The table has a header row, with <th> header elements rather than <td> cells. Your code assumes there will always be <td> elements in each row, and that fails for the first row.
You could skip the row with not enough <td> elements:
for row in soup('table')[6].findAll('tr'):
tds = row('td')
if len(tds) < 2:
continue
print tds[0].string, tds[1].string
at which point you get output:
>>> for row in soup('table')[6].findAll('tr'):
... tds = row('td')
... if len(tds) < 2:
... continue
... print tds[0].string, tds[1].string
...
Responsible Party: Bristol-Myers Squibb
ClinicalTrials.gov Identifier: None
Other Study ID Numbers: AI452-021, 2011‐005409‐65
Study First Received: October 29, 2012
Last Updated: November 7, 2014
Health Authority: None
The last row contains text interspersed with <br/> elements; you could use the element.strings generator to extract all strings and perhaps join them into newlines; I'd strip each string first though:
>>> for row in soup('table')[6].findAll('tr'):
... tds = row('td')
... if len(tds) < 2:
... continue
... print tds[0].string, '\n'.join(filter(unicode.strip, tds[1].strings))
...
Responsible Party: Bristol-Myers Squibb
ClinicalTrials.gov Identifier: NCT01718158
History of Changes
Other Study ID Numbers: AI452-021, 2011‐005409‐65
Study First Received: October 29, 2012
Last Updated: November 7, 2014
Health Authority: United States: Institutional Review Board
United States: Food and Drug Administration
Argentina: Administracion Nacional de Medicamentos, Alimentos y Tecnologia Medica
France: Afssaps - Agence française de sécurité sanitaire des produits de santé (Saint-Denis)
Germany: Federal Institute for Drugs and Medical Devices
Germany: Ministry of Health
Israel: Israeli Health Ministry Pharmaceutical Administration
Israel: Ministry of Health
Italy: Ministry of Health
Italy: National Bioethics Committee
Italy: National Institute of Health
Italy: National Monitoring Centre for Clinical Trials - Ministry of Health
Italy: The Italian Medicines Agency
Japan: Pharmaceuticals and Medical Devices Agency
Japan: Ministry of Health, Labor and Welfare
Korea: Food and Drug Administration
Poland: National Institute of Medicines
Poland: Ministry of Health
Poland: Ministry of Science and Higher Education
Poland: Office for Registration of Medicinal Products, Medical Devices and Biocidal Products
Russia: FSI Scientific Center of Expertise of Medical Application
Russia: Ethics Committee
Russia: Ministry of Health of the Russian Federation
Spain: Spanish Agency of Medicines
Taiwan: Department of Health
Taiwan: National Bureau of Controlled Drugs
United Kingdom: Medicines and Healthcare Products Regulatory Agency