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SPAN AI
RESISTANCE SIGNAL WK 22
IMAGING VISIBLE WK 43
∟ ~151-DAY LEAD
WEEK 0 SERIAL ctDNA · VAF WEEK 48
Span AI · Precision Oncology

Building biological world models for precision oncology.

We predict how a patient’s cancer will evolve — reading resistance from serial ctDNA months before it ever appears on a scan.

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00 — The signal

Read the trajectory, not the snapshot.

In blood, resistance rises along a curve. Span reads that curve as it forms — flagging the shift months before it crosses the imaging threshold.

Serial ctDNA monitoring VAF %
0255075100 ctDNA VAF (%) 0816243240 WEEKS ON THERAPY IMAGING-DETECTABLE TARGETED THERAPY SPAN FLAGS · WK 13 VISIBLE ON SCAN · WK 35 ≈ 151-DAY LEAD
Resistant subclone Sensitive clone Total ctDNA Imaging threshold
01 — The shift

AI learned language. Then vision. Then the rules of proteins. The next frontier is disease over time.

Not disease as static snapshots, but as living systems that evolve. Cancer is the proving ground — and drug resistance is where those trajectories are most learnable.

Language Vision Proteins Disease over time
Scroll to advance · one representation, four frontiers
02 — The problem

Care is decided from snapshots. Disease moves in trajectories.

A single biopsy, scan, or genomic report captures one moment in a moving disease. Yet more than 240 targeted therapies exist and nearly all eventually stop working — and resistance follows predictable biological pathways, often detectable in blood long before it shows on imaging.

~151
days, median

Lead time by which serial ctDNA can detect disease progression before it becomes visible on standard imaging.

03 — The product

A longitudinal prediction layer on the tests hospitals already run.

Span turns isolated data points — serial ctDNA, EHR context, and standard-of-care imaging — into a patient trajectory. It doesn’t replace or compete with the assays you already use. It sits on top of all of them.

For pharma R&D

Find the right patient, earlier.

Identifies patients approaching specific resistance mechanisms and eligible for trials — weeks to months before standard screening would catch them.

Cohort screen · approaching resistance
Trial-eligible · flagged early
For the treating oncologist

See the next line before it’s needed.

Estimated time-to-resistance, the most likely resistance mechanism, and a ranked list of next-line options — including eligible trials.

Est. time-to-resistancetracking
Likely mechanismResistance pathway
Next-line options01 · 02 · 03 + trials
04 — How it works

From data points to a trajectory.

INPUT · SERIAL LIQUID BIOPSY ctDNA every 6–8 weeks wk0wk8wk16wk24wk32 EHR IMAGING TRAJECTORY MODEL OUTPUT 01 EST. TIME-TO-RESISTANCE 02 LIKELY RESISTANCE MECHANISM 03 RANKED NEXT-LINE + TRIALS
Inputs

Serial signals over time

Serial ctDNA every 6–8 weeks, EHR context, and standard-of-care imaging.

Trajectory model

A world model of disease

Learns how each patient’s disease evolves, not just where it stands today.

Outputs

A decision, ahead of time

Time-to-resistance, the likely mechanism, and ranked next-line options and trials.

05 — Why now

The window just opened.

240+
Targeted therapies

Standard of care has shifted from chemo to a deep arsenal of targeted drugs — each with its own resistance pathways.

Validated
ctDNA monitoring

Serial ctDNA has crossed clinical validation — detecting progression a median of ~151 days before imaging.

Ready
Next-line drugs exist

Therapies built to overcome resistance are already here. The missing piece is finding the right patient before the window closes.

06 — At scale

Every patient makes the model better.

Span learns from the shape of disease over time — patient by patient, trajectory by trajectory. The more patients it helps, the sharper its predictions become.

Serial liquid-biopsy signals · illustrative
07 — The belief

Disease moves as a trajectory.
So should the medicine.

We’re building a longitudinal understanding of how each patient’s disease evolves — learned one trajectory at a time. Our ambition is the world’s most accurate biological world models for precision oncology, so every patient receives the right therapy at the right time.

08 — Team

Built by a small, focused team.

Aarchi Singh Thakur
Aarchi Singh Thakur
CEO

Leads Span’s vision and the partnerships that turn serial data into clinical decisions.

Abhijoy Sarkar
Abhijoy Sarkar
CTO

Builds the trajectory model and the systems that make each patient’s data compound.

Predict the trajectory. Act before the window closes.

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