Capstan Therapeutics

Capstan Therapeutics was a clinical-stage biotechnology company based in San Diego, California, developing in vivo cell engineering medicines built on a proprietary targeted lipid nanoparticle (tLNP) platform that delivers mRNA and other RNA payloads to specific cell types inside the body. Its lead candidate CPTX2309 is an anti-CD19 in vivo CAR-T therapy in Phase 1 for B cell-mediated autoimmune disease, intended to achieve deep B cell depletion without lymphodepleting chemotherapy. AbbVie completed its acquisition of Capstan on 19 August 2025 for up to $2.1 billion. The company's own domain now redirects to AbbVie and its DNS is served by AbbVie nameservers; it operates no developer program, public API, SDK, or machine-readable specification.

Capstan Therapeutics is profiled on the APIs.io network. Tagged areas include Company, Biotechnology, Pharmaceuticals, Cell Therapy, and Immunology.

🌐 Visit website 📡 Source on GitHub

1.8/100 minimal ▬ flat Agent 0/100 human only Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

0 APIs

Company Biotechnology Pharmaceuticals Cell Therapy Immunology Life Sciences Acquired

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 1.8/100 · minimal

Contract Quality 0.0 / 21

Developer Ergonomics 0.0 / 17

Access Clarity 0.0 / 17

Operational Transparency 0.0 / 11

Contract Governance 0.0 / 10

Discoverability 3.9 / 9

Regulatory Posture 0.0 / 15

Agent readiness — 0/100 · human only

Machine-Readable Contract 0 / 18

Agentic Access Contract 0 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 0 / 10

Idempotency 0 / 9

Stable Error Semantics 0 / 8

Request/Response Examples 0 / 7

Rate-Limit Signaling 0 / 7

Typed Event Surface 0 / 6

Agent Skills 0 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Regulatory Posture applies to this provider. Its tags matched the Health regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.

The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/capstan-therapeutics: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Resources

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: capstan-therapeutics
name: Capstan Therapeutics
description: Capstan Therapeutics was a clinical-stage biotechnology company based in San Diego, California, developing in
  vivo cell engineering medicines built on a proprietary targeted lipid nanoparticle (tLNP) platform that delivers mRNA and
  other RNA payloads to specific cell types inside the body. Its lead candidate CPTX2309 is an anti-CD19 in vivo CAR-T therapy
  in Phase 1 for B cell-mediated autoimmune disease, intended to achieve deep B cell depletion without lymphodepleting chemotherapy.
  AbbVie completed its acquisition of Capstan on 19 August 2025 for up to $2.1 billion. The company's own domain now redirects
  to AbbVie and its DNS is served by AbbVie nameservers; it operates no developer program, public API, SDK, or machine-readable
  specification.
url: https://raw.githubusercontent.com/api-evangelist/capstan-therapeutics/refs/heads/main/apis.yml
x-type: company
x-source: harvest:secondary-market
x-source-url: https://forgeglobal.com/capstan-therapeutics_stock/
x-tier: stub
x-tier-reason: harvest
deliveryModel:
  model: unknown
  open_source: false
  commercial: false
  callable_host: false
  label: Delivery model not determined — needs a product licence on record
  confidence: low
  source:
  - none
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: unknown
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Unknown
  confidence: low
  source:
  - url: https://capstantx.com/
    status: 301
    note: declared website redirects to https://www.abbvie.com/capstan-therapeutics.html — a different registrable domain
      (capstantx.com -> abbvie.com), possible rename or acquisition (probed 2026-09-03, roadmap#169)
  generated: '2026-09-03'
  method: derived
specificationVersion: '0.23'
created: '2026-08-09'
modified: '2026-08-09'
tags:
- Company
- Biotechnology
- Pharmaceuticals
- Cell Therapy
- Immunology
- Life Sciences
- Acquired
apis: []
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: Website
  url: https://capstantx.com/
x-enrichment:
  date: '2026-08-09'
  status: nochange
  artifacts_added: 0
  pass: local-v1
x-coverage:
  state: none
  reason: defunct
  detail: 'Capstan''s own site is gone: capstantx.com 301s to www.abbvie.com/capstan-therapeutics.html and its nameservers
    are now ns1-4.abbviedns.com, following AbbVie''s completed acquisition on 19 August 2025 — the company was a clinical-stage
    biotech that never operated a developer program, GitHub org, or public API.'
  evidence:
  - url: https://capstantx.com/
    status: 301
  - url: https://www.capstantx.com/
    status: 301
  - url: https://capstantx.com/.well-known/agent-card.json
    status: 403
  - url: https://capstantx.com/openapi.json
    status: 403
  - url: https://api.github.com/orgs/capstantx
    status: 404
  checked: '2026-08-09'

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/capstan-therapeutics"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/capstan-therapeutics/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/capstan-therapeutics/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.