Cancer Medicine Should Not Have an Age Order

Day One built a new model for finding and developing targeted cancer medicines without asking children to wait behind adults.

Modern cancer care is full of breakthroughs, but they have not reached every patient at the same speed. For decades, the default sequence was to develop a medicine for adults first and consider children later. The logic was understandable. Adult cancer populations are larger, and their clinical programs can be easier to finance.

But for a family whose child has cancer, “later” can mean years without a therapy designed or approved for that child’s disease. When our partner Julie Grant wrote about this gap at Day One’s launch, she noted that more than 200 adult oncology drugs had been approved over the prior two decades, compared with fewer than 10 for children. At the time, medicines took a median of 6.5 years to move from a first adult trial to a first pediatric trial.

Day One was built to change that order. Julie and pediatric oncologist Dr. Samuel Blackman incubated the company at Canaan in 2018, and we backed its Series A. In April of 2026, Servier completed its acquisition of Day One, bringing an approved medicine and rare-cancer pipeline into a larger oncology organization. For us, that outcome affirmed an early belief: putting children closer to the start of drug development could create patient impact and a durable company.

The traditional approach did not leave children behind because people cared less. Drug development rewarded scale. Pediatric cancers are rare, eligible patients can be hard to find, trials are difficult to run, and adult-only approval can create reimbursement barriers for children.

That bargain made historical sense, but it treated age as the organizing principle. Advances in tumor sequencing made another approach possible. Scientists could increasingly define cancer by the molecular alteration driving it, then ask which patients shared that biology across ages. The rare-disease model also showed that small, identifiable populations with serious unmet needs could support focused trials and align patients, physicians, regulators, payers, and investors.

Day One brought those ideas together. Pediatric cancer could be treated as a rare disease within oncology, and the right medicine could begin with the patients who needed it most rather than the largest market.

Day One calls its approach “search and development.” It looks for promising targeted medicines outside another pharmaceutical company’s core strategy, then builds a development plan around the patients and tumor biology for which they may matter most.

Its first program made the idea concrete. The compound that became tovorafenib had been developed as TAK-580 for adult cancers before Takeda stopped that work. Day One licensed it and focused on pediatric low-grade glioma, a childhood brain tumor often driven by alterations in the BRAF gene.

In plain English, tovorafenib is designed to interrupt a growth signal used by certain tumors. Day One defined the opportunity around a molecular mechanism that appears across ages, while choosing to start where the unmet need was urgent.

On Apr 23, 2024, the FDA granted accelerated approval to tovorafenib, marketed as OJEMDA, for patients six months and older with relapsed or refractory pediatric low-grade glioma carrying specified BRAF alterations. It was the first FDA-approved systemic therapy for this disease with BRAF rearrangements, including fusions. A shelved adult program had become an approved medicine for children awaiting a targeted option.

The inequity was obvious. The company design was not.

What stood out to us was that Julie and Sam built a business model around the constraint. Molecular diagnostics could identify the right patients, rare-disease development could create a focused path, and partnerships could give overlooked assets another chance. The same structure could extend a medicine’s benefit across ages when the biology supported it.

We also believed the mission could be a competitive advantage. Day One takes its name from the conversation when a family first learns that a child has cancer and discusses treatment. That urgency helped attract clinicians, scientists, advocates, and partners who understood that speed mattered, but rigor could not be compromised.

The point was not to build a charitable exception inside oncology. It was to prove that a company could make children central to its strategy and still create the incentives and value needed to keep developing medicines.

Day One’s path matters beyond one drug. The company expanded across childhood and adult rare cancers, and Servier gives that work a broader platform.

The larger lesson is that scarcity is not always scientific. Sometimes a promising medicine exists, but the organization or development plan needed to connect it to patients does not. Day One built around repairing those breaks.

Childhood cancer treatment is not only about survival. Tumors and treatment can shape vision, movement, speech, development, and daily life. Getting a better-targeted option to a child sooner can change the trajectory of a life.

The question Day One is asking is not simply whether a cancer medicine can be developed for children first. It is whether drug development can begin with biological need instead of treating market size or patient age as destiny.

When we helped create Day One, that future was far from assured. Today it is part of Servier, its first program is an approved medicine, and the original insight still matters: children should not have to receive progress secondhand. If the industry can organize around the right patient and biology from the start, age no longer has to determine the order in which hope arrives.