Even though President Trump keeps attacking the pharmaceutical industry over drug pricing issues, the biotech sector is holding up well this year. That's likely because institutional money managers are stepping in to buy any dips.

To get a better sense of the sector, Jim Cramer looked at the charts in his "Off the Charts" segment of Mad Money Tuesday night with guest and colleague  Bob Lang, founder of ExplosiveOptions.net and a contributor to TheStreet's Trifecta Stocks newsletter.

Cramer and Lang started by looking at a chart of Gilead (GILD) , a one-time market darling that went out of style in 2015 when its hepatitis C cure proved so effective it reduced repeat sales. After grinding along for several quarters, shares are finally showing signs of life. Lang likes the recent pattern of higher highs and higher lows. He likes that Gilead has broken through both its 50- and 200-day moving average, as well as its previous ceiling of resistance at $75. The Chaikin Money Flow, which measures the level of buying or selling pressure in a stock, went positive in June, and the Relative Strength Index, an important momentum indicator, is higher than it's been since February.

Gilead's Moving Average Convergence Divergence or MACD line, which helps technician's detect changes in a stock's trajectory before they happen, made a strong buy signal a few weeks ago, with the black line crossing above the red one. This tends to be a very bullish sign. In addition, there has been some unusually positive options flow, with heavy call buying out in October and January. Lang thinks Gilead is ready to jump. At the moment, the stock is overbought, and the next ceiling comes in around $82. But given everything else he sees in this chart, Lang believes Gilead can keep climbing. It's his favorite name in the group and he wouldn't be surprised if it's challenging its old highs at around $110 by the end of the year.

Cramer and Lang next looked at Celgene (CELG) which has been punished mercilessly since late last year based on worries about competition for its main drug, Revlimid, as well as concerns about the pipeline of drugs in development. The stock is down 20% year-to-date, but, just like Gilead, it's started picking up in recent weeks.

The Chaikin Money Flow at the bottom of the chart has spent a long time in negative territory but recently turned green, meaning the big institutional buyers are finally stepping in. Lang also points out that Celgene seems to have made a W shaped bottom here. That's a bullish sign, especially with the stock now breaking out. Where does Lang see it going? Right now Celgene's at $86, he thinks it could make a move to the 200-day moving average, which is currently round $97, in the coming weeks. And he may well be right if the recent rotation into biotech continues.

Finally, Cramer and Lang looked at the weekly chart of Illumina, (ILMN) . Shares have nearly doubled over the past year and a half and as far as Lang is concerned, the chart is a thing of beauty. The Chaikin Money Flow remains robust. The MACD indicator is strong, with a continued pattern of higher highs and lows. Volume trends are positive as well, rising on high volume and declining on low volume.

Illumina is overbought, but it has been overbought frequently since 2017 allowing investors to simply wait for the next pullback and use that weakness to do some buying.

Where's Illumina going? Lang doesn't have a target but he thinks the general direction is higher and suggests using weakness to do some buying, and occasionally trimming positions by selling into strength.

Cramer and the AAP team are taking a different look at the markets through the lens of charting analysis. Find out what they're telling their investment club members and get in on the conversation with a free trial subscription to Action Alerts PLUS.

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