How Lextract extracted 126 fields from a 6th lease amendment for Karyopharm Therapeutics: step rent schedule, TI allowance, and renewal options from an amendment-only document.
By Angel Campa, Founder · Updated March 2026
Location
Newton, MA
Size
52,000 RSF
Annual Rent
$2.3M/yr
Term
60 months
Tenant
Karyopharm Therapeutics
Landlord
ARE-MA Region No. 28
This lease is a sixth amendment to an existing agreement, meaning the document contains no standalone lease terms — only changes to prior provisions. Extracting base rent requires reconciling escalation steps across multiple document layers. The amendment-only format confuses tools that expect a full lease document.
Lextract identified the amendment structure from the document header, cross-referenced the step rent schedule, and extracted all 126 fields including the escalation schedule, option terms, and pro rata share from the amendment-only format. The extraction correctly flagged the absence of some base terms as expected for an amendment document.
126
Fields Extracted
Under 3 minutes
Extraction Time
| Field | Extracted Value | Why It Matters |
|---|---|---|
| Lease Structure | Sixth Amendment | Signals amendment-only extraction; no standalone lease base terms present |
| Annual Base Rent | $2,340,000 | Step rent schedule extracted across 60-month term |
| Square Footage | 52,000 RSF | Rentable square feet confirmed from amendment exhibit |
| Escalation Type | Fixed step | Year-by-year rent steps extracted for underwriting models |
| Renewal Options | 2 × 5-year options | Renewal rights carried forward from original lease |
| Tenant Improvement Allowance | $45/RSF | TI allowance negotiated in this amendment |
Yes. Lextract identifies amendment documents by their structure and extracts whatever fields are present. For fields not defined in the amendment (which carry forward from earlier documents), the extraction notes their absence rather than returning incorrect data.
The extraction model parses rent tables and step schedules found anywhere in the document, including exhibits. Each rent step is extracted as a structured record with effective date, annual amount, and monthly amount.
Biotech tenants often negotiate lab-ready TI packages, specialized HVAC provisions, hazardous materials clauses, and above-market security deposits. These provisions appear in non-standard locations in the document and require domain-aware extraction.
What accuracy can you realistically expect from AI lease abstraction tools? We break down field-level accuracy rates, where AI excels, where it struggles, and how to validate output.
Compare the top AI lease abstraction tools for commercial real estate in 2026. We review Lextract, Prophia, Kolena, Leasecake, MRI Software, and more — with pricing, accuracy, and use-case guidance.
Free AI lease abstraction tools are fast and easy — but they have real limitations. Here is what free tools deliver, what they miss, and when you need structured output instead.
Upload any commercial lease PDF and get 126 structured fields extracted — just like the case study above. Works for any property type, lease structure, or jurisdiction. $20 per lease.
Upload Your Lease