Investors often compare new drugs to the most effective treatments on efficacy alone. In practice, dermatologists will almost always choose a safer drug with lower efficacy first, creating a huge market for treatments that aren't "best-in-class" but have a superior safety profile.

Terns' CML drug is an allosteric inhibitor, targeting a different site on the target protein than older drugs. This mechanism provides greater selectivity, avoiding off-target effects like arterial blockages common with active-site inhibitors. This technical advantage creates a compelling safety and tolerability profile, a key differentiator in a market with established therapies.

The primary advantage of subcutaneous amivantamab extends beyond clinical safety to operational efficiency and patient well-being. It significantly reduces infusion time, freeing up limited oncology clinic resources and, more importantly, allowing patients with a limited life expectancy to spend less time in treatment and more with loved ones.

The drug's wide safety window is not just a separate benefit; it enables higher doses without toxicity. This increased dosage leads to better target coverage and potency, resulting in efficacy rates that are double the previous best. The improved safety profile is the direct cause of the enhanced efficacy.

With zero reported cases of severe side effects like CRS or ICANS, Allogene's therapy can be administered in an outpatient setting. This is a deliberate commercial strategy to access the 85% of lymphoma patients treated in community clinics, not the major academic centers required for existing, more toxic CAR-T therapies.

The emerging Amylin class of obesity drugs shows a consistently more favorable side effect profile than GLP-1 agonists. While weight loss efficacy may be comparable, the superior tolerability positions Amylin as a strong future competitor, either as a standalone option for sensitive patients or as a backbone for combination therapies.

As the obesity market matures, the key differentiator may shift from maximum weight loss to tolerability. High discontinuation rates for GLP-1s due to GI side effects create an opportunity for drugs with slightly lower efficacy but a stellar safety profile, which could capture a large and underserved patient segment.

For diseases like Idiopathic Pulmonary Fibrosis (IPF), existing treatments have such severe side effects that over half of patients refuse them. MannKind's strategy with its inhaled Nintendanib is based on the insight that physicians will prioritize a drug that patients can actually tolerate, even if it offers slightly less efficacy.

Ron Cooper highlights a key disconnect: Wall Street values the highest efficacy ("more is better"), but community physicians, who treat most patients, weigh three factors equally: efficacy, tolerability, and ease of administration. A drug that seamlessly integrates into their practice flow can win significant market share without best-in-class efficacy.