When the FDA approved the first CAR-T therapy for leukaemia in 2017, the assumption across the industry was that the blood cancer playbook would translate quickly into solid tumours. It did not. Seven years of disappointing trial readouts later, cell therapy is on the edge of a second act — and the capital is flowing again, this time more cautiously and, overwhelmingly, into Boston.

According to data compiled by PitchBook, Boston-headquartered cell therapy companies raised a combined $2.3 billion in private-round financing in the twelve months to March 2026, more than San Francisco, San Diego and the UK combined. The Kendall Square cluster now houses six companies working on T-cell receptor therapies for solid tumours, three on natural killer cell platforms, and two publicly traded CAR-T-next-generation developers.

Crucially, the mix of investors has shifted. Generalist crossover funds that drove the 2021 bubble have largely exited the space. The capital coming in now is from specialist biotech investors — Flagship Pioneering, ARCH Venture Partners, OrbiMed, SV Health — and, increasingly, from the strategic arms of established pharma. Novartis Ventures has led three Boston cell therapy rounds in the past eighteen months; Bristol Myers Squibb's corporate venture arm has led two.

The reason cited, off the record, by most Boston-based investors is talent. The city retains a concentration of cell therapy operators — from the original Kite Pharma and Juno alumni — that simply cannot be replicated in a year or two. It also retains infrastructure: GMP manufacturing capacity, specialist CROs, and a clinical trial network that knows how to run apheresis-based protocols.

The open question is commercial. None of the second-generation cell therapy platforms has yet produced a pivotal solid-tumour readout. The investors who moved early on CAR-T got their exits. The ones writing cheques today are making a bet on a science that, for now, is still gathering its evidence.