GLP-1 Drug Boom Echoes PD-1 Inhibitor Rise, but Market Dynamics Differ

The pharmaceutical industry is witnessing a surge in GLP-1 weight loss drugs, reminiscent of the PD-1 inhibitor revolution in cancer treatment a decade ago. However, key market differences suggest that the trajectory of GLP-1 therapies may diverge from their immunotherapy predecessors.

PD-1 Inhibitors: A Tale of Winners and Losers

The PD-1 inhibitor market, which reshaped cancer treatment, offers valuable lessons for the burgeoning GLP-1 sector. Merck's Keytruda and Bristol Myers Squibb's Opdivo emerged as early leaders, with Keytruda ultimately dominating the market. In 2024, Keytruda generated global sales of $29.4 billion, while Opdivo brought in $9.3 billion.

Despite the market concentration, other major players like Roche and AstraZeneca carved out substantial market shares with their PD-L1 inhibitors, Tecentriq and Imfinzi, respectively. Tecentriq achieved sales of $4.1 billion in 2024, while Imfinzi generated $4.7 billion.

However, the PD-1 landscape is also littered with unsuccessful followers. Pfizer's Bavencio and Novartis' Tevimbra struggled to gain traction, with 2024 sales of $735 million and $621 million, respectively. Smaller companies attempting to develop combination therapies often faced setbacks, as exemplified by the failures of Nektar Therapeutics and BMS's investigational combination therapy, and Innate Pharma and AstraZeneca's monalizumab trial.

GLP-1 Market: Unique Challenges and Opportunities

While the GLP-1 weight loss drug market shares similarities with the PD-1 boom, it faces distinct challenges:

1. Consumer-driven demand: Unlike the physician-led PD-1 market, GLP-1 therapies have captured public attention, extending beyond traditional medical circles.

2. Pricing pressures: Ongoing discussions between drug developers and payers regarding discounts and rebates may impact revenue for market entrants.

3. Patient retention: GLP-1 treatments face significant "patient churn," with most patients discontinuing use within one year, a challenge not encountered by PD-1 therapies.

4. Market size uncertainty: While some analysts project the weight loss drug market to reach $150 billion by the early 2030s, these estimates may be overly optimistic due to unresolved patient retention issues.

Despite these challenges, GLP-1 developers are pursuing strategies similar to those employed in the PD-1 market. Novo Nordisk and Eli Lilly are expanding their drugs' indications, with Novo's Wegovy receiving approval for reducing cardiovascular risk and Lilly's treatment gaining an FDA nod for obstructive sleep apnea. Both companies are also exploring applications in metabolic dysfunction-associated steatohepatitis (MASH), kidney disease, Alzheimer's, and alcohol use disorder.

The Road Ahead for GLP-1 Therapies

For companies seeking to develop successful GLP-1 therapies, three key considerations have emerged:

1. Improving efficacy to attract more patient interest
2. Enhancing tolerability to increase treatment duration
3. Developing small molecule formulations for manufacturing and dosing advantages

Unlike the early PD-1 market, which focused on rapid development of "me-too" treatments, the GLP-1 space requires a more nuanced approach to differentiation. As the market evolves, investors and drug developers alike are still in the "early innings" of discovering how to best serve patients in this rapidly expanding field.