He trained to prescribe drugs. He decided to build them instead - and pinned a whole company on a molecule most of biology had given up on.
The Assignment
Inside a tumor there is a quiet sabotage. Interleukin-18, a small signaling protein the immune system uses to rally its killers, gets neutralized almost the instant it appears. The body makes its own decoy - a protein called IL-18BP - that mops up IL-18 before it can do any damage to cancer. For years that decoy made IL-18 look like a dead end for drug developers. Promising in a dish, useless in a patient.
Sanuj Ravindran runs the company built to ignore that decoy. Simcha Therapeutics, a clinical-stage immunobiology shop headquartered in New Haven, engineers a version of IL-18 that the decoy cannot grab. The lead candidate, ST-067, is the first in what Simcha calls a new class of IL-18-based immunotherapies. It is in Phase 1/2 trials in patients with solid tumors who have already run out of road on other immunotherapies.
That is the bet: take an immune signal the body silences, redesign it so the silence never lands, and let it switch the tumor's environment back on. It is a precise, almost mechanical idea - which suits the man running it.
Ravindran took the job in August 2022. He arrived calling Simcha a company "built on a remarkable scientific foundation" and a "bold vision." The science came from immunologist Aaron Ring, whose lab re-engineered IL-18 into something the decoy could not stop. Ravindran's job is the part that turns a clever protein into a medicine: the trials, the money, the team, the decade of grind between a good idea and an approval.
He is, by training, a doctor. Internal medicine, board-certified, residency at Thomas Jefferson University Hospital. He could be at a bedside. Instead he chose the slower, stranger work of building the things a doctor reaches for.
The Science, Briefly
Cytokines are the immune system's messengers - hormone-like proteins that switch defenses on and off. IL-18 is one of the loud ones, capable of activating immune cells that attack cancer. The catch is the decoy receptor.
IL-18 normally tells immune cells to switch on and hunt tumor cells.
Tumors lean on IL-18BP, a natural decoy that captures IL-18 and silences it.
ST-067 is engineered so the decoy can't grab it - the signal gets through.
The Long Way Around
"I feel privileged to build and lead a patient and product focused organization with a commitment to pioneering truly transformational therapies."
Sanuj Ravindran, M.D. - Simcha Therapeutics
The Shape Of Him
Most biotech CEOs come up one lane - the scientist who founded the thing, the financier who funded it, or the operator who scaled it. Ravindran has driven in all three. He spent a decade deciding which companies deserved money, then years on the other side of the table structuring billions in deals, then years actually running the companies he once would have evaluated.
It is an unusual resume, and it shows in how Simcha is framed. The pitch is not hype. It is mechanism - a decoy, a redesign, a signal that gets through. The kind of story a person tells when they have read both the clinical data and the cap table and decided the two finally agree.
His through-line across PellePharm, Phoenix Tissue Repair, and now Simcha is not a disease. It is a method: take a serious, specific biological problem and build the smallest possible organization that can prove or kill the idea. Rare skin disease one year, solid tumors the next - same discipline, different target.