The first cell therapies made from a patient’s own cells were cancer treatments— T cells engineered to hit tumors. Immusoft is taking a similar approach with a different type of immune cell, aiming to deliver these cell therapies into the brain. The biotech startup is still preclinical, but Takeda Pharmaceutical sees enough promise to begin a research and development alliance that could yield new treatments for rare neurometabolic diseases.

Seattle-based Immusoft develops its treatments by reprogramming B cells, a type of white blood cell. The process for making this treatment is nearly identical to that of CAR T, the first autologous cancer cell therapies. Blood is collected from the patient and the desired immune cells are selected. Those cells are engineered, then multiplied in a lab. After the process produces enough cells, that treatment is infused into the patient.

Besides the type of cell that is used, the key difference between CAR T and Immusoft’s approach is the engineering step. In CAR T, this stage involves engineering T cells to recognize a particular antigen on tumors. For Immusoft, this step means programing B cells with DNA that enables them to produce large amounts of therapeutic protein. Immusoft calls its technology Immune System Programing, or ISP.

Takeda and Immusoft did not specify the diseases they aim to address under their new alliance, though the companies said the collaboration will focus on delivering therapies across the blood-brain barrier, the protective layer that keeps certain substances, including some drugs, from reaching the organ. By reaching the brain, these B cell therapies have the potential to address a range of neurological disorders.

“We continue to build our internal capabilities as well as partner with innovative companies early on in the discovery process to advance our next-generation gene and cell therapy ambitions for rare genetic and hematologic diseases,” Takeda Rare Diseases Drug Discovery Unit Head Madhu Natarajan said in a prepared statement. “Working together with Immusoft, we hope to validate their ISP technology for [central nervous system] delivery of innovative therapeutics for rare neurometabolic diseases.”

Rare neurometabolic disease is already one of the areas of focus for Immusoft. The rare enzyme deficiency Hurler syndrome is the target for its most advanced internal program, ISP-001. That cell therapy candidate is on track for an investigational new drug application filing by the end of this year, according to the company’s website.

According to deal terms announced Wednesday, Takeda will pay Seattle-based Immusoft an upfront payment as well as research funding. The specific amounts were not disclosed. When the drug candidates covered under the partnership reach preclinical development, Takeda may elect to choose an unspecified number of them to continue their development. The Japanese pharma giant would owe option fees plus milestone payments tied to the progress of those programs. The companies gave no specific breakdown of those payments, other than to say the total value could top $900 million if all options are exercised and all milestones are achieved.

Working with B cells offer several advantages over other approaches to treating disease. Gene therapies delivered via engineered viruses can’t be re-dosed because the antibodies that patients develop to the virus will render subsequent doses ineffective. By using a patient’s own cells, Immusoft aims to produce therapies that can be dosed multiple times. Also, gene therapies made by collecting a patient’s stem cells require a “preconditioning” step that knocks out the immune system to make room for the transplanted stem cells to grow. This step opens the door to a range of potential complications. Takeda’s recent dealmaking shows the pharma giant’s interest in avoiding therapies that employ viral delivery. In unveiling a multi-program alliance with Poseida Therapeutics on Tuesday, the pharma giant cited the biotech’s non-viral technologies.

There are other companies developing ways to engineer B cells into new therapies. South San Francisco-based Walking Fish Therapeutics unveiled a $50 million Series A round of funding last month to support its research, still preclinical. Be Biopharma of Boston emerged nearly a year ago with a $52 million Series A financing.

Immusoft’s research so far has produced a preclinical drug pipeline spanning both rare and common diseases. Besides the Hurler syndrome candidate, the other rare disease programs include potential treatments for muscle-wasting disorders amyotrophic lateral sclerosis and Duchenne muscular dystrophy; the metabolic disease Hunter syndrome; and Pompe and Gaucher diseases, both enzyme deficiency disorders. Immusoft’s common disease research is still in the discovery stage. For common diseases, Immusoft is developing treatments for cardiovascular disorders, rheumatoid arthritis, and Parkinson’s disease.

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