Discussion Guide — Chapter 27

Six prompts, with what to listen for. Roughly ten minutes each; prompts 3 and 5 will run longer.

1. "Peptides have been standard cancer care for forty years and almost nobody knows it. Whose fault is that, and does it matter?"

What to listen for: Students who blame only the pharmaceutical industry have missed three of the chapter's four reasons. Strong contributions distinguish between neglect (nobody chose this) and interest (someone benefits from the silence) and recognize that both are operating. Listen for the observation that a therapy which has worked reliably for decades generates no news — this is a real structural feature of medical communication, not a conspiracy.

Push if needed: "Does it matter, though? The patients getting leuprolide are getting it either way." The best answer is that it matters for how the next claim is evaluated: a public that thinks peptides are unproven is equally unequipped to recognize the ones that are proven and the ones that are not.

2. "Is the flare a side effect?"

What to listen for: This should not resolve quickly. Strong discussions separate three different senses of the question — regulatory (what goes in the label), clinical (what you plan for), and mechanistic (what caused it) — and notice that the answer differs across them. Weak discussions treat it as a definitional quibble.

The insight to land: mechanism does not partition into good effects and bad effects. Once students have that, ask them to apply it to any Part III compound marketed as working "with your body's natural signaling."

Push if needed: "If a company invented a GnRH agonist tomorrow with no flare, what would they have actually invented?" (An antagonist, or something that is not an agonist at that receptor.)

3. "In PRRT, what is the drug?"

What to listen for: First answers usually name the peptide. Let that stand for a moment, then ask what the peptide does to the tumor cell. Watch the realization arrive. Strong contributions go on to ask what evidence would be relevant for an address that is not relevant for a drug — biodistribution, retention, tumor-to-background ratio — and notice that receptor pharmacology matters only insofar as it answers those.

Extension: ask for the other two variants of "the peptide is not always the drug" (target, Ch 22; protected substrate, Ch 28). Students who can produce all three unprompted are ready for Part 6.

4. "The chapter volunteers that most PSMA ligands are not peptides — a fact that makes its own headline less impressive. Why do that?"

What to listen for: The obvious answer (accuracy) is correct but shallow. Push toward the second answer: a book that inflates its own numbers cannot be trusted when it later says something is thin, and the book's entire value proposition is that its ❌ ratings mean something. Volunteering an inconvenient fact is how a source earns the right to be believed elsewhere.

Good follow-up: "Name a source you read regularly that never does this. What does that tell you?"

5. "What is in the fourth box?"

Set-up: Put the three boxes from §27.8 on the board — shut down an axis, replace an inhibitory hormone, deliver to an address. Do not draw the fourth. Ask the class to fill it.

What to listen for: Students will propose candidates. Take each seriously and test it against the question "what is the approved indication, and what endpoint was measured?" They will run out. The silence when they run out is the pedagogical event; let it sit before naming what happened.

The insight to land: the absence is not because oncologists dislike peptides — they have been prescribing them since 1985 — but because "supports," "modulates," and "optimizes" are not jobs. They are descriptions with no endpoint attached, and you cannot power a trial for them.

Push if needed: "Design a phase 3 trial for a peptide that 'supports healthy cellular function.' What is your primary endpoint? What is your stopping rule?"

6. "Read this indication aloud." (Pull up a real oncology label — lutetium Lu 177 dotatate works best — and have a student read the INDICATIONS section verbatim.)

What to listen for: Ask the class to count the qualifying clauses. Then ask what population the sentence covers and, separately, what populations it does not. Strong discussions notice that the qualifiers are the content and that removing them is not simplification but a change of claim.

The insight to land: an approval is a narrow, checkable statement, not a general endorsement. This is the chapter's contribution to the Dossier and the most transferable thing in it.

Close with: "Now describe a compound whose Field 7 reads, in full, not approved for any indication in any major jurisdiction." Most students have one on their dossier list. The contrast between the two entries does more teaching than either does alone.