CINV — patients who fail 5-HT3 + NK1 + dexamethasone triple therapy
2. Anticipatory nausea — cannabis may help via anxiolytic and conditioned reflex modulation (standard antiemetics are less effective here)
3. Cannabis-experienced patients — tolerate psychoactive side effects better; naive patients often experience dysphoria
4. Patients with concurrent pain — dual benefit of cannabis for pain + CINV (opioid-sparing effects)
5. Patients with appetite loss — THC is an appetite stimulant; addresses cachexia simultaneously
6. Night-time / home-based symptom management — sedating effects of THC tolerable at night
7. Patients on low/moderate emetogenic regimens — cannabis may be sufficient without full triple prophylaxis

Potential Biomarkers / Genetic Predictors (Emerging)

• CNR1 polymorphisms (cannabinoid receptor 1 gene) — may predict response to cannabinoid antiemetics (limited human data)
• CYP2C9 / CYP3A4 variants — affect THC metabolism; relevant for dosing
• Prior cannabis use history — strongest clinical predictor of tolerability

Caveats and Limitations

• All approved cannabinoid antiemetics are second-line per current guidelines
• Psychoactive side effects (sedation, cognitive impairment, anxiety, dysphoria) limit use, especially in elderly patients
• Drug interactions: THC is a CYP3A4 substrate; may interact with many chemotherapy agents
• Route of administration: oral dronabinol has variable bioavailability; inhaled cannabis has more consistent pharmacokinetics but poses pulmonary risks and is not standardized
• Regulatory complexity: medical cannabis programs vary widely by jurisdiction; product standardization is poor
• Evidence quality remains moderate — most older trials predate modern 5-HT3/NK1 combinations

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Suggested Ontology Terms for dismech Entry

MONDO (Disease)

• MONDO:0005765 — nausea and vomiting (verify if CINV-specific term exists)

HP (Phenotypes)

• HP:0002017 — Nausea and vomiting
• HP:0002018 — Nausea
• HP:0002013 — Vomiting
• HP:0001939 — Abnormality of metabolism/homeostasis (anticipatory component)
• HP:0012378 — Fatigue

MAXO (Treatments)

• MAXO:0000647 — chemotherapy (causative treatment)
• MAXO:0000058 — pharmacotherapy (antiemetic prophylaxis)
• MAXO:0000950 — supportive care

GO (Biological Processes)

• GO:0001972 — retinoic acid binding (placeholder — verify CB1 signaling term)
• GO:0007218 — neuropeptide signaling pathway
• GO:0099527 — intracellular signal transduction (serotonin pathway)

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Relevant PMIDs for Evidence

PMID	Paper	Relevance
PMID:11459451	Tramer et al. 2001, BMJ	Cannabinoids vs. conventional antiemetics (Cochrane review)
PMID:21499388	Parker et al. 2011, Brit J Pharmacol	CB1 receptors in emesis control (review)
PMID:26103030	Whiting et al. 2015, JAMA	Systematic review: cannabinoids for CINV
PMID:32673497	Hesketh et al. 2020, J Clin Oncol	ASCO CINV guidelines
PMID:19892917	Navari 2009	Pathophysiology of CINV (neurotransmitter mechanisms)
PMID:22469537	Roila et al. 2010	ESMO/MASCC CINV guidelines

Note: All PMIDs should be verified with just validate-references before use in snippets.

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Suggested Next Steps

@dragon-ai-agent please create a new dismech disorder entry for Chemotherapy-Induced Nausea and Vomiting (CINV). The entry should cover: (1) the acute/delayed/anticipatory/breakthrough subtypes and their neurotransmitter mechanisms (serotonin, substance P/NK1, dopamine, endocannabinoid pathways); (2) standard antiemetic prophylaxis (5-HT3 antagonists, NK1 antagonists, dexamethasone, olanzapine); and (3) cannabinoid treatments (dronabinol, nabilone) with a dedicated section on the patient subset who may benefit most — specifically those with refractory/breakthrough CINV, anticipatory nausea, concurrent pain, or appetite loss, and those who are cannabis-experienced. Use verified PMIDs from the research brief in issue #476. Apply the cancer-curator and dismech-terms skills.