ANAB · AnaptysBio, Inc.

The thesis

AnaptysBio's value rests on a Delaware court ordering Jemperli rights back from GSK's Tesaro unit. The 20 October 2026 oral argument has passed, and a written judgment, which the company expects in the fourth quarter of 2026 or the first quarter of 2027, settles the case. The FDA's 19 October 2026 approval of Jemperli in rectal cancer widens the sales base on which the royalty is paid, but it does not change the legal question.

The shares closed at $49.63 on 27 October 2026 (adjusted daily closes), up from $46.67 on 14 October 2026. They remain 28.9% below the 52-week high of $69.81 and are down 9.8% over three months. The narrative is maturing: the label expansion arrived ahead of its February 2027 action date and the shares have rebounded from the 14 October 2026 low area, yet no court ruling had been reported by 28 October 2026.

The evidence still rates the shares more likely to lag the S&P 500 than lead it over the next three months. The one event that moves the valuation has no scheduled date, and royalty cash stays committed to Sagard until the second half of 2027.

Bullish and bearish views on AnaptysBio, Inc.

The bull case on AnaptysBio, Inc. (ANAB), in brief: A new Jemperli indication is approved. The bear case: The legal outcome is binary and undated.

Bull case

• A new Jemperli indication is approved. GSK announced on 19 October 2026 that the FDA granted accelerated approval to Jemperli for stage II or III MSI-H/dMMR locally advanced rectal cancer, on the single-arm AZUR-1 trial of 154 previously untreated patients. The decision came ahead of the February 2027 action date that Anaptys cited on 21 September 2026. The tiered 8-25% royalty applies to all Jemperli net sales.
• Royalties are growing. Anaptys reported on 21 September 2026 that Q2 2026 collaboration revenue was $27.5 million against $22.3 million a year earlier, with Jemperli royalties up 25% for the quarter.
• The court has already ruled for Anaptys once. On 24 April 2026 Delaware Chancery dismissed Tesaro's anticipatory breach claim and rejected its royalty reduction request, preserving current royalty rates.
• Analysts remain far above the price. HC Wainwright reiterated Buy with a $95 target in September 2026. Leerink kept Outperform with an $81 target on 23 September 2026. MarketBeat showed a consensus target of $79.85 on 22 September 2026.
• A second royalty is near. Imsidolimab, licensed to Vanda, has an FDA action date of 12 December 2026 for generalised pustular psoriasis, according to the 21 September 2026 release.

Bear case

• The legal outcome is binary and undated. The court has set no judgment date. A written opinion can arrive weeks or months after the 20 October 2026 argument, and no ruling had been reported by 28 October 2026.
• The new label is narrow and accelerated. The rectal cancer approval covers MSI-H or dMMR tumors only, and it is an accelerated approval resting on interim, single-arm evidence (FDA and GSK, 19 October 2026). Sources differ on how large this group is, from about 3% of locally advanced rectal cancers (FDA estimate cited by MediSearcher) to 5-10% (Medscape).
• Analysts cut targets into the argument. JP Morgan lowered its target to $60 on 30 September 2026 and Leerink lowered its target to $81 on 23 September 2026. TD Cowen had cut to $70 on 25 August 2026. No target changes after the approval turned up in a search on 28 October 2026.
• The Sagard paydown moved later. The 21 September 2026 release puts the remaining roughly $299 million non-recourse obligation at the second half of 2027, later than the earlier end-of-Q2-2027 guidance. Extra Jemperli sales raise that cash flow, but Sagard collects it first.
• No shares had been repurchased under the $100 million authorisation through 30 June 2026, and it expires 31 December 2026.
• Reported profit is not operating profit. Six-month net income from continuing operations of $176.4 million included a $181.5 million non-cash tax benefit. Operating activities used $72.9 million of cash.

Price setup

The shares closed at $49.63 on 27 October 2026. That is above the $46.67 close of 14 October 2026, the low area the prior note referenced, and below the $48.63 close of 1 October 2026 only in the sense that it has since recovered past it. The 52-week high is $69.81 on the split- and distribution-adjusted series. The 14-day relative strength index (RSI), a momentum gauge on a 0-100 scale, was 61.6 on 27 October 2026 after 24.4 on 14 October 2026, so the rebound has moved the reading from deeply oversold to mid-range.

The level that matters on the downside is a daily close below $44, under the 14 October 2026 close and near the lowest area of the post-spin decline. The shares trade 28.9% under the 52-week high, so there is no wide gap above a rising moving average to point to.

Crowding evidence is thin. No insider transactions or share issuance appear in company filings since the prior note, and the buyback authorisation sits unused through 30 June 2026. The next earnings date is not confirmed. The sharp move in RSI over two weeks shows how fast the shares react to Jemperli news.

Catalysts, next 30 days

• Undated: Delaware Chancery written opinion. The company expects it in Q4 2026 or Q1 2027. It could land inside the next 30 days, but nothing schedules it.
• Late October to early November 2026, est.: GSK third-quarter results. They would show Jemperli net sales for the September quarter, the base for Anaptys's royalty. The date is an estimate.
• 12 December 2026: FDA action date for imsidolimab (Vanda). It falls outside the 30 days. An approval would start a second royalty stream.
• 31 December 2026: expiry of the $100 million repurchase authorisation. It shows whether the company uses it near the post-spin low.

Elapsed catalysts

• 2026-11, est.: Anaptys results for the September quarter. The date is unconfirmed. It would show cash against $164.1 million at 30 June 2026 and any buyback activity. (passed 129d ago)

What would change the view

The case breaks if the Chancery court issues a written judgment denying reversion of Jemperli rights, or limits the remedy to damages. It also weakens if the Sagard paydown date moves past the second half of 2027, or if GSK's reported Jemperli sales growth slows well below the 26% rate of the June quarter. A daily close below $44 would put the shares under the 14 October 2026 low area and end the thesis as written.

On the upside, a written opinion ordering Jemperli rights returned to Anaptys would resolve the central question in the company's favour. Until a ruling appears, the approval and the price rebound do not settle it.

What it trades with

Anaptys's royalty income moves with GSK's Jemperli sales, so GSK's quarterly reports and label news carry through to Anaptys revenue. The imsidolimab royalty depends on Vanda's 12 December 2026 FDA decision. The clinical pipeline went to First Tracks Biotherapeutics in the April 2026 spin-off, so Anaptys no longer carries drug-development spending in the same way. The shares have traded on Delaware court headlines and analyst target changes more than on small-cap biotech sector moves.