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R1 Therapeutics raises $78M for its kidney disease drug & CytomX's shares surge over 60% after Phase 1 results

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Joachim Eeckhout & Eduardo Longoria
March 18, 2026

Good morning! The AI arms race in pharma is starting to look a lot like the one in Silicon Valley. Roche has expanded its Nvidia partnership, adding 2,176 Blackwell GPUs to bring its total to 3,500 and build what it calls the industry’s largest known hybrid-cloud AI factory. The move lands just after Eli Lilly unveiled its own Nvidia-powered supercomputer, making clear that they’re also in the chip-pilling game.

Why it matters: These systems do not just burn power (and water), they also burn through premium memory, especially RAM, which is already in painfully short supply thanks to the broader AI boom, with prices going up to 600% last year. As pharma joins Big Tech in buying Nvidia hardware at scale, the ripple effects on consumer electronics won’t get better.

Bottom line: The next casualty of pharma’s AI ambitions may be your dream gamer PC.

— Joachim E.

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SNAPSHOT

R1 Therapeutics raises $78M to develop a simpler, more potent kidney disease drug

Woman is holding medicines in her hands

R1 Therapeutics launched with $77.5M in funding from Abingworth, F-Prime Capital, DaVita Venture Group, and U.S. Renal Care to advance AP306, a pill that could outperform current treatments for high phosphate levels in chronic kidney disease patients.

Why it matters: Existing therapies for hyperphosphatemia are hard to tolerate and require multiple pills per meal, creating a heavy burden for dialysis patients. A more effective, lower-pill option could improve adherence and outcomes.

Backstory: Hyperphosphatemia is a common complication in advanced kidney disease, leading to bone weakening and heart damage. The current drugs meant to treat hyperphosphatemia, like Renvela and Xphozah, bind phosphate in the gut and block phosphate transport, respectively. However, both come with limitations.

Zoom in: AP306 is a small molecule designed to target multiple phosphate transport pathways. In a Phase 2 study in China, a three-times-daily regimen lowered phosphorus levels more effectively than a standard binder over 12 weeks. It also helped more patients reach normal phosphate levels, though safety advantages remain unproven. AP306 was originally developed by Chugai, later licensed to Alebund in China, and acquired by R1 for ex-China rights in 2025.

Big picture: The race to improve chronic kidney disease treatments is intensifying, with startups targeting better efficacy and patient convenience. R1’s contribution to a better kidney treatment is significantly reducing “pill burden,” a top concern among nephrologists.

What’s next: AP306 will enter Phase 2b trials in dialysis patients later in 2026, with results expected in 2027.

 

SNIPPETS

What’s happening in biotech today?

 📊 Trial boost: CytomX Therapeutics, which we covered yesterday as it ended its partnership with Astellas, has seen its shares surge over 60% after the company reported encouraging Phase 1 expansion data for its experimental “masked” antibody-drug conjugate, Varseta-M, in late-stage colorectal cancer. The study showed response rates of 20% to 32% at higher doses and progression-free survival of around seven months, with generally manageable side effects, though 10% of patients experienced severe diarrhea. Varseta-M targets EpCAM using a conditionally activated approach designed to improve tolerability. CytomX plans to consult regulators on next steps while analysts note that long-term success will depend on balancing efficacy with side-effect management.

💰Cash infusion: Mestag Therapeutics has raised $40 million and appointed two senior biotech executives as it prepares to enter the clinic with its lead cancer program, MST-0312, in mid-2026. The funding will support a Phase 1 trial of the drug, a FAP-targeted bispecific antibody designed to stimulate immune activity in “cold” tumors by inducing tertiary lymphoid structures and enhancing lymphocyte entry. Backed by major investors and partnerships with companies like Janssen and MSD, Mestag is transitioning from platform development to clinical execution, with the upcoming trial set to test whether its fibroblast-focused immunotherapy approach can deliver meaningful results in patients.

🧬 CDK4 upgrade: Pfizer reported positive Phase 2 data for atirmociclib, a next-generation CDK4 inhibitor designed to improve upon its blockbuster breast cancer drug Ibrance, showing a 40% reduction in the risk of disease progression or death when combined with fulvestrant in patients with metastatic HR+/HER2- breast cancer who had previously received CDK4/6 inhibitors. The drug may offer better efficacy and tolerability by targeting CDK4 specifically and showed promise even in patients with limited treatment options. Seen as a key component of Pfizer’s oncology strategy, atirmociclib is advancing into Phase 3 trials, with analysts projecting potential peak sales of $2.6 billion and a possible launch in 2027.

🧫 Cirrhosis play: BioVie is planning a roughly $20 million IPO for its spinout, Option Therapeutics, which will focus on developing BIV201, a reformulated version of the approved kidney drug terlipressin, as a treatment for liver cirrhosis complications such as ascites. The offering aims to fund a Phase 3 trial already cleared by the FDA, targeting patients with decompensated cirrhosis and recent kidney injury, while BioVie will retain at least 60% ownership. Previously paused due to time and funding constraints, the program addresses a condition with no approved therapies and a potential $2.3 billion market.

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